Valdas Jankūnas wrote:
> Marc Weustink rašė:
>
>> A faster way, (which might work in most cases) is when you have a 24bit
>> depth description with a 32bits per pixel image.
>
> How retrieve image description from TBitmap?
IntfImage.DataDescription
>
>> Then you can simply add
>> an alpha description (precision=8, shift=24 or 0) to the rawimage.
>
> How i can do that?
if Description.BitsPerPixel = 32
then begin
if (Description.RedShift <> 0)
and (Description.BlueShift <> 0)
and (Description.GreenShift <> 0)
then begin
Description.AlphaPrec := 8;
Description.AlphaShift := 0;
end
else
if (Description.RedShift <> 24)
and (Description.BlueShift <> 24)
and (Description.GreenShift <> 24)
then begin
Description.AlphaPrec := 8;
Description.AlphaShift := 24;
end;
end;
>> Another thing, I'm not sure if loading form IntfImage/RawImage sets the
>> right pixelformat (and thus image description).
>> Anyway, maybe the bmp is OK. How do you paint it ?
>
> I use Canvas.Draw method.
Bmp.Canvas.Draw(bitmap) draws in the dept of bmp and not the depth of
bitmap. This means if bmp is only created it has pixelformat=pfDevice.
Currently that creates a context(and canvas) without alpha channel)
> I found another solution to not use a proxy image, but load resource
> from stream directly to LazIntfImage (created with
> Init_BPP32_B8G8R8A8_BIO_TTB description). Now i always got alpha channel
> and code is flexible to various image types (need just change image
> reader type). I thing il stay with this solution.
Thats ways faster.
Marc
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