Karl,

Thanks, "changed" is it ... (embarrassed) I kept looking for flush, redraw, 
reset and similar names .. Milan
On May 2, 2005 12:53 am, karl wrote:
> Milan Zimmermann wrote:
> >On May 1, 2005 05:33 pm, Bert Freudenberg wrote:
> >>Am 01.05.2005 um 19:54 schrieb Milan Zimmermann:
> >>>Hi,
> >>>
> >>>I am trying to paint (draw lines) on Canvas from workspace. I use:
> >>>
> >>>aDrawingForm := Form extent: 400 at 600 depth: Display depth.
> >>>aCanvas := aDrawingForm getCanvas.
> >>>aCanvas fillColor: (Color yellow).
> >>>aDrawingForm asMorph openInWorld.
> >>><Alt-d>
> >>>
> >>>This shows yeallow canvas. Then I do
> >>>
> >>>aCanvas line: 10 at 10 to: 50 at 30 width: 3 color: (Color black).
> >>>aCanvas flush.
> >>><Alt-d>
> >
> ><<snip>>
> >
> >>What your code does is draw into the form of an ImageMorph. Of
> >>course, the Morph does not know that you modified the form. So it
> >>does not repaint itself (that is, copy its form to the Display). It
> >>does redisplay when you move it, however.
> >>
> >>I'm not sure what you're actually trying to achieve. If you want to
> >>draw directly to the display, then use
> >>
> >>     aCanvas := Display getCanvas.
> >
> >Thanks, I tried this, but do not really want to draw on the "basic
> > display" (not sure about the correct name) as it draws on the whole
> > world. Obviously I do not know about the way Squeak graphic works, this
> > is one part of my small project which I use to learn Smalltalk. I should
> > have explained what I am trying to achieve:
> >
> >I am trying to draw (lines, rectangles etc) onto some object that I could
> >manipulate in world as a window or a morph (which would provide clipping
> > as well). The only way I found to do this is to draw on a Canvas inside a
> > form, but obviously failing to make the Canvas changes to tell the
> > container how to refresh (I am sure my terminology is wrong too)
> >
> >I tried to search the Swiki for code examples to do this, but did not get
> > far enough ... so far,
>
> Try sending a 'changed' message to the morph after drawing on it.
> Karl