Re: [ft] How to draw FT_Bitmap to the ARGB image?

[John Found]

On Wed, 4 Nov 2015 02:59:00 +0100
Wojciech Mamrak <address@hidden> wrote:

> I am afraid this is the property of dual source blending - your
> background must be opaque. If you can't satisfy this condition your
> only option is to store the three alpha channels obtained from FT and
> blend them with background later, when it is opaque (and eventually it
> will be), 

Then why to compute Da from your equations? If the background, is opaque, 
then Da will always be 1.0 (255).

> or use normal alpha blending (one alpha channel).

What you mean here? I am using "normal alpha blending" in the images.
Or you mean to use non-pre-multiplied alpha? I can, if it will help.

BTW, I tried to create some image with black text on transparent background
with sub-pixel antialiasing and I was able to make it with LibreOffice Draw. 
See the attachment: BlackOnTransparent.png

It is not the best quality, but at least does not appears as a black rectangles.


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John Found <address@hidden>

BlackOnTransparent.png
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