TWICImage 的 Width、Height 屬性, 可以讀取但不能賦值.

調整 TWICImage 的大小、比例, 可以通過 IWICBitmapScaler 介面.

//IWICBitmapScaler.Initialize 函式有四種比例變換的演算法:
WICBitmapInterpolationModeNearestNeighbor = 0;
WICBitmapInterpolationModeLinear     = $1;
WICBitmapInterpolationModeCubic      = $2;
WICBitmapInterpolationModeFant      = $3
 
;

測試程式碼:

unit Unit1;

interface

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

type
 TForm1 = class(TForm)
  Button1: TButton;
  procedure Button1Click(Sender: TObject);
 end;

var
 Form1: TForm1;

implementation

{$R *.dfm}

uses Wincodec;

procedure
 
 TForm1.Button1Click(Sender: TObject);
var
 WicImg: TWICImage;
 Factory: IWICImagingFactory;
 Scaler: IWICBitmapScaler; {影象比例變換介面}
begin
 WicImg := TWICImage.Create;
 WicImg.LoadFromFile('c:\temp\test.jpg');

 Factory := WicImg.ImagingFactory;
 Factory.CreateBitmapScaler(Scaler);

 Scaler.Initialize(WicImg.Handle,
          WicImg.Width div
 
 2, WicImg.Height div 3,
          WICBitmapInterpolationModeFant);

 WicImg.Handle := IWICBitmap(Scaler);
 Canvas.Draw(0, 0, WicImg);

 Scaler := nil;
 Factory := nil;
 WicImg.Free;
end;

end.