/*-------------------------------------
 *  PNGFILE.C -- Image File Functions
 *-------------------------------------
 *
 * Copyright 2000,2017 Willem van Schaik.
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
 * and license in png.h
 */

#include <windows.h>
#include <commdlg.h>
#include <stdio.h>
#include <stdlib.h>
#include <zlib.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)
     ;
#ifdef PNG_CONSOLE_IO_SUPPORTED
   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_sig_cmp(pbSig, 0, 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 */

#ifdef PNG_STDIO_SUPPORTED
        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 */
        /* let the library process alpha, transparency, background, etc. */

#ifdef PNG_READ_16_TO_8_SUPPORTED
    if (iBitDepth == 16)
#  ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
        png_set_scale_16(png_ptr);
#  else
        png_set_strip_16(png_ptr);
#  endif
#endif
        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 are 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 ((*piHeight) > ((size_t)(-1))/ulRowBytes) {
        {
            png_error(png_ptr, "Visual PNG: image is too big");
        }
        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 */

#ifdef PNG_STDIO_SUPPORTED
        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;
}

#ifndef PNG_STDIO_SUPPORTED

static void
png_read_data(png_structp png_ptr, png_bytep data, size_t length)
{
   size_t check;

   /* fread() returns 0 on error, so it is OK to store this in a size_t
    * instead of an int, which is what fread() actually returns.
    */
   check = fread(data, 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, 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
 *-----------------
 */