Diagrams(3) User documentation of the Diagrams package

SYNOPSIS

package require Tcl 8.4

package require Tk 8.4

package require Diagrams 0.2

::Diagrams::drawin canvas

::Diagrams::saveps filename

::Diagrams::direction newdir

::Diagrams::currentpos pos

::Diagrams::getpos anchor obj

::Diagrams::position xcoord ycoord

::Diagrams::box text width height

::Diagrams::plaintext text width height

::Diagrams::circle text radius

::Diagrams::slanted text width height angle

::Diagrams::diamond text width height

::Diagrams::drum text width height

::Diagrams::arrow text length heads

::Diagrams::line args

::Diagrams::attach anchor

::Diagrams::color name

::Diagrams::fillcolor name

::Diagrams::textcolor name

::Diagrams::usegap use

::Diagrams::xgap value

::Diagrams::ygap value

::Diagrams::textfont name

::Diagrams::linewidth pixels

::Diagrams::linestyle style

::Diagrams::pushstate

::Diagrams::popstate

::Diagrams::computepos

::Diagrams::boxcoords x1 y1 x2 y2

::Diagrams::moveobject obj




DESCRIPTION

The Diagrams package is meant to help drawing diagrams, like flowcharts. The philosophy is that you should be concentrating on the contents of the diagram, rather than the exact positioning and sizing of all items within it. The Diagrams package uses a few simple rules to layout the items:

  • Each item (or object) in the diagram has a number of "anchors" - places where arrows and lines can be connected to.
  • You can draw an arrow or a line from an object in a preset direction
  • Sizing and positioning should be done as automatic as possible: this is achieved for instance by drawing boxes and circles with text, rather than first drawing a rectangle and then drawing the text inside it or vice versa.

The commands within this package can be split up in several categories. Each category is described in a separate section.

GENERAL COMMANDS FOR POSITIONING AND SETUP

::Diagrams::drawin canvas
Set the canvas widget in which to draw
widget canvas
Widget to draw in

::Diagrams::saveps filename
Save the drawing in a PostScript file
filename string
Name of the file to save the drawing in

::Diagrams::direction newdir
Set the direction for moving the current position. The direction is one of: north northeast east southeast south southwest west northwest N NE E SE S SW W NW up up-right left down-right down down-left left up-left centre center C
newdir string
New direction

::Diagrams::currentpos pos
Set the current position explicitly (argument must be a position "object")
pos list
New position (retrieve via getpos for instance)

::Diagrams::getpos anchor obj
Get the position of a particular "anchor" point of an object anchor should be one of the direction strings
anchor string
Name of the anchor (one of the directions - see the direction command
obj list
The object in question

::Diagrams::position xcoord ycoord
Create a position "object"
xcoord float
X-coordinate of the position
ycoord float
Y-coordinate of the position

DRAWING OBJECTS

::Diagrams::box text width height
Draw a box from the current position (width and height are both optional; if not given, the text determines the width and height)
string text
Text to be shown inside the box
float width
Width (if any) of the box in pixels
float height
Height (if any) of the box in pixels

::Diagrams::plaintext text width height
Draw plain text from the current position (width and height are both optional; if not given, the text determines the width and height)
string text
Text to be shown
float width
Width (if any) of the (invisible) box in which to position the text
float height
Height (if any) of the box

::Diagrams::circle text radius
Draw a circle from the current position (the radius is optional)
string text
Text to be shown inside the circle
float radius
Radius (if any) of the circle in pixels

::Diagrams::slanted text width height angle
Draw a slanted box from the current position (width, height and angle are optional)
string text
Text to be shown inside the box
float width
Width (if any) of the box in pixels
float height
Height (if any) of the box in pixels
float angle
Angle of the slanted box

::Diagrams::diamond text width height
Draw a diamond-shaped box from the current position (width and height are both optional; if not given, the text determines the width and height)
string text
Text to be shown inside the diamond
float width
Width (if any) of the diamond in pixels
float height
Height (if any) of the diamond in pixels

::Diagrams::drum text width height
Draw a drumshaped item from th ecurrent position (width and height are both optional; if not given, the text determines the width and height)
string text
Text to be shown inside the drum
float width
Width (if any) of the drum in pixels
float height
Height (if any) of the drum in pixels

::Diagrams::arrow text length heads
Draw an arrow from the current position to the next. The text is drawn next to the arrow, the length (in pixels) is optional. If not given the gap parameters are used.
string text
Text to be shown along the arrow
float length
Length of the arrow in pixels
float heads
Which arrow heads to draw (first, last or both - defaults to last)

::Diagrams::line args
Draw a line specified via positions or via line segments The arguments are either position or length-angle pairs
list args
List of positions or of length-angle pairs

ATTRIBUTES

(Note: attributes are persistent)
::Diagrams::attach anchor
Set the anchor point for attaching arrows to
string anchor
Any one of the valid anchor (e.g. N or North)

::Diagrams::color name
Set the color for the outline of a box etc.
color name
Name of the colour to be used

::Diagrams::fillcolor name
Set the color to fill the objects
color name
Name of the colour to be used

::Diagrams::textcolor name
Set the color to draw the text in
color name
Name of the colour to be used

::Diagrams::usegap use
Turn the gap on (1) or off (0). Note: usually a small gap is used when positioning objects.
boolean use
Use the gap to compute the position of the next object or not

::Diagrams::xgap value
Size of the gap in horizontal direction (in pixels)
integer value
Gap width in pixels

::Diagrams::ygap value
Size of the gap in vertical direction (in pixels)
integer value
Gap height in pixels

::Diagrams::textfont name
Set the name of the font to use
string name
Name of a text font

::Diagrams::linewidth pixels
Set the width of the lines (in line objects and arrows and the outline of boxes and other objects)
integer pixels
Number of pixels the lines are wide

::Diagrams::linestyle style
Set the style of the lines and arrows and of the outline of boxes and other objects. The predefined line styles are: solid, dot, dash, dash-dot, dash-dot-dot (these are the distinguishable line styles on Windows). You can also use the style patterns from the canvas directly.
string style
Name of a valid line style

COMMANDS FOR IMPLEMENTING NEW OBJECTS

Note: it is best to study how for instance box objects are implemented first.
::Diagrams::pushstate
Save the current global settings Used when defining an object that is composed of other objects
::Diagrams::popstate
Restore the previously saved global settings
::Diagrams::computepos
Compute the current position
::Diagrams::boxcoords x1 y1 x2 y2
Compute the anchor coordinates for a box-like object (this is merely a convenience routine. In general, you will have to compute the list of coordinates yourself - see for instance the diamond object)
float x1
X coordinate of upper-left corner
float y1
Y coordinate of upper-left corner
float x2
X coordinate of lower-right corner
float y2
Y coordinate of lower-right corner

::Diagrams::moveobject obj
Move the object to the right position and return the new information
list obj
List of data representing the object

KEYWORDS

diagrams, drawing

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