BGRABitmap图像操作5：使用层、遮罩

unit Unit1;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs,
  BGRABitmap, BGRABitmapTypes;

type

  { TForm1 }

  TForm1 = class(TForm)
    procedure FormPaint(Sender: TObject);
  private
    { private declarations }
  public
    { public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.lfm}

{ TForm1 }

procedure TForm1.FormPaint(Sender: TObject);
var temp,tex,mask: TBGRABitmap;
begin
  temp:= TBGRABitmap.Create(640,480,ColorToBGRA(ColorToRGB(clBtnFace)));

  //loading and scaling texture
  tex := TBGRABitmap.Create('3333.jpg');
  BGRAReplace(tex,tex.Resample(128,80));

  //show image in the upper-left corner
  temp.PutImage(10,10,tex,dmDrawWithTransparency);

  //create a mask with ellipse and rectangle
  mask := TBGRABitmap.Create(128,80,BGRABlack);
  mask.FillEllipseAntialias(40,40,30,30,BGRAWhite);
  mask.FillRectAntialias(60,40,100,70,BGRAWhite);

  //show mask in the upper-right corner
  temp.PutImage(150,10,mask,dmDrawWithTransparency);

  //apply the mask to the image
  tex.ApplyMask(mask);

  //show the result image in the lower-left corner
  temp.PutImage(10,100,tex,dmDrawWithTransparency);

  mask.Free;
  tex.Free;

  //show everything on the screen
  temp.Draw(Canvas,0,0,True);
  temp.Free;

end;

end.

转载自：https://blog.csdn.net/bq_cui/article/details/52410629