4 Canvas

▼ |  | Framework: Racket GUI Application Framework

1 | Framework Libraries Overview
2 | Application
3 | Autosave
4 | Canvas
5 | Color Model
6 | Color Prefs
7 | Color
8 | Comment Box
9 | Decorated Editor Snip
10 | Editor Snip
11 | Editor
12 | Exit
13 | Finder
14 | Frame
15 | Group
16 | GUI Utilities
17 | Handler
18 | Icon
19 | Keymap
20 | Menu
21 | Mode
22 | Notify-boxes
23 | Number Snip
24 | Panel
25 | Pasteboard
26 | Path Utils
27 | Preferences
28 | Preferences, Textual
29 | Racket
30 | Text
31 | Splash
32 | Test
33 | Version
34 | Backwards Compatibility
35 | Signatures
36 | Unit
| Index

On this page:

canvas: basic<%>
canvas: basic-mixin
canvas: color<%>
canvas: color-mixin
canvas: delegate<%>
canvas: delegate-mixin
on-superwindow-show
canvas: info<%>
canvas: info-mixin
on-focus
set-editor
canvas: wide-snip<%>
recalc-snips
add-wide-snip
add-tall-snip
canvas: wide-snip-mixin
on-size
canvas: basic%
canvas: color%
canvas: info%
canvas: delegate%
canvas: wide-snip%

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### 4`` Canvas

interface canvas:basic<%> : interface?
implements: | editor-canvas%

mixin canvas:basic-mixin : (class? . -> . class?)
argument extends/implements: | editor-canvas%
result implements: | canvas:basic<%>

interface canvas:color<%> : interface?
implements: | canvas:basic<%>

Mixins that implement this interface initialize the background color of the canvas to the value of the 'framework:basic-canvas-background preference. Adds a callback so that when that preference is modified, the background color changes.

mixin canvas:color-mixin : (class? . -> . class?)
argument extends/implements: | canvas:basic<%>
result implements: | canvas:color<%>

interface canvas:delegate<%> : interface?
implements: | canvas:basic<%>

This class is part of the delegate window implementation.

mixin canvas:delegate-mixin : (class? . -> . class?)
argument extends/implements: | canvas:basic<%>
result implements: | canvas:delegate<%>

Provides an implementation of canvas:delegate<%>.

> > method (send a-canvas:delegate on-superwindow-show shown?) → void?
> > shown? : boolean?

> Overrides on-superwindow-show in window<%>.
> Notifies the delegate window when the original window is visible. When invisible, the blue highlighting is erased.

interface canvas:info<%> : interface?
implements: | canvas:basic<%>

mixin canvas:info-mixin : (class? . -> . class?)
argument extends/implements: | canvas:basic<%>
result implements: | canvas:info<%>

> > method (send a-canvas:info on-focus) → void?

> Overrides on-focus in editor-canvas%.
> sets the canvas that the frame displays info about.

> > method (send a-canvas:info set-editor) → void?

> Overrides set-editor in editor-canvas%.
> Calls update-info to update the frame’s info panel.

interface canvas:wide-snip<%> : interface?
implements: | canvas:basic<%>

Any canvas% that matches this interface will automatically resize selected snips when its size changes. Use add-tall-snip and add-wide-snip to specify which snips should be resized.

> > method (send a-canvas:wide-snip recalc-snips) → void?

> Recalculates the sizes of the wide snips.

> > method (send a-canvas:wide-snip add-wide-snip snip) → void?
> > snip : (is-a?/c snip%)

> Snips passed to this method will be resized when the canvas’s size changes. Their width will be set so they take up all of the space from their lefts to the right edge of the canvas.

> > method (send a-canvas:wide-snip add-tall-snip snip) → void?
> > snip : (is-a?/c snip%)

> Snips passed to this method will be resized when the canvas’s size changes. Their height will be set so they take up all of the space from their tops to the bottom of the canvas.

mixin canvas:wide-snip-mixin : (class? . -> . class?)
argument extends/implements: | canvas:basic<%>
result implements: | canvas:wide-snip<%>

This canvas maintains a list of wide and tall snips and adjusts their heights and widths when the canvas’s size changes.
The result of this mixin uses the same initialization arguments as the mixin’s argument.

> > > method
> > > (send a-canvas:wide-snip on-size |  | width |  |  |  |
> > > |  | height) |  | → |  | void?
> > width : dimension-integer?
> > height : dimension-integer?

> Overrides on-size in editor-canvas%.
> Adjusts the sizes of the marked snips.

> See add-wide-snip and add-tall-snip.

class canvas:basic% : class?
superclass: (canvas:basic-mixin editor-canvas%)

class canvas:color% : class?
superclass: (canvas:color-mixin canvas:basic%)

class canvas:info% : class?
superclass: (canvas:info-mixin canvas:basic%)

class canvas:delegate% : class?
superclass: (canvas:delegate-mixin canvas:basic%)

class canvas:wide-snip% : class?
superclass: (canvas:wide-snip-mixin canvas:basic%)

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