/*-------------------------------------

* PNGFILE.C -- Image File Functions

*-------------------------------------

*

* Copyright 2000, 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 ((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, 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

*-----------------

*/