Tk - Canvas Widgets


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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 −

Sr.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 −

Canvas Widget Example

Widgets for Drawing in Canvas

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

Sr.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 −

Canvas Widget Example2

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