stretchable-snip

8.12

stretchable-snip🔗ℹ

This package provides mixins to make stretchable snips. Stretchable snups have on-size method, that will be called, when the size of the canvas is changed. It can be used to implement snips, whose view depends on the size of the editor-canvas, such as horizontal rule.

All stretchable snips should implement stretchable<%> and be placed inside stretchable editor-canvas% (either stretchable-editor-canvas%, or result of stretchable-editor-canvas-mixin). To implement stretchable<%> one may use stretchable-snip-mixin or stretchable-snip-static-mixin. If you build stretchable<%>, remember, that on-size is called only when editor’s on-size is called. If your snip may be added to already shown editor, you should also override set-admin. See hr% source for example:

(define hr%
  (class* image-snip% (stretchable<%>)
    (inherit set-bitmap)
    (super-make-object (make-object bitmap% 1 1))
    (define/override (set-admin adm)
      (when adm
        (define-values (w h) (canvas-client-size (send (send adm get-editor) get-canvas)))
        (on-size w h))
      (super set-admin adm))
    (define/public (on-size w h)
      (set-bitmap (draw-line w)))))

canvas-client-size returns correct size of availaible space inside the canvas.

mixin
stretchable-editor-canvas-mixin : (class? . -> . class?)

argument extends/implements:

editor-canvas%

Returns stretchable version of its argument.

class
stretchable-editor-canvas% : class?

superclass: editor-canvas%

A stretchable-editor-canvas% is (stretchable-editor-canvas-mixin editor-canvas%)

interface
stretchable<%> : interface?

The stretchable<%> should be implemented by all snips, whose on-size method shoul be called, when editor’s size changes.

class
hr% : class?

superclass: image-snip%

extends:

stretchable<%>

This is a snip, that display horizontal rule like <HR> tag in HTML.

mixin
stretchable-snip-mixin : (class? . -> . class?)

argument extends/implements:

snip%

Returns stretchable version of its argument with on-size argument.

constructor
(new stretchable-snip-mixin
    [ [on-size on-size]]
    ...superclass-args...)
→ (is-a?/c stretchable-snip-mixin)
   on-size : ((is-a?/c stretchable<%>) dimension-integer? dimension-integer? . -> . any)
= (λ (this w h) (void))
Returns snip with given on-size method

procedure
(stretchable-snip-static-mixin [call-on-size])
→ (make-mixin-contract snip%)
call-on-size : ((is-a?/c stretchable<%>) dimension-integer? dimension-integer? . -> . any)
= (λ (this w h) (void))

Returns stretchable version of its argument with call-on-size, called from the on-size method.

procedure
(canvas-client-size canvas)
→
dimension-integer? dimension-integer?
canvas : (is-a?/c editor-canvas%)

Return client width and height for given canvas. Unlike get-client-size method of window<%>, canvas-client-size subtract canvas’s inset and return available to draw space.