//-------------------------------------
// 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 "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_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
#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
//-----------------