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//-------------------------------------
// 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) ; #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 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
#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
//-----------------
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