asp.net中C实现缩放图片的例子

时间：2022-06-25 08:14:14 编辑：袖梨来源：一聚教程网

头文件:

代码如下	复制代码
#include #include #include #include "gdiplus.h" #include using namespace Gdiplus; #pragma comment(lib, "gdiplus.lib")

CPP:

代码如下

复制代码

int GetEncoderClsid(const WCHAR* format, CLSID* pClsid)
{
UINT num = 0; // number of image encoders
UINT size = 0; // size of the image encoder array in bytes

ImageCodecInfo* pImageCodecInfo = NULL;

GetImageEncodersSize(&num, &size);
if(size == 0)
return -1; // Failure www.111com.net

pImageCodecInfo = (ImageCodecInfo*)(malloc(size));
if(pImageCodecInfo == NULL)
return -1; // Failure

GetImageEncoders(num, size, pImageCodecInfo);

for(UINT j = 0; j {
if( wcscmp(pImageCodecInfo[j].MimeType, format) == 0 )
{
*pClsid = pImageCodecInfo[j].Clsid;
free(pImageCodecInfo);
return j; // Success
}
}

free(pImageCodecInfo);
return -1; // Failure
}

void DrawMainWindow(Image* img,int w,int h)
{
HDC hDC = GetDC(AfxGetMainWnd()->m_hWnd);
if (hDC)
{
Graphics graphics(hDC);
graphics.DrawImage(img,w,h,img->GetWidth(),img->GetHeight());
ReleaseDC(AfxGetMainWnd()->m_hWnd,hDC);
}

}

void GetThumbnail(LPCSTR srcFile,LPCSTR dstFile,int width,int height,bool constRatio)
{
GdiplusStartupInput gdiplusStartupInput;
ULONG_PTR gdiplusToken;
GdiplusStartup(&gdiplusToken,&gdiplusStartupInput,NULL);

USES_CONVERSION;
Image srcImage(A2W(srcFile));
Image *dstImage;

int srcWidth = srcImage.GetWidth();
int srcHeight = srcImage.GetHeight();

if( constRatio ){
if ( width / srcWidth height = width * srcHeight / srcWidth;
}
else {
width = height * srcWidth / srcHeight;
}
}
dstImage = srcImage.GetThumbnailImage(width,height);

CLSID imgClsid;
GetEncoderClsid(L"image/jpeg",&imgClsid);
dstImage->Save(A2W(dstFile),&imgClsid,NULL);

DrawMainWindow(&srcImage,0,0);
DrawMainWindow(dstImage,0,srcImage.GetHeight()+10);
delete dstImage;
dstImage = NULL;

//GdiplusShutdown(gdiplusToken);
}

使用方法:

代码如下	复制代码
GetThumbnail("image.jpg","cc.jpg",200,80,TRUE);

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