Hi Alex,

I gave the following script:

Smalltalk compiler evaluate: '
| surface |
surface := AthensCairoSurface extent: 640@480.
surface drawDuring: [ :canvas |
������ surface clear: Color blue.
].

surface asForm asMorph openInWindow
'

Notice that I am wrapping the script in a string that I am passing to the compiler, so that the workspace cannot retain any reference to the surface.

Best regards,
Ronie

2017-03-14 16:12 GMT-03:00 Alexandre Bergel <alexandre.bergel@me.com>:
Hi Ronie,

Below you said:
The problem with asForm, is that the form returned can be used after the cairo surface which holds the pixels is garbage collected.

I cannot reproduce this case. You gave a script:

surface := AthensCairoSurface extent: 640@480.
surface drawDuring: [ :canvas |
������ surface clear: Color blue.
].

surface asForm asMorph openInWindow

I see a blue window.

Cheers,
Alexandre


How about changing AthensCairoSurface >> asForm into the following definition?:
asForm

������ "create a form and copy an image data there"
������ | form |
������ self checkSession.
��������
������ self flush.
������ form := Form extent: (self width@self height) depth: 32.
������ form unhibernate.
������ LibC memCopy: self getDataPtr to: form bits size: self width*self height*4.
������ ^ form

This involves a whole copy, but it removes completely the dependency on the surface plugin.

If we want to keep using the surface plugin with Cairo, the old definition of asForm still has a bug, which can be reproduced with the following snippet:

Smalltalk compiler evaluate: '
| surface |
surface := AthensCairoSurface extent: 640@480.
surface drawDuring: [ :canvas |
������ surface clear: Color blue.
].

surface asForm asMorph openInWindow
'

The problem with asForm, is that the form returned can be used after the cairo surface which holds the pixels is garbage collected.