2015-02-05 6:29 GMT+01:00 Sean P. DeNigris <sean@clipperadams.com>:
The following works as I expect:
morph := Morph new topLeft: 200@400; openInWorld.
outputRect := morph fullBounds. canvas := Display defaultCanvasClass extent: outputRect extent depth: Display depth. scale := 1. t := MorphicTransform offset: outputRect topLeft angle: 0 scale: scale. clipRect := outputRect translateBy: outputRect topLeft negated. canvas transformBy: t clippingTo: clipRect during: [ :aCanvas | aCanvas fullDrawMorph: morph ]. canvas form asMorph openInWindow.
"morph delete."
but if I change scale even a little bit (e.g. 0.95), things quickly go south. Check out scale = 1 vs scale = 0.95 below: <http://forum.world.st/file/n4803830/Screenshot_2015-02-05_00.png> Obviously they differ by more than I expected. If I change scale to 0.5, the morph disappears from view in the canvas completely.
I had both translation and scale working in a spike by translating with FormCanvas>>#translateBy:during: and then magifying with "canvas form magnifyBy: 0.5", but I want to do this in my morph's drawing method, so I want to do both with the canvas.
Where am I going wrong here?
The scaling factor changes the effective coordinates of the morph Morph topLeft 200@400 scale 0.5 Morph draws itself at 100@200 Therefore your MorphicTransform translates to far away (or not far enough?) morph := EllipseMorph new topLeft: 200@400; openInWorld. outputRect := morph fullBounds. canvas := Display defaultCanvasClass extent: outputRect extent depth: Display depth. scale := 0.5. "scale the offset of the translation too" t := MorphicTransform offset: outputRect topLeft * scale angle: 0 scale: scale. clipRect := outputRect translateBy: outputRect topLeft negated. canvas transformBy: t clippingTo: clipRect during: [ :aCanvas | aCanvas fullDrawMorph: morph ]. canvas form asMorph openInWindow. morph delete. What do you want to achieve? Both magnifyBy: and transformBy:clippingTo:during: (with non-pure-translation) actually do the same, they warp-blitting a form.
----- Cheers, Sean -- View this message in context: http://forum.world.st/Canvas-Transform-Goes-Haywire-if-Scaled-tp4803830.html Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.