BGRABitmap图像操作13：标准坐标系统下像素级别例子

翻译于 2016-10-06 17:17:19 发布 · 707 阅读

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本文介绍如何使用Delphi在窗体上绘制简单的图形，包括使用TBGRABitmap类创建位图、清除背景并绘制带有边框的椭圆，最后将绘制好的图形拉伸显示。

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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 image: TBGRABitmap;
begin
  image := TBGRABitmap.Create(10,10);
  with image.Canvas do
  begin
    //clear with white
    brush.color := clWhite;
    FillRect(0,0,image.width,image.height);
    //blue ellipse with black border
    brush.style := bsClear;
    pen.color := clBlack;
    Ellipse(0,0,9,9);
  end;
  // stretch the image so we can see the pixels
  BGRAReplace(image,image.Resample(image.Width*10,image.Height*10,rmSimpleStretch));
  image.Draw(Canvas,0,0,True);
  image.free;
end;

end.