#include #include #include /* Because of a design error in png.h, you must not #include before . If you do, png.h won't compile. */ #include #include "pm_c_util.h" #include "mallocvar.h" #include "nstring.h" #include "pm.h" /* defines (or doesn't) PNG_iTXt_SUPPORTED to tell us whether libpng has facilities related to PNG iTXt chunks. */ #ifdef PNG_iTXt_SUPPORTED #define HAVE_PNGLIB_WITH_ITXT 1 #else #define HAVE_PNGLIB_WITH_ITXT 0 #endif #include "pngx.h" static void errorHandler(png_structp const png_ptr, png_const_charp const msg) { jmp_buf * jmpbufP; /* 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_errormsg("fatal libpng error: %s", msg); jmpbufP = png_get_error_ptr(png_ptr); if (!jmpbufP) pm_longjmp(); else longjmp(*jmpbufP, 1); } void pngx_create(struct pngx ** const pngxPP, pngx_rw const rw, jmp_buf * const jmpbufP) { struct pngx * pngxP; MALLOCVAR(pngxP); if (!pngxP) pm_error("Failed to allocate memory for PNG object"); else { pngxP->infoPrepared = false; pngxP->numPassesRequired = 1; switch(rw) { case PNGX_READ: pngxP->png_ptr = png_create_read_struct( PNG_LIBPNG_VER_STRING, jmpbufP, errorHandler, NULL); break; case PNGX_WRITE: pngxP->png_ptr = png_create_write_struct( PNG_LIBPNG_VER_STRING, jmpbufP, errorHandler, NULL); break; } if (!pngxP->png_ptr) pm_error("cannot allocate main libpng structure (png_ptr)"); else { pngxP->info_ptr = png_create_info_struct(pngxP->png_ptr); if (!pngxP->info_ptr) pm_error("cannot allocate libpng info structure (info_ptr)"); else *pngxPP = pngxP; } pngxP->rw = rw; } } void pngx_destroy(struct pngx * const pngxP) { switch(pngxP->rw) { case PNGX_READ: png_destroy_read_struct(&pngxP->png_ptr, &pngxP->info_ptr, NULL); break; case PNGX_WRITE: png_destroy_write_struct(&pngxP->png_ptr, &pngxP->info_ptr); break; } free(pngxP); } bool pngx_chunkIsPresent(struct pngx * const pngxP, uint32_t const chunkType) { return png_get_valid(pngxP->png_ptr, pngxP->info_ptr, chunkType); } unsigned int pngx_bitDepth(struct pngx * const pngxP) { return png_get_bit_depth(pngxP->png_ptr, pngxP->info_ptr); } png_color_16 pngx_bkgd(struct pngx * const pngxP) { png_color_16 * colorP; png_get_bKGD(pngxP->png_ptr, pngxP->info_ptr, &colorP); return *colorP; } png_byte pngx_colorType(struct pngx * const pngxP) { return png_get_color_type(pngxP->png_ptr, pngxP->info_ptr); } png_byte pngx_filterType(struct pngx * const pngxP) { return png_get_filter_type(pngxP->png_ptr, pngxP->info_ptr); } double pngx_gama(struct pngx * const pngxP) { double retval; png_get_gAMA(pngxP->png_ptr, pngxP->info_ptr, &retval); return retval; } uint32_t pngx_imageHeight(struct pngx * const pngxP) { return png_get_image_height(pngxP->png_ptr, pngxP->info_ptr); } uint32_t pngx_imageWidth(struct pngx * const pngxP) { return png_get_image_width(pngxP->png_ptr, pngxP->info_ptr); } png_byte pngx_interlaceType(struct pngx * const pngxP) { return png_get_interlace_type(pngxP->png_ptr, pngxP->info_ptr); } struct pngx_plte pngx_plte(struct pngx * const pngxP) { struct pngx_plte retval; int size; png_get_PLTE(pngxP->png_ptr, pngxP->info_ptr, &retval.palette, &size); assert(size >= 0); retval.size = size; return retval; } png_color_8 pngx_sbit(struct pngx * const pngxP) { png_color_8 * sbitP; png_get_sBIT(pngxP->png_ptr, pngxP->info_ptr, &sbitP); return *sbitP; } struct pngx_text pngx_text(struct pngx * const pngxP) { struct pngx_text retval; int size; png_get_text(pngxP->png_ptr, pngxP->info_ptr, &retval.line, &size); assert(size >= 0); retval.size = size; return retval; } png_time pngx_time(struct pngx * const pngxP) { png_time * timeP; png_get_tIME(pngxP->png_ptr, pngxP->info_ptr, &timeP); return *timeP; } struct pngx_trns pngx_trns(struct pngx * const pngxP) { struct pngx_trns retval; int numTrans; png_color_16 * transColorP; png_get_tRNS(pngxP->png_ptr, pngxP->info_ptr, &retval.trans, &numTrans, &transColorP); assert(numTrans >= 0); retval.numTrans = numTrans; retval.transColor = *transColorP; return retval; } uint32_t pngx_xPixelsPerMeter(struct pngx * const pngxP) { /*---------------------------------------------------------------------------- Horizontal pixel density in pixel per meter; 0 if unknown. -----------------------------------------------------------------------------*/ return png_get_x_pixels_per_meter(pngxP->png_ptr, pngxP->info_ptr); } float pngx_pixelAspectRatio(struct pngx * const pngxP) { /*---------------------------------------------------------------------------- Aspect ratio - y/x. 0.0 if unknown -----------------------------------------------------------------------------*/ return png_get_pixel_aspect_ratio(pngxP->png_ptr, pngxP->info_ptr); } bool pngx_pixelAspectRatioIsKnown(struct pngx * const pngxP) { /*---------------------------------------------------------------------------- There is pixel aspect ratio information in the PNG image. -----------------------------------------------------------------------------*/ return png_get_pixel_aspect_ratio(pngxP->png_ptr, pngxP->info_ptr) != 0.0; } uint32_t pngx_yPixelsPerMeter(struct pngx * const pngxP) { /*---------------------------------------------------------------------------- Vertical pixel density in pixel per meter; 0 if unknown. -----------------------------------------------------------------------------*/ return png_get_y_pixels_per_meter(pngxP->png_ptr, pngxP->info_ptr); } void pngx_removeChunk(struct pngx * const pngxP, uint32_t const chunkType) { png_set_invalid(pngxP->png_ptr, pngxP->info_ptr, chunkType); } void pngx_setBkgdPalette(struct pngx * const pngxP, unsigned int const backgroundIndex) { png_color_16 background; background.index = backgroundIndex; png_set_bKGD(pngxP->png_ptr, pngxP->info_ptr, &background); } void pngx_setBkgdRgb(struct pngx * const pngxP, png_color_16 const backgroundArg) { png_color_16 background; background = backgroundArg; png_set_bKGD(pngxP->png_ptr, pngxP->info_ptr, &background); } void pngx_setChrm(struct pngx * const pngxP, struct pngx_chroma const chroma) { png_set_cHRM(pngxP->png_ptr, pngxP->info_ptr, chroma.wx, chroma.wy, chroma.rx, chroma.ry, chroma.gx, chroma.gy, chroma.bx, chroma.by); } const char * pngx_srgbIntentDesc(pngx_srgbIntent const srgbIntent) { switch (srgbIntent) { case PNGX_PERCEPTUAL: return "PERCEPTUAL"; case PNGX_RELATIVE_COLORIMETRIC: return "RELATIVE COLORIMETRIC"; case PNGX_SATURATION: return "SATURATION"; case PNGX_ABSOLUTE_COLORIMETRIC: return "ABSOLUTE_COLORIMETRIC"; } assert(false); } static int const libpngSrgbIntentCode(pngx_srgbIntent const srgbIntent) { switch (srgbIntent) { case PNGX_PERCEPTUAL: return 0; case PNGX_RELATIVE_COLORIMETRIC: return 1; case PNGX_SATURATION: return 2; case PNGX_ABSOLUTE_COLORIMETRIC: return 3; } assert(false); /* All cases above return */ } void pngx_setSrgb(struct pngx * const pngxP, pngx_srgbIntent const srgbIntent) { png_set_sRGB(pngxP->png_ptr, pngxP->info_ptr, libpngSrgbIntentCode(srgbIntent)); } void pngx_setCompressionSize(struct pngx * const pngxP, unsigned int const bufferSize) { #if PNG_LIBPNG_VER >= 10009 png_set_compression_buffer_size(pngxP->png_ptr, bufferSize); #else pm_error("Your PNG library cannot set the compression buffer size. " "You need at least Version 1.0.9 of Libpng; you have Version %s", PNG_LIBPNG_VER_STRING); #endif } void pngx_setFilter(struct pngx * const pngxP, int const filterSet) { /* This sets the allowed filters in the compressor. The filters, and thus the interpretation of 'filterSet', is specific to a filter method (aka filter type), which you set with pngx_setIhdr. There is only one filter method defined today, though (PNG_FILTER_TYPE_BASE). For filter method Base, 'filterSet' is the OR of the following masks, each one allowing the compressor to use one filter. Not that the compressor decides on a row-by-row basis what filter to use. PNG_FILTER_NONE PNG_FILTER_SUB PNG_FILTER_UP PNG_FILTER_AVG PNG_FILTER_PAETH There are also PNG_NO_FILTERS PNG_ALL_FILTERS */ png_set_filter(pngxP->png_ptr, 0, filterSet); } void pngx_setGama(struct pngx * const pngxP, float const fileGamma) { png_set_gAMA(pngxP->png_ptr, pngxP->info_ptr, fileGamma); } void pngx_setGamma(struct pngx * const pngxP, float const screenGamma, float const imageGamma) { png_set_gamma(pngxP->png_ptr, screenGamma, imageGamma); } void pngx_setHist(struct pngx * const pngxP, png_uint_16 * const histogram) { png_set_hIST(pngxP->png_ptr, pngxP->info_ptr, histogram); } void pngx_setIhdr(struct pngx * const pngxP, unsigned int const width, unsigned int const height, unsigned int const bitDepth, int const colorType, int const interlaceMethod, int const compressionMethod, int const filterMethod) { png_set_IHDR(pngxP->png_ptr, pngxP->info_ptr, width, height, bitDepth, colorType, interlaceMethod, compressionMethod, filterMethod); } void pngx_setInterlaceHandling(struct pngx * const pngxP) { /* The documentation is vague and contradictory on what this does, but what it appears from reasoning and experimentation to do is the following. It applies to reading and writing by rows (png_write_row, png_read_row) as opposed to whole image (png_write_image, png_read_image). It has no effect on whole image read and write. This is not what makes an image interlaced or tells the decompressor that it is interlaced. All it does is control how you you read and write the raster when the image is interlaced. It has no effect if the image is not interlaced. (You make an image interlaced by setting the IHDR; the decompressor finds out from the IHDR that it is interlaced). In the write case, it controls whether you construct the subimages yourself and feed them to libpng in sequence or you feed libpng the entire image multiple times and libpng picks out the pixels appropriate for each subimage in each pass. In the read case, it controls whether you get the raw subimages and you assemble them into the full image or you read the whole image multiple times into the same buffer, with the pixels that belong to each subimage being filled in on each pass. Note that the only kind of interlacing that exists today is ADAM7 and consequently, the number of passes is always 1 (for no interlacing) or 7 (for interlacing). */ if (!pngxP->infoPrepared) pm_error("pngx_setInterlaceHandling must not be called before " "pngx_writeInfo or pngx_readInfo"); pngxP->numPassesRequired = png_set_interlace_handling(pngxP->png_ptr); } void pngx_setPacking(struct pngx * const pngxP) { if (!pngxP->infoPrepared) pm_error("pngx_setPacking must not be called before " "pngx_writeInfo or pngx_readInfo"); png_set_packing(pngxP->png_ptr); } void pngx_setPhys(struct pngx * const pngxP, struct pngx_phys const phys) { png_set_pHYs(pngxP->png_ptr, pngxP->info_ptr, phys.x, phys.y, phys.unit); } void pngx_setPlte(struct pngx * const pngxP, png_color * const palette, unsigned int const paletteSize) { png_set_PLTE(pngxP->png_ptr, pngxP->info_ptr, palette, paletteSize); } void pngx_setSbit(struct pngx * const pngxP, png_color_8 const sbitArg) { png_color_8 sbit; sbit = sbitArg; png_set_sBIT(pngxP->png_ptr, pngxP->info_ptr, &sbit); } void pngx_setShift(struct pngx * const pngxP, png_color_8 const sigBitArg) { /*---------------------------------------------------------------------------- Tell the number of significant bits in the row buffers that will be given to the compressor. Those bits are the least significant of the 8 bits of space in the row buffer for each sample. For example, if red sample values are in the range 0-7, only the lower 3 bits of the 8-bit byte for each red sample will be used, so one would call this with sigBitArg.red == 3. The name alludes to the fact that to normalize the sample to 8 bits, one shifts it left, and this function tells how much shift has to happen. In the example above, each red sample has to be shifted left 5 bits (so that the upper 3 bits are significant and the lower 5 bits are always zero) to create an 8 bit sample out of the 3 bit samples. -----------------------------------------------------------------------------*/ png_color_8 sigBit; sigBit = sigBitArg; png_set_shift(pngxP->png_ptr, &sigBit); } void pngx_setSigBytes(struct pngx * const pngxP, unsigned int const sigByteCt) { assert(sigByteCt <= INT_MAX); png_set_sig_bytes(pngxP->png_ptr, sigByteCt); } void pngx_setTextKey(png_text * const textP, const char * const key) { /* textP->key is improperly declared in libpng as char *; should be const char * */ textP->key = (char *)pm_strdup(key); } void pngx_setTextLang(png_text * const textP, const char * const language) { #if HAVE_PNGLIB_WITH_ITXT if (language) textP->lang = (char *)pm_strdup(language); else textP->lang = NULL; #else if (language) pm_error("PNG library does not have ability to create an iTXT " "chunk (i.e. to create a PNG with text strings in a language " "other than English)"); #endif } void pngx_setTextLangKey(png_text * const textP, const char * const key) { #if HAVE_PNGLIB_WITH_ITXT textP->lang_key = (char *)pm_strdup(key); #else pm_error("PNG library does not have ability to create an iTXT " "chunk (i.e. to create a PNG with text strings in a language " "other than English)"); #endif } void pngx_termText(png_text * const textP) { pm_strfree(textP->key); #if HAVE_PNGLIB_WITH_ITXT if (textP->lang) { pm_strfree(textP->lang); pm_strfree(textP->lang_key); } #endif free(textP->text); } void pngx_setText(struct pngx * const pngxP, png_text * const textP, unsigned int const count) { png_set_text(pngxP->png_ptr, pngxP->info_ptr, textP, count); } void pngx_setTime(struct pngx * const pngxP, time_t const timeArg) { png_time pngTime; png_convert_from_time_t(&pngTime, timeArg); png_set_tIME(pngxP->png_ptr, pngxP->info_ptr, &pngTime); } void pngx_setTrnsPalette(struct pngx * const pngxP, const png_byte * const transPalette, unsigned int const paletteSize) { png_set_tRNS(pngxP->png_ptr, pngxP->info_ptr, (png_byte *)transPalette, paletteSize, NULL); } void pngx_setTrnsValue(struct pngx * const pngxP, png_color_16 const transColorArg) { png_color_16 transColor; transColor = transColorArg; png_set_tRNS(pngxP->png_ptr, pngxP->info_ptr, NULL, 0, &transColor); } void pngx_readInfo(struct pngx * const pngxP) { png_read_info(pngxP->png_ptr, pngxP->info_ptr); pngxP->infoPrepared = true; } void pngx_writeInfo(struct pngx * const pngxP) { png_write_info(pngxP->png_ptr, pngxP->info_ptr); pngxP->infoPrepared = true; } static void verifyFileIsPng(FILE * const ifP, size_t * const consumedByteCtP) { unsigned char buffer[4]; size_t bytesRead; bytesRead = fread(buffer, 1, sizeof(buffer), ifP); if (bytesRead != sizeof(buffer)) pm_error("input file is empty or too short"); if (png_sig_cmp(buffer, (png_size_t) 0, (png_size_t) sizeof(buffer)) != 0) pm_error("input file is not a PNG file " "(does not have the PNG signature in its first 4 bytes)"); else *consumedByteCtP = bytesRead; } void pngx_readStart(struct pngx * const pngxP, FILE * const ifP) { size_t sigByteCt; verifyFileIsPng(ifP, &sigByteCt); /* Declare that we already read the signature bytes */ pngx_setSigBytes(pngxP, (unsigned int)sigByteCt); png_init_io(pngxP->png_ptr, ifP); pngx_readInfo(pngxP); if (pngx_bitDepth(pngxP) < 8) pngx_setPacking(pngxP); } void pngx_readRow(struct pngx * const pngxP, png_byte * const rowBuf, png_byte * const displayRow) { png_read_row(pngxP->png_ptr, rowBuf, displayRow); } void pngx_readImage(struct pngx * const pngxP, png_byte ** const image) { png_read_image(pngxP->png_ptr, image); } void pngx_writeRow(struct pngx * const pngxP, const png_byte * const line) { png_write_row(pngxP->png_ptr, (png_byte *)line); } void pngx_writeImage(struct pngx * const pngxP, png_byte ** const raster) { png_write_image(pngxP->png_ptr, (png_byte **)raster); } void pngx_readEnd(struct pngx * const pngxP) { /* 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. In particular, text and time chunks may be at the end. Furthermore, they may be in both places, in which case info_ptr contains different information before and after png_read_end(). */ png_read_end(pngxP->png_ptr, pngxP->info_ptr); } void pngx_writeEnd(struct pngx * const pngxP) { png_write_end(pngxP->png_ptr, pngxP->info_ptr); }