flexalpha.int

FlexGraphics是一套创建矢量图形的VCL组件

/////////////////////////////////////////////////////////
//                                                     //
//    FlexGraphics library                             //
//    Copyright (c) 2002-2009, FlexGraphics software.  //
//                                                     //
//    Alpha blending buffer support                    //
//                                                     //
/////////////////////////////////////////////////////////

unit FlexAlpha;

{$I FlexDefs.inc}

interface

uses
  Windows, Classes, Graphics;

type
  PAlphaLine = ^TAlphaLine;
  TAlphaLine = array[0..MaxInt div SizeOf(TRGBQuad)-1] of TRGBQuad;

  TStoreDrawEvent = procedure(Sender: TObject; Canvas: TCanvas;
    Graphic: TGraphic) of object;

  TAlphaBuffer = class
  private
   FParent: TAlphaBuffer;
   FSourceDC: HDC;
   FCanvas: TCanvas;
   FCanvasDC: HDC;
   FCanvasDCBitmap: HBitmap;
   FPaintRect: TRect;
   FPaintWidth: integer;
   FPaintHeight: integer;
   FWidth: integer;
   FHeight: integer;
   FBits: PAlphaLine;
   FBytesPerLine: integer;
   FInfo: TBitmapInfo;
   FHandle: HBitmap;
   FStored: boolean;
  protected
   procedure ResetCanvas(DeleteDIB: boolean = false);
   procedure RecreateDIB(AWidth, AHeight: integer;
     ForceRecreate: boolean = false; FillColor: cardinal = $FF000000);
  public
   constructor Create(AParent: TAlphaBuffer = Nil);
   destructor Destroy; override;
   function  BeginPaint(ASourceDC: HDC;
     const APaintRect: TRect): boolean; virtual;
   function  EndPaint(Transparency: integer): boolean; virtual;
   function  StoreFromGraphic(Graphic: TGraphic;
     OnDraw: TStoreDrawEvent = Nil): boolean;
   function  PaintStored(Dest: TAlphaBuffer; const APaintRect,
     ASrcRect: TRect): boolean;
   property  Canvas: TCanvas read FCanvas;
   property  SourceDC: HDC read FSourceDC;
   property  Handle: HBitmap read FHandle;
   property  Width: integer read FWidth;
   property  Height: integer read FHeight;
  end;

implementation