再学 GDI+[77]: 区域(6) - GetRegionScans - 获取区域中的所有矩形

最新推荐文章于 2024-12-11 17:22:10 发布

转载最新推荐文章于 2024-12-11 17:22:10 发布 · 189 阅读

本文介绍了一个使用GDIP(Graphics Device Interface Plus)在窗体上绘制随机彩色图案的示例程序。通过创建不同的画刷颜色并填充由路径定义的椭圆区域内的矩形，实现了视觉上丰富的效果。

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本例效果图:

代码文件:

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    procedure FormPaint(Sender: TObject);
    procedure FormClick(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

uses GDIPOBJ, GDIPAPI;

procedure TForm1.FormPaint(Sender: TObject);
var
  g: TGPGraphics;
  b: TGPSolidBrush;
  path: TGPGraphicsPath;
  rgn: TGPRegion;
  Matrix: TGPMatrix;
  RectCount: Integer;
  rts: array of TGPRect;
  i: Integer;
begin
  g := TGPGraphics.Create(Canvas.Handle);
  b := TGPSolidBrush.Create(MakeColor(50, 0, 0, 255));

  path := TGPGraphicsPath.Create;
  path.AddEllipse(MakeRect(20, 10, ClientWidth-40, ClientHeight-20));
  rgn := TGPRegion.Create(path);

  Matrix := TGPMatrix.Create; {它在本例中只是个摆设, 因为参选需要}

  RectCount := rgn.GetRegionScansCount(Matrix);
  SetLength(rts, RectCount);
  rgn.GetRegionScans(Matrix, PGPRect(rts), RectCount);

  Randomize;
  for i := 0 to RectCount - 1 do
  begin
    b.SetColor(ColorRefToARGB(Random($FFFFFF)));
    g.FillRectangle(b, rts[i]);
  end;

  Matrix.Free;
  rgn.Free;
  path.Free;
  b.Free;
  g.Free;
end;

procedure TForm1.FormClick(Sender: TObject);
begin
  Repaint;
end;

end.

窗体文件:

object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 217
  ClientWidth = 219
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  Position = poDesktopCenter
  OnClick = FormClick
  OnPaint = FormPaint
  PixelsPerInch = 96
  TextHeight = 13
end