diagram - Diagram drawing
package require Tcl 8.5
package require Tk 8.5
package require diagram 1
::diagram objectName canvas
?script?
diagramObject new direction name ?key
value...?
diagramObject new element name
attributes cmdprefix
diagramObject new alias name
cmdprefix
diagramObject new command name
arguments body
diagramObject new attribute name ?key
value...?
diagramObject unknown attribute cmdprefix
diagramObject draw script
arc attr...
arrow attr...
--> attr...
<--> attr...
<--> attr...
block script attr...
box attr...
circle attr...
O attr...
diamond attr...
<> attr...
drum attr...
ellipse attr...
line attr...
-- attr...
move attr
spline attr...
text attr...
west
w
left
l
south
s
down
bottom
bot
b
east
e
right
r
north
n
up
top
t
northwest
nw
up-left
upleft
leftup
northeast
ne
up-right
upright
rightup
southwest
sw
down-left
downleft
leftdown
southeast
se
down-right
downright
rightdown
number cm
number mm
number inch
number pt
number number
by distance direction
point1 + point2
point1 - point2
point by distance direction
point1 | point2
n between poin1 point2
intersect elem1 elem2
element names ?pattern?
element corner
element corner1 corner2...
element ?corner1... ?names
?pattern??]?
nth ?corner?
nth last ?corner?
nth shape ?corner?
nth last shape ?corner?
last ?corner?
last shape ?corner?
1st
2nd
3rd
Welcome to diagram, a package for the easy construction of
diagrams (sic), i.e. 2D vector graphics, sometimes also called
pictures. Note that this package is not a replacement for Tk's
canvas, but rather a layer sitting on top of it, to make it easier to use.
In other words, using the canvas as the core graphics engine diagram
abstracts away from the minutiae of handling coordinates to position and
size the drawn elements, allowing the user to concentrate on the content of
the diagram instead.
This is similar to Brian Kernighan's PIC language for troff, which
is the spiritual ancestor of this package.
This document contains the reference to the API and drawing
(language) commands. Its intended audience are users of the package wishing
to refresh their memory. Newcomers should read the Diagram Language
Tutorial first. Developers wishing to work on the internals of the
package and its supporting packages should look at section Diagram
Classes first, and then the comments in the sources of the packages
itself.
In the remainder of the document we first describe the APIs of the
diagram class and its instances, followed by the language reference for the
drawing language itself.
The package exports the API described here.
- ::diagram objectName canvas ?script?
- The command creates a new instance of a diagram controller and returns the
fully qualified name of the object command as its result. The new instance
is connected to the specified canvas object, which is used as the
diagrams graphics engine. This is usually an instance of Tk's canvas,
however any object which is API compatible to Tk's canvas can be used
here.
The API of this object command is described in the following
section, Object API. It may be used to invoke various operations
on the object.
If the script argument is specified then method
draw will be invoked on it.
Instances of the diagram class support the following methods:
- diagramObject
new direction name ?key value...?
- This method defines a new named direction and its attributes. The latter
is given through the key/value pairs coming after the
name.
Users are mostly free to specify arbitrary attributes with
whatever meaning they desire. The exception are the names angle
and opposite. They are special to the diagram package and have a
fixed meaning.
- angle
- This attribute specifies the angle of the direction in degrees, where 0
points east (to the right) and 90 points north (up).
- opposite
- This attribute specifies the name of the direction which should be
considered as complementary to the named one.
- diagramObject
new element name attributes cmdprefix
- This method defines a new graphics element for the drawing language. I.e.
name will become a new command in the language, and the specified
command prefix (cmdprefix) will be called to perform the actual
drawing.
attributes specifies the set of attributes for which
data has to be available. I.e. the system will run the ...-callbacks for
these attributes. See the method new attribute for more
information on attribute definitions.
The command prefix is expected to conform to the following
signature:
- cmdprefix
canvas attributes
- Where canvas is the handle of the canvas widget to draw to, and
attributes is a dictionary holding the attributes for the element,
be they user-specified, or defaults.
The results of the command has to be a list containing at
least two and at most four items. These are, in order:
- [1]
- The list of canvas items the drawn element consists of.
- [2]
- The dictionary of named locations in the element, its corners.
- [3]
- An optional mode, either "relative" or "absolute".
When not returned "relative" is assumed. In the case of a
relative element position the attributes "with" and
"at" are used to determine the final position of the new
element.
- [4]
- An optional name of a direction. If not the empty string this is handed to
the automatic layouter as the new direction to follow.
- diagramObject
new alias name cmdprefix
- This method defines a new command for the drawing language. I.e.
name will become a new command in the language, and the specified
command prefix (cmdprefix) will be called on use of this new
command. Any arguments given to the command are simply passed to the
prefix. There is no fixed siganture.
Note that the prefix is run in the context of the drawing
language, allowing the direct use of any existing commands.
- diagramObject
new command name arguments body
- This is like new alias except that the new command is defined as a
procedure in the language's context, with regular argument list and
body.
- diagramObject
new attribute name ?key value...?
- This method defines a new named attribute which can be used by graphical
elements. The handling of the attribute by the processor is declared
through the key/value pairs coming after the name.
The accepted keys and their meanings are:
- key
- The value of this key is the name of the key under which the attribute's
value shall be stored in the attribute dictionary given to the drawing
command after attribute processing is complete.
This key is optional. If it is not specified it defaults to
the name of the attribute.
- get
- The value of this key is a command prefix which will be invoked to
retrieve the attribute's argument(s) from the command line.
This key is optional. If it is not specified a default is used
which takes the single word after the attribute name as the attribute's
value.
The signature of the command prefix is
- cmdprefix
wordqueue
- Where wordqueue is the handle of a queue object conforming to the
API of the queues provided by package struct::queue. This queue
contains the not-yet-processed part of the attribute definitions, with one
entry per word, with the first entry the word after name of the
attribute. In other words, the attribute's name has already been removed
from the queue.
The result of the command is the value of the attribute, which
may have been taken from the queue, or not.
- transform
- The value of this key is a command prefix which will be invoked to
transform the retrieved value (See get) into their final form.
This key is optional. If it is not specified no transformation
is done. The signature of the command prefix is
- cmdprefix
value
- Where value is the value to transform.
The result of the command is the final value of the
attribute.
- type
- The value of this key is a command prefix which will be invoked to
validate the attribute's argument(s).
This key is optional. If it is not specified no validation is
done.
The signature of the command prefix is that of snit validation
types. See the documentation of the snit package.
- merge
- The value of this key is a command prefix which will be invoked to insert
the transformed and validated attribute value into the dictionary of
collected attributes.
This key is optional. If it is not specified a default merge
is chosen, based on the data for key aggregate, see below. The
signature of the command prefix is
- cmdprefix
value dict
- Where value is the value to insert, and dict the dictionary
of attributes and values collected so far.
The result of the command is the new dictionary of
attributes.
- aggregate
- The value of this key is a boolean flag. It has an effect if and only if
the key merge was not specified. This key is optional. If it is not
specified it defaults to False.
If the key is effective, the value of False means that
the attribute's value is set into the dictionary using the value
of key key (see above) as index, overwriting any
previously specified value.
If the key is effective, the value of True means that
the attribute's value is added to the dictionary using the value
of key key (see above) as index, extending any previously
specified value. This means that the final value of the attribute as
seen after processing will be a list of the collected values.
- default
- The value of this key is a command prefix which will be invoked after
collection of attributes has been completed and this attribute is in the
list of required attributes for the drawing element (See argument
attributes of method new element).
Note that the connection is made through the value of key
key, not through the attribute name per se.
Further note that this command prefix is invoked even if a
user specified attribute value is present. This allows the command to go
beyond simply setting defaults, it can calculate and store derived
values as well.
This key is optional. If an element requires this attribute,
but default is not specified then nothing will be done.
The signature of the command prefix is
- cmdprefix
init
- This method is run when the attribute is defined, its responsibility is to
initialize anything in the language namespace for the attribute and
default processing.
The result of this method is ignored.
- cmdprefix
fill varname
- This method is run to put defaults, or derived values into the attribute
dictionary named by varname. This variable will be found in the
calling context.
The result of this method is ignored.
- cmdprefix
set name value
- This method is run to push current a attribute value into the language
namespace, to make it the new default.
The result of this method is ignored.
- linked
- This key is effective if and only if key default is not specified.
In that case is supplies a default handling for default, linking
the attribute to a variable in the language context.
The value for this key is a 2-element list containing the name
of the variable to link to, and its initial value, in this order.
- diagramObject
unknown attribute cmdprefix
- This method registers the command prefix with the subsystem processing the
attributes for element commands, telling it to call it when it encounters
an attribute it is unable to handle on its on.
It is allowed to register more than callback, these will be
called in order of registration (i.e. first to last), until one of the
callbacks accepts the current input. The command prefix is expected to
conform to the following signature:
- cmdprefix
wordqueue
- Where wordqueue is the handle of a queue object conforming to the
API of the queues provided by package struct::queue. This queue
contains the not-yet-processed part of the attribute definitions, with one
entry per word, with the first entry the name of the attribute which could
not be processed.
The results of the command has to be a boolean value where
True signals that this callback has accepted the attribute,
processed it, and the new state of the wordqueue is where the
general processing shall continue.
Given the signature the command has basically two ways of
handling (rewriting) the attributes it recognizes:
- [1]
- Replace the attribute (and arguments) with a different attribute and
arguments.
- [2]
- Push additional words in front to get the general processing unstuck.
- diagramObject
draw script
- This method runs the given script in the context of the drawing
language definitions. See section Language Reference for details on
the available commands.
Note that script is trusted. It is
executed in the current interpreter with access to its full abilities.
For the execution of untrusted diagram scripts this interpreter should
be a safe one.
This section lists the commands for the predefined drawing
elements, aka shapes. These commands are all defined in the language's
context. All commands of this section return the handle of the newly created
element as their result. This handle also exists as a command which can be
used to query the element for its corners (names, values). See section
Miscellaneous Commands. IMAGE: figure-02-basic-shapes
- arc
attr...
- IMAGE: figure-02-arc An open element with the corresponding corners, i.e.
"start", "end", and "center". Note however
that it also has the compass rose of closed elements as its corners, with
the center of the arc's circle as the center of the compass and the other
points on the circle the arc is part of. It handles the attributes
- anchor
name
- ljust
- rjust
- above
- below
- IMAGE: figure-22-text-anchoring-3 Specifies the anchor of the text which
is to be placed at the element's center, by name. I.e. this attribute
defines the text's position relative to the element's center. The value is
ignored if no text was specified for the element. If not specified the
system falls back to the value taken from the language variable
anchor, which itself defaults to center. The legal values
are all those accepted by Tk_GetAnchor
[http://www.tcl.tk/man/tcl8.5/TkLib/GetAnchor.htm]. The commands without
arguments are all shorthands with the anchor implied. Note that they do
not combine, only the last is used. For comined directions the main
attribute command, anchor has to be used.
- clockwise
- cw
- Specifies the direction of the arc element, here going clockwise.
The complementary attribute is counterclockwise. If not specified
the system falls back to the value taken from the language variable
clockwise, which itself defaults to false, for
counter-clockwise direction.
- color
spec
- IMAGE: figure-21-style-colors Specifies the color used to draw the lines
of the element. If not specified the system falls back to the value taken
from the language variable linecolor, which itself defaults to
black.
- counterclockwise
- ccw
- Specifies the direction of the arc element, here counter-clockwise.
The complementary attribute is clockwise. If not specified the
system falls back to the value taken from the language variable
clockwise, which itself defaults to false, for
counter-clockwise direction.
- fillcolor
spec
- IMAGE: figure-21-style-colors Specifies the color used to draw the inside
of the element. If not specified the system falls back to the value taken
from the language variable fillcolor, which itself defaults to the
empty string, signaling "no filling".
- from
location
- Specifies the location where the arc element begins. Defaults to
the current location as maintained by the layouting system.
- justify
left|center|right
- Specifies how multi-line text associated with the element is positioned
within its box. The value is ignored if no text was specified for the
element. If not specified the system falls back to the value taken from
the language variable justify, which itself defaults to
left. The legal values are left, right, and
center.
- radius
length
- Specifies the radius of the arc element, or rather, the radius of
the circle the shown arc is a part of. If not specified the system falls
back to the value taken from the language variable arcradius, which
itself defaults to the pixel equivalent of 1 cm.
- stroke
width
- IMAGE: figure-20-style-stroke Specifies the width of the lines drawn for
the the element, in pixels. If not specified the system falls back to the
value taken from the language variable linewidth, which itself
defaults to 1.
- style
spec
- IMAGE: figure-18-style-dash Specifies the style used to draw the lines of
the element. If not specified the system falls back to the value taken
from the language variable linestyle, which itself defaults to
solid lines. The legal values are all those accepted by
Tk_GetDash [http://www.tcl.tk/man/tcl8.5/TkLib/GetDash.htm], and
additionally all which are listed below:
- Note that the values "solid", "dot(ted)",
"dash(ed)", "dash-dot", and "dash-dot-dot"
are all accepted as shorthands for the style command using them as
argument.
- text
string
- Specifies the text to associate with the element. Defaults to nothing.
When specified multiple times the actually shown text is the concatenation
of the individual strings, vertically stacked, with the first string
specified being the topmost element.
- textcolor
spec
- Specifies the color used to draw the text of an element with. Ignored if
there is no text. If not specified the system falls back to the value
taken from the language variable textcolor, which itself defaults
to black.
- textfont
spec
- Specifies the font used to draw the text of an element with. Ignored if
there is no text. If not specified the system falls back to the value
taken from the language variable textfont, which itself defaults to
Helvetica 12pt.
- to location
- Specifies the location where the arc element ends. Defaults to a
location such that a 90-degree arc is drawn in the chosen direction,
starting at from.
- arrow
attr...
- --> attr...
- <--> attr...
- <--> attr...
- IMAGE: figure-02-arrow An alias for the line element (see below),
with the attribute arrowhead preset to ->,
<->, or <-. The arrow is equivalent to
-->.
- block script
attr...
- A closed element with the corresponding corners, i.e. the eight directions
of the compass rose, and "center". The main effect is the
aggregration of all elements created by the script into one
element. This also means that while the elements created by the script are
visible in the element history while the script is executing, afterward
the history contains only the block itself, and not the elements it is
composed of.
The script has access to the current state of all variables in
the language context. Any changes to the variables will be reverted
after execution of the block. However, also, any variables set in the
script will be exported as corners of the element, allowing users to
define their own named locations in the block.
Regarding the layout mechanism any changes made by the script
are reverted after the element is done. In other words, a block is an
implicit group.
Blocks handle all attributes, propgating their settings into
the script as the default values active during script execution.
- box
attr...
- IMAGE: figure-02-box A closed element with the corresponding corners, i.e.
the eight directions of the compass rose, and "center". It
handles the attributes
- anchor
name
- ljust
- rjust
- above
- below
- IMAGE: figure-22-text-anchoring-3 Specifies the anchor of the text which
is to be placed at the element's center, by name. I.e. this attribute
defines the text's position relative to the element's center. The value is
ignored if no text was specified for the element. If not specified the
system falls back to the value taken from the language variable
anchor, which itself defaults to center. The legal values
are all those accepted by Tk_GetAnchor
[http://www.tcl.tk/man/tcl8.5/TkLib/GetAnchor.htm]. The commands without
arguments are all shorthands with the anchor implied. Note that they do
not combine, only the last is used. For comined directions the main
attribute command, anchor has to be used.
- at location
- Specifies the location of the element's corner named by the attribute
with. Defaults to the current location as maintained by the
layouting system.
- color
spec
- IMAGE: figure-21-style-colors Specifies the color used to draw the lines
of the element. If not specified the system falls back to the value taken
from the language variable linecolor, which itself defaults to
black.
- fillcolor
spec
- IMAGE: figure-21-style-colors Specifies the color used to draw the inside
of the element. If not specified the system falls back to the value taken
from the language variable fillcolor, which itself defaults to the
empty string, signaling "no filling".
- height
length
- ht length
- Specifies the height of the element. If not specified the system falls
back to the value taken from the language variable boxheight, which
itself defaults to the pixel equivalent of 2 cm.
- justify
left|center|right
- Specifies how multi-line text associated with the element is positioned
within its box. The value is ignored if no text was specified for the
element. If not specified the system falls back to the value taken from
the language variable justify, which itself defaults to
left. The legal values are left, right, and
center.
- slant
angle
- Specifies the angle by which the box element is slanted, in
degrees. If not specified the system falls back to the value taken from
the language variable slant, which itself defaults to 90,
i.e. vertical, no slant. 0 degrees is slanting straight east, pointing to
the right. 90 degrees is slanting to the north, pointing straight up.
- stroke
width
- IMAGE: figure-20-style-stroke Specifies the width of the lines drawn for
the the element, in pixels. If not specified the system falls back to the
value taken from the language variable linewidth, which itself
defaults to 1.
- style
spec
- IMAGE: figure-18-style-dash Specifies the style used to draw the lines of
the element. If not specified the system falls back to the value taken
from the language variable linestyle, which itself defaults to
solid lines. The legal values are all those accepted by
Tk_GetDash [http://www.tcl.tk/man/tcl8.5/TkLib/GetDash.htm], and
additionally all which are listed below:
- Note that the values "solid", "dot(ted)",
"dash(ed)", "dash-dot", and "dash-dot-dot"
are all accepted as shorthands for the style command using them as
argument.
- text
string
- Specifies the text to associate with the element. Defaults to nothing.
When specified multiple times the actually shown text is the concatenation
of the individual strings, vertically stacked, with the first string
specified being the topmost element.
- textcolor
spec
- Specifies the color used to draw the text of an element with. Ignored if
there is no text. If not specified the system falls back to the value
taken from the language variable textcolor, which itself defaults
to black.
- textfont
spec
- Specifies the font used to draw the text of an element with. Ignored if
there is no text. If not specified the system falls back to the value
taken from the language variable textfont, which itself defaults to
Helvetica 12pt.
- width
length
- wid
length
- Specifies the width of the element. If not specified the system falls back
to the value taken from the language variable boxwidth, which
itself defaults to the pixel equivalent of 2 cm.
- with
corner
- Specifies the corner of the element to place at the location given by the
attribute at. Defaults to the current corner as maintained by the
layouting system, except if the value for at was specified by the
user. In that case it defaults to center.
- circle
attr...
- O attr...
- IMAGE: figure-02-circle A closed element with the corresponding corners,
i.e. the eight directions of the compass rose, and "center". It
handles the attributes
- anchor
name
- ljust
- rjust
- above
- below
- IMAGE: figure-22-text-anchoring-3 Specifies the anchor of the text which
is to be placed at the element's center, by name. I.e. this attribute
defines the text's position relative to the element's center. The value is
ignored if no text was specified for the element. If not specified the
system falls back to the value taken from the language variable
anchor, which itself defaults to center. The legal values
are all those accepted by Tk_GetAnchor
[http://www.tcl.tk/man/tcl8.5/TkLib/GetAnchor.htm]. The commands without
arguments are all shorthands with the anchor implied. Note that they do
not combine, only the last is used. For comined directions the main
attribute command, anchor has to be used.
- at
location
- Specifies the location of the element's corner named by the attribute
with. Defaults to the current location as maintained by the
layouting system.
- color
spec
- IMAGE: figure-21-style-colors Specifies the color used to draw the lines
of the element. If not specified the system falls back to the value taken
from the language variable linecolor, which itself defaults to
black.
- diameter
length
- diam
length
- Specifies the diameter of the circle element, as an alternative way
to specify its radius. Effective if and only if the radius was not
specified. I.e. if both diameter and radius are specified then the radius
infomration has precendence. This attribute has no default, because the
defaults are taken from the radius.
- fillcolor
spec
- IMAGE: figure-21-style-colors Specifies the color used to draw the inside
of the element. If not specified the system falls back to the value taken
from the language variable fillcolor, which itself defaults to the
empty string, signaling "no filling".
- justify
left|center|right
- Specifies how multi-line text associated with the element is positioned
within its box. The value is ignored if no text was specified for the
element. If not specified the system falls back to the value taken from
the language variable justify, which itself defaults to
left. The legal values are left, right, and
center.
- radius
length
- rad
length
- Specifies the radius of the circle element. If not specified the
system falls back to the value taken from the language variable
circleradius, which itself defaults to the pixel equivalent of 1
cm.
- stroke
width
- IMAGE: figure-20-style-stroke Specifies the width of the lines drawn for
the the element, in pixels. If not specified the system falls back to the
value taken from the language variable linewidth, which itself
defaults to 1.
- style
spec
- IMAGE: figure-18-style-dash Specifies the style used to draw the lines of
the element. If not specified the system falls back to the value taken
from the language variable linestyle, which itself defaults to
solid lines. The legal values are all those accepted by
Tk_GetDash [http://www.tcl.tk/man/tcl8.5/TkLib/GetDash.htm], and
additionally all which are listed below:
- Note that the values "solid", "dot(ted)",
"dash(ed)", "dash-dot", and "dash-dot-dot"
are all accepted as shorthands for the style command using them as
argument.
- text
string
- Specifies the text to associate with the element. Defaults to nothing.
When specified multiple times the actually shown text is the concatenation
of the individual strings, vertically stacked, with the first string
specified being the topmost element.
- textcolor
spec
- Specifies the color used to draw the text of an element with. Ignored if
there is no text. If not specified the system falls back to the value
taken from the language variable textcolor, which itself defaults
to black.
- textfont
spec
- Specifies the font used to draw the text of an element with. Ignored if
there is no text. If not specified the system falls back to the value
taken from the language variable textfont, which itself defaults to
Helvetica 12pt.
- with
corner
- Specifies the corner of the element to place at the location given by the
attribute at. Defaults to the current corner as maintained by the
layouting system, except if the value for at was specified by the
user. In that case it defaults to center.
- diamond
attr...
- <> attr...
- IMAGE: figure-02-diamond A closed element with the corresponding corners,
i.e. the eight directions of the compass rose, and "center". It
handles the attributes
- anchor
name
- ljust
- rjust
- above
- below
- IMAGE: figure-22-text-anchoring-3 Specifies the anchor of the text which
is to be placed at the element's center, by name. I.e. this attribute
defines the text's position relative to the element's center. The value is
ignored if no text was specified for the element. If not specified the
system falls back to the value taken from the language variable
anchor, which itself defaults to center. The legal values
are all those accepted by Tk_GetAnchor
[http://www.tcl.tk/man/tcl8.5/TkLib/GetAnchor.htm]. The commands without
arguments are all shorthands with the anchor implied. Note that they do
not combine, only the last is used. For comined directions the main
attribute command, anchor has to be used.
- aspect
number
- Specifies the aspect ratio, i.e ratio of width to height, of the
diamond element. The manner in which a default is calculated when
not specified also depends on the specifications of the attributes
width and height, if any.
If both width, and height are specified then any
specification of aspect is ignored, as it is implicitly defined
in the width and height as well, and this takes precedence. A missing
specification is ignored in that case well, i.e. no defaults are
required.
If the aspect is specified, and one of the attributes
width or height, then the missing attribute is calculated
from the two which are specified. No defaults are required for these
cases either.
If only one of the attributes width or height is
specified then the system uses a fallback for the aspect, the
value taken from the language variable diamondaspect, which
itselfs defaults to 2.
If none of of the attributes width or height is
specified then the system uses a fallback for the width, the
value taken from the language variable boxwidth, which itselfs
defaults to the pixel equivalent of 2 cm. For the aspect it uses
either the user-specified value or the default taken as described in the
previous paragraph.
- at
location
- Specifies the location of the element's corner named by the attribute
with. Defaults to the current location as maintained by the
layouting system.
- color
spec
- IMAGE: figure-21-style-colors Specifies the color used to draw the lines
of the element. If not specified the system falls back to the value taken
from the language variable linecolor, which itself defaults to
black.
- fillcolor
spec
- IMAGE: figure-21-style-colors Specifies the color used to draw the inside
of the element. If not specified the system falls back to the value taken
from the language variable fillcolor, which itself defaults to the
empty string, signaling "no filling".
- height
length
- Specifies the height of the diamond element. The manner in which a
default is calculated when not specified also depends on the
specifications of the attributes aspect and width, if any.
If both width, and height are specified then any
specification of aspect is ignored, as it is implicitly defined
in the width and height as well, and this takes precedence. A missing
specification is ignored in that case well, i.e. no defaults are
required.
If the aspect is specified, and one of the attributes
width or height, then the missing attribute is calculated
from the two which are specified. No defaults are required for these
cases either.
If only one of the attributes width or height is
specified then the system uses a fallback for the aspect, the
value taken from the language variable diamondaspect, which
itselfs defaults to 2.
If none of of the attributes width or height is
specified then the system uses a fallback for the width, the
value taken from the language variable boxwidth, which itselfs
defaults to the pixel equivalent of 2 cm. For the aspect it uses
either the user-specified value or the default taken as described in the
previous paragraph.
- justify
left|center|right
- Specifies how multi-line text associated with the element is positioned
within its box. The value is ignored if no text was specified for the
element. If not specified the system falls back to the value taken from
the language variable justify, which itself defaults to
left. The legal values are left, right, and
center.
- stroke
width
- IMAGE: figure-20-style-stroke Specifies the width of the lines drawn for
the the element, in pixels. If not specified the system falls back to the
value taken from the language variable linewidth, which itself
defaults to 1.
- style
spec
- IMAGE: figure-18-style-dash Specifies the style used to draw the lines of
the element. If not specified the system falls back to the value taken
from the language variable linestyle, which itself defaults to
solid lines. The legal values are all those accepted by
Tk_GetDash [http://www.tcl.tk/man/tcl8.5/TkLib/GetDash.htm], and
additionally all which are listed below:
- Note that the values "solid", "dot(ted)",
"dash(ed)", "dash-dot", and "dash-dot-dot"
are all accepted as shorthands for the style command using them as
argument.
- text
string
- Specifies the text to associate with the element. Defaults to nothing.
When specified multiple times the actually shown text is the concatenation
of the individual strings, vertically stacked, with the first string
specified being the topmost element.
- textcolor
spec
- Specifies the color used to draw the text of an element with. Ignored if
there is no text. If not specified the system falls back to the value
taken from the language variable textcolor, which itself defaults
to black.
- textfont
spec
- Specifies the font used to draw the text of an element with. Ignored if
there is no text. If not specified the system falls back to the value
taken from the language variable textfont, which itself defaults to
Helvetica 12pt.
- width
length
- Specifies the width of the diamond element. The manner in which a
default is calculated when not specified also depends on the
specifications of the attributes aspect and height, if any.
If both width, and height are specified then any
specification of aspect is ignored, as it is implicitly defined
in the width and height as well, and this takes precedence. A missing
specification is ignored in that case well, i.e. no defaults are
required.
If the aspect is specified, and one of the attributes
width or height, then the missing attribute is calculated
from the two which are specified. No defaults are required for these
cases either.
If only one of the attributes width or height is
specified then the system uses a fallback for the aspect, the
value taken from the language variable diamondaspect, which
itselfs defaults to 2.
If none of of the attributes width or height is
specified then the system uses a fallback for the width, the
value taken from the language variable boxwidth, which itselfs
defaults to the pixel equivalent of 2 cm. For the aspect it uses
either the user-specified value or the default taken as described in the
previous paragraph.
- with
corner
- Specifies the corner of the element to place at the location given by the
attribute at. Defaults to the current corner as maintained by the
layouting system, except if the value for at was specified by the
user. In that case it defaults to center.
- drum
attr...
- IMAGE: figure-02-drum A closed element with the corresponding corners,
i.e. the eight directions of the compass rose, and "center". It
handles the attributes
- anchor
name
- ljust
- rjust
- above
- below
- IMAGE: figure-22-text-anchoring-3 Specifies the anchor of the text which
is to be placed at the element's center, by name. I.e. this attribute
defines the text's position relative to the element's center. The value is
ignored if no text was specified for the element. If not specified the
system falls back to the value taken from the language variable
anchor, which itself defaults to center. The legal values
are all those accepted by Tk_GetAnchor
[http://www.tcl.tk/man/tcl8.5/TkLib/GetAnchor.htm]. The commands without
arguments are all shorthands with the anchor implied. Note that they do
not combine, only the last is used. For comined directions the main
attribute command, anchor has to be used.
- aspect
number
- Specifies the aspect ratio, i.e ratio of width to height, of the ellipses
which are used to draw the top and bottom of the drum element. If
not specified the system falls back to the value taken from the language
variable drumaspect, which itself defaults to 0.35.
- at
location
- Specifies the location of the element's corner named by the attribute
with. Defaults to the current location as maintained by the
layouting system.
- color
spec
- IMAGE: figure-21-style-colors Specifies the color used to draw the lines
of the element. If not specified the system falls back to the value taken
from the language variable linecolor, which itself defaults to
black.
- fillcolor
spec
- IMAGE: figure-21-style-colors Specifies the color used to draw the inside
of the element. If not specified the system falls back to the value taken
from the language variable fillcolor, which itself defaults to the
empty string, signaling "no filling".
- height
length
- ht
length
- Specifies the height of the element. If not specified the system falls
back to the value taken from the language variable boxheight, which
itself defaults to the pixel equivalent of 2 cm.
- justify
left|center|right
- Specifies how multi-line text associated with the element is positioned
within its box. The value is ignored if no text was specified for the
element. If not specified the system falls back to the value taken from
the language variable justify, which itself defaults to
left. The legal values are left, right, and
center.
- stroke
width
- IMAGE: figure-20-style-stroke Specifies the width of the lines drawn for
the the element, in pixels. If not specified the system falls back to the
value taken from the language variable linewidth, which itself
defaults to 1.
- style
spec
- IMAGE: figure-18-style-dash Specifies the style used to draw the lines of
the element. If not specified the system falls back to the value taken
from the language variable linestyle, which itself defaults to
solid lines. The legal values are all those accepted by
Tk_GetDash [http://www.tcl.tk/man/tcl8.5/TkLib/GetDash.htm], and
additionally all which are listed below:
- Note that the values "solid", "dot(ted)",
"dash(ed)", "dash-dot", and "dash-dot-dot"
are all accepted as shorthands for the style command using them as
argument.
- text
string
- Specifies the text to associate with the element. Defaults to nothing.
When specified multiple times the actually shown text is the concatenation
of the individual strings, vertically stacked, with the first string
specified being the topmost element.
- textcolor
spec
- Specifies the color used to draw the text of an element with. Ignored if
there is no text. If not specified the system falls back to the value
taken from the language variable textcolor, which itself defaults
to black.
- textfont
spec
- Specifies the font used to draw the text of an element with. Ignored if
there is no text. If not specified the system falls back to the value
taken from the language variable textfont, which itself defaults to
Helvetica 12pt.
- width
length
- wid
length
- Specifies the width of the element. If not specified the system falls back
to the value taken from the language variable boxwidth, which
itself defaults to the pixel equivalent of 2 cm.
- with
corner
- Specifies the corner of the element to place at the location given by the
attribute at. Defaults to the current corner as maintained by the
layouting system, except if the value for at was specified by the
user. In that case it defaults to center.
- ellipse
attr...
- IMAGE: figure-02-ellipse A closed element with the corresponding corners,
i.e. the eight directions of the compass rose, and "center". It
handles the attributes
- anchor
name
- ljust
- rjust
- above
- below
- IMAGE: figure-22-text-anchoring-3 Specifies the anchor of the text which
is to be placed at the element's center, by name. I.e. this attribute
defines the text's position relative to the element's center. The value is
ignored if no text was specified for the element. If not specified the
system falls back to the value taken from the language variable
anchor, which itself defaults to center. The legal values
are all those accepted by Tk_GetAnchor
[http://www.tcl.tk/man/tcl8.5/TkLib/GetAnchor.htm]. The commands without
arguments are all shorthands with the anchor implied. Note that they do
not combine, only the last is used. For comined directions the main
attribute command, anchor has to be used.
- at
location
- Specifies the location of the element's corner named by the attribute
with. Defaults to the current location as maintained by the
layouting system.
- color
spec
- IMAGE: figure-21-style-colors Specifies the color used to draw the lines
of the element. If not specified the system falls back to the value taken
from the language variable linecolor, which itself defaults to
black.
- fillcolor
spec
- IMAGE: figure-21-style-colors Specifies the color used to draw the inside
of the element. If not specified the system falls back to the value taken
from the language variable fillcolor, which itself defaults to the
empty string, signaling "no filling".
- height
length
- ht
length
- Specifies the height of the element. If not specified the system falls
back to the value taken from the language variable boxheight, which
itself defaults to the pixel equivalent of 2 cm.
- justify
left|center|right
- Specifies how multi-line text associated with the element is positioned
within its box. The value is ignored if no text was specified for the
element. If not specified the system falls back to the value taken from
the language variable justify, which itself defaults to
left. The legal values are left, right, and
center.
- stroke
width
- IMAGE: figure-20-style-stroke Specifies the width of the lines drawn for
the the element, in pixels. If not specified the system falls back to the
value taken from the language variable linewidth, which itself
defaults to 1.
- style
spec
- IMAGE: figure-18-style-dash Specifies the style used to draw the lines of
the element. If not specified the system falls back to the value taken
from the language variable linestyle, which itself defaults to
solid lines. The legal values are all those accepted by
Tk_GetDash [http://www.tcl.tk/man/tcl8.5/TkLib/GetDash.htm], and
additionally all which are listed below:
- Note that the values "solid", "dot(ted)",
"dash(ed)", "dash-dot", and "dash-dot-dot"
are all accepted as shorthands for the style command using them as
argument.
- text
string
- Specifies the text to associate with the element. Defaults to nothing.
When specified multiple times the actually shown text is the concatenation
of the individual strings, vertically stacked, with the first string
specified being the topmost element.
- textcolor
spec
- Specifies the color used to draw the text of an element with. Ignored if
there is no text. If not specified the system falls back to the value
taken from the language variable textcolor, which itself defaults
to black.
- textfont
spec
- Specifies the font used to draw the text of an element with. Ignored if
there is no text. If not specified the system falls back to the value
taken from the language variable textfont, which itself defaults to
Helvetica 12pt.
- width
length
- wid
length
- Specifies the width of the element. If not specified the system falls back
to the value taken from the language variable boxwidth, which
itself defaults to the pixel equivalent of 2 cm.
- with
corner
- Specifies the corner of the element to place at the location given by the
attribute at. Defaults to the current corner as maintained by the
layouting system, except if the value for at was specified by the
user. In that case it defaults to center.
- line
attr...
- --
attr...
- IMAGE: figure-02-line An open element with the corresponding corners, i.e.
"start", "end", and "center". It handles the
attributes
- anchor
name
- ljust
- rjust
- above
- below
- IMAGE: figure-22-text-anchoring-3 Specifies the anchor of the text which
is to be placed at the element's center, by name. I.e. this attribute
defines the text's position relative to the element's center. The value is
ignored if no text was specified for the element. If not specified the
system falls back to the value taken from the language variable
anchor, which itself defaults to center. The legal values
are all those accepted by Tk_GetAnchor
[http://www.tcl.tk/man/tcl8.5/TkLib/GetAnchor.htm]. The commands without
arguments are all shorthands with the anchor implied. Note that they do
not combine, only the last is used. For comined directions the main
attribute command, anchor has to be used.
- arrowhead
spec
- IMAGE: figure-19-style-arrowheads Specifies where to draw arrowheads on
the line element, at the beginning or end, at both ends, or none.
If not specified the system falls back to the value taken from the
language variable arrowhead, which itself defaults to none.
The legal values are
- none, -
- Draw no arrowheads, at neither end of the line.
- start, first,
<-
- Draw an arrowhead at the beginning of the line, but not at its end.
- end, last,
->
- Draw an arrowhead at the end of the line, but not at its beginning.
- both,
<->
- Draw arrowheads at both ends of the line.
- Note that the values "start", "end", "-",
"->", "<-", and "<->" are all
accepted as shorthands for the arrowhead command using them as
argument.
- at
location
- Line elements are normally positioned absolutely, using the
locations specified through the attributes from, then, and
to. If at is specified however then these positions are
translated a last time, moving the line's corner named by the attribute
with to the location given by this attribute.
- chop
?length?
- Specifies the length of the line element to remove from the
beginning and/or end. Defaults to nothing. If specified once the chopping
applies to both beginning and end of the line. If specified twice or more
the last two specifications are used, and applied to beginning and end of
the line, in this order. Whenever the attribute is specified without an
explicit length, the system falls back to the value taken from the
language variable circleradius, which itself defaults to the pixel
equivalent of 1 cm
- color
spec
- IMAGE: figure-21-style-colors Specifies the color used to draw the lines
of the element. If not specified the system falls back to the value taken
from the language variable linecolor, which itself defaults to
black.
- fillcolor
spec
- IMAGE: figure-21-style-colors Specifies the color used to draw the inside
of the element. If not specified the system falls back to the value taken
from the language variable fillcolor, which itself defaults to the
empty string, signaling "no filling".
- from
location
- Specifies the location where the line element begins. Defaults to
the current location as maintained by the layouting system.
- justify
left|center|right
- Specifies how multi-line text associated with the element is positioned
within its box. The value is ignored if no text was specified for the
element. If not specified the system falls back to the value taken from
the language variable justify, which itself defaults to
left. The legal values are left, right, and
center.
- noturn
- Specifies that the direction of line element at its end is not
propagated to the layout management. If not specified the direction of the
line becomes the new direction the layout.
- smooth
- Specifies the use of bezier splines for the line element. If not
specified lines are drawn exactly through the specified waypoints, without
any smooth curves.
- stroke
width
- IMAGE: figure-20-style-stroke Specifies the width of the lines drawn for
the the element, in pixels. If not specified the system falls back to the
value taken from the language variable linewidth, which itself
defaults to 1.
- style
spec
- IMAGE: figure-18-style-dash Specifies the style used to draw the lines of
the element. If not specified the system falls back to the value taken
from the language variable linestyle, which itself defaults to
solid lines. The legal values are all those accepted by
Tk_GetDash [http://www.tcl.tk/man/tcl8.5/TkLib/GetDash.htm], and
additionally all which are listed below:
- Note that the values "solid", "dot(ted)",
"dash(ed)", "dash-dot", and "dash-dot-dot"
are all accepted as shorthands for the style command using them as
argument.
- text
string
- Specifies the text to associate with the element. Defaults to nothing.
When specified multiple times the actually shown text is the concatenation
of the individual strings, vertically stacked, with the first string
specified being the topmost element.
- textcolor
spec
- Specifies the color used to draw the text of an element with. Ignored if
there is no text. If not specified the system falls back to the value
taken from the language variable textcolor, which itself defaults
to black.
- textfont
spec
- Specifies the font used to draw the text of an element with. Ignored if
there is no text. If not specified the system falls back to the value
taken from the language variable textfont, which itself defaults to
Helvetica 12pt.
- then
location
- then
(<direction> ?length?)...
- (<direction> ?length?)...
- This attribute specifies an intermediate location the line element
has to go through. It can be specified multiple times, with each use
adding one additional location to the series which the line will go
through. These location will be traversed in the order they were
specified.
The location can be given explicitly, or as a series of
directions with distances. In the latter case the names of all known
directions are accepted for the direction part. If no distance is
specified for a direction the system falls back to the value taken from
the language variable movelength, which itself defaults to the
pixel equivalent of 2 cm. The whole set of direction,distance
pairs is treated as a series of translations which are added up to
provide the final translation specifying the intermediate point
(relative to the preceding point).
The last named direction is propagated to the layout system as
the direction to follow. The use of noturn is not able to overide
this behaviour.
At last, the names of the registered directions also serve as
attribute commands, with an implicit attribute then in front of
them.
If no intermediate or last location is specified for the line
the system falls back to a point movelength pixels away from the
starting location, in the current direction as maintained by the
layouting system
- to
location
- Specifies the location where the line element ends. This attribute
has no default. The default is handled by the attribute then, which
makes it appear as if to has a default when not specified.
- with
corner
- Line elements are normally positioned absolutely, using the
locations specified through the attributes from, then, and
to. If at is specified however then these positions are
translated a last time, moving the line's corner named by the attribute
with to the location given by this attribute. This means that
with is effective if and only if the attribute at was
specified as well for the line.
- move
attr
- An open element with the corresponding corners, i.e. "start",
"end", and "center". A move element is in
essence an invisible line. While the main effect we are interested
in is the change it makes to the layout system, it is an actual element,
i.e. it has the same corners as an ordinary line, and shows up in the
history as well, allowing future references to all the places it touched.
It handles the same attibutes as line elements.
- spline
attr...
- IMAGE: figure-02-spline An alias for the line element (see above),
with the attribute smooth preset.
- text
attr...
- IMAGE: figure-02-text A closed element with the corresponding corners,
i.e. the eight directions of the compass rose, and "center". It
handles the attributes
- anchor
name
- ljust
- rjust
- above
- below
- IMAGE: figure-22-text-anchoring-3 Specifies the anchor of the text which
is to be placed at the element's center, by name. I.e. this attribute
defines the text's position relative to the element's center. The value is
ignored if no text was specified for the element. If not specified the
system falls back to the value taken from the language variable
anchor, which itself defaults to center. The legal values
are all those accepted by Tk_GetAnchor
[http://www.tcl.tk/man/tcl8.5/TkLib/GetAnchor.htm]. The commands without
arguments are all shorthands with the anchor implied. Note that they do
not combine, only the last is used. For comined directions the main
attribute command, anchor has to be used.
- at
location
- Specifies the location of the element's corner named by the attribute
with. Defaults to the current location as maintained by the
layouting system.
- height
length
- Specifies the height of the text element. Defaults to the natural
height of its text.
- justify
left|center|right
- Specifies how multi-line text associated with the element is positioned
within its box. The value is ignored if no text was specified for the
element. If not specified the system falls back to the value taken from
the language variable justify, which itself defaults to
left. The legal values are left, right, and
center.
- text
string
- Specifies the text to associate with the element. Defaults to nothing.
When specified multiple times the actually shown text is the concatenation
of the individual strings, vertically stacked, with the first string
specified being the topmost element.
- textcolor
spec
- Specifies the color used to draw the text of an element with. Ignored if
there is no text. If not specified the system falls back to the value
taken from the language variable textcolor, which itself defaults
to black.
- textfont
spec
- Specifies the font used to draw the text of an element with. Ignored if
there is no text. If not specified the system falls back to the value
taken from the language variable textfont, which itself defaults to
Helvetica 12pt.
- width
length
- Specifies the width of the text element. Defaults to the natural
width of its text.
- with
corner
- Specifies the corner of the element to place at the location given by the
attribute at. Defaults to the current corner as maintained by the
layouting system, except if the value for at was specified by the
user. In that case it defaults to center.
The set of all attributes supported by all the element commands is
shown below. While we speak of them as commands, and provide a syntax, they
are not truly available as actual commands, but only as part of the
arguments for an element command.
Note that some of the attribute names are overloaded, i.e. have
multiple, different, definitions. During processing of attributes for an
element the actual definition used is chosen based on the type of the
element the processing is for.
Further, as a catch-all clause, any attribute which could not be
processed according to the definitions below will be treated as the argument
of an implicit text attribute.
- anchor
name
- ljust
- rjust
- above
- below
- IMAGE: figure-22-text-anchoring-3 Specifies the anchor of the text which
is to be placed at the element's center, by name. I.e. this attribute
defines the text's position relative to the element's center. The value is
ignored if no text was specified for the element. If not specified the
system falls back to the value taken from the language variable
anchor, which itself defaults to center. The legal values
are all those accepted by Tk_GetAnchor
[http://www.tcl.tk/man/tcl8.5/TkLib/GetAnchor.htm]. The commands without
arguments are all shorthands with the anchor implied. Note that they do
not combine, only the last is used. For comined directions the main
attribute command, anchor has to be used.
- arrowhead
spec
- IMAGE: figure-19-style-arrowheads Specifies where to draw arrowheads on
the line element, at the beginning or end, at both ends, or none.
If not specified the system falls back to the value taken from the
language variable arrowhead, which itself defaults to none.
The legal values are
- none,
-
- Draw no arrowheads, at neither end of the line.
- start,
first, <-
- Draw an arrowhead at the beginning of the line, but not at its end.
- end, last,
->
- Draw an arrowhead at the end of the line, but not at its beginning.
- both,
<->
- Draw arrowheads at both ends of the line.
- Note that the values "start", "end", "-",
"->", "<-", and "<->" are all
accepted as shorthands for the arrowhead command using them as
argument.
- aspect
number
- Specifies the aspect ratio, i.e ratio of width to height, of the
diamond element. The manner in which a default is calculated when
not specified also depends on the specifications of the attributes
width and height, if any.
If both width, and height are specified then any
specification of aspect is ignored, as it is implicitly defined
in the width and height as well, and this takes precedence. A missing
specification is ignored in that case well, i.e. no defaults are
required.
If the aspect is specified, and one of the attributes
width or height, then the missing attribute is calculated
from the two which are specified. No defaults are required for these
cases either.
If only one of the attributes width or height is
specified then the system uses a fallback for the aspect, the
value taken from the language variable diamondaspect, which
itselfs defaults to 2.
If none of of the attributes width or height is
specified then the system uses a fallback for the width, the
value taken from the language variable boxwidth, which itselfs
defaults to the pixel equivalent of 2 cm. For the aspect it uses
either the user-specified value or the default taken as described in the
previous paragraph.
- aspect
number
- Specifies the aspect ratio, i.e ratio of width to height, of the ellipses
which are used to draw the top and bottom of the drum element. If
not specified the system falls back to the value taken from the language
variable drumaspect, which itself defaults to 0.35.
- at
location
- Specifies the location of the element's corner named by the attribute
with. Defaults to the current location as maintained by the
layouting system.
- at
location
- Line elements are normally positioned absolutely, using the
locations specified through the attributes from, then, and
to. If at is specified however then these positions are
translated a last time, moving the line's corner named by the attribute
with to the location given by this attribute.
- chop
?length?
- Specifies the length of the line element to remove from the
beginning and/or end. Defaults to nothing. If specified once the chopping
applies to both beginning and end of the line. If specified twice or more
the last two specifications are used, and applied to beginning and end of
the line, in this order. Whenever the attribute is specified without an
explicit length, the system falls back to the value taken from the
language variable circleradius, which itself defaults to the pixel
equivalent of 1 cm
- clockwise
- cw
- Specifies the direction of the arc element, here going clockwise.
The complementary attribute is counterclockwise. If not specified
the system falls back to the value taken from the language variable
clockwise, which itself defaults to false, for
counter-clockwise direction.
- color
spec
- IMAGE: figure-21-style-colors Specifies the color used to draw the lines
of the element. If not specified the system falls back to the value taken
from the language variable linecolor, which itself defaults to
black.
- counterclockwise
- ccw
- Specifies the direction of the arc element, here counter-clockwise.
The complementary attribute is clockwise. If not specified the
system falls back to the value taken from the language variable
clockwise, which itself defaults to false, for
counter-clockwise direction.
- diameter
length
- diam
length
- Specifies the diameter of the circle element, as an alternative way
to specify its radius. Effective if and only if the radius was not
specified. I.e. if both diameter and radius are specified then the radius
infomration has precendence. This attribute has no default, because the
defaults are taken from the radius.
- fillcolor
spec
- IMAGE: figure-21-style-colors Specifies the color used to draw the inside
of the element. If not specified the system falls back to the value taken
from the language variable fillcolor, which itself defaults to the
empty string, signaling "no filling".
- from
location
- Specifies the location where the line element begins. Defaults to
the current location as maintained by the layouting system.
- from
location
- Specifies the location where the arc element begins. Defaults to
the current location as maintained by the layouting system.
- height
length
- ht
length
- Specifies the height of the element. If not specified the system falls
back to the value taken from the language variable boxheight, which
itself defaults to the pixel equivalent of 2 cm.
- height
length
- Specifies the height of the diamond element. The manner in which a
default is calculated when not specified also depends on the
specifications of the attributes aspect and width, if any.
If both width, and height are specified then any
specification of aspect is ignored, as it is implicitly defined
in the width and height as well, and this takes precedence. A missing
specification is ignored in that case well, i.e. no defaults are
required.
If the aspect is specified, and one of the attributes
width or height, then the missing attribute is calculated
from the two which are specified. No defaults are required for these
cases either.
If only one of the attributes width or height is
specified then the system uses a fallback for the aspect, the
value taken from the language variable diamondaspect, which
itselfs defaults to 2.
If none of of the attributes width or height is
specified then the system uses a fallback for the width, the
value taken from the language variable boxwidth, which itselfs
defaults to the pixel equivalent of 2 cm. For the aspect it uses
either the user-specified value or the default taken as described in the
previous paragraph.
- height
length
- Specifies the height of the text element. Defaults to the natural
height of its text.
- justify
left|center|right
- Specifies how multi-line text associated with the element is positioned
within its box. The value is ignored if no text was specified for the
element. If not specified the system falls back to the value taken from
the language variable justify, which itself defaults to
left. The legal values are left, right, and
center.
- noturn
- Specifies that the direction of line element at its end is not
propagated to the layout management. If not specified the direction of the
line becomes the new direction the layout.
- radius
length
- rad
length
- Specifies the radius of the circle element. If not specified the
system falls back to the value taken from the language variable
circleradius, which itself defaults to the pixel equivalent of 1
cm.
- radius
length
- Specifies the radius of the arc element, or rather, the radius of
the circle the shown arc is a part of. If not specified the system falls
back to the value taken from the language variable arcradius, which
itself defaults to the pixel equivalent of 1 cm.
- slant
angle
- Specifies the angle by which the box element is slanted, in
degrees. If not specified the system falls back to the value taken from
the language variable slant, which itself defaults to 90,
i.e. vertical, no slant. 0 degrees is slanting straight east, pointing to
the right. 90 degrees is slanting to the north, pointing straight up.
- smooth
- Specifies the use of bezier splines for the line element. If not
specified lines are drawn exactly through the specified waypoints, without
any smooth curves.
- stroke
width
- IMAGE: figure-20-style-stroke Specifies the width of the lines drawn for
the the element, in pixels. If not specified the system falls back to the
value taken from the language variable linewidth, which itself
defaults to 1.
- style
spec
- IMAGE: figure-18-style-dash Specifies the style used to draw the lines of
the element. If not specified the system falls back to the value taken
from the language variable linestyle, which itself defaults to
solid lines. The legal values are all those accepted by
Tk_GetDash [http://www.tcl.tk/man/tcl8.5/TkLib/GetDash.htm], and
additionally all which are listed below:
- Note that the values "solid", "dot(ted)",
"dash(ed)", "dash-dot", and "dash-dot-dot"
are all accepted as shorthands for the style command using them as
argument.
- text
string
- Specifies the text to associate with the element. Defaults to nothing.
When specified multiple times the actually shown text is the concatenation
of the individual strings, vertically stacked, with the first string
specified being the topmost element.
- textcolor
spec
- Specifies the color used to draw the text of an element with. Ignored if
there is no text. If not specified the system falls back to the value
taken from the language variable textcolor, which itself defaults
to black.
- textfont
spec
- Specifies the font used to draw the text of an element with. Ignored if
there is no text. If not specified the system falls back to the value
taken from the language variable textfont, which itself defaults to
Helvetica 12pt.
- then
location
- then
(<direction> ?length?)...
- (<direction> ?length?)...
- This attribute specifies an intermediate location the line element
has to go through. It can be specified multiple times, with each use
adding one additional location to the series which the line will go
through. These location will be traversed in the order they were
specified.
The location can be given explicitly, or as a series of
directions with distances. In the latter case the names of all known
directions are accepted for the direction part. If no distance is
specified for a direction the system falls back to the value taken from
the language variable movelength, which itself defaults to the
pixel equivalent of 2 cm. The whole set of direction,distance
pairs is treated as a series of translations which are added up to
provide the final translation specifying the intermediate point
(relative to the preceding point).
The last named direction is propagated to the layout system as
the direction to follow. The use of noturn is not able to overide
this behaviour.
At last, the names of the registered directions also serve as
attribute commands, with an implicit attribute then in front of
them.
If no intermediate or last location is specified for the line
the system falls back to a point movelength pixels away from the
starting location, in the current direction as maintained by the
layouting system
- to
location
- Specifies the location where the line element ends. This attribute
has no default. The default is handled by the attribute then, which
makes it appear as if to has a default when not specified.
- to
location
- Specifies the location where the arc element ends. Defaults to a
location such that a 90-degree arc is drawn in the chosen direction,
starting at from.
- width
length
- wid
length
- Specifies the width of the element. If not specified the system falls back
to the value taken from the language variable boxwidth, which
itself defaults to the pixel equivalent of 2 cm.
- width
length
- Specifies the width of the diamond element. The manner in which a
default is calculated when not specified also depends on the
specifications of the attributes aspect and height, if any.
If both width, and height are specified then any
specification of aspect is ignored, as it is implicitly defined
in the width and height as well, and this takes precedence. A missing
specification is ignored in that case well, i.e. no defaults are
required.
If the aspect is specified, and one of the attributes
width or height, then the missing attribute is calculated
from the two which are specified. No defaults are required for these
cases either.
If only one of the attributes width or height is
specified then the system uses a fallback for the aspect, the
value taken from the language variable diamondaspect, which
itselfs defaults to 2.
If none of of the attributes width or height is
specified then the system uses a fallback for the width, the
value taken from the language variable boxwidth, which itselfs
defaults to the pixel equivalent of 2 cm. For the aspect it uses
either the user-specified value or the default taken as described in the
previous paragraph.
- width
length
- Specifies the width of the text element. Defaults to the natural
width of its text.
- with
corner
- Specifies the corner of the element to place at the location given by the
attribute at. Defaults to the current corner as maintained by the
layouting system, except if the value for at was specified by the
user. In that case it defaults to center.
- with
corner
- Line elements are normally positioned absolutely, using the
locations specified through the attributes from, then, and
to. If at is specified however then these positions are
translated a last time, moving the line's corner named by the attribute
with to the location given by this attribute. This means that
with is effective if and only if the attribute at was
specified as well for the line.
Corners are named values for in elements, usually locations.
- The closed elements define corners for the compass rose, including
the "center", and their "width" and
"height".
IMAGE: figure-27-corners-closed
- block elements additionally export all variables which were set
during their definition as corners.
- The open elements on the other hand define "start",
"end", and "center". The first two map to the
locations originally provided through the attributes from and
to of the element.
IMAGE: figure-28-corners-open
- The center of line and move elements is the location halfway
between "start" and "end" corners, this is regardless
of any intermediate locations the element may have.
- The line and move elements additionally name all their
locations as corners using numbers as names, starting from 1
(equivalent to "start"), in order of traversal.
IMAGE: figure-15-spline-1
- The center of arc elements is the center of the circle the arc is
part off.
- The arc elements additionally define the compass rose of closed
elements as well.
The named directions are commands which tell the layout system in
which direction to go when placing the next element without an explicit
position specification. They can also be used as arguments to the attribute
then, and the command by for relative points, see there for
the relevant syntax.
The diagram core defines the directions of the compass rose, plus
a number of aliases. See below for the full list.
IMAGE: figure-27-corners-closed
This overlaps with the pre-defined corners for closed elements.
This is used by the layout system, when are going in direction X the name of
the opposite direction is the name of the corner at which the new element
will be attached to the current position, and if this corner does not exist
the nearest actual corner by angle is used.
- west
- w
- left
- l
- south
- s
- down
- bottom
- bot
- b
- east
- e
- right
- r
- north
- n
- up
- top
- t
- northwest
- nw
- up-left
- upleft
- leftup
- northeast
- ne
- up-right
- upright
- rightup
- southwest
- sw
- down-left
- downleft
- leftdown
- southeast
- se
- down-right
- downright
- rightdown
- number
cm
- number
mm
- number
inch
- number
pt
- These commands allow the specification of distances and coordinates in
metric and imperial units, returning the equivalent distance or coordinate
in pixels, which is the unit used internally for all calculations.
The conversion factors are based on the result of tk
scaling and are computed once, at the time the package is sourced,
future changes of the tk scaling factor have no effect.
- number
number
-
IMAGE: figure-50-point-cons-absolute
This command takes the x and y coordinates of a location and
returns the absolute point for it.
- by distance
direction
-
IMAGE: figure-51-point-cons-relative
This command takes a distance and direction
(angle in degress, or registered direction name) and returns the
relative point for it, i.e. the delta or
translation it represents.
Note also the (dis)similarities to the directional
specifications for the attribute then of line and
move elements. Where we say here
- for the attribute we say
- or just
- point1 +
point2
-
IMAGE: figure-48-point-vectoradd
This command interprets two points as vectors and adds them
together. If at least one of the points is absolute the result is
absolute as well. The result is a relative point if and only if
both points are relative.
- point1 -
point2
-
IMAGE: figure-49-point-vectorsub
This command interprets two points as vectors and subtracts
the second from the first. If at least one of the points is
absolute the result is absolute as well. The result is a
relative point if and only if both points are
relative.
- point by
distance direction
- This command is a more convenient, or at least shorter, form of
[$point + [by $distance $direction]]
- point1 |
point2
-
IMAGE: figure-31-point-projection
This command calculates the projection of two points,
i.e. the result is the point having the x-coordinate of point1
and the y-coordinate of point2.
- n between
poin1 point2
-
IMAGE: figure-29-point-interpolation-1
This command computes the point which is n*100 percent
of the way between point1 and point2, and returns it as
its result. This means that for
- n == 0
- The result is point1.
- n == 1
- The result is point2.
- n == 0.5
- The result is half way between the two points.
- etc. Note that it is allowed to use values < 0 and > 1 for
n
- intersect
elem1 elem2
-
IMAGE: figure-32-point-intersection
This command takes two open elements, computes the
lines going through their "start"- and
"end"-corners, and returns the point where these two lines
intersect. The command throws an error if the lines do not intersect, or
are coincident.
- element
names ?pattern?
- This command returns a list containing the names of all corners for the
element. If a pattern is specified then only the names matching it
(via string match are returned. Otherwise all names are returned
(equivalent to a default pattern of *).
- element
corner
- This command returns the value for the corner of the
element. This can be anything, including points and elements.
- element
corner1 corner2...
- This is a convenience shorthand for
[[[$elem $corner1] $corner2] ...]
- assuming that the value for
- etc. is again an element.
- element
?corner1... ?names ?pattern??]?
- This is a convenience shorthand for
[[[$elem $corner1] ...] names ?pattern?]
- assuming that the value for
- etc. is again an element.
- nth
?corner?
- This command asks the diagram history for the nth element created,
searching from the beginning of the history (counting from 1) and returns
it as its result. If the corner is specified then the value for
this corner is returned instead.
- nth last
?corner?
- This command asks the diagram history for the nth element created,
searching from the end of the history and returns it as its result. If the
corner is specified then the value for this corner is returned
instead.
- nth shape
?corner?
- This command asks the diagram history for the nth element created,
of the given shape, searching from the beginning of the history
(counting from 1) and returns it as its result. If the corner is
specified then the value for this corner is returned instead.
- nth last
shape ?corner?
- This command asks the diagram history for the nth element created,
of the given shape, searching from the end of the history and
returns it as its result. If the corner is specified then the value
for this corner is returned instead.
- last
?corner?
- last shape
?corner?
- Convenience commands mapping to "1st last" and
"1st last shape".
- 1st
- 2nd
- 3rd
- Aliases for 1th, 2th, and 3th, for readability,
usable whereever nth can ocur.
The language context contains a number of predefined variables
which hold the default values for various attributes. These variables, their
uses, and values are:
- anchor
- The default value for the attribute anchor. Initialized to
center. The legal values are all those accepted by
Tk_GetAnchor
[http://www.tcl.tk/man/tcl8.5/TkLib/GetAnchor.htm].
- arcradius
- The default value for the attribute radius of arc elements.
Initialized to the pixel equivalent of 1 cm.
- arrowhead
- The default value for the attribute arrowhead. Initialized to
none. The legal values are
- none,
-
- Draw no arrowheads, at neither end of the line.
- start,
first, <-
- Draw an arrowhead at the beginning of the line, but not at its end.
- end, last,
->
- Draw an arrowhead at the end of the line, but not at its beginning.
- both,
<->
- Draw arrowheads at both ends of the line.
- boxheight
- The default value for the attribute height of box,
diamond and ellipse elements. Initialized to the pixel
equivalent of 2 cm.
- boxwidth
- The default value for the attribute width of box,
diamond and ellipse elements. Initialized to the pixel
equivalent of 2 cm.
- clockwise
- The default value for the attributes clockwise and
counterclockwise of arc elements. Initialized to
False, for counter-clockwise direction.
- circleradius
- The default value for the attribute radius of circle
elements, and also the default for the attribute chop, when
specified without an explicit length. Initialized to the pixel equivalent
of 1 cm.
- drumaspect
- The default value for the attribute aspect of drum elements.
Initialized to 0.35.
- fillcolor
- The default value for the attribute fillcolor of all elements which
can be filled. Initialized to the empty string, signaling that the element
is not filled.
- justify
- The default value for the attribute justify. Initialized to
left. The legal values are left, right, and
center.
- linecolor
- The default value for the attribute color of all elements having to
draw lines (all but text). Initialized to black.
- linestyle
- The default value for the attribute style of all elements having to
draw some line. Initialized to solid. The legal values are all
those accepted by Tk_GetDash
[http://www.tcl.tk/man/tcl8.5/TkLib/GetDash.htm], and additionally all
which are listed below:
- linewidth
- The default value for the attribute stroke of all elements having
to draw some line. Initialized to 1 (pixels).
- movelength
- The default value for the directional specification of intermediate
locations by the attribute then of line and move
elements. Initialized to the pixel equivalent of 2 cm.
- slant
- The default value for the attribute slant of box elements.
Initialized to 90 degrees, i.e. slant straight up.
- textcolor
- The default value for the attribute textcolor of all elements
having to draw some text. Initialized to black.
- textfont
- The default value for the attribute textfont of all elements having
to draw some text. Initialized to Helvetica 12pt.
on the internals of the diagram package. Regular users of
diagram can skip this section without missing anything.
The main information seen here is the figure below, showing the
hierarchy of the classes implementing diagram.
IMAGE: figure-00-dependencies
At the bottom, all at the same level are the supporting packages
like snit, etc. These can all be found in Tcllib.
Above them is the set of diagram classes implementing the various
aspects of the system, i.e.:
- diagram
- The main class, that which is seen by the user.
- diagram::core
- The core engine, itself distributed over four helper classes.
- diagram::basic
- The implementation of the standard shapes, like box, circle, etc., based
on the extension features of the core.
- diagram::element
- Core support class, the database of created elements. It also keeps the
history, i.e. the order in which elements were created.
- diagram::attribute
- Core support class, the generic handling of definition and processing of
attributes.
- diagram::direction
- Core support class, the database of named directions.
- diagram::navigation
- Core support class, the state of layout engine, i.e. current position and
directin, and operations on it.
- diagram::point
- General support class handling various vector operations.
This document, and the package it describes, will undoubtedly
contain bugs and other problems. Please report such in the category
diagram of the Tklib Trackers
[http://core.tcl.tk/tklib/reportlist]. Please also report any ideas for
enhancements you may have for either package and/or documentation.
2D geometry, arc, arrow, box, canvas, circle, diagram, diamond,
drawing, drum, ellipse, image, interpolation, intersection, line, move,
picture, plane geometry, plotting, point, raster image, spline, text,
vector