bmpshape.pas

一个delphi制作的mp3播放器！

unit BmpShape;
{
2002/08/22  by ultrared
根据BMP文件创建窗口
注意：
1. BMP文件最左上的一个点颜色作为背景色
2. BmpShape控件只能用在TForm容器上
3. BMP文件可以是256色或者24位色
4。大块背景色必须和背景色绝对相等才能获得正常效果
}
interface

uses
 Forms,Windows, Messages, SysUtils, Classes, Controls, ExtCtrls,Graphics;

type
 TBmpShape = class(TImage)
 private
  { Private declarations }
  BackColor:TColor;//背景颜色
  FColorDither:boolean;//是否允许背景颜色有一定的抖动
  function GetRegion:HRGN;//前景图片的区域
  procedure setColorDither(cd:Boolean);
 protected
  { Protected declarations }
 public
  { Public declarations }
  constructor Create(AOwner:TComponent);override;
  procedure Apply;//使用效果
 published
  { Published declarations }
  property Dither:Boolean read FColorDither write setColorDither;
 end;

procedure Register;

implementation

procedure Register;
begin
 RegisterComponents('Samples', [TBmpShape]);
end;

procedure TBmpShape.setColorDither(cd:Boolean);
begin
 if cd<>FColorDither then
  FColorDither:=cd;
end;

constructor TBmpShape.Create(AOwner:TComponent);
begin
 inherited Create(AOwner);
 BackColor:=RGB(0,0,0);
 FColorDither:=FALSE;
end;

//核心子程序，获得BMP图片的前景区域
function TBmpShape.GetRegion:HRGN;
var
 i,j:integer;
 rgn1,rgn2:HRGN;
 StartY:integer;
 r,g,b,r1,g1,b1:BYTE;
 cc:TColor;
begin
 if Picture.Bitmap<>nil then
 begin
  BackColor:=Picture.Bitmap.Canvas.Pixels[0,0];
  rgn1:=CreateRectRgn(0,0,0,0);
  for i:=0 to Picture.Bitmap.Width-1 do
  begin
   StartY:=-1;
   for j:=0 to Picture.Bitmap.Height-1 do
   begin
    cc:=Picture.Bitmap.Canvas.Pixels[i,j];
    if FColorDither then
    begin
     //允许和背景有一定的色差
     r:=(cc and $FF0000) shr 16;
     g:=(cc and $FF00) shr 8;
     b:=cc and $FF;
     r1:=(BackColor and $FF0000) shr 16;
     g1:=(BackColor and $FF00) shr 8;
     b1:=BackColor and $FF;
     if (abs(r-r1)<10) and (abs(g-g1)<10) and (abs(b-b1)<10) then
     begin
      if (StartY>=0) and (j>=StartY) then
      begin
       rgn2:=CreateRectRgn(i,StartY,i+1,j);
       CombineRgn(rgn1,rgn1,rgn2,RGN_OR);
       StartY:=-1;
      end;
     end
     else
     begin
      if Starty<0 then
       StartY:=j
      else if j=(Picture.Bitmap.Height-1) then //最下面一个点
      begin
       rgn2:=CreateRectRgn(i,StartY,i+1,j);
       CombineRgn(rgn1,rgn1,rgn2,RGN_OR);
      end;
     end;
    end
    else //不允许色差
    begin
     if cc=BackColor then
     begin
      if (StartY>=0) and (j>=StartY) then
      begin
       rgn2:=CreateRectRgn(i,StartY,i+1,j);
       CombineRgn(rgn1,rgn1,rgn2,RGN_OR);
       StartY:=-1;
      end;
     end
     else
     begin
      if Starty<0 then
       StartY:=j
      else if j=(Picture.Bitmap.Height-1) then //最下面一个点
      begin
       rgn2:=CreateRectRgn(i,StartY,i+1,j);
       CombineRgn(rgn1,rgn1,rgn2,RGN_OR);
      end;
     end;
    end;
   end;
  end;
  result:=rgn1;
 end
 else
  result:=0;
end;

procedure TBmpShape.Apply;
begin
 if Parent is TForm then
 begin
  Left:=0;
  Top:=0;
  Width:=Picture.Bitmap.Width;
  Height:=Picture.Bitmap.Height;
  with (Parent as Tform) do
  begin
   BorderStyle:=bsNone;
   Width:=Self.Width;
   Height:=Self.Height;
  end;
  SetWindowRgn(Parent.Handle,GetRegion,FALSE);
 end;
end;

end.