/* pngwutil.c - utilities to write a PNG file * * Last changed in libpng 1.2.56 [December 17, 2015] * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) * * This code is released under the libpng license. * For conditions of distribution and use, see the disclaimer * and license in png.h */ #define PNG_INTERNAL #define PNG_NO_PEDANTIC_WARNINGS #include "png.h" #ifdef PNG_WRITE_SUPPORTED /* Place a 32-bit number into a buffer in PNG byte order. We work * with unsigned numbers for convenience, although one supported * ancillary chunk uses signed (two's complement) numbers. */ void PNGAPI png_save_uint_32(png_bytep buf, png_uint_32 i) { buf[0] = (png_byte)((i >> 24) & 0xff); buf[1] = (png_byte)((i >> 16) & 0xff); buf[2] = (png_byte)((i >> 8) & 0xff); buf[3] = (png_byte)(i & 0xff); } /* The png_save_int_32 function assumes integers are stored in two's * complement format. If this isn't the case, then this routine needs to * be modified to write data in two's complement format. */ void PNGAPI png_save_int_32(png_bytep buf, png_int_32 i) { buf[0] = (png_byte)((i >> 24) & 0xff); buf[1] = (png_byte)((i >> 16) & 0xff); buf[2] = (png_byte)((i >> 8) & 0xff); buf[3] = (png_byte)(i & 0xff); } /* Place a 16-bit number into a buffer in PNG byte order. * The parameter is declared unsigned int, not png_uint_16, * just to avoid potential problems on pre-ANSI C compilers. */ void PNGAPI png_save_uint_16(png_bytep buf, unsigned int i) { buf[0] = (png_byte)((i >> 8) & 0xff); buf[1] = (png_byte)(i & 0xff); } /* Simple function to write the signature. If we have already written * the magic bytes of the signature, or more likely, the PNG stream is * being embedded into another stream and doesn't need its own signature, * we should call png_set_sig_bytes() to tell libpng how many of the * bytes have already been written. */ void /* PRIVATE */ png_write_sig(png_structp png_ptr) { png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10}; /* Write the rest of the 8 byte signature */ png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes], (png_size_t)(8 - png_ptr->sig_bytes)); if (png_ptr->sig_bytes < 3) png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE; } /* Write a PNG chunk all at once. The type is an array of ASCII characters * representing the chunk name. The array must be at least 4 bytes in * length, and does not need to be null terminated. To be safe, pass the * pre-defined chunk names here, and if you need a new one, define it * where the others are defined. The length is the length of the data. * All the data must be present. If that is not possible, use the * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end() * functions instead. */ void PNGAPI png_write_chunk(png_structp png_ptr, png_bytep chunk_name, png_bytep data, png_size_t length) { if (png_ptr == NULL) return; png_write_chunk_start(png_ptr, chunk_name, (png_uint_32)length); png_write_chunk_data(png_ptr, data, (png_size_t)length); png_write_chunk_end(png_ptr); } /* Write the start of a PNG chunk. The type is the chunk type. * The total_length is the sum of the lengths of all the data you will be * passing in png_write_chunk_data(). */ void PNGAPI png_write_chunk_start(png_structp png_ptr, png_bytep chunk_name, png_uint_32 length) { png_byte buf[8]; png_debug2(0, "Writing %s chunk, length = %lu", chunk_name, (unsigned long)length); if (png_ptr == NULL) return; /* Write the length and the chunk name */ png_save_uint_32(buf, length); png_memcpy(buf + 4, chunk_name, 4); png_write_data(png_ptr, buf, (png_size_t)8); /* Put the chunk name into png_ptr->chunk_name */ png_memcpy(png_ptr->chunk_name, chunk_name, 4); /* Reset the crc and run it over the chunk name */ png_reset_crc(png_ptr); png_calculate_crc(png_ptr, chunk_name, (png_size_t)4); } /* Write the data of a PNG chunk started with png_write_chunk_start(). * Note that multiple calls to this function are allowed, and that the * sum of the lengths from these calls *must* add up to the total_length * given to png_write_chunk_start(). */ void PNGAPI png_write_chunk_data(png_structp png_ptr, png_bytep data, png_size_t length) { /* Write the data, and run the CRC over it */ if (png_ptr == NULL) return; if (data != NULL && length > 0) { png_write_data(png_ptr, data, length); /* Update the CRC after writing the data, * in case that the user I/O routine alters it. */ png_calculate_crc(png_ptr, data, length); } } /* Finish a chunk started with png_write_chunk_start(). */ void PNGAPI png_write_chunk_end(png_structp png_ptr) { png_byte buf[4]; if (png_ptr == NULL) return; /* Write the crc in a single operation */ png_save_uint_32(buf, png_ptr->crc); png_write_data(png_ptr, buf, (png_size_t)4); } #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_iCCP_SUPPORTED) /* This pair of functions encapsulates the operation of (a) compressing a * text string, and (b) issuing it later as a series of chunk data writes. * The compression_state structure is shared context for these functions * set up by the caller in order to make the whole mess thread-safe. */ typedef struct { char *input; /* The uncompressed input data */ int input_len; /* Its length */ int num_output_ptr; /* Number of output pointers used */ int max_output_ptr; /* Size of output_ptr */ png_charpp output_ptr; /* Array of pointers to output */ } compression_state; /* Compress given text into storage in the png_ptr structure */ static int /* PRIVATE */ png_text_compress(png_structp png_ptr, png_charp text, png_size_t text_len, int compression, compression_state *comp) { int ret; comp->num_output_ptr = 0; comp->max_output_ptr = 0; comp->output_ptr = NULL; comp->input = NULL; comp->input_len = 0; /* We may just want to pass the text right through */ if (compression == PNG_TEXT_COMPRESSION_NONE) { comp->input = text; comp->input_len = text_len; return((int)text_len); } if (compression >= PNG_TEXT_COMPRESSION_LAST) { #if defined(PNG_STDIO_SUPPORTED) && !defined(_WIN32_WCE) char msg[50]; png_snprintf(msg, 50, "Unknown compression type %d", compression); png_warning(png_ptr, msg); #else png_warning(png_ptr, "Unknown compression type"); #endif } /* We can't write the chunk until we find out how much data we have, * which means we need to run the compressor first and save the * output. This shouldn't be a problem, as the vast majority of * comments should be reasonable, but we will set up an array of * malloc'd pointers to be sure. * * If we knew the application was well behaved, we could simplify this * greatly by assuming we can always malloc an output buffer large * enough to hold the compressed text ((1001 * text_len / 1000) + 12) * and malloc this directly. The only time this would be a bad idea is * if we can't malloc more than 64K and we have 64K of random input * data, or if the input string is incredibly large (although this * wouldn't cause a failure, just a slowdown due to swapping). */ /* Set up the compression buffers */ png_ptr->zstream.avail_in = (uInt)text_len; png_ptr->zstream.next_in = (Bytef *)text; png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; png_ptr->zstream.next_out = (Bytef *)png_ptr->zbuf; /* This is the same compression loop as in png_write_row() */ do { /* Compress the data */ ret = deflate(&png_ptr->zstream, Z_NO_FLUSH); if (ret != Z_OK) { /* Error */ if (png_ptr->zstream.msg != NULL) png_error(png_ptr, png_ptr->zstream.msg); else png_error(png_ptr, "zlib error"); } /* Check to see if we need more room */ if (!(png_ptr->zstream.avail_out)) { /* Make sure the output array has room */ if (comp->num_output_ptr >= comp->max_output_ptr) { int old_max; old_max = comp->max_output_ptr; comp->max_output_ptr = comp->num_output_ptr + 4; if (comp->output_ptr != NULL) { png_charpp old_ptr; old_ptr = comp->output_ptr; comp->output_ptr = (png_charpp)png_malloc(png_ptr, (png_uint_32) (comp->max_output_ptr * png_sizeof(png_charp))); png_memcpy(comp->output_ptr, old_ptr, old_max * png_sizeof(png_charp)); png_free(png_ptr, old_ptr); } else comp->output_ptr = (png_charpp)png_malloc(png_ptr, (png_uint_32) (comp->max_output_ptr * png_sizeof(png_charp))); } /* Save the data */ comp->output_ptr[comp->num_output_ptr] = (png_charp)png_malloc(png_ptr, (png_uint_32)png_ptr->zbuf_size); png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf, png_ptr->zbuf_size); comp->num_output_ptr++; /* and reset the buffer */ png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; png_ptr->zstream.next_out = png_ptr->zbuf; } /* Continue until we don't have any more to compress */ } while (png_ptr->zstream.avail_in); /* Finish the compression */ do { /* Tell zlib we are finished */ ret = deflate(&png_ptr->zstream, Z_FINISH); if (ret == Z_OK) { /* Check to see if we need more room */ if (!(png_ptr->zstream.avail_out)) { /* Check to make sure our output array has room */ if (comp->num_output_ptr >= comp->max_output_ptr) { int old_max; old_max = comp->max_output_ptr; comp->max_output_ptr = comp->num_output_ptr + 4; if (comp->output_ptr != NULL) { png_charpp old_ptr; old_ptr = comp->output_ptr; /* This could be optimized to realloc() */ comp->output_ptr = (png_charpp)png_malloc(png_ptr, (png_uint_32)(comp->max_output_ptr * png_sizeof(png_charp))); png_memcpy(comp->output_ptr, old_ptr, old_max * png_sizeof(png_charp)); png_free(png_ptr, old_ptr); } else comp->output_ptr = (png_charpp)png_malloc(png_ptr, (png_uint_32)(comp->max_output_ptr * png_sizeof(png_charp))); } /* Save the data */ comp->output_ptr[comp->num_output_ptr] = (png_charp)png_malloc(png_ptr, (png_uint_32)png_ptr->zbuf_size); png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf, png_ptr->zbuf_size); comp->num_output_ptr++; /* and reset the buffer pointers */ png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; png_ptr->zstream.next_out = png_ptr->zbuf; } } else if (ret != Z_STREAM_END) { /* We got an error */ if (png_ptr->zstream.msg != NULL) png_error(png_ptr, png_ptr->zstream.msg); else png_error(png_ptr, "zlib error"); } } while (ret != Z_STREAM_END); /* Text length is number of buffers plus last buffer */ text_len = png_ptr->zbuf_size * comp->num_output_ptr; if (png_ptr->zstream.avail_out < png_ptr->zbuf_size) text_len += png_ptr->zbuf_size - (png_size_t)png_ptr->zstream.avail_out; return((int)text_len); } /* Ship the compressed text out via chunk writes */ static void /* PRIVATE */ png_write_compressed_data_out(png_structp png_ptr, compression_state *comp) { int i; /* Handle the no-compression case */ if (comp->input) { png_write_chunk_data(png_ptr, (png_bytep)comp->input, (png_size_t)comp->input_len); return; } /* Write saved output buffers, if any */ for (i = 0; i < comp->num_output_ptr; i++) { png_write_chunk_data(png_ptr, (png_bytep)comp->output_ptr[i], (png_size_t)png_ptr->zbuf_size); png_free(png_ptr, comp->output_ptr[i]); comp->output_ptr[i]=NULL; } if (comp->max_output_ptr != 0) png_free(png_ptr, comp->output_ptr); comp->output_ptr=NULL; /* Write anything left in zbuf */ if (png_ptr->zstream.avail_out < (png_uint_32)png_ptr->zbuf_size) png_write_chunk_data(png_ptr, png_ptr->zbuf, (png_size_t)(png_ptr->zbuf_size - png_ptr->zstream.avail_out)); /* Reset zlib for another zTXt/iTXt or image data */ deflateReset(&png_ptr->zstream); png_ptr->zstream.data_type = Z_BINARY; } #endif /* Write the IHDR chunk, and update the png_struct with the necessary * information. Note that the rest of this code depends upon this * information being correct. */ void /* PRIVATE */ png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height, int bit_depth, int color_type, int compression_type, int filter_type, int interlace_type) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_IHDR; #endif int ret; png_byte buf[13]; /* Buffer to store the IHDR info */ png_debug(1, "in png_write_IHDR"); /* Check that we have valid input data from the application info */ switch (color_type) { case PNG_COLOR_TYPE_GRAY: switch (bit_depth) { case 1: case 2: case 4: case 8: case 16: png_ptr->channels = 1; break; default: png_error(png_ptr, "Invalid bit depth for grayscale image"); } break; case PNG_COLOR_TYPE_RGB: if (bit_depth != 8 && bit_depth != 16) png_error(png_ptr, "Invalid bit depth for RGB image"); png_ptr->channels = 3; break; case PNG_COLOR_TYPE_PALETTE: switch (bit_depth) { case 1: case 2: case 4: case 8: png_ptr->channels = 1; break; default: png_error(png_ptr, "Invalid bit depth for paletted image"); } break; case PNG_COLOR_TYPE_GRAY_ALPHA: if (bit_depth != 8 && bit_depth != 16) png_error(png_ptr, "Invalid bit depth for grayscale+alpha image"); png_ptr->channels = 2; break; case PNG_COLOR_TYPE_RGB_ALPHA: if (bit_depth != 8 && bit_depth != 16) png_error(png_ptr, "Invalid bit depth for RGBA image"); png_ptr->channels = 4; break; default: png_error(png_ptr, "Invalid image color type specified"); } if (compression_type != PNG_COMPRESSION_TYPE_BASE) { png_warning(png_ptr, "Invalid compression type specified"); compression_type = PNG_COMPRESSION_TYPE_BASE; } /* Write filter_method 64 (intrapixel differencing) only if * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and * 2. Libpng did not write a PNG signature (this filter_method is only * used in PNG datastreams that are embedded in MNG datastreams) and * 3. The application called png_permit_mng_features with a mask that * included PNG_FLAG_MNG_FILTER_64 and * 4. The filter_method is 64 and * 5. The color_type is RGB or RGBA */ if ( #ifdef PNG_MNG_FEATURES_SUPPORTED !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) && ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) && (color_type == PNG_COLOR_TYPE_RGB || color_type == PNG_COLOR_TYPE_RGB_ALPHA) && (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) && #endif filter_type != PNG_FILTER_TYPE_BASE) { png_warning(png_ptr, "Invalid filter type specified"); filter_type = PNG_FILTER_TYPE_BASE; } #ifdef PNG_WRITE_INTERLACING_SUPPORTED if (interlace_type != PNG_INTERLACE_NONE && interlace_type != PNG_INTERLACE_ADAM7) { png_warning(png_ptr, "Invalid interlace type specified"); interlace_type = PNG_INTERLACE_ADAM7; } #else interlace_type=PNG_INTERLACE_NONE; #endif /* Save the relevent information */ png_ptr->bit_depth = (png_byte)bit_depth; png_ptr->color_type = (png_byte)color_type; png_ptr->interlaced = (png_byte)interlace_type; #ifdef PNG_MNG_FEATURES_SUPPORTED png_ptr->filter_type = (png_byte)filter_type; #endif png_ptr->compression_type = (png_byte)compression_type; png_ptr->width = width; png_ptr->height = height; png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels); png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width); /* Set the usr info, so any transformations can modify it */ png_ptr->usr_width = png_ptr->width; png_ptr->usr_bit_depth = png_ptr->bit_depth; png_ptr->usr_channels = png_ptr->channels; /* Pack the header information into the buffer */ png_save_uint_32(buf, width); png_save_uint_32(buf + 4, height); buf[8] = (png_byte)bit_depth; buf[9] = (png_byte)color_type; buf[10] = (png_byte)compression_type; buf[11] = (png_byte)filter_type; buf[12] = (png_byte)interlace_type; /* Write the chunk */ png_write_chunk(png_ptr, (png_bytep)png_IHDR, buf, (png_size_t)13); /* Initialize zlib with PNG info */ png_ptr->zstream.zalloc = png_zalloc; png_ptr->zstream.zfree = png_zfree; png_ptr->zstream.opaque = (voidpf)png_ptr; if (!(png_ptr->do_filter)) { if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE || png_ptr->bit_depth < 8) png_ptr->do_filter = PNG_FILTER_NONE; else png_ptr->do_filter = PNG_ALL_FILTERS; } if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY)) { if (png_ptr->do_filter != PNG_FILTER_NONE) png_ptr->zlib_strategy = Z_FILTERED; else png_ptr->zlib_strategy = Z_DEFAULT_STRATEGY; } if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_LEVEL)) png_ptr->zlib_level = Z_DEFAULT_COMPRESSION; if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL)) png_ptr->zlib_mem_level = 8; if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS)) png_ptr->zlib_window_bits = 15; if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_METHOD)) png_ptr->zlib_method = 8; ret = deflateInit2(&png_ptr->zstream, png_ptr->zlib_level, png_ptr->zlib_method, png_ptr->zlib_window_bits, png_ptr->zlib_mem_level, png_ptr->zlib_strategy); if (ret != Z_OK) { if (ret == Z_VERSION_ERROR) png_error(png_ptr, "zlib failed to initialize compressor -- version error"); if (ret == Z_STREAM_ERROR) png_error(png_ptr, "zlib failed to initialize compressor -- stream error"); if (ret == Z_MEM_ERROR) png_error(png_ptr, "zlib failed to initialize compressor -- mem error"); png_error(png_ptr, "zlib failed to initialize compressor"); } png_ptr->zstream.next_out = png_ptr->zbuf; png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; /* libpng is not interested in zstream.data_type */ /* Set it to a predefined value, to avoid its evaluation inside zlib */ png_ptr->zstream.data_type = Z_BINARY; png_ptr->mode = PNG_HAVE_IHDR; } /* Write the palette. We are careful not to trust png_color to be in the * correct order for PNG, so people can redefine it to any convenient * structure. */ void /* PRIVATE */ png_write_PLTE(png_structp png_ptr, png_colorp palette, png_uint_32 num_pal) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_PLTE; #endif png_uint_32 max_palette_length, i; png_colorp pal_ptr; png_byte buf[3]; png_debug(1, "in png_write_PLTE"); max_palette_length = (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ? (1 << png_ptr->bit_depth) : PNG_MAX_PALETTE_LENGTH; if (( #ifdef PNG_MNG_FEATURES_SUPPORTED !(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) && #endif num_pal == 0) || num_pal > max_palette_length) { if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) { png_error(png_ptr, "Invalid number of colors in palette"); } else { png_warning(png_ptr, "Invalid number of colors in palette"); return; } } if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR)) { png_warning(png_ptr, "Ignoring request to write a PLTE chunk in grayscale PNG"); return; } png_ptr->num_palette = (png_uint_16)num_pal; png_debug1(3, "num_palette = %d", png_ptr->num_palette); png_write_chunk_start(png_ptr, (png_bytep)png_PLTE, (png_uint_32)(num_pal * 3)); #ifdef PNG_POINTER_INDEXING_SUPPORTED for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++) { buf[0] = pal_ptr->red; buf[1] = pal_ptr->green; buf[2] = pal_ptr->blue; png_write_chunk_data(png_ptr, buf, (png_size_t)3); } #else /* This is a little slower but some buggy compilers need to do this * instead */ pal_ptr=palette; for (i = 0; i < num_pal; i++) { buf[0] = pal_ptr[i].red; buf[1] = pal_ptr[i].green; buf[2] = pal_ptr[i].blue; png_write_chunk_data(png_ptr, buf, (png_size_t)3); } #endif png_write_chunk_end(png_ptr); png_ptr->mode |= PNG_HAVE_PLTE; } /* Write an IDAT chunk */ void /* PRIVATE */ png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_IDAT; #endif png_debug(1, "in png_write_IDAT"); /* Optimize the CMF field in the zlib stream. */ /* This hack of the zlib stream is compliant to the stream specification. */ if (!(png_ptr->mode & PNG_HAVE_IDAT) && png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE) { unsigned int z_cmf = data[0]; /* zlib compression method and flags */ if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70) { /* Avoid memory underflows and multiplication overflows. * * The conditions below are practically always satisfied; * however, they still must be checked. */ if (length >= 2 && png_ptr->height < 16384 && png_ptr->width < 16384) { png_uint_32 uncompressed_idat_size = png_ptr->height * ((png_ptr->width * png_ptr->channels * png_ptr->bit_depth + 15) >> 3); unsigned int z_cinfo = z_cmf >> 4; unsigned int half_z_window_size = 1 << (z_cinfo + 7); while (uncompressed_idat_size <= half_z_window_size && half_z_window_size >= 256) { z_cinfo--; half_z_window_size >>= 1; } z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4); if (data[0] != (png_byte)z_cmf) { data[0] = (png_byte)z_cmf; data[1] &= 0xe0; data[1] += (png_byte)(0x1f - ((z_cmf << 8) + data[1]) % 0x1f); } } } else png_error(png_ptr, "Invalid zlib compression method or flags in IDAT"); } png_write_chunk(png_ptr, (png_bytep)png_IDAT, data, length); png_ptr->mode |= PNG_HAVE_IDAT; } /* Write an IEND chunk */ void /* PRIVATE */ png_write_IEND(png_structp png_ptr) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_IEND; #endif png_debug(1, "in png_write_IEND"); png_write_chunk(png_ptr, (png_bytep)png_IEND, png_bytep_NULL, (png_size_t)0); png_ptr->mode |= PNG_HAVE_IEND; } #ifdef PNG_WRITE_gAMA_SUPPORTED /* Write a gAMA chunk */ #ifdef PNG_FLOATING_POINT_SUPPORTED void /* PRIVATE */ png_write_gAMA(png_structp png_ptr, double file_gamma) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_gAMA; #endif png_uint_32 igamma; png_byte buf[4]; png_debug(1, "in png_write_gAMA"); /* file_gamma is saved in 1/100,000ths */ igamma = (png_uint_32)(file_gamma * 100000.0 + 0.5); png_save_uint_32(buf, igamma); png_write_chunk(png_ptr, (png_bytep)png_gAMA, buf, (png_size_t)4); } #endif #ifdef PNG_FIXED_POINT_SUPPORTED void /* PRIVATE */ png_write_gAMA_fixed(png_structp png_ptr, png_fixed_point file_gamma) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_gAMA; #endif png_byte buf[4]; png_debug(1, "in png_write_gAMA"); /* file_gamma is saved in 1/100,000ths */ png_save_uint_32(buf, (png_uint_32)file_gamma); png_write_chunk(png_ptr, (png_bytep)png_gAMA, buf, (png_size_t)4); } #endif #endif #ifdef PNG_WRITE_sRGB_SUPPORTED /* Write a sRGB chunk */ void /* PRIVATE */ png_write_sRGB(png_structp png_ptr, int srgb_intent) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_sRGB; #endif png_byte buf[1]; png_debug(1, "in png_write_sRGB"); if (srgb_intent >= PNG_sRGB_INTENT_LAST) png_warning(png_ptr, "Invalid sRGB rendering intent specified"); buf[0]=(png_byte)srgb_intent; png_write_chunk(png_ptr, (png_bytep)png_sRGB, buf, (png_size_t)1); } #endif #ifdef PNG_WRITE_iCCP_SUPPORTED /* Write an iCCP chunk */ void /* PRIVATE */ png_write_iCCP(png_structp png_ptr, png_charp name, int compression_type, png_charp profile, int profile_len) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_iCCP; #endif png_size_t name_len; png_charp new_name; compression_state comp; int embedded_profile_len = 0; png_debug(1, "in png_write_iCCP"); comp.num_output_ptr = 0; comp.max_output_ptr = 0; comp.output_ptr = NULL; comp.input = NULL; comp.input_len = 0; if ((name_len = png_check_keyword(png_ptr, name, &new_name)) == 0) return; if (compression_type != PNG_COMPRESSION_TYPE_BASE) png_warning(png_ptr, "Unknown compression type in iCCP chunk"); if (profile == NULL) profile_len = 0; if (profile_len > 3) embedded_profile_len = ((*( (png_bytep)profile ))<<24) | ((*( (png_bytep)profile + 1))<<16) | ((*( (png_bytep)profile + 2))<< 8) | ((*( (png_bytep)profile + 3)) ); if (embedded_profile_len < 0) { png_warning(png_ptr, "Embedded profile length in iCCP chunk is negative"); png_free(png_ptr, new_name); return; } if (profile_len < embedded_profile_len) { png_warning(png_ptr, "Embedded profile length too large in iCCP chunk"); png_free(png_ptr, new_name); return; } if (profile_len > embedded_profile_len) { png_warning(png_ptr, "Truncating profile to actual length in iCCP chunk"); profile_len = embedded_profile_len; } if (profile_len) profile_len = png_text_compress(png_ptr, profile, (png_size_t)profile_len, PNG_COMPRESSION_TYPE_BASE, &comp); /* Make sure we include the NULL after the name and the compression type */ png_write_chunk_start(png_ptr, (png_bytep)png_iCCP, (png_uint_32)(name_len + profile_len + 2)); new_name[name_len + 1] = 0x00; png_write_chunk_data(png_ptr, (png_bytep)new_name, (png_size_t)(name_len + 2)); if (profile_len) png_write_compressed_data_out(png_ptr, &comp); png_write_chunk_end(png_ptr); png_free(png_ptr, new_name); } #endif #ifdef PNG_WRITE_sPLT_SUPPORTED /* Write a sPLT chunk */ void /* PRIVATE */ png_write_sPLT(png_structp png_ptr, png_sPLT_tp spalette) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_sPLT; #endif png_size_t name_len; png_charp new_name; png_byte entrybuf[10]; int entry_size = (spalette->depth == 8 ? 6 : 10); int palette_size = entry_size * spalette->nentries; png_sPLT_entryp ep; #ifndef PNG_POINTER_INDEXING_SUPPORTED int i; #endif png_debug(1, "in png_write_sPLT"); if ((name_len = png_check_keyword(png_ptr,spalette->name, &new_name))==0) return; /* Make sure we include the NULL after the name */ png_write_chunk_start(png_ptr, (png_bytep)png_sPLT, (png_uint_32)(name_len + 2 + palette_size)); png_write_chunk_data(png_ptr, (png_bytep)new_name, (png_size_t)(name_len + 1)); png_write_chunk_data(png_ptr, (png_bytep)&spalette->depth, (png_size_t)1); /* Loop through each palette entry, writing appropriately */ #ifdef PNG_POINTER_INDEXING_SUPPORTED for (ep = spalette->entries; epentries + spalette->nentries; ep++) { if (spalette->depth == 8) { entrybuf[0] = (png_byte)ep->red; entrybuf[1] = (png_byte)ep->green; entrybuf[2] = (png_byte)ep->blue; entrybuf[3] = (png_byte)ep->alpha; png_save_uint_16(entrybuf + 4, ep->frequency); } else { png_save_uint_16(entrybuf + 0, ep->red); png_save_uint_16(entrybuf + 2, ep->green); png_save_uint_16(entrybuf + 4, ep->blue); png_save_uint_16(entrybuf + 6, ep->alpha); png_save_uint_16(entrybuf + 8, ep->frequency); } png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size); } #else ep=spalette->entries; for (i=0; i>spalette->nentries; i++) { if (spalette->depth == 8) { entrybuf[0] = (png_byte)ep[i].red; entrybuf[1] = (png_byte)ep[i].green; entrybuf[2] = (png_byte)ep[i].blue; entrybuf[3] = (png_byte)ep[i].alpha; png_save_uint_16(entrybuf + 4, ep[i].frequency); } else { png_save_uint_16(entrybuf + 0, ep[i].red); png_save_uint_16(entrybuf + 2, ep[i].green); png_save_uint_16(entrybuf + 4, ep[i].blue); png_save_uint_16(entrybuf + 6, ep[i].alpha); png_save_uint_16(entrybuf + 8, ep[i].frequency); } png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size); } #endif png_write_chunk_end(png_ptr); png_free(png_ptr, new_name); } #endif #ifdef PNG_WRITE_sBIT_SUPPORTED /* Write the sBIT chunk */ void /* PRIVATE */ png_write_sBIT(png_structp png_ptr, png_color_8p sbit, int color_type) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_sBIT; #endif png_byte buf[4]; png_size_t size; png_debug(1, "in png_write_sBIT"); /* Make sure we don't depend upon the order of PNG_COLOR_8 */ if (color_type & PNG_COLOR_MASK_COLOR) { png_byte maxbits; maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 : png_ptr->usr_bit_depth); if (sbit->red == 0 || sbit->red > maxbits || sbit->green == 0 || sbit->green > maxbits || sbit->blue == 0 || sbit->blue > maxbits) { png_warning(png_ptr, "Invalid sBIT depth specified"); return; } buf[0] = sbit->red; buf[1] = sbit->green; buf[2] = sbit->blue; size = 3; } else { if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth) { png_warning(png_ptr, "Invalid sBIT depth specified"); return; } buf[0] = sbit->gray; size = 1; } if (color_type & PNG_COLOR_MASK_ALPHA) { if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth) { png_warning(png_ptr, "Invalid sBIT depth specified"); return; } buf[size++] = sbit->alpha; } png_write_chunk(png_ptr, (png_bytep)png_sBIT, buf, size); } #endif #ifdef PNG_WRITE_cHRM_SUPPORTED /* Write the cHRM chunk */ #ifdef PNG_FLOATING_POINT_SUPPORTED void /* PRIVATE */ png_write_cHRM(png_structp png_ptr, double white_x, double white_y, double red_x, double red_y, double green_x, double green_y, double blue_x, double blue_y) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_cHRM; #endif png_byte buf[32]; png_fixed_point int_white_x, int_white_y, int_red_x, int_red_y, int_green_x, int_green_y, int_blue_x, int_blue_y; png_debug(1, "in png_write_cHRM"); int_white_x = (png_uint_32)(white_x * 100000.0 + 0.5); int_white_y = (png_uint_32)(white_y * 100000.0 + 0.5); int_red_x = (png_uint_32)(red_x * 100000.0 + 0.5); int_red_y = (png_uint_32)(red_y * 100000.0 + 0.5); int_green_x = (png_uint_32)(green_x * 100000.0 + 0.5); int_green_y = (png_uint_32)(green_y * 100000.0 + 0.5); int_blue_x = (png_uint_32)(blue_x * 100000.0 + 0.5); int_blue_y = (png_uint_32)(blue_y * 100000.0 + 0.5); #ifdef PNG_CHECK_cHRM_SUPPORTED if (png_check_cHRM_fixed(png_ptr, int_white_x, int_white_y, int_red_x, int_red_y, int_green_x, int_green_y, int_blue_x, int_blue_y)) #endif { /* Each value is saved in 1/100,000ths */ png_save_uint_32(buf, int_white_x); png_save_uint_32(buf + 4, int_white_y); png_save_uint_32(buf + 8, int_red_x); png_save_uint_32(buf + 12, int_red_y); png_save_uint_32(buf + 16, int_green_x); png_save_uint_32(buf + 20, int_green_y); png_save_uint_32(buf + 24, int_blue_x); png_save_uint_32(buf + 28, int_blue_y); png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32); } } #endif #ifdef PNG_FIXED_POINT_SUPPORTED void /* PRIVATE */ png_write_cHRM_fixed(png_structp png_ptr, png_fixed_point white_x, png_fixed_point white_y, png_fixed_point red_x, png_fixed_point red_y, png_fixed_point green_x, png_fixed_point green_y, png_fixed_point blue_x, png_fixed_point blue_y) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_cHRM; #endif png_byte buf[32]; png_debug(1, "in png_write_cHRM"); /* Each value is saved in 1/100,000ths */ #ifdef PNG_CHECK_cHRM_SUPPORTED if (png_check_cHRM_fixed(png_ptr, white_x, white_y, red_x, red_y, green_x, green_y, blue_x, blue_y)) #endif { png_save_uint_32(buf, (png_uint_32)white_x); png_save_uint_32(buf + 4, (png_uint_32)white_y); png_save_uint_32(buf + 8, (png_uint_32)red_x); png_save_uint_32(buf + 12, (png_uint_32)red_y); png_save_uint_32(buf + 16, (png_uint_32)green_x); png_save_uint_32(buf + 20, (png_uint_32)green_y); png_save_uint_32(buf + 24, (png_uint_32)blue_x); png_save_uint_32(buf + 28, (png_uint_32)blue_y); png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32); } } #endif #endif #ifdef PNG_WRITE_tRNS_SUPPORTED /* Write the tRNS chunk */ void /* PRIVATE */ png_write_tRNS(png_structp png_ptr, png_bytep trans, png_color_16p tran, int num_trans, int color_type) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_tRNS; #endif png_byte buf[6]; png_debug(1, "in png_write_tRNS"); if (color_type == PNG_COLOR_TYPE_PALETTE) { if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette) { png_warning(png_ptr, "Invalid number of transparent colors specified"); return; } /* Write the chunk out as it is */ png_write_chunk(png_ptr, (png_bytep)png_tRNS, trans, (png_size_t)num_trans); } else if (color_type == PNG_COLOR_TYPE_GRAY) { /* One 16 bit value */ if (tran->gray >= (1 << png_ptr->bit_depth)) { png_warning(png_ptr, "Ignoring attempt to write tRNS chunk out-of-range for bit_depth"); return; } png_save_uint_16(buf, tran->gray); png_write_chunk(png_ptr, (png_bytep)png_tRNS, buf, (png_size_t)2); } else if (color_type == PNG_COLOR_TYPE_RGB) { /* Three 16 bit values */ png_save_uint_16(buf, tran->red); png_save_uint_16(buf + 2, tran->green); png_save_uint_16(buf + 4, tran->blue); if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4])) { png_warning(png_ptr, "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8"); return; } png_write_chunk(png_ptr, (png_bytep)png_tRNS, buf, (png_size_t)6); } else { png_warning(png_ptr, "Can't write tRNS with an alpha channel"); } } #endif #ifdef PNG_WRITE_bKGD_SUPPORTED /* Write the background chunk */ void /* PRIVATE */ png_write_bKGD(png_structp png_ptr, png_color_16p back, int color_type) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_bKGD; #endif png_byte buf[6]; png_debug(1, "in png_write_bKGD"); if (color_type == PNG_COLOR_TYPE_PALETTE) { if ( #ifdef PNG_MNG_FEATURES_SUPPORTED (png_ptr->num_palette || (!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) && #endif back->index >= png_ptr->num_palette) { png_warning(png_ptr, "Invalid background palette index"); return; } buf[0] = back->index; png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)1); } else if (color_type & PNG_COLOR_MASK_COLOR) { png_save_uint_16(buf, back->red); png_save_uint_16(buf + 2, back->green); png_save_uint_16(buf + 4, back->blue); if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4])) { png_warning(png_ptr, "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8"); return; } png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)6); } else { if (back->gray >= (1 << png_ptr->bit_depth)) { png_warning(png_ptr, "Ignoring attempt to write bKGD chunk out-of-range for bit_depth"); return; } png_save_uint_16(buf, back->gray); png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)2); } } #endif #ifdef PNG_WRITE_hIST_SUPPORTED /* Write the histogram */ void /* PRIVATE */ png_write_hIST(png_structp png_ptr, png_uint_16p hist, int num_hist) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_hIST; #endif int i; png_byte buf[3]; png_debug(1, "in png_write_hIST"); if (num_hist > (int)png_ptr->num_palette) { png_debug2(3, "num_hist = %d, num_palette = %d", num_hist, png_ptr->num_palette); png_warning(png_ptr, "Invalid number of histogram entries specified"); return; } png_write_chunk_start(png_ptr, (png_bytep)png_hIST, (png_uint_32)(num_hist * 2)); for (i = 0; i < num_hist; i++) { png_save_uint_16(buf, hist[i]); png_write_chunk_data(png_ptr, buf, (png_size_t)2); } png_write_chunk_end(png_ptr); } #endif #ifdef PNG_WRITE_tEXt_SUPPORTED /* Write a tEXt chunk */ void /* PRIVATE */ png_write_tEXt(png_structp png_ptr, png_charp key, png_charp text, png_size_t text_len) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_tEXt; #endif png_size_t key_len; png_charp new_key; png_debug(1, "in png_write_tEXt"); if ((key_len = png_check_keyword(png_ptr, key, &new_key))==0) return; if (text == NULL || *text == '\0') text_len = 0; else text_len = png_strlen(text); /* Make sure we include the 0 after the key */ png_write_chunk_start(png_ptr, (png_bytep)png_tEXt, (png_uint_32)(key_len + text_len + 1)); /* * We leave it to the application to meet PNG-1.0 requirements on the * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them. * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG. */ png_write_chunk_data(png_ptr, (png_bytep)new_key, (png_size_t)(key_len + 1)); if (text_len) png_write_chunk_data(png_ptr, (png_bytep)text, (png_size_t)text_len); png_write_chunk_end(png_ptr); png_free(png_ptr, new_key); } #endif #ifdef PNG_WRITE_zTXt_SUPPORTED /* Write a compressed text chunk */ void /* PRIVATE */ png_write_zTXt(png_structp png_ptr, png_charp key, png_charp text, png_size_t text_len, int compression) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_zTXt; #endif png_size_t key_len; char buf[1]; png_charp new_key; compression_state comp; png_debug(1, "in png_write_zTXt"); comp.num_output_ptr = 0; comp.max_output_ptr = 0; comp.output_ptr = NULL; comp.input = NULL; comp.input_len = 0; if ((key_len = png_check_keyword(png_ptr, key, &new_key))==0) { png_free(png_ptr, new_key); return; } if (text == NULL || *text == '\0' || compression==PNG_TEXT_COMPRESSION_NONE) { png_write_tEXt(png_ptr, new_key, text, (png_size_t)0); png_free(png_ptr, new_key); return; } text_len = png_strlen(text); /* Compute the compressed data; do it now for the length */ text_len = png_text_compress(png_ptr, text, text_len, compression, &comp); /* Write start of chunk */ png_write_chunk_start(png_ptr, (png_bytep)png_zTXt, (png_uint_32)(key_len+text_len + 2)); /* Write key */ png_write_chunk_data(png_ptr, (png_bytep)new_key, (png_size_t)(key_len + 1)); png_free(png_ptr, new_key); buf[0] = (png_byte)compression; /* Write compression */ png_write_chunk_data(png_ptr, (png_bytep)buf, (png_size_t)1); /* Write the compressed data */ png_write_compressed_data_out(png_ptr, &comp); /* Close the chunk */ png_write_chunk_end(png_ptr); } #endif #ifdef PNG_WRITE_iTXt_SUPPORTED /* Write an iTXt chunk */ void /* PRIVATE */ png_write_iTXt(png_structp png_ptr, int compression, png_charp key, png_charp lang, png_charp lang_key, png_charp text) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_iTXt; #endif png_size_t lang_len, key_len, lang_key_len, text_len; png_charp new_lang; png_charp new_key = NULL; png_byte cbuf[2]; compression_state comp; png_debug(1, "in png_write_iTXt"); comp.num_output_ptr = 0; comp.max_output_ptr = 0; comp.output_ptr = NULL; comp.input = NULL; if ((key_len = png_check_keyword(png_ptr, key, &new_key))==0) return; if ((lang_len = png_check_keyword(png_ptr, lang, &new_lang))==0) { png_warning(png_ptr, "Empty language field in iTXt chunk"); new_lang = NULL; lang_len = 0; } if (lang_key == NULL) lang_key_len = 0; else lang_key_len = png_strlen(lang_key); if (text == NULL) text_len = 0; else text_len = png_strlen(text); /* Compute the compressed data; do it now for the length */ text_len = png_text_compress(png_ptr, text, text_len, compression-2, &comp); /* Make sure we include the compression flag, the compression byte, * and the NULs after the key, lang, and lang_key parts */ png_write_chunk_start(png_ptr, (png_bytep)png_iTXt, (png_uint_32)( 5 /* comp byte, comp flag, terminators for key, lang and lang_key */ + key_len + lang_len + lang_key_len + text_len)); /* We leave it to the application to meet PNG-1.0 requirements on the * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them. * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG. */ png_write_chunk_data(png_ptr, (png_bytep)new_key, (png_size_t)(key_len + 1)); /* Set the compression flag */ if (compression == PNG_ITXT_COMPRESSION_NONE || \ compression == PNG_TEXT_COMPRESSION_NONE) cbuf[0] = 0; else /* compression == PNG_ITXT_COMPRESSION_zTXt */ cbuf[0] = 1; /* Set the compression method */ cbuf[1] = 0; png_write_chunk_data(png_ptr, cbuf, (png_size_t)2); cbuf[0] = 0; png_write_chunk_data(png_ptr, (new_lang ? (png_bytep)new_lang : cbuf), (png_size_t)(lang_len + 1)); png_write_chunk_data(png_ptr, (lang_key ? (png_bytep)lang_key : cbuf), (png_size_t)(lang_key_len + 1)); png_write_compressed_data_out(png_ptr, &comp); png_write_chunk_end(png_ptr); png_free(png_ptr, new_key); png_free(png_ptr, new_lang); } #endif #ifdef PNG_WRITE_oFFs_SUPPORTED /* Write the oFFs chunk */ void /* PRIVATE */ png_write_oFFs(png_structp png_ptr, png_int_32 x_offset, png_int_32 y_offset, int unit_type) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_oFFs; #endif png_byte buf[9]; png_debug(1, "in png_write_oFFs"); if (unit_type >= PNG_OFFSET_LAST) png_warning(png_ptr, "Unrecognized unit type for oFFs chunk"); png_save_int_32(buf, x_offset); png_save_int_32(buf + 4, y_offset); buf[8] = (png_byte)unit_type; png_write_chunk(png_ptr, (png_bytep)png_oFFs, buf, (png_size_t)9); } #endif #ifdef PNG_WRITE_pCAL_SUPPORTED /* Write the pCAL chunk (described in the PNG extensions document) */ void /* PRIVATE */ png_write_pCAL(png_structp png_ptr, png_charp purpose, png_int_32 X0, png_int_32 X1, int type, int nparams, png_charp units, png_charpp params) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_pCAL; #endif png_size_t purpose_len, units_len, total_len; png_uint_32p params_len; png_byte buf[10]; png_charp new_purpose; int i; png_debug1(1, "in png_write_pCAL (%d parameters)", nparams); if (type >= PNG_EQUATION_LAST) png_warning(png_ptr, "Unrecognized equation type for pCAL chunk"); purpose_len = png_check_keyword(png_ptr, purpose, &new_purpose) + 1; png_debug1(3, "pCAL purpose length = %d", (int)purpose_len); units_len = png_strlen(units) + (nparams == 0 ? 0 : 1); png_debug1(3, "pCAL units length = %d", (int)units_len); total_len = purpose_len + units_len + 10; params_len = (png_uint_32p)png_malloc(png_ptr, (png_uint_32)(nparams * png_sizeof(png_uint_32))); /* Find the length of each parameter, making sure we don't count the null terminator for the last parameter. */ for (i = 0; i < nparams; i++) { params_len[i] = png_strlen(params[i]) + (i == nparams - 1 ? 0 : 1); png_debug2(3, "pCAL parameter %d length = %lu", i, (unsigned long) params_len[i]); total_len += (png_size_t)params_len[i]; } png_debug1(3, "pCAL total length = %d", (int)total_len); png_write_chunk_start(png_ptr, (png_bytep)png_pCAL, (png_uint_32)total_len); png_write_chunk_data(png_ptr, (png_bytep)new_purpose, (png_size_t)purpose_len); png_save_int_32(buf, X0); png_save_int_32(buf + 4, X1); buf[8] = (png_byte)type; buf[9] = (png_byte)nparams; png_write_chunk_data(png_ptr, buf, (png_size_t)10); png_write_chunk_data(png_ptr, (png_bytep)units, (png_size_t)units_len); png_free(png_ptr, new_purpose); for (i = 0; i < nparams; i++) { png_write_chunk_data(png_ptr, (png_bytep)params[i], (png_size_t)params_len[i]); } png_free(png_ptr, params_len); png_write_chunk_end(png_ptr); } #endif #ifdef PNG_WRITE_sCAL_SUPPORTED /* Write the sCAL chunk */ #if defined(PNG_FLOATING_POINT_SUPPORTED) && defined(PNG_STDIO_SUPPORTED) void /* PRIVATE */ png_write_sCAL(png_structp png_ptr, int unit, double width, double height) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_sCAL; #endif char buf[64]; png_size_t total_len; png_debug(1, "in png_write_sCAL"); buf[0] = (char)unit; #ifdef _WIN32_WCE /* sprintf() function is not supported on WindowsCE */ { wchar_t wc_buf[32]; size_t wc_len; swprintf(wc_buf, TEXT("%12.12e"), width); wc_len = wcslen(wc_buf); WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, buf + 1, wc_len, NULL, NULL); total_len = wc_len + 2; swprintf(wc_buf, TEXT("%12.12e"), height); wc_len = wcslen(wc_buf); WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, buf + total_len, wc_len, NULL, NULL); total_len += wc_len; } #else png_snprintf(buf + 1, 63, "%12.12e", width); total_len = 1 + png_strlen(buf + 1) + 1; png_snprintf(buf + total_len, 64-total_len, "%12.12e", height); total_len += png_strlen(buf + total_len); #endif png_debug1(3, "sCAL total length = %u", (unsigned int)total_len); png_write_chunk(png_ptr, (png_bytep)png_sCAL, (png_bytep)buf, total_len); } #else #ifdef PNG_FIXED_POINT_SUPPORTED void /* PRIVATE */ png_write_sCAL_s(png_structp png_ptr, int unit, png_charp width, png_charp height) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_sCAL; #endif png_byte buf[64]; png_size_t wlen, hlen, total_len; png_debug(1, "in png_write_sCAL_s"); wlen = png_strlen(width); hlen = png_strlen(height); total_len = wlen + hlen + 2; if (total_len > 64) { png_warning(png_ptr, "Can't write sCAL (buffer too small)"); return; } buf[0] = (png_byte)unit; png_memcpy(buf + 1, width, wlen + 1); /* Append the '\0' here */ png_memcpy(buf + wlen + 2, height, hlen); /* Do NOT append the '\0' here */ png_debug1(3, "sCAL total length = %u", (unsigned int)total_len); png_write_chunk(png_ptr, (png_bytep)png_sCAL, buf, total_len); } #endif #endif #endif #ifdef PNG_WRITE_pHYs_SUPPORTED /* Write the pHYs chunk */ void /* PRIVATE */ png_write_pHYs(png_structp png_ptr, png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit, int unit_type) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_pHYs; #endif png_byte buf[9]; png_debug(1, "in png_write_pHYs"); if (unit_type >= PNG_RESOLUTION_LAST) png_warning(png_ptr, "Unrecognized unit type for pHYs chunk"); png_save_uint_32(buf, x_pixels_per_unit); png_save_uint_32(buf + 4, y_pixels_per_unit); buf[8] = (png_byte)unit_type; png_write_chunk(png_ptr, (png_bytep)png_pHYs, buf, (png_size_t)9); } #endif #ifdef PNG_WRITE_tIME_SUPPORTED /* Write the tIME chunk. Use either png_convert_from_struct_tm() * or png_convert_from_time_t(), or fill in the structure yourself. */ void /* PRIVATE */ png_write_tIME(png_structp png_ptr, png_timep mod_time) { #ifdef PNG_USE_LOCAL_ARRAYS PNG_tIME; #endif png_byte buf[7]; png_debug(1, "in png_write_tIME"); if (mod_time->month > 12 || mod_time->month < 1 || mod_time->day > 31 || mod_time->day < 1 || mod_time->hour > 23 || mod_time->second > 60) { png_warning(png_ptr, "Invalid time specified for tIME chunk"); return; } png_save_uint_16(buf, mod_time->year); buf[2] = mod_time->month; buf[3] = mod_time->day; buf[4] = mod_time->hour; buf[5] = mod_time->minute; buf[6] = mod_time->second; png_write_chunk(png_ptr, (png_bytep)png_tIME, buf, (png_size_t)7); } #endif /* Initializes the row writing capability of libpng */ void /* PRIVATE */ png_write_start_row(png_structp png_ptr) { #ifdef PNG_WRITE_INTERLACING_SUPPORTED #ifndef PNG_USE_GLOBAL_ARRAYS /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ /* Start of interlace block */ int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; /* Offset to next interlace block */ int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; /* Start of interlace block in the y direction */ int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; /* Offset to next interlace block in the y direction */ int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; #endif #endif png_size_t buf_size; png_debug(1, "in png_write_start_row"); buf_size = (png_size_t)(PNG_ROWBYTES( png_ptr->usr_channels*png_ptr->usr_bit_depth, png_ptr->width) + 1); /* Set up row buffer */ png_ptr->row_buf = (png_bytep)png_malloc(png_ptr, (png_uint_32)buf_size); png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE; #ifdef PNG_WRITE_FILTER_SUPPORTED /* Set up filtering buffer, if using this filter */ if (png_ptr->do_filter & PNG_FILTER_SUB) { png_ptr->sub_row = (png_bytep)png_malloc(png_ptr, (png_uint_32)(png_ptr->rowbytes + 1)); png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB; } /* We only need to keep the previous row if we are using one of these. */ if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH)) { /* Set up previous row buffer */ png_ptr->prev_row = (png_bytep)png_calloc(png_ptr, (png_uint_32)buf_size); if (png_ptr->do_filter & PNG_FILTER_UP) { png_ptr->up_row = (png_bytep)png_malloc(png_ptr, (png_uint_32)(png_ptr->rowbytes + 1)); png_ptr->up_row[0] = PNG_FILTER_VALUE_UP; } if (png_ptr->do_filter & PNG_FILTER_AVG) { png_ptr->avg_row = (png_bytep)png_malloc(png_ptr, (png_uint_32)(png_ptr->rowbytes + 1)); png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG; } if (png_ptr->do_filter & PNG_FILTER_PAETH) { png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr, (png_uint_32)(png_ptr->rowbytes + 1)); png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH; } } #endif /* PNG_WRITE_FILTER_SUPPORTED */ #ifdef PNG_WRITE_INTERLACING_SUPPORTED /* If interlaced, we need to set up width and height of pass */ if (png_ptr->interlaced) { if (!(png_ptr->transformations & PNG_INTERLACE)) { png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 - png_pass_ystart[0]) / png_pass_yinc[0]; png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 - png_pass_start[0]) / png_pass_inc[0]; } else { png_ptr->num_rows = png_ptr->height; png_ptr->usr_width = png_ptr->width; } } else #endif { png_ptr->num_rows = png_ptr->height; png_ptr->usr_width = png_ptr->width; } png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; png_ptr->zstream.next_out = png_ptr->zbuf; } /* Internal use only. Called when finished processing a row of data. */ void /* PRIVATE */ png_write_finish_row(png_structp png_ptr) { #ifdef PNG_WRITE_INTERLACING_SUPPORTED #ifndef PNG_USE_GLOBAL_ARRAYS /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ /* Start of interlace block */ int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; /* Offset to next interlace block */ int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; /* Start of interlace block in the y direction */ int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; /* Offset to next interlace block in the y direction */ int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; #endif #endif int ret; png_debug(1, "in png_write_finish_row"); /* Next row */ png_ptr->row_number++; /* See if we are done */ if (png_ptr->row_number < png_ptr->num_rows) return; #ifdef PNG_WRITE_INTERLACING_SUPPORTED /* If interlaced, go to next pass */ if (png_ptr->interlaced) { png_ptr->row_number = 0; if (png_ptr->transformations & PNG_INTERLACE) { png_ptr->pass++; } else { /* Loop until we find a non-zero width or height pass */ do { png_ptr->pass++; if (png_ptr->pass >= 7) break; png_ptr->usr_width = (png_ptr->width + png_pass_inc[png_ptr->pass] - 1 - png_pass_start[png_ptr->pass]) / png_pass_inc[png_ptr->pass]; png_ptr->num_rows = (png_ptr->height + png_pass_yinc[png_ptr->pass] - 1 - png_pass_ystart[png_ptr->pass]) / png_pass_yinc[png_ptr->pass]; if (png_ptr->transformations & PNG_INTERLACE) break; } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0); } /* Reset the row above the image for the next pass */ if (png_ptr->pass < 7) { if (png_ptr->prev_row != NULL) png_memset(png_ptr->prev_row, 0, (png_size_t)(PNG_ROWBYTES(png_ptr->usr_channels* png_ptr->usr_bit_depth, png_ptr->width)) + 1); return; } } #endif /* If we get here, we've just written the last row, so we need to flush the compressor */ do { /* Tell the compressor we are done */ ret = deflate(&png_ptr->zstream, Z_FINISH); /* Check for an error */ if (ret == Z_OK) { /* Check to see if we need more room */ if (!(png_ptr->zstream.avail_out)) { png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size); png_ptr->zstream.next_out = png_ptr->zbuf; png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; } } else if (ret != Z_STREAM_END) { if (png_ptr->zstream.msg != NULL) png_error(png_ptr, png_ptr->zstream.msg); else png_error(png_ptr, "zlib error"); } } while (ret != Z_STREAM_END); /* Write any extra space */ if (png_ptr->zstream.avail_out < png_ptr->zbuf_size) { png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size - png_ptr->zstream.avail_out); } deflateReset(&png_ptr->zstream); png_ptr->zstream.data_type = Z_BINARY; } #ifdef PNG_WRITE_INTERLACING_SUPPORTED /* Pick out the correct pixels for the interlace pass. * The basic idea here is to go through the row with a source * pointer and a destination pointer (sp and dp), and copy the * correct pixels for the pass. As the row gets compacted, * sp will always be >= dp, so we should never overwrite anything. * See the default: case for the easiest code to understand. */ void /* PRIVATE */ png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass) { /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ #ifndef PNG_USE_GLOBAL_ARRAYS /* Start of interlace block */ int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; /* Offset to next interlace block */ int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; #endif png_debug(1, "in png_do_write_interlace"); /* We don't have to do anything on the last pass (6) */ #ifdef PNG_USELESS_TESTS_SUPPORTED if (row != NULL && row_info != NULL && pass < 6) #else if (pass < 6) #endif { /* Each pixel depth is handled separately */ switch (row_info->pixel_depth) { case 1: { png_bytep sp; png_bytep dp; int shift; int d; int value; png_uint_32 i; png_uint_32 row_width = row_info->width; dp = row; d = 0; shift = 7; for (i = png_pass_start[pass]; i < row_width; i += png_pass_inc[pass]) { sp = row + (png_size_t)(i >> 3); value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01; d |= (value << shift); if (shift == 0) { shift = 7; *dp++ = (png_byte)d; d = 0; } else shift--; } if (shift != 7) *dp = (png_byte)d; break; } case 2: { png_bytep sp; png_bytep dp; int shift; int d; int value; png_uint_32 i; png_uint_32 row_width = row_info->width; dp = row; shift = 6; d = 0; for (i = png_pass_start[pass]; i < row_width; i += png_pass_inc[pass]) { sp = row + (png_size_t)(i >> 2); value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03; d |= (value << shift); if (shift == 0) { shift = 6; *dp++ = (png_byte)d; d = 0; } else shift -= 2; } if (shift != 6) *dp = (png_byte)d; break; } case 4: { png_bytep sp; png_bytep dp; int shift; int d; int value; png_uint_32 i; png_uint_32 row_width = row_info->width; dp = row; shift = 4; d = 0; for (i = png_pass_start[pass]; i < row_width; i += png_pass_inc[pass]) { sp = row + (png_size_t)(i >> 1); value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f; d |= (value << shift); if (shift == 0) { shift = 4; *dp++ = (png_byte)d; d = 0; } else shift -= 4; } if (shift != 4) *dp = (png_byte)d; break; } default: { png_bytep sp; png_bytep dp; png_uint_32 i; png_uint_32 row_width = row_info->width; png_size_t pixel_bytes; /* Start at the beginning */ dp = row; /* Find out how many bytes each pixel takes up */ pixel_bytes = (row_info->pixel_depth >> 3); /* Loop through the row, only looking at the pixels that matter */ for (i = png_pass_start[pass]; i < row_width; i += png_pass_inc[pass]) { /* Find out where the original pixel is */ sp = row + (png_size_t)i * pixel_bytes; /* Move the pixel */ if (dp != sp) png_memcpy(dp, sp, pixel_bytes); /* Next pixel */ dp += pixel_bytes; } break; } } /* Set new row width */ row_info->width = (row_info->width + png_pass_inc[pass] - 1 - png_pass_start[pass]) / png_pass_inc[pass]; row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_info->width); } } #endif /* This filters the row, chooses which filter to use, if it has not already * been specified by the application, and then writes the row out with the * chosen filter. */ #define PNG_MAXSUM (((png_uint_32)(-1)) >> 1) #define PNG_HISHIFT 10 #define PNG_LOMASK ((png_uint_32)0xffffL) #define PNG_HIMASK ((png_uint_32)(~PNG_LOMASK >> PNG_HISHIFT)) void /* PRIVATE */ png_write_find_filter(png_structp png_ptr, png_row_infop row_info) { png_bytep best_row; #ifdef PNG_WRITE_FILTER_SUPPORTED png_bytep prev_row, row_buf; png_uint_32 mins, bpp; png_byte filter_to_do = png_ptr->do_filter; png_uint_32 row_bytes = row_info->rowbytes; png_debug(1, "in png_write_find_filter"); /* Find out how many bytes offset each pixel is */ bpp = (row_info->pixel_depth + 7) >> 3; prev_row = png_ptr->prev_row; #endif best_row = png_ptr->row_buf; #ifdef PNG_WRITE_FILTER_SUPPORTED row_buf = best_row; mins = PNG_MAXSUM; /* The prediction method we use is to find which method provides the * smallest value when summing the absolute values of the distances * from zero, using anything >= 128 as negative numbers. This is known * as the "minimum sum of absolute differences" heuristic. Other * heuristics are the "weighted minimum sum of absolute differences" * (experimental and can in theory improve compression), and the "zlib * predictive" method (not implemented yet), which does test compressions * of lines using different filter methods, and then chooses the * (series of) filter(s) that give minimum compressed data size (VERY * computationally expensive). * * GRR 980525: consider also * (1) minimum sum of absolute differences from running average (i.e., * keep running sum of non-absolute differences & count of bytes) * [track dispersion, too? restart average if dispersion too large?] * (1b) minimum sum of absolute differences from sliding average, probably * with window size <= deflate window (usually 32K) * (2) minimum sum of squared differences from zero or running average * (i.e., ~ root-mean-square approach) */ /* We don't need to test the 'no filter' case if this is the only filter * that has been chosen, as it doesn't actually do anything to the data. */ if ((filter_to_do & PNG_FILTER_NONE) && filter_to_do != PNG_FILTER_NONE) { png_bytep rp; png_uint_32 sum = 0; png_uint_32 i; int v; for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++) { v = *rp; sum += (v < 128) ? v : 256 - v; } mins = sum; } /* Sub filter */ if (filter_to_do == PNG_FILTER_SUB) /* It's the only filter so no testing is needed */ { png_bytep rp, lp, dp; png_uint_32 i; for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp; i++, rp++, dp++) { *dp = *rp; } for (lp = row_buf + 1; i < row_bytes; i++, rp++, lp++, dp++) { *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff); } best_row = png_ptr->sub_row; } else if (filter_to_do & PNG_FILTER_SUB) { png_bytep rp, dp, lp; png_uint_32 sum = 0, lmins = mins; png_uint_32 i; int v; for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp; i++, rp++, dp++) { v = *dp = *rp; sum += (v < 128) ? v : 256 - v; } for (lp = row_buf + 1; i < row_bytes; i++, rp++, lp++, dp++) { v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff); sum += (v < 128) ? v : 256 - v; if (sum > lmins) /* We are already worse, don't continue. */ break; } if (sum < mins) { mins = sum; best_row = png_ptr->sub_row; } } /* Up filter */ if (filter_to_do == PNG_FILTER_UP) { png_bytep rp, dp, pp; png_uint_32 i; for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1, pp = prev_row + 1; i < row_bytes; i++, rp++, pp++, dp++) { *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff); } best_row = png_ptr->up_row; } else if (filter_to_do & PNG_FILTER_UP) { png_bytep rp, dp, pp; png_uint_32 sum = 0, lmins = mins; png_uint_32 i; int v; for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1, pp = prev_row + 1; i < row_bytes; i++) { v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff); sum += (v < 128) ? v : 256 - v; if (sum > lmins) /* We are already worse, don't continue. */ break; } if (sum < mins) { mins = sum; best_row = png_ptr->up_row; } } /* Avg filter */ if (filter_to_do == PNG_FILTER_AVG) { png_bytep rp, dp, pp, lp; png_uint_32 i; for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1, pp = prev_row + 1; i < bpp; i++) { *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff); } for (lp = row_buf + 1; i < row_bytes; i++) { *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff); } best_row = png_ptr->avg_row; } else if (filter_to_do & PNG_FILTER_AVG) { png_bytep rp, dp, pp, lp; png_uint_32 sum = 0, lmins = mins; png_uint_32 i; int v; for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1, pp = prev_row + 1; i < bpp; i++) { v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff); sum += (v < 128) ? v : 256 - v; } for (lp = row_buf + 1; i < row_bytes; i++) { v = *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff); sum += (v < 128) ? v : 256 - v; if (sum > lmins) /* We are already worse, don't continue. */ break; } if (sum < mins) { mins = sum; best_row = png_ptr->avg_row; } } /* Paeth filter */ if (filter_to_do == PNG_FILTER_PAETH) { png_bytep rp, dp, pp, cp, lp; png_uint_32 i; for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1, pp = prev_row + 1; i < bpp; i++) { *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff); } for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++) { int a, b, c, pa, pb, pc, p; b = *pp++; c = *cp++; a = *lp++; p = b - c; pc = a - c; #ifdef PNG_USE_ABS pa = abs(p); pb = abs(pc); pc = abs(p + pc); #else pa = p < 0 ? -p : p; pb = pc < 0 ? -pc : pc; pc = (p + pc) < 0 ? -(p + pc) : p + pc; #endif p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c; *dp++ = (png_byte)(((int)*rp++ - p) & 0xff); } best_row = png_ptr->paeth_row; } else if (filter_to_do & PNG_FILTER_PAETH) { png_bytep rp, dp, pp, cp, lp; png_uint_32 sum = 0, lmins = mins; png_uint_32 i; int v; for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1, pp = prev_row + 1; i < bpp; i++) { v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff); sum += (v < 128) ? v : 256 - v; } for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++) { int a, b, c, pa, pb, pc, p; b = *pp++; c = *cp++; a = *lp++; #ifndef PNG_SLOW_PAETH p = b - c; pc = a - c; #ifdef PNG_USE_ABS pa = abs(p); pb = abs(pc); pc = abs(p + pc); #else pa = p < 0 ? -p : p; pb = pc < 0 ? -pc : pc; pc = (p + pc) < 0 ? -(p + pc) : p + pc; #endif p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c; #else /* PNG_SLOW_PAETH */ p = a + b - c; pa = abs(p - a); pb = abs(p - b); pc = abs(p - c); if (pa <= pb && pa <= pc) p = a; else if (pb <= pc) p = b; else p = c; #endif /* PNG_SLOW_PAETH */ v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff); sum += (v < 128) ? v : 256 - v; if (sum > lmins) /* We are already worse, don't continue. */ break; } if (sum < mins) { best_row = png_ptr->paeth_row; } } #endif /* PNG_WRITE_FILTER_SUPPORTED */ /* Do the actual writing of the filtered row data from the chosen filter. */ png_write_filtered_row(png_ptr, best_row); } /* Do the actual writing of a previously filtered row. */ void /* PRIVATE */ png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row) { png_debug(1, "in png_write_filtered_row"); png_debug1(2, "filter = %d", filtered_row[0]); /* Set up the zlib input buffer */ png_ptr->zstream.next_in = filtered_row; png_ptr->zstream.avail_in = (uInt)png_ptr->row_info.rowbytes + 1; /* Repeat until we have compressed all the data */ do { int ret; /* Return of zlib */ /* Compress the data */ ret = deflate(&png_ptr->zstream, Z_NO_FLUSH); /* Check for compression errors */ if (ret != Z_OK) { if (png_ptr->zstream.msg != NULL) png_error(png_ptr, png_ptr->zstream.msg); else png_error(png_ptr, "zlib error"); } /* See if it is time to write another IDAT */ if (!(png_ptr->zstream.avail_out)) { /* Write the IDAT and reset the zlib output buffer */ png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size); png_ptr->zstream.next_out = png_ptr->zbuf; png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; } /* Repeat until all data has been compressed */ } while (png_ptr->zstream.avail_in); /* Swap the current and previous rows */ if (png_ptr->prev_row != NULL) { png_bytep tptr; tptr = png_ptr->prev_row; png_ptr->prev_row = png_ptr->row_buf; png_ptr->row_buf = tptr; } /* Finish row - updates counters and flushes zlib if last row */ png_write_finish_row(png_ptr); #ifdef PNG_WRITE_FLUSH_SUPPORTED png_ptr->flush_rows++; if (png_ptr->flush_dist > 0 && png_ptr->flush_rows >= png_ptr->flush_dist) { png_write_flush(png_ptr); } #endif } #endif /* PNG_WRITE_SUPPORTED */