How to mix or separate three color channels (Views: 30)
Problem/Question/Abstract: I need to send a picture to 3 separate monochrome monitors in an embedded application I am writing. I could simply allow only one monitor to work at a time but thought it might be possible to drive the RGB outputs separately. This could be achieved by creating 3 pictures, one with red shades, one with green shades and one with blue shades and blending them together. I could do this by mixing the pictures pixel by pixel but suspect this would be extremely slow. Answer: But it's the only way (all other ways I can think of go back to the same). Use scanline and it is not that "extremely slow": { ... } var Ptr1, Ptr2, Ptr3: ^Byte; PtrMix: ^Byte; X, Y: Integer; begin for Y := 0 to Height - 1 do begin Ptr1 := RedBitmap.ScanLine[Y]; Ptr2 := GreenBitmap.ScanLine[Y]; Ptr3 := BlueBitmap.ScanLine[Y]; PtrMix := MixBitmap.ScanLine[Y]; for X := 0 to Width - 1 do begin PtrMix^ := Ptr1^; Inc(Ptr1); Inc(PtrMix); PtrMix^ := Ptr2^; Inc(Ptr2); Inc(PtrMix); PtrMix^ := Ptr3^; Inc(Ptr3); Inc(PtrMix); end; end; end; Make sure MixBitmap has 24 bit format, Red-, Green- and BlueBitmap have 8 bit format (or change the code for other formats). All bitmaps should have the same size (or use the smallest size for Width and Height). Separating 3 color channels (instead of mixing) is very similar. Simply change PtrMix^ := Ptr1^; to Ptr1^ := PtrMix^; (and for the other channels, too). |