How to apply the Windows Shutdown screen effect to a bitmap (Views: 33)
Problem/Question/Abstract: I would like to apply this "screening" effect to a bitmap. I have tried PatBlt, DrawState, and BitBlt, but I don't know what combination of params I need. Answer: Create an 8 x 8 bitmap, where the pixels alternate black and white (as in a checkerboard). Load that bitmap into the Brush.Bitmap property of whatever Canvas it is that you're trying to modify. Set the canvas's CopyMode to $00A000C9. (This ANDs the destination with the pattern). Use CopyRect to draw the canvas onto itself. Example: var Bmp: TBitmap; begin Bmp := TBitmap.Create; Bmp.LoadFromFile('brush.bmp'); with Image1.Picture.Bitmap do begin Canvas.Brush.Bitmap := Bmp; Canvas.CopyMode := $00A000C9; Canvas.CopyRect(Rect(0, 0, Width, Height), Canvas, Rect(0, 0, 0, 0)); end; Bmp.Free; end; |