NAME¶
pie - 2D or 3D pie chart object in a canvas
SYNOPSIS¶
package require
stooop 4.1
package require
switched 2.2
package require
tkpiechart 6.6
stooop::new pie canvas x y ?options?
switched::configure pieObject ?options?
switched::cget pieObject option
stooop::delete pieObject
pie::newSlice
pieObject ?labelText?
pie::deleteSlice
pieObject sliceObject
pie::sizeSlice
pieObject sliceObject unitShare
?displayedValue?
pie::labelSlice
pieObject sliceObject string
pie::selectedSlices
pieObject
DESCRIPTION¶
A pie object is used to visualize a set of values, usually as shares of a total.
Each value is represented by a colored slice, which may have a 2 dimensional
or 3 dimensional look. Each slice is associated with a label displaying the
data name, and a numerical field showing the percentage taken by the slice.
The labels are placed by the chosen labeler object (
-labeler option).
Each label color matches its related slice.
A pie chart is made of Tk canvas items, found in
pieBoxLabeler,
piePeripheralLabeler and
canvasLabel objects, that compose the
pie object. The pie constructor creates the pie itself and its background
slice within the parent canvas. Once the pie object exists, slices can be
created and resized. At the time the pie is created, the parent Tk
canvas widget must exist.
Slice colors are automatically generated, using a default color list for all
pies, unless another list is used (using the
-colors option). When a 3D
look is used, the slice edge is darker than its top while using the same color
tone.
- stooop::new pie canvas x
y ?options?
- Creates a pie object in the specified Tk canvas. The upper
left corner of the pie is placed at the specified coordinates in the
canvas. The pie object identifier is returned (referred to as
pieObject in this document).
- switched::configure pieObject ?options?
- Configures a pie object or returns all the options with
their current values if no options are passed as parameters.
- switched::cget pieObject option
- Returns an option value for the specified pie object.
- stooop::delete pieObject
- Deletes the specified pie object.
OVERVIEW¶
The pie class is part of the tkpiechart extension that allows the programmer to
create and dynamically update 2D or 3D pie charts in a Tcl/Tk application. The
tkpiechart package is written in Tcl only, using object oriented techniques
thanks to the stooop package, included in tcllib.
OPTIONS¶
- -autoupdate boolean
- Boolean value specifying whether all the slices and their
labels are redrawn when a slice size is changed. On by default. Turn it
off and invoke pie::update if you change many slices at once and
want to improve performance.
- -background color
- Slices may or may not fill up the 100% of the pie. The
unoccupied part of the pie is a slice that takes 100% of the pie. It is by
default transparent with a black border. The color of this background
slice may be set by the user using color names as in the
-background standard option (see the Tk options manual page
for more details). When the pie has a 3D look, the background of a slice
edge is darker than the top and uses the same color tone.
- -colors list
- Specifies a list of colors for slices. In this case, the
slice colors will successively be drawn from the list in the list order,
cycling through if there are more slices than colors in the list. Colors
are specified in the same format as the -background option.
- -height value
- Specifies the total height for the pie, including the room
taken by the labeler labels. The pie slices are resized when labels are
added or deleted (when adding or deleting slices) so that the total height
remains constant. This value may be specified in any of the forms
described in the canvas COORDINATES manual section.
- -labeler object
- Specifies a placer object for the slice labels, so that,
for example, slice values may be placed next to them. If not specified,
the pieBoxLabeler (see corresponding manual) is used, the other
option being the piePeripheralLabeler class. Each labeler has a
specific behavior which may be set via its options. The labeler object is
automatically deleted when the pie object is itself deleted. The labeler
cannot be changed once the pie is created.
- -selectable boolean
- Boolean value specifying whether slices are selectable or
not. Acceptable values are those defined by the Tcl language itself for
boolean values. If selectable, slices can be selected with the first mouse
button, by clicking on either the slice or its label. Selection can be
extended by using the classical control or shift clicks. The
list of currently selected slices can be retrieved at any time using the
selectedSlices pie class member procedure.
- -title text
- Title text to be placed above the pie.
- -titlefont value
- Font for the title text.
- -titleoffset value
- Distance between the bottom of the title text and the top
of the pie slices. This value may be specified in any of the forms
described in the sizes section below.
- -thickness value
- The thickness is set to 0 by default, giving the pie a
simple 2D shape, much faster to display. A positive thickness value will
give the pie a 3D look with matched darker colors for the slices edges.
These values may be specified in any of the forms described in the
SIZES section below.
- -width value
- Specifies the total width for the pie, including the room
taken by the labeler labels. The pie slices are resized when labels are
added or deleted (when adding or deleting slices) so that the total width
remains constant. This value may be specified in any of the forms
described in the canvas COORDINATES manual section.
MEMBER PROCEDURES¶
- pie::newSlice pieObject ?labelText?
- Creates a slice. A unique object identifier is returned
(referred to as sliceObject in this document). The slice color is
automatically allocated and the slice label placed using the specified
labeler (using the -labeler option). The slice itself is placed
after (clockwise) the existing slices. The slice object identifier will be
used for sizing and resizing the slice.
If the label text is not specified, it will be set to "slice
n", n being the number of the slice in the order of
creation (first slice is number 1).
- pie::deleteSlice pieObject sliceObject
- Deletes a slice. The following slices (clockwise) if any
are then moved to compensate for the empty space left by the deleted
slice.
- pie::sizeSlice pieObject sliceObject
unitShare ?displayedValue?
- Sizes or resizes a slice. The slice is then automatically
recalculated so it occupies the proper share of the whole pie. The
unitShare parameter is a floating point number expressed in share
(between 0 and 1) of the whole pie. The following slices (clockwise) are
moved to accommodate the new slice size. The slice size value next to the
slice label is also updated with the new share value or
displayedValue if specified.
- pie::labelSlice pieObject sliceObject
string
- Updates a slice label. Can be invoked at any time.
- pie::selectedSlices pieObject
- Returns a list of currently selected slice objects.
The whole pie, the pie graphics (all slices), and each slice have the following
specific tags:
- •
- pie(pieObject)
- •
- pieSlices(pieObject)
- •
- slice(sliceObject)
For example, the whole pie can be moved using the
canvas move
command on the pie tag, or bindings on slices can be set using the slice tags
(see the
canvas manual page
ITEM IDS AND TAGS section for more
information).
SIZES¶
All sizes related to pies are stored as floating point numbers. The coordinates
and sizes are specified in screen units, which are floating point numbers
optionally followed by one of several letters as specified in the
canvas COORDINATES manual section.
LIMITATIONS¶
If the number of slices is too big, identical colors will be used for some of
the slices. You may set your own colors in this case.
SEE ALSO¶
canvasLabel, pieBoxLabeler, piePeripheralLabeler
KEYWORDS¶
canvas, labeler, pie, slice
COPYRIGHT¶
Copyright (c) 1995-2004 Jean-Luc Fontaine <jfontain@free.fr>