//-------------------------------------//  PNGFILE.C -- Image File Functions//-------------------------------------// Copyright 2000, Willem van Schaik.  For conditions of distribution and// use, see the copyright/license/disclaimer notice in png.h#include <windows.h>#include <commdlg.h>#include <stdio.h>#include <stdlib.h>#include "png.h"#include "pngfile.h"#include "cexcept.h"define_exception_type(const char *);extern struct exception_context the_exception_context[1];struct exception_context the_exception_context[1];png_const_charp msg;static OPENFILENAME ofn;static png_structp png_ptr = NULL;static png_infop info_ptr = NULL;// cexcept interfacestatic voidpng_cexcept_error(png_structp png_ptr, png_const_charp msg){   if(png_ptr)     ;#ifndef PNG_NO_CONSOLE_IO   fprintf(stderr, "libpng error: %s\n", msg);#endif   {      Throw msg;   }}// Windows open-file functionsvoid PngFileInitialize (HWND hwnd){    static TCHAR szFilter[] = TEXT ("PNG Files (*.PNG)\0*.png\0")        TEXT ("All Files (*.*)\0*.*\0\0");    ofn.lStructSize       = sizeof (OPENFILENAME);    ofn.hwndOwner         = hwnd;    ofn.hInstance         = NULL;    ofn.lpstrFilter       = szFilter;    ofn.lpstrCustomFilter = NULL;    ofn.nMaxCustFilter    = 0;    ofn.nFilterIndex      = 0;    ofn.lpstrFile         = NULL;          // Set in Open and Close functions    ofn.nMaxFile          = MAX_PATH;    ofn.lpstrFileTitle    = NULL;          // Set in Open and Close functions    ofn.nMaxFileTitle     = MAX_PATH;    ofn.lpstrInitialDir   = NULL;    ofn.lpstrTitle        = NULL;    ofn.Flags             = 0;             // Set in Open and Close functions    ofn.nFileOffset       = 0;    ofn.nFileExtension    = 0;    ofn.lpstrDefExt       = TEXT ("png");    ofn.lCustData         = 0;    ofn.lpfnHook          = NULL;    ofn.lpTemplateName    = NULL;}BOOL PngFileOpenDlg (HWND hwnd, PTSTR pstrFileName, PTSTR pstrTitleName){    ofn.hwndOwner         = hwnd;    ofn.lpstrFile         = pstrFileName;    ofn.lpstrFileTitle    = pstrTitleName;    ofn.Flags             = OFN_HIDEREADONLY;    return GetOpenFileName (&ofn);}BOOL PngFileSaveDlg (HWND hwnd, PTSTR pstrFileName, PTSTR pstrTitleName){    ofn.hwndOwner         = hwnd;    ofn.lpstrFile         = pstrFileName;    ofn.lpstrFileTitle    = pstrTitleName;    ofn.Flags             = OFN_HIDEREADONLY | OFN_OVERWRITEPROMPT;    return GetSaveFileName (&ofn);}// PNG image handler functionsBOOL PngLoadImage (PTSTR pstrFileName, png_byte **ppbImageData,                   int *piWidth, int *piHeight, int *piChannels, png_color *pBkgColor){    static FILE        *pfFile;    png_byte            pbSig[8];    int                 iBitDepth;    int                 iColorType;    double              dGamma;    png_color_16       *pBackground;    png_uint_32         ulChannels;    png_uint_32         ulRowBytes;    png_byte           *pbImageData = *ppbImageData;    static png_byte   **ppbRowPointers = NULL;    int                 i;    // open the PNG input file    if (!pstrFileName)    {        *ppbImageData = pbImageData = NULL;        return FALSE;    }    if (!(pfFile = fopen(pstrFileName, "rb")))    {        *ppbImageData = pbImageData = NULL;        return FALSE;    }    // first check the eight byte PNG signature    fread(pbSig, 1, 8, pfFile);    if (!png_check_sig(pbSig, 8))    {        *ppbImageData = pbImageData = NULL;        return FALSE;    }    // create the two png(-info) structures    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL,      (png_error_ptr)png_cexcept_error, (png_error_ptr)NULL);    if (!png_ptr)    {        *ppbImageData = pbImageData = NULL;        return FALSE;    }    info_ptr = png_create_info_struct(png_ptr);    if (!info_ptr)    {        png_destroy_read_struct(&png_ptr, NULL, NULL);        *ppbImageData = pbImageData = NULL;        return FALSE;    }    Try    {                // initialize the png structure        #if !defined(PNG_NO_STDIO)        png_init_io(png_ptr, pfFile);#else        png_set_read_fn(png_ptr, (png_voidp)pfFile, png_read_data);#endif                png_set_sig_bytes(png_ptr, 8);                // read all PNG info up to image data                png_read_info(png_ptr, info_ptr);                // get width, height, bit-depth and color-type                png_get_IHDR(png_ptr, info_ptr, piWidth, piHeight, &iBitDepth,            &iColorType, NULL, NULL, NULL);                // expand images of all color-type and bit-depth to 3x8 bit RGB images        // let the library process things like alpha, transparency, background                if (iBitDepth == 16)            png_set_strip_16(png_ptr);        if (iColorType == PNG_COLOR_TYPE_PALETTE)            png_set_expand(png_ptr);        if (iBitDepth < 8)            png_set_expand(png_ptr);        if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))            png_set_expand(png_ptr);        if (iColorType == PNG_COLOR_TYPE_GRAY ||            iColorType == PNG_COLOR_TYPE_GRAY_ALPHA)            png_set_gray_to_rgb(png_ptr);                // set the background color to draw transparent and alpha images over.        if (png_get_bKGD(png_ptr, info_ptr, &pBackground))        {            png_set_background(png_ptr, pBackground, PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);            pBkgColor->red   = (byte) pBackground->red;            pBkgColor->green = (byte) pBackground->green;            pBkgColor->blue  = (byte) pBackground->blue;        }        else        {            pBkgColor = NULL;        }                // if required set gamma conversion        if (png_get_gAMA(png_ptr, info_ptr, &dGamma))            png_set_gamma(png_ptr, (double) 2.2, dGamma);                // after the transformations have been registered update info_ptr data                png_read_update_info(png_ptr, info_ptr);                // get again width, height and the new bit-depth and color-type                png_get_IHDR(png_ptr, info_ptr, piWidth, piHeight, &iBitDepth,            &iColorType, NULL, NULL, NULL);                        // row_bytes is the width x number of channels                ulRowBytes = png_get_rowbytes(png_ptr, info_ptr);        ulChannels = png_get_channels(png_ptr, info_ptr);                *piChannels = ulChannels;                // now we can allocate memory to store the image                if (pbImageData)        {            free (pbImageData);            pbImageData = NULL;        }        if ((pbImageData = (png_byte *) malloc(ulRowBytes * (*piHeight)                            * sizeof(png_byte))) == NULL)        {            png_error(png_ptr, "Visual PNG: out of memory");        }        *ppbImageData = pbImageData;                // and allocate memory for an array of row-pointers                if ((ppbRowPointers = (png_bytepp) malloc((*piHeight)                            * sizeof(png_bytep))) == NULL)        {            png_error(png_ptr, "Visual PNG: out of memory");        }                // set the individual row-pointers to point at the correct offsets                for (i = 0; i < (*piHeight); i++)            ppbRowPointers[i] = pbImageData + i * ulRowBytes;                // now we can go ahead and just read the whole image                png_read_image(png_ptr, ppbRowPointers);                // read the additional chunks in the PNG file (not really needed)                png_read_end(png_ptr, NULL);                // and we're done                free (ppbRowPointers);        ppbRowPointers = NULL;                // yepp, done    }    Catch (msg)    {        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);        *ppbImageData = pbImageData = NULL;                if(ppbRowPointers)            free (ppbRowPointers);        fclose(pfFile);        return FALSE;    }    fclose (pfFile);    return TRUE;}BOOL PngSaveImage (PTSTR pstrFileName, png_byte *pDiData,                   int iWidth, int iHeight, png_color bkgColor){    const int           ciBitDepth = 8;    const int           ciChannels = 3;    static FILE        *pfFile;    png_uint_32         ulRowBytes;    static png_byte   **ppbRowPointers = NULL;    int                 i;    // open the PNG output file    if (!pstrFileName)        return FALSE;    if (!(pfFile = fopen(pstrFileName, "wb")))        return FALSE;    // prepare the standard PNG structures    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL,      (png_error_ptr)png_cexcept_error, (png_error_ptr)NULL);    if (!png_ptr)    {        fclose(pfFile);        return FALSE;    }    info_ptr = png_create_info_struct(png_ptr);    if (!info_ptr) {        fclose(pfFile);        png_destroy_write_struct(&png_ptr, (png_infopp) NULL);        return FALSE;    }    Try    {        // initialize the png structure        #if !defined(PNG_NO_STDIO)        png_init_io(png_ptr, pfFile);#else        png_set_write_fn(png_ptr, (png_voidp)pfFile, png_write_data, png_flush);#endif                // we're going to write a very simple 3x8 bit RGB image                png_set_IHDR(png_ptr, info_ptr, iWidth, iHeight, ciBitDepth,            PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE,            PNG_FILTER_TYPE_BASE);                // write the file header information                png_write_info(png_ptr, info_ptr);                // swap the BGR pixels in the DiData structure to RGB                png_set_bgr(png_ptr);                // row_bytes is the width x number of channels                ulRowBytes = iWidth * ciChannels;                // we can allocate memory for an array of row-pointers                if ((ppbRowPointers = (png_bytepp) malloc(iHeight * sizeof(png_bytep))) == NULL)            Throw "Visualpng: Out of memory";                // set the individual row-pointers to point at the correct offsets                for (i = 0; i < iHeight; i++)            ppbRowPointers[i] = pDiData + i * (((ulRowBytes + 3) >> 2) << 2);                // write out the entire image data in one call                png_write_image (png_ptr, ppbRowPointers);                // write the additional chunks to the PNG file (not really needed)                png_write_end(png_ptr, info_ptr);                // and we're done                free (ppbRowPointers);        ppbRowPointers = NULL;                // clean up after the write, and free any memory allocated                png_destroy_write_struct(&png_ptr, (png_infopp) NULL);                // yepp, done    }    Catch (msg)    {        png_destroy_write_struct(&png_ptr, (png_infopp) NULL);        if(ppbRowPointers)            free (ppbRowPointers);        fclose(pfFile);        return FALSE;    }        fclose (pfFile);        return TRUE;}#ifdef PNG_NO_STDIOstatic voidpng_read_data(png_structp png_ptr, png_bytep data, png_size_t length){   png_size_t check;   /* fread() returns 0 on error, so it is OK to store this in a png_size_t    * instead of an int, which is what fread() actually returns.    */   check = (png_size_t)fread(data, (png_size_t)1, length,      (FILE *)png_ptr->io_ptr);   if (check != length)   {      png_error(png_ptr, "Read Error");   }}static voidpng_write_data(png_structp png_ptr, png_bytep data, png_size_t length){   png_uint_32 check;   check = fwrite(data, 1, length, (FILE *)(png_ptr->io_ptr));   if (check != length)   {      png_error(png_ptr, "Write Error");   }}static voidpng_flush(png_structp png_ptr){   FILE *io_ptr;   io_ptr = (FILE *)CVT_PTR((png_ptr->io_ptr));   if (io_ptr != NULL)      fflush(io_ptr);}#endif//-----------------//  end of source//-----------------