Tk - Canvas Widgets

Canvas is used for providing drawing areas. The syntax for canvas widget is shown below −

canvas canvasName options

Options

The options available for the canvas widget are listed below in the following table −

S.No.	Syntax & Description
1	-background color Used to set background color for widget.
2	-closeenough distance Sets the closeness of mouse cursor to a displayable item. The default is 1.0 pixel. This value may be a fraction and must be positive.
3	-scrollregion boundingBox The bounding box for the total area of this canvas.
4	-height number Used to set height for widget.
5	-width number Sets the width for widget.
6	-xscrollincrement size The amount to scroll horizontally when scrolling is requested.
7	-yscrollincrement size The amount to scroll vertically when scrolling is requested.

A simple example for canvas widget is shown below −

#!/usr/bin/wish

canvas .myCanvas -background red -width 100 -height 100 
pack .myCanvas

When we run the above program, we will get the following output −

Widgets for Drawing in Canvas

The list of the available widgets for drawing in canvas is listed below −

S.No.	Widget & Description
1	Line Draws a line.
2	Arc Draws an arc.
3	Rectangle Draws a rectangle.
4	Oval Draws an oval.
5	Polygon Draws a polygon.
6	Text Draws a text.
7	Bitmap Draws a bitmap.
8	Image Draws an image.

An example using different canvas widgets is shown below −

#!/usr/bin/wish

canvas .myCanvas -background red -width 200 -height 200 
pack .myCanvas
.myCanvas create arc 10 10 50 50 -fill yellow
.myCanvas create line 10 30 50 50 100 10 -arrow both -fill yellow -smooth true
   -splinesteps 2
.myCanvas create oval 50 50 100 80 -fill yellow
.myCanvas create polygon 50 150 100 80 120 120 100 190 -fill yellow -outline green
.myCanvas create rectangle 150 150 170 170  -fill yellow
.myCanvas create text 170 20 -fill yellow -text "Hello" -font {Helvetica -18 bold}
.myCanvas create bitmap 180 50 -bitmap info

When we run the above program, we will get the following output −