[squeak-dev] The Trunk: project view title is all black

> Looks like some of the changes in trunk broke the mechanisms by which
> the project view displays the project name:
>
> I have not yet found the culprit, my suspicion is that this could be a
> side effect of antialiased font rendering.
> The core of the problem is somewhere in the drawing of a string morph on
> a fresh canvas.
> When you execute "(StringMorph contents: 'X') imageForm bits asArray"
> you will get different results in the current trunk image and in a
> 3.10.2 image, for example. I have not yet tried it in other images.

> Hans-Martin Mosner wrote:
>> Looks like some of the changes in trunk broke the mechanisms by which
>> the project view displays the project name:
>>
>> I have not yet found the culprit, my suspicion is that this could be
>> a side effect of antialiased font rendering.
>> The core of the problem is somewhere in the drawing of a string morph
>> on a fresh canvas.
>> When you execute "(StringMorph contents: 'X') imageForm bits asArray"
>> you will get different results in the current trunk image and in a
>> 3.10.2 image, for example. I have not yet tried it in other images.
>
> Correct. I tried to dig in a little and the issue seems to be a result
> of the 16->32 bpp expansion of the anti-aliased font glyphs. An easy
> test case is this:
>
> self assert: ((StringMorph new contents: ' ') imageFormDepth: 32) bits
> first = 0.
>
> It would be interesting to see if this is an artifact of just the
> expansion (in the StrikeFont's glyphs) or if there is more than that.
> If anyone has a 32bpp version of one of the fonts I'd like to try.
>
> Cheers,
>   - Andreas

> Juan Vuletich wrote:
>> The fix is in the trunk. There are several issues here.
>> 1) StringMorphs can not be cached by the hand anymore. This has no
>> relation with the problem you fond, but I found it while testing. So
>> I added StringMorph >> hasTranslucentColor
>
> Makes sense. With anti-aliased fonts the caching logic is way to
> simplistic.
>
>> 2) ProjectViewMorph used #stencil:at:color: to draw the project name.
>> Changed it to #drawImage:at:
>
> Good choice for the moment. It beats an all-black rectangle ;-)
>
>> 3) We have a bug in BitBlt. When using #rgbAdd, alpha values are not
>> actually added. What happens is more like (alpha1+alpha2)>0 ifTrue: [
>> 1.0] ifFalse: [0.0]. The strange thing is that the code seems to be
>> right, and it works ok in the simulator. Just sent an email to VM-Dev
>> asking for help on this. As a workaround, I defined
>> StringMorph>>imageForm:forRectangle: to use a white background
>> instead of a transparent one.
>
> How strange. I saw your post but didn't realize it was related to this
> issue.
>
> In any case thanks for the quick help!
>
> Cheers,
>   - Andreas