ThumbNail.cpp

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#include <stdio.h>
#include <gd.h>
#include <dcl/core/String.h>
 
#if __DCL_HAVE_THIS_FILE__
#undef __THIS_FILE__
static const char_t __THIS_FILE__[] = L"fastpage/ThumbNail.cpp";
#endif
 
__DCL_BEGIN_NAMESPACE
 
// result ContentType
//      image/jpeg
 
bool GenThumbnailImage(
    const char* pszSrcFile,
    const char* pszContentType,
    const char* pszThumbnailFile,
    int nSize // = 110
)
{
    __DCL_ASSERT(pszSrcFile != NULL);
    __DCL_ASSERT(pszContentType != NULL);
    __DCL_ASSERT(pszThumbnailFile != NULL);
 
    for( ; *pszContentType; pszContentType++) {
        if (*pszContentType == '/')
        {
            pszContentType++;
            break;
        }
    }
 
#define IMAGE_UNKNOWN 0
#define IMAGE_JPEG  1
#define IMAGE_GIF   2
#define IMAGE_PNG   3
 
    int nSrcType = IMAGE_UNKNOWN;
    if (String::compareNoCase(pszContentType, L"jpeg") == 0
        || String::compareNoCase(pszContentType, L"pjpeg") == 0)
        nSrcType = IMAGE_JPEG;
    else if (String::compareNoCase(pszContentType, L"gif") == 0)
        nSrcType = IMAGE_GIF;
    else if (String::compareNoCase(pszContentType, L"png") == 0)
        nSrcType = IMAGE_PNG;
 
    if (nSrcType == IMAGE_UNKNOWN)
        return false;
 
    gdImagePtr inImage = NULL;
    FILE* inFile = fopen(pszSrcFile, L"rb");
    if (!inFile)
        return false;
 
    switch(nSrcType) {
        case IMAGE_JPEG :
            inImage = gdImageCreateFromJpeg(inFile);
            break;
        case IMAGE_GIF :
            inImage = gdImageCreateFromGif(inFile);
            break;
        case IMAGE_PNG :
            inImage = gdImageCreateFromPng(inFile);
            break;
        default :
            __DCL_ASSERT(false);
    }
    fclose(inFile);
 
    if (!inImage)
        return false;
 
    int nWidth;
    int nHeight;
    if (gdImageSX(inImage) > nSize || gdImageSY(inImage) > nSize) {
        double fRate = 1.0;
        if (gdImageSX(inImage) >= gdImageSY(inImage))
            fRate = (double)nSize / (double)gdImageSX(inImage);
        else
            fRate = (double)nSize / (double)gdImageSY(inImage);
 
        nWidth = (int)(((double)gdImageSX(inImage)) * fRate);
        nHeight = (int)(((double)gdImageSY(inImage)) * fRate);
    }
    else {
        nWidth = gdImageSX(inImage);
        nHeight = gdImageSY(inImage);
    }
 
    gdImagePtr outImage = gdImageCreateTrueColor(nWidth, nHeight);
    if (!outImage) {
        gdImageDestroy(inImage);
        return false;
    }
 
//  gdImageCopyResized(
    gdImageCopyResampled(
        outImage,       // dst
        inImage,        // src
        0,              // dstX
        0,              // dstY
        0,              // srcX
        0,              // srcY
        nWidth,         // dstW     
        nHeight,            // dstH
        gdImageSX(inImage), // srcW
        gdImageSY(inImage)  // srcH
    );
 
    FILE* outFile = fopen(pszThumbnailFile, L"wb");
    if (!outFile) {
        gdImageDestroy(inImage);
        gdImageDestroy(outImage);
        return false;
    }
    gdImageJpeg(outImage, outFile, -1);
    fclose(outFile);
 
    gdImageDestroy(inImage);
    gdImageDestroy(outImage);
 
    return true;
}
 
__DCL_END_NAMESPACE