//-------------------------------------

//  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 interface

static void

png_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 functions

void 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 functions

BOOL 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_STDIO

static void

png_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 void

png_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 void

png_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

//-----------------