pie(n) tkpiechart pie class pie(n)
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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
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DESCRIPTION
A pie object is used to visualize a set of values, usually as shares of a total. Each value is repre-sented represented
sented by a colored slice, which may have a 2 dimensional or 3 dimensional look. Each slice is asso-ciated associated
ciated 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 dynami-cally dynamically
cally 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 dis-play. display.
play. 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.
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 accom-modate accommodate
modate 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.
TAGS
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 speci-fied specified
fied 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>
tkpiechart 6.6 pie(n)
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