/* ** pngtopnm.c - ** read a Portable Network Graphics file and produce a portable anymap ** ** Copyright (C) 1995,1998 by Alexander Lehmann ** and Willem van Schaik ** ** Permission to use, copy, modify, and distribute this software and its ** documentation for any purpose and without fee is hereby granted, provided ** that the above copyright notice appear in all copies and that both that ** copyright notice and this permission notice appear in supporting ** documentation. This software is provided "as is" without express or ** implied warranty. ** ** modeled after giftopnm by David Koblas and ** with lots of bits pasted from libpng.txt by Guy Eric Schalnat */ #ifndef PNMTOPNG_WARNING_LEVEL # define PNMTOPNG_WARNING_LEVEL 0 /* use 0 for backward compatibility, */ #endif /* 2 for warnings (1 == error) */ #include #include #include /* includes zlib.h and setjmp.h */ #define VERSION "2.37.4 (5 December 1999) +netpbm" #include "pm_c_util.h" #include "mallocvar.h" #include "nstring.h" #include "shhopt.h" #include "pnm.h" typedef struct _jmpbuf_wrapper { jmp_buf jmpbuf; } jmpbuf_wrapper; enum alpha_handling {ALPHA_NONE, ALPHA_ONLY, ALPHA_MIX}; struct cmdlineInfo { /* All the information the user supplied in the command line, in a form easy for the program to use. */ const char *inputFilespec; /* '-' if stdin */ unsigned int verbose; enum alpha_handling alpha; const char * background; float gamma; /* -1.0 means unspecified */ const char * text; unsigned int time; }; typedef struct { /*---------------------------------------------------------------------------- A color in a format compatible with the PNG library. Note that the PNG library declares types png_color and png_color_16 which are similar. -----------------------------------------------------------------------------*/ png_uint_16 r; png_uint_16 g; png_uint_16 b; } pngcolor; static png_uint_16 maxval; static bool verbose; static jmpbuf_wrapper pngtopnm_jmpbuf_struct; static void parseCommandLine(int argc, const char ** argv, struct cmdlineInfo * cmdlineP ) { /*---------------------------------------------------------------------------- Parse program command line described in Unix standard form by argc and argv. Return the information in the options as *cmdlineP. If command line is internally inconsistent (invalid options, etc.), issue error message to stderr and abort program. Note that the strings we return are stored in the storage that was passed to us as the argv array. We also trash *argv. -----------------------------------------------------------------------------*/ optEntry * option_def; /* Instructions to optParseOptions3 on how to parse our options. */ optStruct3 opt; unsigned int option_def_index; unsigned int alphaSpec, mixSpec, backgroundSpec, gammaSpec, textSpec; MALLOCARRAY(option_def, 100); option_def_index = 0; /* incremented by OPTENT3 */ OPTENT3(0, "verbose", OPT_FLAG, NULL, &cmdlineP->verbose, 0); OPTENT3(0, "alpha", OPT_FLAG, NULL, &alphaSpec, 0); OPTENT3(0, "mix", OPT_FLAG, NULL, &mixSpec, 0); OPTENT3(0, "background", OPT_STRING, &cmdlineP->background, &backgroundSpec, 0); OPTENT3(0, "gamma", OPT_FLOAT, &cmdlineP->gamma, &gammaSpec, 0); OPTENT3(0, "text", OPT_STRING, &cmdlineP->text, &textSpec, 0); OPTENT3(0, "time", OPT_FLAG, NULL, &cmdlineP->time, 0); opt.opt_table = option_def; opt.short_allowed = FALSE; /* We have no short (old-fashioned) options */ opt.allowNegNum = FALSE; /* We have no parms that are negative numbers */ optParseOptions3(&argc, (char **)argv, opt, sizeof(opt), 0); /* Uses and sets argc, argv, and some of *cmdlineP and others. */ if (alphaSpec && mixSpec) pm_error("You cannot specify both -alpha and -mix"); else if (alphaSpec) cmdlineP->alpha = ALPHA_ONLY; else if (mixSpec) cmdlineP->alpha = ALPHA_MIX; else cmdlineP->alpha = ALPHA_NONE; if (backgroundSpec && !mixSpec) pm_error("-background is useless without -mix"); if (!backgroundSpec) cmdlineP->background = NULL; if (!gammaSpec) cmdlineP->gamma = -1.0; if (!textSpec) cmdlineP->text = NULL; if (argc-1 < 1) cmdlineP->inputFilespec = "-"; else if (argc-1 == 1) cmdlineP->inputFilespec = argv[1]; else pm_error("Program takes at most one argument: input file name. " "you specified %d", argc-1); } static png_uint_16 get_png_val(const png_byte ** const pp, int const bit_depth) { png_uint_16 c; if (bit_depth == 16) c = (*((*pp)++)) << 8; else c = 0; c |= (*((*pp)++)); return c; } static bool isGrayscale(pngcolor const color) { return color.r == color.g && color.r == color.b; } static void setXel(xel * const xelP, pngcolor const foreground, pngcolor const background, enum alpha_handling const alpha_handling, png_uint_16 const alpha) { if (alpha_handling == ALPHA_ONLY) { PNM_ASSIGN1(*xelP, alpha); } else { if ((alpha_handling == ALPHA_MIX) && (alpha != maxval)) { double const opacity = (double)alpha / maxval; double const transparency = 1.0 - opacity; pngcolor mix; mix.r = foreground.r * opacity + background.r * transparency + 0.5; mix.g = foreground.g * opacity + background.g * transparency + 0.5; mix.b = foreground.b * opacity + background.b * transparency + 0.5; PPM_ASSIGN(*xelP, mix.r, mix.g, mix.b); } else PPM_ASSIGN(*xelP, foreground.r, foreground.g, foreground.b); } } static png_uint_16 gamma_correct(png_uint_16 const v, float const g) { if (g != -1.0) return (png_uint_16) ROUNDU(pow((double) v / maxval, (1.0 / g)) * maxval); else return v; } static int iscolor (png_color c) { return c.red != c.green || c.green != c.blue; } static void save_text (png_info *info_ptr, FILE *tfp) { int i, j, k; for (i = 0 ; i < info_ptr->num_text ; i++) { j = 0; while (info_ptr->text[i].key[j] != '\0' && info_ptr->text[i].key[j] != ' ') j++; if (info_ptr->text[i].key[j] != ' ') { fprintf (tfp, "%s", info_ptr->text[i].key); for (j = strlen (info_ptr->text[i].key) ; j < 15 ; j++) putc (' ', tfp); } else { fprintf (tfp, "\"%s\"", info_ptr->text[i].key); for (j = strlen (info_ptr->text[i].key) ; j < 13 ; j++) putc (' ', tfp); } putc (' ', tfp); /* at least one space between key and text */ for (j = 0 ; j < info_ptr->text[i].text_length ; j++) { putc (info_ptr->text[i].text[j], tfp); if (info_ptr->text[i].text[j] == '\n') for (k = 0 ; k < 16 ; k++) putc ((int)' ', tfp); } putc ((int)'\n', tfp); } } static void show_time (png_info *info_ptr) { static const char * const month[] = { "", "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December" }; if (info_ptr->valid & PNG_INFO_tIME) { pm_message ("modification time: %02d %s %d %02d:%02d:%02d", info_ptr->mod_time.day, month[info_ptr->mod_time.month], info_ptr->mod_time.year, info_ptr->mod_time.hour, info_ptr->mod_time.minute, info_ptr->mod_time.second); } } static void pngtopnm_error_handler (png_structp png_ptr, png_const_charp msg) { jmpbuf_wrapper *jmpbuf_ptr; /* this function, aside from the extra step of retrieving the "error * pointer" (below) and the fact that it exists within the application * rather than within libpng, is essentially identical to libpng's * default error handler. The second point is critical: since both * setjmp() and longjmp() are called from the same code, they are * guaranteed to have compatible notions of how big a jmp_buf is, * regardless of whether _BSD_SOURCE or anything else has (or has not) * been defined. */ pm_message("fatal libpng error: %s", msg); jmpbuf_ptr = png_get_error_ptr(png_ptr); if (jmpbuf_ptr == NULL) { /* we are completely hosed now */ pm_error("EXTREMELY fatal error: jmpbuf unrecoverable; terminating."); } longjmp(jmpbuf_ptr->jmpbuf, 1); } static void dump_png_info(png_info *info_ptr) { const char *type_string; const char *filter_string; switch (info_ptr->color_type) { case PNG_COLOR_TYPE_GRAY: type_string = "gray"; break; case PNG_COLOR_TYPE_GRAY_ALPHA: type_string = "gray+alpha"; break; case PNG_COLOR_TYPE_PALETTE: type_string = "palette"; break; case PNG_COLOR_TYPE_RGB: type_string = "truecolor"; break; case PNG_COLOR_TYPE_RGB_ALPHA: type_string = "truecolor+alpha"; break; } switch (info_ptr->filter_type) { case PNG_FILTER_TYPE_BASE: asprintfN(&filter_string, "base filter"); break; default: asprintfN(&filter_string, "unknown filter type %d", info_ptr->filter_type); } pm_message("reading a %ldw x %ldh image, %d bit%s", info_ptr->width, info_ptr->height, info_ptr->bit_depth, info_ptr->bit_depth > 1 ? "s" : ""); pm_message("%s, %s, %s", type_string, info_ptr->interlace_type ? "Adam7 interlaced" : "not interlaced", filter_string); pm_message("background {index, gray, red, green, blue} = " "{%d, %d, %d, %d, %d}", info_ptr->background.index, info_ptr->background.gray, info_ptr->background.red, info_ptr->background.green, info_ptr->background.blue); strfree(filter_string); if (info_ptr->valid & PNG_INFO_tRNS) pm_message("tRNS chunk (transparency): %u entries", info_ptr->num_trans); else pm_message("tRNS chunk (transparency): not present"); if (info_ptr->valid & PNG_INFO_gAMA) pm_message("gAMA chunk (image gamma): gamma = %4.2f", info_ptr->gamma); else pm_message("gAMA chunk (image gamma): not present"); if (info_ptr->valid & PNG_INFO_sBIT) pm_message("sBIT chunk: present"); else pm_message("sBIT chunk: not present"); if (info_ptr->valid & PNG_INFO_cHRM) pm_message("cHRM chunk: present"); else pm_message("cHRM chunk: not present"); if (info_ptr->valid & PNG_INFO_PLTE) pm_message("PLTE chunk: %d entries", info_ptr->num_palette); else pm_message("PLTE chunk: not present"); if (info_ptr->valid & PNG_INFO_bKGD) pm_message("bKGD chunk: present"); else pm_message("bKGD chunk: not present"); if (info_ptr->valid & PNG_INFO_PLTE) pm_message("hIST chunk: present"); else pm_message("hIST chunk: not present"); if (info_ptr->valid & PNG_INFO_pHYs) pm_message("pHYs chunk: present"); else pm_message("pHYs chunk: not present"); if (info_ptr->valid & PNG_INFO_oFFs) pm_message("oFFs chunk: present"); else pm_message("oFFs chunk: not present"); if (info_ptr->valid & PNG_INFO_tIME) pm_message("tIME chunk: present"); else pm_message("tIME chunk: not present"); if (info_ptr->valid & PNG_INFO_pCAL) pm_message("pCAL chunk: present"); else pm_message("pCAL chunk: not present"); if (info_ptr->valid & PNG_INFO_sRGB) pm_message("sRGB chunk: present"); else pm_message("sRGB chunk: not present"); } static unsigned int computePngLineSize(png_info * const pngInfoP) { unsigned int const bytesPerSample = pngInfoP->bit_depth == 16 ? 2 : 1; unsigned int samplesPerPixel; switch (pngInfoP->color_type) { case PNG_COLOR_TYPE_GRAY_ALPHA: samplesPerPixel = 2; break; case PNG_COLOR_TYPE_RGB: samplesPerPixel = 3; break; case PNG_COLOR_TYPE_RGB_ALPHA: samplesPerPixel = 4; break; default: samplesPerPixel = 1; } if (UINT_MAX / bytesPerSample / samplesPerPixel < pngInfoP->width) pm_error("Width %u of PNG is uncomputably large", (unsigned int)pngInfoP->width); return pngInfoP->width * bytesPerSample * samplesPerPixel; } static void allocPngRaster(png_info * const pngInfoP, png_byte *** const pngImageP) { unsigned int const lineSize = computePngLineSize(pngInfoP); png_byte ** pngImage; unsigned int row; MALLOCARRAY(pngImage, pngInfoP->height); if (pngImage == NULL) pm_error("couldn't allocate space for %u PNG raster rows", (unsigned int)pngInfoP->height); for (row = 0; row < pngInfoP->height; ++row) { MALLOCARRAY(pngImage[row], lineSize); if (pngImage[row] == NULL) pm_error("couldn't allocate space for %uth row of PNG raster", row); } *pngImageP = pngImage; } static void freePngRaster(png_byte ** const pngRaster, png_info * const pngInfoP) { unsigned int row; for (row = 0; row < pngInfoP->height; ++row) free(pngRaster[row]); free(pngRaster); } static bool isTransparentColor(pngcolor const color, png_info * const pngInfoP, double const totalgamma) { /*---------------------------------------------------------------------------- Return TRUE iff pixels of color 'color' are supposed to be transparent everywhere they occur. Assume it's an RGB image. 'color' has been gamma-corrected. -----------------------------------------------------------------------------*/ bool retval; if (pngInfoP->valid & PNG_INFO_tRNS) { const png_color_16 * const transColorP = &pngInfoP->trans_values; /* It seems odd that libpng lets you get gamma-corrected pixel values, but not gamma-corrected transparency or background values. But as that is the case, we have to gamma-correct the transparency values. Note that because we compare the gamma-corrected values and there may be many-to-one mapping of uncorrected to corrected values, more pixels may be transparent than what the user intended. We could fix this by not letting libpng gamma-correct the pixels, and just do it ourselves. */ switch (pngInfoP->color_type) { case PNG_COLOR_TYPE_GRAY: retval = color.r == gamma_correct(transColorP->gray, totalgamma); break; default: retval = color.r == gamma_correct(transColorP->red, totalgamma) && color.g == gamma_correct(transColorP->green, totalgamma) && color.b == gamma_correct(transColorP->blue, totalgamma); } } else retval = FALSE; return retval; } #define SIG_CHECK_SIZE 4 static void read_sig_buf(FILE * const ifP) { unsigned char sig_buf[SIG_CHECK_SIZE]; size_t bytesRead; bytesRead = fread(sig_buf, 1, SIG_CHECK_SIZE, ifP); if (bytesRead != SIG_CHECK_SIZE) pm_error ("input file is empty or too short"); if (png_sig_cmp(sig_buf, (png_size_t) 0, (png_size_t) SIG_CHECK_SIZE) != 0) pm_error ("input file is not a PNG file"); } static void setupGammaCorrection(png_struct * const png_ptr, png_info * const info_ptr, float const displaygamma, float * const totalgammaP) { if (displaygamma == -1.0) *totalgammaP = -1.0; else { float imageGamma; if (info_ptr->valid & PNG_INFO_gAMA) imageGamma = info_ptr->gamma; else { if (verbose) pm_message("PNG doesn't specify image gamma. Assuming 1.0"); imageGamma = 1.0; } if (fabs(displaygamma * imageGamma - 1.0) < .01) { *totalgammaP = -1.0; if (verbose) pm_message("image gamma %4.2f matches " "display gamma %4.2f. No conversion.", imageGamma, displaygamma); } else { png_set_gamma(png_ptr, displaygamma, imageGamma); *totalgammaP = imageGamma * displaygamma; /* in case of gamma-corrections, sBIT's as in the PNG-file are not valid anymore */ info_ptr->valid &= ~PNG_INFO_sBIT; if (verbose) pm_message("image gamma is %4.2f, " "converted for display gamma of %4.2f", imageGamma, displaygamma); } } } static bool paletteHasPartialTransparency(png_info * const info_ptr) { bool retval; if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) { if (info_ptr->valid & PNG_INFO_tRNS) { bool foundGray; unsigned int i; for (i = 0, foundGray = FALSE; i < info_ptr->num_trans && !foundGray; ++i) { if (info_ptr->trans[i] != 0 && info_ptr->trans[i] != maxval) { foundGray = TRUE; } } retval = foundGray; } else retval = FALSE; } else retval = FALSE; return retval; } static void setupSignificantBits(png_struct * const png_ptr, png_info * const info_ptr, enum alpha_handling const alpha, png_uint_16 * const maxvalP, int * const errorlevelP) { /*---------------------------------------------------------------------------- Figure out what maxval would best express the information in the PNG described by 'png_ptr' and 'info_ptr', with 'alpha' telling which information in the PNG we care about (image or alpha mask). Return the result as *maxvalP. -----------------------------------------------------------------------------*/ /* Initial assumption of maxval */ if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) { if (alpha == ALPHA_ONLY) { if (info_ptr->color_type == PNG_COLOR_TYPE_GRAY || info_ptr->color_type == PNG_COLOR_TYPE_RGB) /* The alpha mask will be all opaque, so maxval 1 is plenty */ *maxvalP = 1; else if (paletteHasPartialTransparency(info_ptr)) /* Use same maxval as PNG transparency palette for simplicity*/ *maxvalP = 255; else /* A common case, so we conserve bits */ *maxvalP = 1; } else /* Use same maxval as PNG palette for simplicity */ *maxvalP = 255; } else { *maxvalP = (1l << info_ptr->bit_depth) - 1; } /* sBIT handling is very tricky. If we are extracting only the image, we can use the sBIT info for grayscale and color images, if the three values agree. If we extract the transparency/alpha mask, sBIT is irrelevant for trans and valid for alpha. If we mix both, the multiplication may result in values that require the normal bit depth, so we will use the sBIT info only for transparency, if we know that only solid and fully transparent is used */ if (info_ptr->valid & PNG_INFO_sBIT) { switch (alpha) { case ALPHA_MIX: if (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA || info_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) break; if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE && (info_ptr->valid & PNG_INFO_tRNS)) { bool trans_mix; unsigned int i; trans_mix = TRUE; for (i = 0; i < info_ptr->num_trans; ++i) if (info_ptr->trans[i] != 0 && info_ptr->trans[i] != 255) { trans_mix = FALSE; break; } if (!trans_mix) break; } /* else fall though to normal case */ case ALPHA_NONE: if ((info_ptr->color_type == PNG_COLOR_TYPE_PALETTE || info_ptr->color_type == PNG_COLOR_TYPE_RGB || info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA) && (info_ptr->sig_bit.red != info_ptr->sig_bit.green || info_ptr->sig_bit.red != info_ptr->sig_bit.blue) && alpha == ALPHA_NONE) { pm_message("This program cannot handle " "different bit depths for color channels"); pm_message("writing file with %d bit resolution", info_ptr->bit_depth); *errorlevelP = PNMTOPNG_WARNING_LEVEL; } else { if ((info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) && (info_ptr->sig_bit.red < 255)) { unsigned int i; for (i = 0; i < info_ptr->num_palette; ++i) { info_ptr->palette[i].red >>= (8 - info_ptr->sig_bit.red); info_ptr->palette[i].green >>= (8 - info_ptr->sig_bit.green); info_ptr->palette[i].blue >>= (8 - info_ptr->sig_bit.blue); } *maxvalP = (1l << info_ptr->sig_bit.red) - 1; if (verbose) pm_message ("image has fewer significant bits, " "writing file with %d bits per channel", info_ptr->sig_bit.red); } else if ((info_ptr->color_type == PNG_COLOR_TYPE_RGB || info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA) && (info_ptr->sig_bit.red < info_ptr->bit_depth)) { png_set_shift (png_ptr, &(info_ptr->sig_bit)); *maxvalP = (1l << info_ptr->sig_bit.red) - 1; if (verbose) pm_message("image has fewer significant bits, " "writing file with %d " "bits per channel", info_ptr->sig_bit.red); } else if ((info_ptr->color_type == PNG_COLOR_TYPE_GRAY || info_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) && (info_ptr->sig_bit.gray < info_ptr->bit_depth)) { png_set_shift (png_ptr, &(info_ptr->sig_bit)); *maxvalP = (1l << info_ptr->sig_bit.gray) - 1; if (verbose) pm_message("image has fewer significant bits, " "writing file with %d bits", info_ptr->sig_bit.gray); } } break; case ALPHA_ONLY: if ((info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA || info_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) && (info_ptr->sig_bit.gray < info_ptr->bit_depth)) { png_set_shift (png_ptr, &(info_ptr->sig_bit)); if (verbose) pm_message ("image has fewer significant bits, " "writing file with %d bits", info_ptr->sig_bit.alpha); *maxvalP = (1l << info_ptr->sig_bit.alpha) - 1; } break; } } } static bool imageHasColor(png_info * const info_ptr) { bool retval; if (info_ptr->color_type == PNG_COLOR_TYPE_GRAY || info_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) retval = FALSE; else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) { bool foundColor; unsigned int i; for (i = 0, foundColor = FALSE; i < info_ptr->num_palette && !foundColor; ++i) { if (iscolor(info_ptr->palette[i])) foundColor = TRUE; } retval = foundColor; } else retval = TRUE; return retval; } static void determineOutputType(png_info * const info_ptr, enum alpha_handling const alphaHandling, pngcolor const bgColor, xelval const maxval, int * const pnmTypeP) { if (alphaHandling != ALPHA_ONLY && (imageHasColor(info_ptr) || !isGrayscale(bgColor))) *pnmTypeP = PPM_TYPE; else { if (maxval > 1) *pnmTypeP = PGM_TYPE; else *pnmTypeP = PBM_TYPE; } } static void getBackgroundColor(png_info * const info_ptr, const char * const requestedColor, float const totalgamma, xelval const maxval, pngcolor * const bgColorP) { /*---------------------------------------------------------------------------- Figure out what the background color should be. If the user requested a particular color ('requestedColor' not null), that's the one. Otherwise, if the PNG specifies a background color, that's the one. And otherwise, it's white. -----------------------------------------------------------------------------*/ if (requestedColor) { /* Background was specified from the command-line; we always use that. I chose to do no gamma-correction in this case; which is a bit arbitrary. */ pixel const backcolor = ppm_parsecolor(requestedColor, maxval); bgColorP->r = PPM_GETR(backcolor); bgColorP->g = PPM_GETG(backcolor); bgColorP->b = PPM_GETB(backcolor); } else if (info_ptr->valid & PNG_INFO_bKGD) { /* didn't manage to get libpng to work (bugs?) concerning background processing, therefore we do our own. */ switch (info_ptr->color_type) { case PNG_COLOR_TYPE_GRAY: case PNG_COLOR_TYPE_GRAY_ALPHA: bgColorP->r = bgColorP->g = bgColorP->b = gamma_correct(info_ptr->background.gray, totalgamma); break; case PNG_COLOR_TYPE_PALETTE: { png_color const rawBgcolor = info_ptr->palette[info_ptr->background.index]; bgColorP->r = gamma_correct(rawBgcolor.red, totalgamma); bgColorP->g = gamma_correct(rawBgcolor.green, totalgamma); bgColorP->b = gamma_correct(rawBgcolor.blue, totalgamma); } break; case PNG_COLOR_TYPE_RGB: case PNG_COLOR_TYPE_RGB_ALPHA: { png_color_16 const rawBgcolor = info_ptr->background; bgColorP->r = gamma_correct(rawBgcolor.red, totalgamma); bgColorP->g = gamma_correct(rawBgcolor.green, totalgamma); bgColorP->b = gamma_correct(rawBgcolor.blue, totalgamma); } break; } } else /* when no background given, we use white [from version 2.37] */ bgColorP->r = bgColorP->g = bgColorP->b = maxval; } #define GET_PNG_VAL(p) get_png_val(&(p), pngInfoP->bit_depth) static void makeXelRow(xel * const xelrow, xelval const maxval, int const pnmType, png_info * const pngInfoP, const png_byte * const pngRasterRow, pngcolor const bgColor, enum alpha_handling const alphaHandling, double const totalgamma) { const png_byte * pngPixelP; unsigned int col; pngPixelP = &pngRasterRow[0]; /* initial value */ for (col = 0; col < pngInfoP->width; ++col) { switch (pngInfoP->color_type) { case PNG_COLOR_TYPE_GRAY: { pngcolor fgColor; fgColor.r = fgColor.g = fgColor.b = GET_PNG_VAL(pngPixelP); setXel(&xelrow[col], fgColor, bgColor, alphaHandling, isTransparentColor(fgColor, pngInfoP, totalgamma) ? 0 : maxval); } break; case PNG_COLOR_TYPE_GRAY_ALPHA: { pngcolor fgColor; png_uint_16 alpha; fgColor.r = fgColor.g = fgColor.b = GET_PNG_VAL(pngPixelP); alpha = GET_PNG_VAL(pngPixelP); setXel(&xelrow[col], fgColor, bgColor, alphaHandling, alpha); } break; case PNG_COLOR_TYPE_PALETTE: { png_uint_16 const index = GET_PNG_VAL(pngPixelP); png_color const paletteColor = pngInfoP->palette[index]; pngcolor fgColor; fgColor.r = paletteColor.red; fgColor.g = paletteColor.green; fgColor.b = paletteColor.blue; setXel(&xelrow[col], fgColor, bgColor, alphaHandling, (pngInfoP->valid & PNG_INFO_tRNS) && index < pngInfoP->num_trans ? pngInfoP->trans[index] : maxval); } break; case PNG_COLOR_TYPE_RGB: { pngcolor fgColor; fgColor.r = GET_PNG_VAL(pngPixelP); fgColor.g = GET_PNG_VAL(pngPixelP); fgColor.b = GET_PNG_VAL(pngPixelP); setXel(&xelrow[col], fgColor, bgColor, alphaHandling, isTransparentColor(fgColor, pngInfoP, totalgamma) ? 0 : maxval); } break; case PNG_COLOR_TYPE_RGB_ALPHA: { pngcolor fgColor; png_uint_16 alpha; fgColor.r = GET_PNG_VAL(pngPixelP); fgColor.g = GET_PNG_VAL(pngPixelP); fgColor.b = GET_PNG_VAL(pngPixelP); alpha = GET_PNG_VAL(pngPixelP); setXel(&xelrow[col], fgColor, bgColor, alphaHandling, alpha); } break; default: pm_error("unknown PNG color type: %d", pngInfoP->color_type); } } } static void writePnm(FILE * const ofP, xelval const maxval, int const pnmType, png_info * const pngInfoP, png_byte ** const pngRaster, pngcolor const bgColor, enum alpha_handling const alphaHandling, double const totalgamma) { /*---------------------------------------------------------------------------- Write a PNM of either the image or the alpha mask, according to 'alphaHandling' that is in the PNG image described by 'pngInfoP' and pngRaster. 'pnmType' and 'maxval' are of the output image. Use background color 'bgColor' in the output if the PNG is such that a background color is needed. -----------------------------------------------------------------------------*/ xel * xelrow; unsigned int row; if (verbose) pm_message("writing a %s file (maxval=%u)", pnmType == PBM_TYPE ? "PBM" : pnmType == PGM_TYPE ? "PGM" : pnmType == PPM_TYPE ? "PPM" : "UNKNOWN!", maxval); xelrow = pnm_allocrow(pngInfoP->width); pnm_writepnminit(stdout, pngInfoP->width, pngInfoP->height, maxval, pnmType, FALSE); for (row = 0; row < pngInfoP->height; ++row) { makeXelRow(xelrow, maxval, pnmType, pngInfoP, pngRaster[row], bgColor, alphaHandling, totalgamma); pnm_writepnmrow(ofP, xelrow, pngInfoP->width, maxval, pnmType, FALSE); } pnm_freerow (xelrow); } static void convertpng(FILE * const ifp, FILE * const tfp, struct cmdlineInfo const cmdline, int * const errorlevelP) { png_struct * png_ptr; png_info * info_ptr; png_byte ** png_image; int pnm_type; pngcolor bgColor; float totalgamma; *errorlevelP = 0; read_sig_buf(ifp); png_ptr = png_create_read_struct( PNG_LIBPNG_VER_STRING, &pngtopnm_jmpbuf_struct, pngtopnm_error_handler, NULL); if (png_ptr == NULL) pm_error("cannot allocate main libpng structure (png_ptr)"); info_ptr = png_create_info_struct (png_ptr); if (info_ptr == NULL) pm_error("cannot allocate LIBPNG structures"); if (setjmp(pngtopnm_jmpbuf_struct.jmpbuf)) pm_error ("setjmp returns error condition"); png_init_io (png_ptr, ifp); png_set_sig_bytes (png_ptr, SIG_CHECK_SIZE); png_read_info (png_ptr, info_ptr); allocPngRaster(info_ptr, &png_image); if (info_ptr->bit_depth < 8) png_set_packing (png_ptr); setupGammaCorrection(png_ptr, info_ptr, cmdline.gamma, &totalgamma); setupSignificantBits(png_ptr, info_ptr, cmdline.alpha, &maxval, errorlevelP); getBackgroundColor(info_ptr, cmdline.background, totalgamma, maxval, &bgColor); png_read_image(png_ptr, png_image); png_read_end(png_ptr, info_ptr); if (verbose) /* Note that some of info_ptr is not defined until png_read_end() completes. That's because it comes from chunks that are at the end of the stream. */ dump_png_info(info_ptr); if (cmdline.time) show_time(info_ptr); if (tfp) save_text(info_ptr, tfp); if (info_ptr->valid & PNG_INFO_pHYs) { float const r = (float)info_ptr->x_pixels_per_unit / info_ptr->y_pixels_per_unit; if (r != 1.0) { pm_message ("warning - non-square pixels; " "to fix do a 'pamscale -%cscale %g'", r < 1.0 ? 'x' : 'y', r < 1.0 ? 1.0 / r : r ); *errorlevelP = PNMTOPNG_WARNING_LEVEL; } } determineOutputType(info_ptr, cmdline.alpha, bgColor, maxval, &pnm_type); writePnm(stdout, maxval, pnm_type, info_ptr, png_image, bgColor, cmdline.alpha, totalgamma); fflush(stdout); freePngRaster(png_image, info_ptr); png_destroy_read_struct(&png_ptr, &info_ptr, NULL); } int main(int argc, const char *argv[]) { struct cmdlineInfo cmdline; FILE * ifP; FILE * tfP; int errorlevel; pm_proginit(&argc, argv); parseCommandLine(argc, argv, &cmdline); verbose = cmdline.verbose; ifP = pm_openr(cmdline.inputFilespec); if (cmdline.text) tfP = pm_openw(cmdline.text); else tfP = NULL; convertpng(ifP, tfP, cmdline, &errorlevel); if (tfP) pm_close(tfP); pm_close(ifP); pm_close(stdout); return errorlevel; }