* Initial implementation of alpha blending for gtk, gtk2, qt

git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@1093 8e941d3f-bd1b-0410-a28a-d453659cc2b4

components/virtualtreeview-new/trunk/VTGraphics.pas

@@ -0,0 +1,32 @@
+unit VTGraphics; 
+
+{$mode delphi}
+
+interface
+
+uses
+  DelphiCompat, Types, LCLIntf, LCLType;
+
+type
+  // Describes the mode how to blend pixels.
+  TBlendMode = (
+    bmConstantAlpha,         // apply given constant alpha
+    bmPerPixelAlpha,         // use alpha value of the source pixel
+    bmMasterAlpha,           // use alpha value of source pixel and multiply it with the constant alpha value
+    bmConstantAlphaAndColor  // blend the destination color with the given constant color und the constant alpha value
+  );
+
+
+
+procedure AlphaBlend(Source, Destination: HDC; const R: TRect; const Target: TPoint; Mode: TBlendMode; ConstantAlpha, Bias: Integer);
+
+function CalculateScanline(Bits: Pointer; Width, Height, Row: Integer): Pointer;
+
+function GetBitmapBitsFromBitmap(Bitmap: HBITMAP): Pointer;
+
+implementation
+
+{$i vtgraphicsi.inc}
+
+end.
+