| |
| /* pngwutil.c - utilities to write a png file |
| |
| libpng 1.0 beta 1 - version 0.71 |
| For conditions of distribution and use, see copyright notice in png.h |
| Copyright (c) 1995 Guy Eric Schalnat, Group 42, Inc. |
| June 26, 1995 |
| */ |
| #define PNG_INTERNAL |
| #include "png.h" |
| |
| /* place a 32 bit number into a buffer in png byte order. We work |
| with unsigned numbers for convenience, you may have to cast |
| signed numbers (if you use any, most png data is unsigned). */ |
| void |
| png_save_uint_32(png_byte *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); |
| } |
| |
| /* place a 16 bit number into a buffer in png byte order */ |
| void |
| png_save_uint_16(png_byte *buf, png_uint_16 i) |
| { |
| buf[0] = (png_byte)((i >> 8) & 0xff); |
| buf[1] = (png_byte)(i & 0xff); |
| } |
| |
| /* write a 32 bit number */ |
| void |
| png_write_uint_32(png_struct *png_ptr, png_uint_32 i) |
| { |
| png_byte buf[4]; |
| |
| 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); |
| png_write_data(png_ptr, buf, 4); |
| } |
| |
| /* write a 16 bit number */ |
| void |
| png_write_uint_16(png_struct *png_ptr, png_uint_16 i) |
| { |
| png_byte buf[2]; |
| |
| buf[0] = (png_byte)((i >> 8) & 0xff); |
| buf[1] = (png_byte)(i & 0xff); |
| png_write_data(png_ptr, buf, 2); |
| } |
| |
| /* 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 |
| png_write_chunk(png_struct *png_ptr, png_byte *type, |
| png_byte *data, png_uint_32 length) |
| { |
| /* write length */ |
| png_write_uint_32(png_ptr, length); |
| /* write chunk name */ |
| png_write_data(png_ptr, type, (png_uint_32)4); |
| /* reset the crc and run the chunk name over it */ |
| png_reset_crc(png_ptr); |
| png_calculate_crc(png_ptr, type, (png_uint_32)4); |
| /* write the data and update the crc */ |
| if (length) |
| { |
| png_calculate_crc(png_ptr, data, length); |
| png_write_data(png_ptr, data, length); |
| } |
| /* write the crc */ |
| png_write_uint_32(png_ptr, ~png_ptr->crc); |
| } |
| |
| /* 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 |
| png_write_chunk_start(png_struct *png_ptr, png_byte *type, |
| png_uint_32 total_length) |
| { |
| /* write the length */ |
| png_write_uint_32(png_ptr, total_length); |
| /* write the chunk name */ |
| png_write_data(png_ptr, type, (png_uint_32)4); |
| /* reset the crc and run it over the chunk name */ |
| png_reset_crc(png_ptr); |
| png_calculate_crc(png_ptr, type, (png_uint_32)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 |
| png_write_chunk_data(png_struct *png_ptr, png_byte *data, png_uint_32 length) |
| { |
| /* write the data, and run the crc over it */ |
| if (length) |
| { |
| png_calculate_crc(png_ptr, data, length); |
| png_write_data(png_ptr, data, length); |
| } |
| } |
| |
| /* finish a chunk started with png_write_chunk_start() */ |
| void |
| png_write_chunk_end(png_struct *png_ptr) |
| { |
| /* write the crc */ |
| png_write_uint_32(png_ptr, ~png_ptr->crc); |
| } |
| |
| /* simple function to write the signature */ |
| void |
| png_write_sig(png_struct *png_ptr) |
| { |
| /* write the 8 byte signature */ |
| png_write_data(png_ptr, png_sig, (png_uint_32)8); |
| } |
| |
| /* 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 |
| png_write_IHDR(png_struct *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) |
| { |
| png_byte buf[13]; /* buffer to store the IHDR info */ |
| |
| /* pack the header information into the buffer */ |
| png_save_uint_32(buf, width); |
| png_save_uint_32(buf + 4, height); |
| buf[8] = bit_depth; |
| buf[9] = color_type; |
| buf[10] = compression_type; |
| buf[11] = filter_type; |
| buf[12] = interlace_type; |
| /* save off the relevent information */ |
| png_ptr->bit_depth = bit_depth; |
| png_ptr->color_type = color_type; |
| png_ptr->interlaced = interlace_type; |
| png_ptr->width = width; |
| png_ptr->height = height; |
| |
| switch (color_type) |
| { |
| case 0: |
| case 3: |
| png_ptr->channels = 1; |
| break; |
| case 2: |
| png_ptr->channels = 3; |
| break; |
| case 4: |
| png_ptr->channels = 2; |
| break; |
| case 6: |
| png_ptr->channels = 4; |
| break; |
| } |
| png_ptr->pixel_depth = bit_depth * png_ptr->channels; |
| png_ptr->rowbytes = ((width * (png_uint_32)png_ptr->pixel_depth + 7) >> 3); |
| /* 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; |
| |
| /* write the chunk */ |
| png_write_chunk(png_ptr, png_IHDR, buf, (png_uint_32)13); |
| } |
| |
| /* 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 convient |
| structure. */ |
| void |
| png_write_PLTE(png_struct *png_ptr, png_color *palette, int number) |
| { |
| int i; |
| png_color *pal_ptr; |
| png_byte buf[3]; |
| |
| png_write_chunk_start(png_ptr, png_PLTE, number * 3); |
| for (i = 0, pal_ptr = palette; |
| i < number; |
| 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_uint_32)3); |
| } |
| png_write_chunk_end(png_ptr); |
| } |
| |
| /* write an IDAT chunk */ |
| void |
| png_write_IDAT(png_struct *png_ptr, png_byte *data, png_uint_32 length) |
| { |
| #ifdef zlibinout |
| /* temp zlib problem */ |
| { |
| extern FILE *fpzlibout; |
| |
| fwrite(data, 1, length, fpzlibout); |
| } |
| /* end temp zlib problem */ |
| #endif |
| |
| png_write_chunk(png_ptr, png_IDAT, data, length); |
| } |
| |
| /* write an IEND chunk */ |
| void |
| png_write_IEND(png_struct *png_ptr) |
| { |
| png_write_chunk(png_ptr, png_IEND, NULL, (png_uint_32)0); |
| } |
| |
| /* write a gAMA chunk */ |
| void |
| png_write_gAMA(png_struct *png_ptr, float gamma) |
| { |
| png_uint_32 igamma; |
| png_byte buf[4]; |
| |
| /* gamma is saved in 1/100,000ths */ |
| igamma = (png_uint_32)(gamma * 100000.0 + 0.5); |
| png_save_uint_32(buf, igamma); |
| png_write_chunk(png_ptr, png_gAMA, buf, (png_uint_32)4); |
| } |
| |
| /* write the sBIT chunk */ |
| void |
| png_write_sBIT(png_struct *png_ptr, png_color_8 *sbit, int color_type) |
| { |
| png_byte buf[4]; |
| int size; |
| |
| /* make sure we don't depend upon the order of png_color_8 */ |
| if (color_type & PNG_COLOR_MASK_COLOR) |
| { |
| buf[0] = sbit->red; |
| buf[1] = sbit->green; |
| buf[2] = sbit->blue; |
| size = 3; |
| } |
| else |
| { |
| buf[0] = sbit->gray; |
| size = 1; |
| } |
| |
| if (color_type & PNG_COLOR_MASK_ALPHA) |
| { |
| buf[size++] = sbit->alpha; |
| } |
| |
| png_write_chunk(png_ptr, png_sBIT, buf, (png_uint_32)size); |
| } |
| |
| /* write the cHRM chunk */ |
| void |
| png_write_cHRM(png_struct *png_ptr, float white_x, float white_y, |
| float red_x, float red_y, float green_x, float green_y, |
| float blue_x, float blue_y) |
| { |
| png_uint_32 itemp; |
| png_byte buf[32]; |
| |
| /* each value is saved int 1/100,000ths */ |
| itemp = (png_uint_32)(white_x * 100000.0 + 0.5); |
| png_save_uint_32(buf, itemp); |
| itemp = (png_uint_32)(white_y * 100000.0 + 0.5); |
| png_save_uint_32(buf + 4, itemp); |
| itemp = (png_uint_32)(red_x * 100000.0 + 0.5); |
| png_save_uint_32(buf + 8, itemp); |
| itemp = (png_uint_32)(red_y * 100000.0 + 0.5); |
| png_save_uint_32(buf + 12, itemp); |
| itemp = (png_uint_32)(green_x * 100000.0 + 0.5); |
| png_save_uint_32(buf + 16, itemp); |
| itemp = (png_uint_32)(green_y * 100000.0 + 0.5); |
| png_save_uint_32(buf + 20, itemp); |
| itemp = (png_uint_32)(blue_x * 100000.0 + 0.5); |
| png_save_uint_32(buf + 24, itemp); |
| itemp = (png_uint_32)(blue_y * 100000.0 + 0.5); |
| png_save_uint_32(buf + 28, itemp); |
| png_write_chunk(png_ptr, png_cHRM, buf, (png_uint_32)32); |
| } |
| |
| /* write the tRNS chunk */ |
| void |
| png_write_tRNS(png_struct *png_ptr, png_byte *trans, png_color_16 *tran, |
| int num_trans, int color_type) |
| { |
| png_byte buf[6]; |
| |
| if (color_type == PNG_COLOR_TYPE_PALETTE) |
| { |
| /* write the chunk out as it is */ |
| png_write_chunk(png_ptr, png_tRNS, trans, (png_uint_32)num_trans); |
| } |
| else if (color_type == PNG_COLOR_TYPE_GRAY) |
| { |
| /* one 16 bit value */ |
| png_save_uint_16(buf, tran->gray); |
| png_write_chunk(png_ptr, png_tRNS, buf, (png_uint_32)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); |
| png_write_chunk(png_ptr, png_tRNS, buf, (png_uint_32)6); |
| } |
| } |
| |
| /* write the background chunk */ |
| void |
| png_write_bKGD(png_struct *png_ptr, png_color_16 *back, int color_type) |
| { |
| png_byte buf[6]; |
| |
| if (color_type == PNG_COLOR_TYPE_PALETTE) |
| { |
| buf[0] = back->index; |
| png_write_chunk(png_ptr, png_bKGD, buf, (png_uint_32)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); |
| png_write_chunk(png_ptr, png_bKGD, buf, (png_uint_32)6); |
| } |
| else |
| { |
| png_save_uint_16(buf, back->gray); |
| png_write_chunk(png_ptr, png_bKGD, buf, (png_uint_32)2); |
| } |
| } |
| |
| /* write the histogram */ |
| void |
| png_write_hIST(png_struct *png_ptr, png_uint_16 *hist, int number) |
| { |
| int i; |
| png_byte buf[3]; |
| |
| png_write_chunk_start(png_ptr, png_hIST, (png_uint_32)(number * 2)); |
| for (i = 0; i < number; i++) |
| { |
| png_save_uint_16(buf, hist[i]); |
| png_write_chunk_data(png_ptr, buf, (png_uint_32)2); |
| } |
| png_write_chunk_end(png_ptr); |
| } |
| |
| /* write a tEXt chunk */ |
| void |
| png_write_tEXt(png_struct *png_ptr, char *key, char *text, |
| png_uint_32 text_len) |
| { |
| int key_len; |
| |
| key_len = strlen(key); |
| /* make sure we count the 0 after the key */ |
| png_write_chunk_start(png_ptr, png_tEXt, |
| (png_uint_32)(key_len + text_len + 1)); |
| /* key has an 0 at the end. How nice */ |
| png_write_chunk_data(png_ptr, (png_byte *)key, (png_uint_32)(key_len + 1)); |
| if (text && text_len) |
| png_write_chunk_data(png_ptr, (png_byte *)text, (png_uint_32)text_len); |
| png_write_chunk_end(png_ptr); |
| } |
| |
| /* write a compressed chunk */ |
| void |
| png_write_zTXt(png_struct *png_ptr, char *key, char *text, |
| png_uint_32 text_len, int compression) |
| { |
| int key_len; |
| char buf[1]; |
| int i, ret; |
| char **output_ptr = NULL; /* array of pointers to output */ |
| int num_output_ptr = 0; /* number of output pointers used */ |
| int max_output_ptr = 0; /* size of output_ptr */ |
| |
| key_len = strlen(key); |
| |
| /* we can't write the chunk until we find out how much data we have, |
| which means we need to run the compresser 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 |
| malloced pointers to be sure. */ |
| |
| /* set up the compression buffers */ |
| png_ptr->zstream->avail_in = (uInt)text_len; |
| png_ptr->zstream->next_in = (Byte *)text; |
| png_ptr->zstream->avail_out = (uInt)png_ptr->zbuf_size; |
| png_ptr->zstream->next_out = (Byte *)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) |
| 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 && png_ptr->zstream->avail_in) |
| { |
| /* make sure the output array has room */ |
| if (num_output_ptr >= max_output_ptr) |
| { |
| max_output_ptr = num_output_ptr + 4; |
| if (output_ptr) |
| output_ptr = png_realloc(png_ptr, output_ptr, |
| max_output_ptr * sizeof (char *)); |
| else |
| output_ptr = png_malloc(png_ptr, |
| max_output_ptr * sizeof (char *)); |
| } |
| |
| /* save the data */ |
| output_ptr[num_output_ptr] = png_large_malloc(png_ptr, |
| png_ptr->zbuf_size); |
| memcpy(output_ptr[num_output_ptr], png_ptr->zbuf, |
| (png_size_t)png_ptr->zbuf_size); |
| 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 anymore 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 && ret != Z_STREAM_END) |
| { |
| /* we got an error */ |
| if (png_ptr->zstream->msg) |
| 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 && ret == Z_OK) |
| { |
| /* check to make sure our output array has room */ |
| if (num_output_ptr >= max_output_ptr) |
| { |
| max_output_ptr = num_output_ptr + 4; |
| if (output_ptr) |
| output_ptr = png_realloc(png_ptr, output_ptr, |
| max_output_ptr * sizeof (char *)); |
| else |
| output_ptr = png_malloc(png_ptr, |
| max_output_ptr * sizeof (char *)); |
| } |
| |
| /* save off the data */ |
| output_ptr[num_output_ptr] = png_large_malloc(png_ptr, |
| png_ptr->zbuf_size); |
| memcpy(output_ptr[num_output_ptr], png_ptr->zbuf, |
| (png_size_t)png_ptr->zbuf_size); |
| 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; |
| } |
| } while (ret != Z_STREAM_END); |
| |
| /* text length is number of buffers plus last buffer */ |
| text_len = png_ptr->zbuf_size * num_output_ptr; |
| if (png_ptr->zstream->avail_out < png_ptr->zbuf_size) |
| text_len += (png_uint_32)(png_ptr->zbuf_size - |
| png_ptr->zstream->avail_out); |
| |
| /* write start of chunk */ |
| png_write_chunk_start(png_ptr, png_zTXt, |
| (png_uint_32)(key_len + text_len + 2)); |
| /* write key */ |
| png_write_chunk_data(png_ptr, (png_byte *)key, (png_uint_32)(key_len + 1)); |
| buf[0] = compression; |
| /* write compression */ |
| png_write_chunk_data(png_ptr, (png_byte *)buf, (png_uint_32)1); |
| |
| /* write saved output buffers, if any */ |
| for (i = 0; i < num_output_ptr; i++) |
| { |
| png_write_chunk_data(png_ptr, (png_byte *)output_ptr[i], png_ptr->zbuf_size); |
| png_large_free(png_ptr, output_ptr[i]); |
| } |
| if (max_output_ptr) |
| png_free(png_ptr, output_ptr); |
| /* write anything left in zbuf */ |
| if (png_ptr->zstream->avail_out < png_ptr->zbuf_size) |
| png_write_chunk_data(png_ptr, png_ptr->zbuf, |
| png_ptr->zbuf_size - png_ptr->zstream->avail_out); |
| /* close the chunk */ |
| png_write_chunk_end(png_ptr); |
| |
| /* reset zlib for another zTXt or the image data */ |
| /* deflateReset(png_ptr->zstream); */ |
| deflateEnd(png_ptr->zstream); |
| deflateInit(png_ptr->zstream, -1); |
| } |
| |
| /* write the pHYs chunk */ |
| void |
| png_write_pHYs(png_struct *png_ptr, png_uint_32 x_pixels_per_unit, |
| png_uint_32 y_pixels_per_unit, |
| int unit_type) |
| { |
| png_byte buf[9]; |
| |
| png_save_uint_32(buf, x_pixels_per_unit); |
| png_save_uint_32(buf + 4, y_pixels_per_unit); |
| buf[8] = unit_type; |
| |
| png_write_chunk(png_ptr, png_pHYs, buf, (png_uint_32)9); |
| } |
| |
| /* write the oFFs chunk */ |
| void |
| png_write_oFFs(png_struct *png_ptr, png_uint_32 x_offset, |
| png_uint_32 y_offset, |
| int unit_type) |
| { |
| png_byte buf[9]; |
| |
| png_save_uint_32(buf, x_offset); |
| png_save_uint_32(buf + 4, y_offset); |
| buf[8] = unit_type; |
| |
| png_write_chunk(png_ptr, png_oFFs, buf, (png_uint_32)9); |
| } |
| |
| /* two time chunks are given. This chunk assumes you have a gmtime() |
| function. If you don't have that, use the other tIME function */ |
| void |
| png_write_tIME(png_struct *png_ptr, png_time *mod_time) |
| { |
| png_byte buf[7]; |
| |
| 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_tIME, buf, (png_uint_32)7); |
| } |
| |
| /* initializes the row writing capability of libpng */ |
| void |
| png_write_start_row(png_struct *png_ptr) |
| { |
| /* set up row buffer */ |
| png_ptr->row_buf = (png_byte *)png_large_malloc(png_ptr, |
| (((png_uint_32)png_ptr->usr_channels * |
| (png_uint_32)png_ptr->usr_bit_depth * |
| png_ptr->width) >> 3) + 1); |
| /* set up filtering buffers, if filtering */ |
| if (png_ptr->bit_depth >= 8 && png_ptr->color_type != 3) |
| { |
| png_ptr->prev_row = (png_byte *)png_large_malloc(png_ptr, |
| png_ptr->rowbytes + 1); |
| memset(png_ptr->prev_row, 0, (png_size_t)png_ptr->rowbytes + 1); |
| png_ptr->save_row = (png_byte *)png_large_malloc(png_ptr, |
| png_ptr->rowbytes + 1); |
| memset(png_ptr->save_row, 0, (png_size_t)png_ptr->rowbytes + 1); |
| } |
| |
| /* 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 |
| { |
| 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 |
| png_write_finish_row(png_struct *png_ptr) |
| { |
| int ret; |
| |
| /* next row */ |
| png_ptr->row_number++; |
| /* see if we are done */ |
| if (png_ptr->row_number < png_ptr->num_rows) |
| return; |
| |
| /* 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]; |
| } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0); |
| |
| } |
| |
| /* reset filter row */ |
| if (png_ptr->prev_row) |
| memset(png_ptr->prev_row, 0, (png_size_t)png_ptr->rowbytes + 1); |
| /* if we have more data to get, go get it */ |
| if (png_ptr->pass < 7) |
| return; |
| } |
| |
| /* 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 && ret != Z_STREAM_END) |
| { |
| if (png_ptr->zstream->msg) |
| 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 && ret == Z_OK) |
| { |
| 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; |
| } |
| } 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); */ |
| deflateEnd(png_ptr->zstream); |
| deflateInit(png_ptr->zstream, -1); |
| |
| } |
| |
| /* 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 |
| png_do_write_interlace(png_row_info *row_info, png_byte *row, int pass) |
| { |
| /* we don't have to do anything on the last pass (6) */ |
| if (row && row_info && pass < 6) |
| { |
| /* each pixel depth is handled seperately */ |
| switch (row_info->pixel_depth) |
| { |
| case 1: |
| { |
| png_byte *sp; |
| png_byte *dp; |
| int shift; |
| int d; |
| int value; |
| png_uint_32 i; |
| |
| dp = row; |
| d = 0; |
| shift = 7; |
| for (i = png_pass_start[pass]; |
| i < row_info->width; |
| i += png_pass_inc[pass]) |
| { |
| sp = row + (png_size_t)(i >> 3); |
| value = (int)(*sp >> (7 - (int)(i & 7))) & 0x1; |
| d |= (value << shift); |
| |
| if (shift == 0) |
| { |
| shift = 7; |
| *dp++ = d; |
| d = 0; |
| } |
| else |
| shift--; |
| |
| } |
| if (shift != 7) |
| *dp = d; |
| break; |
| } |
| case 2: |
| { |
| png_byte *sp; |
| png_byte *dp; |
| int shift; |
| int d; |
| int value; |
| png_uint_32 i; |
| |
| dp = row; |
| shift = 6; |
| d = 0; |
| for (i = png_pass_start[pass]; |
| i < row_info->width; |
| i += png_pass_inc[pass]) |
| { |
| sp = row + (png_size_t)(i >> 2); |
| value = (*sp >> ((3 - (int)(i & 3)) << 1)) & 0x3; |
| d |= (value << shift); |
| |
| if (shift == 0) |
| { |
| shift = 6; |
| *dp++ = d; |
| d = 0; |
| } |
| else |
| shift -= 2; |
| } |
| if (shift != 6) |
| *dp = d; |
| break; |
| } |
| case 4: |
| { |
| png_byte *sp; |
| png_byte *dp; |
| int shift; |
| int d; |
| int value; |
| png_uint_32 i; |
| |
| dp = row; |
| shift = 4; |
| d = 0; |
| for (i = png_pass_start[pass]; |
| i < row_info->width; |
| i += png_pass_inc[pass]) |
| { |
| sp = row + (png_size_t)(i >> 1); |
| value = (*sp >> ((1 - (int)(i & 1)) << 2)) & 0xf; |
| d |= (value << shift); |
| |
| if (shift == 0) |
| { |
| shift = 4; |
| *dp++ = d; |
| d = 0; |
| } |
| else |
| shift -= 4; |
| } |
| if (shift != 4) |
| *dp = d; |
| break; |
| } |
| default: |
| { |
| png_byte *sp; |
| png_byte *dp; |
| png_uint_32 i; |
| int 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_info->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) |
| 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 = ((row_info->width * |
| row_info->pixel_depth + 7) >> 3); |
| |
| } |
| } |
| |
| /* this filters the row. Both row and prev_row have space at the |
| first byte for the filter byte. */ |
| void |
| png_write_filter_row(png_row_info *row_info, png_byte *row, |
| png_byte *prev_row) |
| { |
| int minf, bpp; |
| png_uint_32 i, v; |
| png_uint_32 s, mins; |
| png_byte *rp, *pp, *cp, *lp; |
| |
| /* find out how many bytes offset each pixel is */ |
| bpp = (row_info->pixel_depth + 7) / 8; |
| if (bpp < 1) |
| bpp = 1; |
| |
| /* the prediction method we use is to find which method provides |
| the smallest value when summing the abs of the distances from |
| zero using anything >= 128 as negitive numbers. */ |
| for (i = 0, s = 0, rp = row + 1; i < row_info->rowbytes; i++, rp++) |
| { |
| v = *rp; |
| if (v < 128) |
| s += v; |
| else |
| s += 256 - (png_int_32)v; |
| } |
| |
| mins = s; |
| minf = 0; |
| |
| /* check sub filter */ |
| for (i = 0, s = 0, rp = row + 1, lp = row + 1 - bpp; |
| i < row_info->rowbytes; i++, rp++, lp++) |
| { |
| if (i >= bpp) |
| v = (png_byte)(((int)*rp - (int)*lp) & 0xff); |
| else |
| v = *rp; |
| |
| if (v < 128) |
| s += v; |
| else |
| s += 256 - v; |
| } |
| |
| if (s < mins) |
| { |
| mins = s; |
| minf = 1; |
| } |
| |
| /* check up filter */ |
| for (i = 0, s = 0, rp = row + 1, pp = prev_row + 1; |
| i < row_info->rowbytes; i++, rp++, pp++) |
| { |
| v = (png_byte)(((int)*rp - (int)*pp) & 0xff); |
| |
| if (v < 128) |
| s += v; |
| else |
| s += 256 - v; |
| } |
| |
| if (s < mins) |
| { |
| mins = s; |
| minf = 2; |
| } |
| |
| /* check avg filter */ |
| for (i = 0, s = 0, rp = row + 1, pp = prev_row + 1, lp = row + 1 - bpp; |
| i < row_info->rowbytes; i++, rp++, pp++, lp++) |
| { |
| if (i >= bpp) |
| v = (png_byte)(((int)*rp - (((int)*pp + (int)*lp) / 2)) & 0xff); |
| else |
| v = (png_byte)(((int)*rp - ((int)*pp / 2)) & 0xff); |
| |
| if (v < 128) |
| s += v; |
| else |
| s += 256 - v; |
| } |
| |
| if (s < mins) |
| { |
| mins = s; |
| minf = 3; |
| } |
| |
| /* check paeth filter */ |
| for (i = 0, s = 0, rp = row + 1, pp = prev_row + 1, lp = row + 1 - bpp, |
| cp = prev_row + 1 - bpp; |
| i < row_info->rowbytes; i++, rp++, pp++, lp++, cp++) |
| { |
| int a, b, c, pa, pb, pc, p; |
| |
| b = *pp; |
| if (i >= bpp) |
| { |
| c = *cp; |
| a = *lp; |
| } |
| else |
| { |
| a = c = 0; |
| } |
| 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; |
| |
| v = (png_byte)(((int)*rp - p) & 0xff); |
| |
| if (v < 128) |
| s += v; |
| else |
| s += 256 - v; |
| } |
| |
| if (s < mins) |
| { |
| mins = s; |
| minf = 4; |
| } |
| |
| /* set filter byte */ |
| row[0] = minf; |
| |
| /* do filter */ |
| switch (minf) |
| { |
| /* sub filter */ |
| case 1: |
| for (i = bpp, rp = row + (png_size_t)row_info->rowbytes, |
| lp = row + (png_size_t)row_info->rowbytes - bpp; |
| i < row_info->rowbytes; i++, rp--, lp--) |
| { |
| *rp = (png_byte)(((int)*rp - (int)*lp) & 0xff); |
| } |
| break; |
| /* up filter */ |
| case 2: |
| for (i = 0, rp = row + (png_size_t)row_info->rowbytes, |
| pp = prev_row + (png_size_t)row_info->rowbytes; |
| i < row_info->rowbytes; i++, rp--, pp--) |
| { |
| *rp = (png_byte)(((int)*rp - (int)*pp) & 0xff); |
| } |
| break; |
| /* avg filter */ |
| case 3: |
| for (i = row_info->rowbytes, |
| rp = row + (png_size_t)row_info->rowbytes, |
| pp = prev_row + (png_size_t)row_info->rowbytes, |
| lp = row + (png_size_t)row_info->rowbytes - bpp; |
| i > bpp; i--, rp--, lp--, pp--) |
| { |
| *rp = (png_byte)(((int)*rp - (((int)*lp + (int)*pp) / |
| 2)) & 0xff); |
| } |
| for (; i > 0; i--, rp--, pp--) |
| { |
| *rp = (png_byte)(((int)*rp - ((int)*pp / 2)) & 0xff); |
| } |
| break; |
| /* paeth filter */ |
| case 4: |
| for (i = row_info->rowbytes, |
| rp = row + (png_size_t)row_info->rowbytes, |
| pp = prev_row + (png_size_t)row_info->rowbytes, |
| lp = row + (png_size_t)row_info->rowbytes - bpp, |
| cp = prev_row + (png_size_t)row_info->rowbytes - bpp; |
| i > 0; i--, rp--, lp--, pp--, cp--) |
| { |
| int a, b, c, pa, pb, pc, p; |
| |
| b = *pp; |
| if (i > bpp) |
| { |
| c = *cp; |
| a = *lp; |
| } |
| else |
| { |
| a = c = 0; |
| } |
| 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; |
| |
| *rp = (png_byte)(((int)*rp - p) & 0xff); |
| } |
| break; |
| } |
| } |
