认识TWICImage类

Graphics 单元新增了 TWICImage 类, 该类的功能源于新增的 Wincodec.pas 单元.

WIC 支持的图像有 BMP、PNG、ICO、JPEG、GIF、TIFF、HDP(HDP 是微软随 Vista 推出的新的图像格式).

TWICImage 的大多功能都非常容易使用, 它最强大的功能是 ImagingFactory: IWICImagingFactory 属性, 这是个类工厂的接口.

通过 TWICImage.ImagingFactory 获取类工厂后, 再调用 CreateBitmapFlipRotator 建立旋转变换接口(IWICBitmapFlipRotator).

然后用 IWICBitmapFlipRotator.Initialize 执行变换, 再把变换后的数据赋给 TWICImage, 至此完成变换.

图片格式的转换：

var
  WicImg: TWICImage;
begin
  WicImg := TWICImage.Create;
  WicImg.LoadFromFile('c:\temp\test.jpg');

  {在窗体上预览图片}
  Canvas.Draw(0, 0, WicImg);

  {转换为 png}
  WicImg.ImageFormat := TWICImageFormat.wifPng;
  WicImg.SaveToFile('c:\temp\test.png');

  WicImg.Free;
end;

图像的旋转变换：

procedure change(kind : Integer);
{
  kind的取值：
  WICBitmapTransformRotate0             = 0;
  WICBitmapTransformRotate90            = $1;
  WICBitmapTransformRotate180           = $2;
  WICBitmapTransformRotate270           = $3;
  WICBitmapTransformFlipHorizontal      = $8;
  WICBitmapTransformFlipVertical        = $10;
}
var
  wicImg : TWICImage;
  factor : IWICImagingFactory;
  flipRotator : IWICBitmapFlipRotator;
begin
  wicImg := TWICImage.Create;
  wicImg.LoadFromFile('C:\Users\Nick\Desktop\1.bmp');
  factor := wicImg.ImagingFactory;
  factor.CreateBitmapFlipRotator(flipRotator);
  flipRotator.Initialize(wicImg.Handle, kind);
  wicImg.Handle := IWICBitmap(flipRotator);

  Form1.Canvas.Draw(0, 0, wicImg);

  flipRotator := nil;
  factor := nil;
  wicImg.Free;
end;

　　　

图像的比例变换：

procedure stretch(kind : Integer);
{
  kind的取值：
  WICBitmapInterpolationModeNearestNeighbor = 0;
  WICBitmapInterpolationModeLinear          = $1;
  WICBitmapInterpolationModeCubic           = $2;
  WICBitmapInterpolationModeFant            = $3;
  WICBITMAPINTERPOLATIONMODE_FORCE_DWORD    = $7FFFFFFF;
}
var
  wicImg : TWICImage;
  factor : IWICImagingFactory;
  scaler : IWICBitmapScaler;
begin
  wicImg := TWICImage.Create;
  wicImg.LoadFromFile('C:\Users\Nick\Desktop\1.bmp');
  factor := wicImg.ImagingFactory;
  factor.CreateBitmapScaler(scaler);
  scaler.Initialize(wicImg.Handle, wicImg.Width * 2, wicImg.Height * 2,
                    kind);
  wicImg.Handle := IWICBitmap(scaler);
  Form1.Canvas.Draw(0, 0, wicImg);

  factor := nil;
  scaler := nil;
  wicImg.Free;
end;

　　

图像的裁剪：

procedure TForm1.Button1Click(Sender: TObject);
var
  WicImg: TWICImage;
  Factory: IWICImagingFactory;
  Clipper: IWICBitmapClipper; {修剪图像的接口}
  r: WICRect;
begin
  WicImg := TWICImage.Create;
  WicImg.LoadFromFile('c:\temp\test.jpg');

  Factory := WicImg.ImagingFactory;
  Factory.CreateBitmapClipper(Clipper);

  r.X := WicImg.Width div 4;
  r.Y := WicImg.Height div 4;
  r.Width := WicImg.Width div 2;
  r.Height := WicImg.Height div 2;
  Clipper.Initialize(WicImg.Handle, r);

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

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