Canvas widgets is used for providing drawing areas in Tk. The syntax for Tk canvas widgets is shown below for −
canvas canvasName options
Options
The options available for the canvas widget are listed below in the following table −
| Sr.No. | Syntax & Description |
|---|---|
| 1 | -background colorUsed to set background color for widget. |
| 2 | -closeenough distanceSets 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 boundingBoxThe bounding box for the total area of this canvas. |
| 4 | -height numberUsed to set height for widget. |
| 5 | -width numberSets the width for widget. |
| 6 | -xscrollincrement sizeThe amount to scroll horizontally when scrolling is requested. |
| 7 | -yscrollincrement sizeThe 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 −
| 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 −
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