Unfortunately Delphi does not scale TSpeedButton.Glyph. The button surface scaled, but the size of the glyph stay the original. I use the naive approach to scale the bitmap by TCanvas.StretchDraw but the result is disgusting.
I search the internet and I found the GDI+ library where I can define the quality.
The soul of the solution is the TIGPGraphics.DrawImage( image, .... )
But here image is an TIGPImage instance. It has no constructor with a TBitmap parameter, it has no property to copy a TBitmap into it. I don't want to stream the bitmap just to pass it for the TIGPImage constructor. Can somebody help me to create the GP image by a TBitmap contents and stretched draw it to another TBitmap (SpeedButtonX.glyph).
I don't stick to GDI plus, I interested in other solutions as well while the result will be better then with TCanvas.StrechDraw.
I downloaded the GPIPlusMod library from here : https://github.com/jackdp/IGDIPlusMod