[news.eclipse.platform.swt] Re: Antialiased rendering on a transparent i

[Matthew Hall <matthall@xxxxxxxxxxxxxxxxx>]

Kirill Grouchnikov wrote:
> I can't say that i agree with this approach. There are two cases:
>
> 1. Black foreground. Here, you convert all the colored pixels into 
> translucent black. This is not how the native rendering works - the 
> final "outlier" pixels (when they are rendered on screen) should stay 
> colored (bluish, yellowish) to reproduce the native rendering with high 
> fidelity.
> 2. Non-black foreground (say white foreground on black background or any 
> other combination). This is not supported at all.
>
> So, even in the first case you're losing the native rendering fidelity, 
> and the second case is not supported at all.
> Thanks
> Kirill

You won't be able to achieve the same effect as subpixel rendering. 
With ClearType the antialiasing (and associated alpha blending) is done 
per subpixel.  With an ImageData the alpha blending appies to the entire 
pixel.  They just don't work the same way.  I tried it and it didn't 
look right.

For case 2, an approach that will work is to draw the swtImage in black 
on white, do a pass to set all your alphas, and do a second pass to just 
set the entire image to the intended foreground color.

Matthew