GDI+ 学习记录(29) 区域 - Region

//创建并填充区域
var
  g:TGPGraphics;
  sb:TGPSolidBrush;
  region:TGPRegion;{定义区域}
begin
  g:=TGPGraphics.Create(Canvas.Handle);
  g.Clear(aclWhite);
  sb:=TGPSolidBrush.Create(aclGold);

  region:=TGPRegion.Create(MakeRect(20,20,150,150));{建立区域}

  g.FillRegion(sb,region);{填充区域}


  region.Free;
  sb.Free;
  g.Free;
end;

//根据路径建立区域
var
  g:TGPGraphics;
  path:TGPGraphicsPath;
  region:TGPRegion;
  sb:TGPSolidBrush;
const
  pts:array[0..3] of TGPPoint =
    ((x:10;y:10),
     (x:150;y:10),
     (x:100;y:75),
     (x:100;y:150));

begin
  g:=TGPGraphics.Create(Canvas.Handle);
  g.Clear(aclWhite);
  sb:=TGPSolidBrush.Create(aclRed);
  path:=TGPGraphicsPath.Create();
  path.AddPolygon(pgppoint(@pts),Length(pts));

  region:=TGPRegion.Create(path);//根据路径建立区域
  g.FillRegion(sb,region);

  region.Free;
  path.Free;
  sb.Free;
  g.Free;

end;

//区域联合
var
  g:TGPGraphics;
  region:TGPRegion;
  sb:TGPSolidBrush;
begin
  g:=TGPGraphics.Create(Canvas.Handle);
  g.Clear(aclWhite);
  sb:=TGPSolidBrush.Create(aclRed);
  region:=TGPRegion.Create(MakeRect(60,10,50,150));{建立区域}
  region.Union(MakeRect(10,60,160,50));{区域联合}

  g.FillRegion(sb,region);{填充}

  region.Free;
  sb.Free;
  g.Free;
end;

//用区域剪切画板
var
  g:TGPGraphics;
  p:TGPPen;
  sb:TGPSolidBrush;
  region:TGPRegion;
  font:TGPFont;
begin
  g:=TGPGraphics.Create(Canvas.Handle);
  p:=TGPPen.Create(aclRed);
  sb:=TGPSolidBrush.Create(aclYellowGreen);
  font:=TGPFont.Create('宋体',12);

  region:=TGPRegion.Create(MakeRect(60,0,50,150));{建立区域}
  region.Union(MakeRect(10,60,160,50));{区域联合}

  g.FillRegion(sb,region);

  g.SetClip(region);{用区域剪切画板}

  g.DrawLine(p,0,0,100,100);{测试画板剪切后的直线}

  sb.SetColor(aclBlack);
  g.DrawString('巅枫 巅枫 巅枫 巅枫',-1,font,makepoint(20.0,20.0),sb);{测试文本}

  sb.Free;
  region.Free;
  font.Free;
  p.Free;
  g.Free;

end;