再学 GDI+[82]: TGPImage(2) GetThumbnailImage 略缩图

本例效果图:

---

代码文件:

---

unit Unit1;

interface

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

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

var
  Form1: TForm1;

implementation

{$R *.dfm}

uses GDIPOBJ, GDIPAPI;

procedure TForm1.FormPaint(Sender: TObject);
var
  g: TGPGraphics;
  img,imgSmall: TGPImage;
begin
  g := TGPGraphics.Create(Self.Canvas.Handle);

  img := TGPImage.Create('C:\temp\test.png');

  {如果图像没有携带略缩图, 将缩放生成; 略缩图一般不应超过 120*120}
  imgSmall := img.GetThumbnailImage(32, 32, nil, nil);

  g.DrawImage(img, 0, 0, img.GetWidth, img.GetHeight);
  g.DrawImage(imgSmall, img.GetWidth + 4, 0, imgSmall.GetWidth, imgSmall.GetHeight);

  imgSmall.Free;
  img.Free;
  g.Free;
end;

end.

窗体文件:

---

object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 151
  ClientWidth = 230
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  OnPaint = FormPaint
  PixelsPerInch = 96
  TextHeight = 13
end