Load PNG, scale, draw to canvas with transparency

[Thomas Munk]

Is there a build-in way to do the following:
(or do I need an external library?)




(1)  Load a 32-bit PNG-image (with alpha transparency) from disk


(2) Scale this image (up or down) to another in-memory-image, using a quality interpolation, keeping alpha


(3) Draw this in-memory-image to the Form's Canvas, blending with the background (using alpha)




If I didn't need (2) then everything works fine with TPortableNetworkGraphic and Form.Canvas.Draw...

[User137]

The "quality interpolation" part is not possible without external library, or manual pixel calculations. You can try BGRABitmap library, as it is commonly hinted on these forums.