/* makepng.c */
#define _ISOC99_SOURCE
/* Copyright: */
#define COPYRIGHT "\251 2013,2015 John Cunningham Bowler"
/*
* Last changed in libpng 1.6.20 [November 24, 2015]
*
* This code is released under the libpng license.
* For conditions of distribution and use, see the disclaimer
* and license in png.h
*
* Make a test PNG image. The arguments are as follows:
*
* makepng [--sRGB|--linear|--1.8] [--tRNS] [--nofilters] \
* color-type bit-depth [file-name]
*
* The color-type may be numeric (and must match the numbers used by the PNG
* specification) or one of the format names listed below. The bit-depth is the
* component bit depth, or the pixel bit-depth for a color-mapped image.
*
* Without any options no color-space information is written, with the options
* an sRGB or the appropriate gAMA chunk is written. "1.8" refers to the
* display system used on older Apple computers to correct for high ambient
* light levels in the viewing environment; it applies a transform of
* approximately value^(1/1.45) to the color values and so a gAMA chunk of 65909
* is written (1.45/2.2).
*
* The image data is generated internally. Unless --color is given the images
* used are as follows:
*
* 1 channel: a square image with a diamond, the least luminous colors are on
* the edge of the image, the most luminous in the center.
*
* 2 channels: the color channel increases in luminosity from top to bottom, the
* alpha channel increases in opacity from left to right.
*
* 3 channels: linear combinations of, from the top-left corner clockwise,
* black, green, white, red.
*
* 4 channels: linear combinations of, from the top-left corner clockwise,
* transparent, red, green, blue.
*
* For color-mapped images a four channel color-map is used and if --tRNS is
* given the PNG file has a tRNS chunk, as follows:
*
* 1-bit: entry 0 is transparent-red, entry 1 is opaque-white
* 2-bit: entry 0: transparent-green
* entry 1: 40%-red
* entry 2: 80%-blue
* entry 3: opaque-white
* 4-bit: the 16 combinations of the 2-bit case
* 8-bit: the 256 combinations of the 4-bit case
*
* The palette always has 2^bit-depth entries and the tRNS chunk one fewer. The
* image is the 1-channel diamond, but using palette index, not luminosity.
*
* For formats other than color-mapped ones if --tRNS is specified a tRNS chunk
* is generated with all channels equal to the low bits of 0x0101.
*
* Image size is determined by the final pixel depth in bits, i.e. channels x
* bit-depth, as follows:
*
* 8 bits or less: 64x64
* 16 bits: 256x256
* More than 16 bits: 1024x1024
*
* Row filtering is the libpng default but may be turned off (the 'none' filter
* is used on every row) with the --nofilters option.
*
* The images are not interlaced.
*
* If file-name is given then the PNG is written to that file, else it is
* written to stdout. Notice that stdout is not supported on systems where, by
* default, it assumes text output; this program makes no attempt to change the
* text mode of stdout!
*
* makepng --color=<color> ...
*
* If --color is given then the whole image has that color, color-mapped images
* will have exactly one palette entry and all image files with be 16x16 in
* size. The color value is 1 to 4 decimal numbers as appropriate for the color
* type.
*
* makepng --small ...
*
* If --small is given the images are no larger than required to include every
* possible pixel value for the format.
*
* For formats with pixels 8 bits or fewer in size the images consist of a
* single row with 2^pixel-depth pixels, one of every possible value.
*
* For formats with 16-bit pixels a 256x256 image is generated containing every
* possible pixel value.
*
* For larger pixel sizes a 256x256 image is generated where the first row
* consists of each pixel that has identical byte values throughout the pixel
* followed by rows where the byte values differ within the pixel.
*
* In all cases the pixel values are arranged in such a way that the SUB and UP
* filters give byte sequences for maximal zlib compression. By default (if
* --nofilters is not given) the SUB filter is used on the first row and the UP
* filter on all following rows.
*
* The --small option is meant to provide good test-case coverage, however the
* images are not easy to examine visually. Without the --small option the
* images contain identical color values; the pixel values are adjusted
* according to the gamma encoding with no gamma encoding being interpreted as
* sRGB.
*
* LICENSING
* =========
*
* This code is copyright of the authors, see the COPYRIGHT define above. The
* code is licensed as above, using the libpng license. The code generates
* images which are solely the product of the code; the options choose which of
* the many possibilities to generate. The images that result (but not the code
* which generates them) are licensed as defined here:
*
* IMPORTANT: the COPYRIGHT #define must contain ISO-Latin-1 characters, the
* IMAGE_LICENSING #define must contain UTF-8 characters. The 'copyright'
* symbol 0xA9U (\251) in ISO-Latin-1 encoding and 0xC20xA9 (\302\251) in UTF-8.
*/
#define IMAGE_LICENSING "Dedicated to the public domain per Creative Commons "\
"license \"CC0 1.0\"; https://creativecommons.org/publicdomain/zero/1.0/"
#include <stddef.h> /* for offsetof */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <math.h>
#include <errno.h>
#include <assert.h>
#include <stdint.h>
#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
# include <config.h>
#endif
/* Define the following to use this test against your installed libpng, rather
* than the one being built here:
*/
#ifdef PNG_FREESTANDING_TESTS
# include <png.h>
#else
# include "../../png.h"
#endif
#include <zlib.h>
/* Work round for GCC complaints about casting a (double) function result to
* an unsigned:
*/
static unsigned int
flooru(double d)
{
d = floor(d);
return (unsigned int)d;
}
static png_byte
floorb(double d)
{
d = floor(d);
return (png_byte)d;
}
/* This structure is used for inserting extra chunks (the --insert argument, not
* documented above.)
*/
typedef struct chunk_insert
{
struct chunk_insert *next;
void (*insert)(png_structp, png_infop, int, png_charpp);
int nparams;
png_charp parameters[1];
} chunk_insert;
static unsigned int
channels_of_type(int color_type)
{
if (color_type & PNG_COLOR_MASK_PALETTE)
return 1;
else
{
int channels = 1;
if (color_type & PNG_COLOR_MASK_COLOR)
channels = 3;
if (color_type & PNG_COLOR_MASK_ALPHA)
return channels + 1;
else
return channels;
}
}
static unsigned int
pixel_depth_of_type(int color_type, int bit_depth)
{
return channels_of_type(color_type) * bit_depth;
}
static unsigned int
image_size_of_type(int color_type, int bit_depth, unsigned int *colors,
int small)
{
if (*colors)
return 16;
else
{
int pixel_depth = pixel_depth_of_type(color_type, bit_depth);
if (small)
{
if (pixel_depth <= 8) /* there will be one row */
return 1 << pixel_depth;
else
return 256;
}
else if (pixel_depth < 8)
return 64;
else if (pixel_depth > 16)
return 1024;
else
return 256;
}
}
static void
set_color(png_colorp color, png_bytep trans, unsigned int red,
unsigned int green, unsigned int blue, unsigned int alpha,
png_const_bytep gamma_table)
{
color->red = gamma_table[red];
color->green = gamma_table[green];
color->blue = gamma_table[blue];
*trans = (png_byte)alpha;
}
static int
generate_palette(png_colorp palette, png_bytep trans, int bit_depth,
png_const_bytep gamma_table, unsigned int *colors)
{
/*
* 1-bit: entry 0 is transparent-red, entry 1 is opaque-white
* 2-bit: entry 0: transparent-green
* entry 1: 40%-red
* entry 2: 80%-blue
* entry 3: opaque-white
* 4-bit: the 16 combinations of the 2-bit case
* 8-bit: the 256 combinations of the 4-bit case
*/
switch (colors[0])
{
default:
fprintf(stderr, "makepng: --colors=...: invalid count %u\n",
colors[0]);
exit(1);
case 1:
set_color(palette+0, trans+0, colors[1], colors[1], colors[1], 255,
gamma_table);
return 1;
case 2:
set_color(palette+0, trans+0, colors[1], colors[1], colors[1],
colors[2], gamma_table);
return 1;
case 3:
set_color(palette+0, trans+0, colors[1], colors[2], colors[3], 255,
gamma_table);
return 1;
case 4:
set_color(palette+0, trans+0, colors[1], colors[2], colors[3],
colors[4], gamma_table);
return 1;
case 0:
if (bit_depth == 1)
{
set_color(palette+0, trans+0, 255, 0, 0, 0, gamma_table);
set_color(palette+1, trans+1, 255, 255, 255, 255, gamma_table);
return 2;
}
else
{
unsigned int size = 1U << (bit_depth/2); /* 2, 4 or 16 */
unsigned int x, y;
volatile unsigned int ip = 0;
for (x=0; x<size; ++x) for (y=0; y<size; ++y)
{
ip = x + (size * y);
/* size is at most 16, so the scaled value below fits in 16 bits
*/
# define interp(pos, c1, c2) ((pos * c1) + ((size-pos) * c2))
# define xyinterp(x, y, c1, c2, c3, c4) (((size * size / 2) +\
(interp(x, c1, c2) * y + (size-y) * interp(x, c3, c4))) /\
(size*size))
set_color(palette+ip, trans+ip,
/* color: green, red,blue,white */
xyinterp(x, y, 0, 255, 0, 255),
xyinterp(x, y, 255, 0, 0, 255),
xyinterp(x, y, 0, 0, 255, 255),
/* alpha: 0, 102, 204, 255) */
xyinterp(x, y, 0, 102, 204, 255),
gamma_table);
}
return ip+1;
}
}
}
static void
set_value(png_bytep row, size_t rowbytes, png_uint_32 x, unsigned int bit_depth,
png_uint_32 value, png_const_bytep gamma_table, double conv)
{
unsigned int mask = (1U << bit_depth)-1;
x *= bit_depth; /* Maximum x is 4*1024, maximum bit_depth is 16 */
if (value <= mask)
{
png_uint_32 offset = x >> 3;
if (offset < rowbytes && (bit_depth < 16 || offset+1 < rowbytes))
{
row += offset;
switch (bit_depth)
{
case 1:
case 2:
case 4:
/* Don't gamma correct - values get smashed */
{
unsigned int shift = (8 - bit_depth) - (x & 0x7U);
mask <<= shift;
value = (value << shift) & mask;
*row = (png_byte)((*row & ~mask) | value);
}
return;
default:
fprintf(stderr, "makepng: bad bit depth (internal error)\n");
exit(1);
case 16:
value = flooru(65535*pow(value/65535.,conv)+.5);
*row++ = (png_byte)(value >> 8);
*row = (png_byte)value;
return;
case 8:
*row = gamma_table[value];
return;
}
}
else
{
fprintf(stderr, "makepng: row buffer overflow (internal error)\n");
exit(1);
}
}
else
{
fprintf(stderr, "makepng: component overflow (internal error)\n");
exit(1);
}
}
static int /* filter mask for row */
generate_row(png_bytep row, size_t rowbytes, unsigned int y, int color_type,
int bit_depth, png_const_bytep gamma_table, double conv,
unsigned int *colors, int small)
{
int filters = 0; /* file *MASK*, 0 means the default, not NONE */
png_uint_32 size_max =
image_size_of_type(color_type, bit_depth, colors, small)-1;
png_uint_32 depth_max = (1U << bit_depth)-1; /* up to 65536 */
if (colors[0] == 0) if (small)
{
unsigned int pixel_depth = pixel_depth_of_type(color_type, bit_depth);
/* For pixel depths less than 16 generate a single row containing all the
* possible pixel values. For 16 generate all 65536 byte pair
* combinations in a 256x256 pixel array.
*/
switch (pixel_depth)
{
case 1:
assert(y == 0 && rowbytes == 1 && size_max == 1);
row[0] = 0x6CU; /* binary: 01101100, only top 2 bits used */
filters = PNG_FILTER_NONE;
break;
case 2:
assert(y == 0 && rowbytes == 1 && size_max == 3);
row[0] = 0x1BU; /* binary 00011011, all bits used */
filters = PNG_FILTER_NONE;
break;
case 4:
assert(y == 0 && rowbytes == 8 && size_max == 15);
row[0] = 0x01U;
row[1] = 0x23U; /* SUB gives 0x22U for all following bytes */
row[2] = 0x45U;
row[3] = 0x67U;
row[4] = 0x89U;
row[5] = 0xABU;
row[6] = 0xCDU;
row[7] = 0xEFU;
filters = PNG_FILTER_SUB;
break;
case 8:
/* The row will have all the pixel values in order starting with
* '1', the SUB filter will change every byte into '1' (including
* the last, which generates pixel value '0'). Since the SUB filter
* has value 1 this should result in maximum compression.
*/
assert(y == 0 && rowbytes == 256 && size_max == 255);
for (;;)
{
row[size_max] = 0xFFU & (size_max+1);
if (size_max == 0)
break;
--size_max;
}
filters = PNG_FILTER_SUB;
break;
case 16:
/* Rows are generated such that each row has a constant difference
* between the first and second byte of each pixel and so that the
* difference increases by 1 at each row. The rows start with the
* first byte value of 0 and the value increases to 255 across the
* row.
*
* The difference starts at 1, so the first row is:
*
* 0 1 1 2 2 3 3 4 ... 254 255 255 0
*
* This means that running the SUB filter on the first row produces:
*
* [SUB==1] 0 1 0 1 0 1...
*
* Then the difference is 2 on the next row, giving:
*
* 0 2 1 3 2 4 3 5 ... 254 0 255 1
*
* When the UP filter is run on this libpng produces:
*
* [UP ==2] 0 1 0 1 0 1...
*
* And so on for all the remain rows to the final two * rows:
*
* row 254: 0 255 1 0 2 1 3 2 4 3 ... 254 253 255 254
* row 255: 0 0 1 1 2 2 3 3 4 4 ... 254 254 255 255
*/
assert(rowbytes == 512 && size_max == 255);
for (;;)
{
row[2*size_max ] = 0xFFU & size_max;
row[2*size_max+1] = 0xFFU & (size_max+y+1);
if (size_max == 0)
break;
--size_max;
}
/* The first row must include PNG_FILTER_UP so that libpng knows we
* need to keep it for the following row:
*/
filters = (y == 0 ? PNG_FILTER_SUB+PNG_FILTER_UP : PNG_FILTER_UP);
break;
case 24:
case 32:
case 48:
case 64:
/* The rows are filled by an alogorithm similar to the above, in the
* first row pixel bytes are all equal, increasing from 0 by 1 for
* each pixel. In the second row the bytes within a pixel are
* incremented 1,3,5,7,... from the previous row byte. Using an odd
* number ensures all the possible byte values are used.
*/
assert(size_max == 255 && rowbytes == 256*(pixel_depth>>3));
pixel_depth >>= 3; /* now in bytes */
while (rowbytes > 0)
{
const size_t pixel_index = --rowbytes/pixel_depth;
if (y == 0)
row[rowbytes] = 0xFFU & pixel_index;
else
{
const size_t byte_offset =
rowbytes - pixel_index * pixel_depth;
row[rowbytes] =
0xFFU & (pixel_index + (byte_offset * 2*y) + 1);
}
}
filters = (y == 0 ? PNG_FILTER_SUB+PNG_FILTER_UP : PNG_FILTER_UP);
break;
default:
assert(0/*NOT REACHED*/);
}
}
else switch (channels_of_type(color_type))
{
/* 1 channel: a square image with a diamond, the least luminous colors are on
* the edge of the image, the most luminous in the center.
*/
case 1:
{
png_uint_32 x;
png_uint_32 base = 2*size_max - abs(2*y-size_max);
for (x=0; x<=size_max; ++x)
{
png_uint_32 luma = base - abs(2*x-size_max);
/* 'luma' is now in the range 0..2*size_max, we need
* 0..depth_max
*/
luma = (luma*depth_max + size_max) / (2*size_max);
set_value(row, rowbytes, x, bit_depth, luma, gamma_table, conv);
}
}
break;
/* 2 channels: the color channel increases in luminosity from top to bottom,
* the alpha channel increases in opacity from left to right.
*/
case 2:
{
png_uint_32 alpha = (depth_max * y * 2 + size_max) / (2 * size_max);
png_uint_32 x;
for (x=0; x<=size_max; ++x)
{
set_value(row, rowbytes, 2*x, bit_depth,
(depth_max * x * 2 + size_max) / (2 * size_max), gamma_table,
conv);
set_value(row, rowbytes, 2*x+1, bit_depth, alpha, gamma_table,
conv);
}
}
break;
/* 3 channels: linear combinations of, from the top-left corner clockwise,
* black, green, white, red.
*/
case 3:
{
/* x0: the black->red scale (the value of the red component) at the
* start of the row (blue and green are 0).
* x1: the green->white scale (the value of the red and blue
* components at the end of the row; green is depth_max).
*/
png_uint_32 Y = (depth_max * y * 2 + size_max) / (2 * size_max);
png_uint_32 x;
/* Interpolate x/depth_max from start to end:
*
* start end difference
* red: Y Y 0
* green: 0 depth_max depth_max
* blue: 0 Y Y
*/
for (x=0; x<=size_max; ++x)
{
set_value(row, rowbytes, 3*x+0, bit_depth, /* red */ Y,
gamma_table, conv);
set_value(row, rowbytes, 3*x+1, bit_depth, /* green */
(depth_max * x * 2 + size_max) / (2 * size_max),
gamma_table, conv);
set_value(row, rowbytes, 3*x+2, bit_depth, /* blue */
(Y * x * 2 + size_max) / (2 * size_max),
gamma_table, conv);
}
}
break;
/* 4 channels: linear combinations of, from the top-left corner clockwise,
* transparent, red, green, blue.
*/
case 4:
{
/* x0: the transparent->blue scale (the value of the blue and alpha
* components) at the start of the row (red and green are 0).
* x1: the red->green scale (the value of the red and green
* components at the end of the row; blue is 0 and alpha is
* depth_max).
*/
png_uint_32 Y = (depth_max * y * 2 + size_max) / (2 * size_max);
png_uint_32 x;
/* Interpolate x/depth_max from start to end:
*
* start end difference
* red: 0 depth_max-Y depth_max-Y
* green: 0 Y Y
* blue: Y 0 -Y
* alpha: Y depth_max depth_max-Y
*/
for (x=0; x<=size_max; ++x)
{
set_value(row, rowbytes, 4*x+0, bit_depth, /* red */
((depth_max-Y) * x * 2 + size_max) / (2 * size_max),
gamma_table, conv);
set_value(row, rowbytes, 4*x+1, bit_depth, /* green */
(Y * x * 2 + size_max) / (2 * size_max),
gamma_table, conv);
set_value(row, rowbytes, 4*x+2, bit_depth, /* blue */
Y - (Y * x * 2 + size_max) / (2 * size_max),
gamma_table, conv);
set_value(row, rowbytes, 4*x+3, bit_depth, /* alpha */
Y + ((depth_max-Y) * x * 2 + size_max) / (2 * size_max),
gamma_table, conv);
}
}
break;
default:
fprintf(stderr, "makepng: internal bad channel count\n");
exit(2);
}
else if (color_type & PNG_COLOR_MASK_PALETTE)
{
/* Palette with fixed color: the image rows are all 0 and the image width
* is 16.
*/
memset(row, 0, rowbytes);
}
else if (colors[0] == channels_of_type(color_type))
switch (channels_of_type(color_type))
{
case 1:
{
const png_uint_32 luma = colors[1];
png_uint_32 x;
for (x=0; x<=size_max; ++x)
set_value(row, rowbytes, x, bit_depth, luma, gamma_table,
conv);
}
break;
case 2:
{
const png_uint_32 luma = colors[1];
const png_uint_32 alpha = colors[2];
png_uint_32 x;
for (x=0; x<size_max; ++x)
{
set_value(row, rowbytes, 2*x, bit_depth, luma, gamma_table,
conv);
set_value(row, rowbytes, 2*x+1, bit_depth, alpha, gamma_table,
conv);
}
}
break;
case 3:
{
const png_uint_32 red = colors[1];
const png_uint_32 green = colors[2];
const png_uint_32 blue = colors[3];
png_uint_32 x;
for (x=0; x<=size_max; ++x)
{
set_value(row, rowbytes, 3*x+0, bit_depth, red, gamma_table,
conv);
set_value(row, rowbytes, 3*x+1, bit_depth, green, gamma_table,
conv);
set_value(row, rowbytes, 3*x+2, bit_depth, blue, gamma_table,
conv);
}
}
break;
case 4:
{
const png_uint_32 red = colors[1];
const png_uint_32 green = colors[2];
const png_uint_32 blue = colors[3];
const png_uint_32 alpha = colors[4];
png_uint_32 x;
for (x=0; x<=size_max; ++x)
{
set_value(row, rowbytes, 4*x+0, bit_depth, red, gamma_table,
conv);
set_value(row, rowbytes, 4*x+1, bit_depth, green, gamma_table,
conv);
set_value(row, rowbytes, 4*x+2, bit_depth, blue, gamma_table,
conv);
set_value(row, rowbytes, 4*x+3, bit_depth, alpha, gamma_table,
conv);
}
}
break;
default:
fprintf(stderr, "makepng: internal bad channel count\n");
exit(2);
}
else
{
fprintf(stderr,
"makepng: --color: count(%u) does not match channels(%u)\n",
colors[0], channels_of_type(color_type));
exit(1);
}
return filters;
}
static void PNGCBAPI
makepng_warning(png_structp png_ptr, png_const_charp message)
{
const char **ep = png_get_error_ptr(png_ptr);
const char *name;
if (ep != NULL && *ep != NULL)
name = *ep;
else
name = "makepng";
fprintf(stderr, "%s: warning: %s\n", name, message);
}
static void PNGCBAPI
makepng_error(png_structp png_ptr, png_const_charp message)
{
makepng_warning(png_ptr, message);
png_longjmp(png_ptr, 1);
}
static int /* 0 on success, else an error code */
write_png(const char **name, FILE *fp, int color_type, int bit_depth,
volatile png_fixed_point gamma, chunk_insert * volatile insert,
unsigned int filters, unsigned int *colors, int small, int tRNS)
{
png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
name, makepng_error, makepng_warning);
volatile png_infop info_ptr = NULL;
volatile png_bytep row = NULL;
if (png_ptr == NULL)
{
fprintf(stderr, "makepng: OOM allocating write structure\n");
return 1;
}
if (setjmp(png_jmpbuf(png_ptr)))
{
png_structp nv_ptr = png_ptr;
png_infop nv_info = info_ptr;
png_ptr = NULL;
info_ptr = NULL;
png_destroy_write_struct(&nv_ptr, &nv_info);
if (row != NULL) free(row);
return 1;
}
/* Allow benign errors so that we can write PNGs with errors */
png_set_benign_errors(png_ptr, 1/*allowed*/);
/* Max out the text compression level in an attempt to make the license
* small. If --small then do the same for the IDAT.
*/
if (small)
png_set_compression_level(png_ptr, Z_BEST_COMPRESSION);
png_set_text_compression_level(png_ptr, Z_BEST_COMPRESSION);
png_init_io(png_ptr, fp);
info_ptr = png_create_info_struct(png_ptr);
if (info_ptr == NULL)
png_error(png_ptr, "OOM allocating info structure");
{
const unsigned int size =
image_size_of_type(color_type, bit_depth, colors, small);
unsigned int ysize;
png_fixed_point real_gamma = 45455; /* For sRGB */
png_byte gamma_table[256];
double conv;
/* Normally images are square, but with 'small' we want to simply generate
* all the pixel values, or all that we reasonably can:
*/
if (small)
{
const unsigned int pixel_depth =
pixel_depth_of_type(color_type, bit_depth);
if (pixel_depth <= 8U)
{
assert(size == (1U<<pixel_depth));
ysize = 1U;
}
else
{
assert(size == 256U);
ysize = 256U;
}
}
else
ysize = size;
/* This function uses the libpng values used on read to carry extra
* information about the gamma:
*/
if (gamma == PNG_GAMMA_MAC_18)
gamma = 65909;
else if (gamma > 0 && gamma < 1000)
gamma = PNG_FP_1;
if (gamma > 0)
real_gamma = gamma;
{
unsigned int i;
if (real_gamma == 45455) for (i=0; i<256; ++i)
{
gamma_table[i] = (png_byte)i;
conv = 1.;
}
else
{
/* Convert 'i' from sRGB (45455) to real_gamma, this makes
* the images look the same regardless of the gAMA chunk.
*/
conv = real_gamma;
conv /= 45455;
gamma_table[0] = 0;
for (i=1; i<255; ++i)
gamma_table[i] = floorb(pow(i/255.,conv) * 255 + .5);
gamma_table[255] = 255;
}
}
png_set_IHDR(png_ptr, info_ptr, size, ysize, bit_depth, color_type,
PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
if (color_type & PNG_COLOR_MASK_PALETTE)
{
int npalette;
png_color palette[256];
png_byte trans[256];
npalette = generate_palette(palette, trans, bit_depth, gamma_table,
colors);
png_set_PLTE(png_ptr, info_ptr, palette, npalette);
if (tRNS)
png_set_tRNS(png_ptr, info_ptr, trans, npalette-1,
NULL/*transparent color*/);
/* Reset gamma_table to prevent the image rows being changed */
for (npalette=0; npalette<256; ++npalette)
gamma_table[npalette] = (png_byte)npalette;
}
else if (tRNS)
{
png_color_16 col;
col.red = col.green = col.blue = col.gray =
0x0101U & ((1U<<bit_depth)-1U);
col.index = 0U;
png_set_tRNS(png_ptr, info_ptr, NULL/*trans*/, 1U, &col);
}
if (gamma == PNG_DEFAULT_sRGB)
png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_ABSOLUTE);
else if (gamma > 0) /* Else don't set color space information */
{
png_set_gAMA_fixed(png_ptr, info_ptr, real_gamma);
/* Just use the sRGB values here. */
png_set_cHRM_fixed(png_ptr, info_ptr,
/* color x y */
/* white */ 31270, 32900,
/* red */ 64000, 33000,
/* green */ 30000, 60000,
/* blue */ 15000, 6000
);
}
/* Insert extra information. */
while (insert != NULL)
{
insert->insert(png_ptr, info_ptr, insert->nparams, insert->parameters);
insert = insert->next;
}
/* Write the file header. */
png_write_info(png_ptr, info_ptr);
/* Restrict the filters */
png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, filters);
{
# ifdef PNG_WRITE_INTERLACING_SUPPORTED
int passes = png_set_interlace_handling(png_ptr);
# else /* !WRITE_INTERLACING */
int passes = 1;
# endif /* !WRITE_INTERLACING */
int pass;
png_size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
row = malloc(rowbytes);
if (row == NULL)
png_error(png_ptr, "OOM allocating row buffer");
for (pass = 0; pass < passes; ++pass)
{
unsigned int y;
for (y=0; y<ysize; ++y)
{
unsigned int row_filters =
generate_row(row, rowbytes, y, color_type, bit_depth,
gamma_table, conv, colors, small);
if (row_filters != 0 && filters == PNG_ALL_FILTERS)
png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, row_filters);
png_write_row(png_ptr, row);
}
}
}
}
/* Finish writing the file. */
png_write_end(png_ptr, info_ptr);
{
png_structp nv_ptr = png_ptr;
png_infop nv_info = info_ptr;
png_ptr = NULL;
info_ptr = NULL;
png_destroy_write_struct(&nv_ptr, &nv_info);
}
free(row);
return 0;
}
static size_t
load_file(png_const_charp name, png_bytepp result)
{
FILE *fp = tmpfile();
if (fp != NULL)
{
FILE *ip = fopen(name, "rb");
if (ip != NULL)
{
size_t total = 0;
int ch;
for (;;)
{
ch = getc(ip);
if (ch == EOF) break;
putc(ch, fp);
++total;
}
if (ferror(ip))
{
perror(name);
fprintf(stderr, "%s: read error\n", name);
(void)fclose(ip);
}
else
{
(void)fclose(ip);
if (ferror(fp))
{
perror("temporary file");
fprintf(stderr, "temporary file write error\n");
}
else
{
rewind(fp);
if (total > 0)
{
/* Round up to a multiple of 4 here to allow an iCCP profile
* to be padded to a 4x boundary.
*/
png_bytep data = malloc((total+3)&~3);
if (data != NULL)
{
size_t new_size = 0;
for (;;)
{
ch = getc(fp);
if (ch == EOF) break;
data[new_size++] = (png_byte)ch;
}
if (ferror(fp) || new_size != total)
{
perror("temporary file");
fprintf(stderr, "temporary file read error\n");
free(data);
}
else
{
(void)fclose(fp);
*result = data;
return total;
}
}
else
fprintf(stderr, "%s: out of memory loading file\n", name);
}
else
fprintf(stderr, "%s: empty file\n", name);
}
}
}
else
{
perror(name);
fprintf(stderr, "%s: open failed\n", name);
}
fclose(fp);
}
else
fprintf(stderr, "makepng: %s: could not open temporary file\n", name);
exit(1);
return 0;
}
static png_size_t
load_fake(png_charp param, png_bytepp profile)
{
char *endptr = NULL;
uint64_t size = strtoull(param, &endptr, 0/*base*/);
/* The 'fake' format is <number>*[string] */
if (endptr != NULL && *endptr == '*')
{
size_t len = strlen(++endptr);
size_t result = (size_t)size;
if (len == 0) len = 1; /* capture the terminating '\0' */
/* Now repeat that string to fill 'size' bytes. */
if (result == size && (*profile = malloc(result)) != NULL)
{
png_bytep out = *profile;
if (len == 1)
memset(out, *endptr, result);
else
{
while (size >= len)
{
memcpy(out, endptr, len);
out += len;
size -= len;
}
memcpy(out, endptr, size);
}
return result;
}
else
{
fprintf(stderr, "%s: size exceeds system limits\n", param);
exit(1);
}
}
return 0;
}
static void
check_param_count(int nparams, int expect)
{
if (nparams != expect)
{
fprintf(stderr, "bad parameter count (internal error)\n");
exit(1);
}
}
static void
insert_iCCP(png_structp png_ptr, png_infop info_ptr, int nparams,
png_charpp params)
{
png_bytep profile = NULL;
png_uint_32 proflen = 0;
int result;
check_param_count(nparams, 2);
switch (params[1][0])
{
case '<':
{
png_size_t filelen = load_file(params[1]+1, &profile);
if (filelen > 0xfffffffc) /* Maximum profile length */
{
fprintf(stderr, "%s: file too long (%lu) for an ICC profile\n",
params[1]+1, (unsigned long)filelen);
exit(1);
}
proflen = (png_uint_32)filelen;
}
break;
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
{
png_size_t fake_len = load_fake(params[1], &profile);
if (fake_len > 0) /* else a simple parameter */
{
if (fake_len > 0xffffffff) /* Maximum profile length */
{
fprintf(stderr,
"%s: fake data too long (%lu) for an ICC profile\n",
params[1], (unsigned long)fake_len);
exit(1);
}
proflen = (png_uint_32)(fake_len & ~3U);
/* Always fix up the profile length. */
png_save_uint_32(profile, proflen);
break;
}
}
default:
fprintf(stderr, "--insert iCCP \"%s\": unrecognized\n", params[1]);
fprintf(stderr, " use '<' to read a file: \"<filename\"\n");
exit(1);
}
result = 1;
if (proflen & 3)
{
fprintf(stderr,
"makepng: --insert iCCP %s: profile length made a multiple of 4\n",
params[1]);
/* load_file allocates extra space for this padding, the ICC spec requires
* padding with zero bytes.
*/
while (proflen & 3)
profile[proflen++] = 0;
}
if (profile != NULL && proflen > 3)
{
png_uint_32 prof_header = png_get_uint_32(profile);
if (prof_header != proflen)
{
fprintf(stderr, "--insert iCCP %s: profile length field wrong:\n",
params[1]);
fprintf(stderr, " actual %lu, recorded value %lu (corrected)\n",
(unsigned long)proflen, (unsigned long)prof_header);
png_save_uint_32(profile, proflen);
}
}
if (result && profile != NULL && proflen >=4)
png_set_iCCP(png_ptr, info_ptr, params[0], PNG_COMPRESSION_TYPE_BASE,
profile, proflen);
if (profile)
free(profile);
if (!result)
exit(1);
}
static void
clear_text(png_text *text, png_charp keyword)
{
text->compression = -1; /* none */
text->key = keyword;
text->text = NULL;
text->text_length = 0; /* libpng calculates this */
text->itxt_length = 0; /* libpng calculates this */
text->lang = NULL;
text->lang_key = NULL;
}
static void
set_text(png_structp png_ptr, png_infop info_ptr, png_textp text,
png_charp param)
{
switch (param[0])
{
case '<':
{
png_bytep file = NULL;
text->text_length = load_file(param+1, &file);
text->text = (png_charp)file;
}
break;
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
{
png_bytep data = NULL;
png_size_t fake_len = load_fake(param, &data);
if (fake_len > 0) /* else a simple parameter */
{
text->text_length = fake_len;
text->text = (png_charp)data;
break;
}
}
default:
text->text = param;
break;
}
png_set_text(png_ptr, info_ptr, text, 1);
if (text->text != param)
free(text->text);
}
static void
insert_tEXt(png_structp png_ptr, png_infop info_ptr, int nparams,
png_charpp params)
{
png_text text;
check_param_count(nparams, 2);
clear_text(&text, params[0]);
set_text(png_ptr, info_ptr, &text, params[1]);
}
static void
insert_zTXt(png_structp png_ptr, png_infop info_ptr, int nparams,
png_charpp params)
{
png_text text;
check_param_count(nparams, 2);
clear_text(&text, params[0]);
text.compression = 0; /* deflate */
set_text(png_ptr, info_ptr, &text, params[1]);
}
static void
insert_iTXt(png_structp png_ptr, png_infop info_ptr, int nparams,
png_charpp params)
{
png_text text;
check_param_count(nparams, 4);
clear_text(&text, params[0]);
text.compression = 2; /* iTXt + deflate */
text.lang = params[1];/* language tag */
text.lang_key = params[2]; /* translated keyword */
set_text(png_ptr, info_ptr, &text, params[3]);
}
static void
insert_hIST(png_structp png_ptr, png_infop info_ptr, int nparams,
png_charpp params)
{
int i;
png_uint_16 freq[256];
/* libpng takes the count from the PLTE count; we don't check it here but we
* do set the array to 0 for unspecified entries.
*/
memset(freq, 0, sizeof freq);
for (i=0; i<nparams; ++i)
{
char *endptr = NULL;
unsigned long int l = strtoul(params[i], &endptr, 0/*base*/);
if (params[i][0] && *endptr == 0 && l <= 65535)
freq[i] = (png_uint_16)l;
else
{
fprintf(stderr, "hIST[%d]: %s: invalid frequency\n", i, params[i]);
exit(1);
}
}
png_set_hIST(png_ptr, info_ptr, freq);
}
static png_byte
bval(png_const_structrp png_ptr, png_charp param, unsigned int maxval)
{
char *endptr = NULL;
unsigned long int l = strtoul(param, &endptr, 0/*base*/);
if (param[0] && *endptr == 0 && l <= maxval)
return (png_byte)l;
else
png_error(png_ptr, "sBIT: invalid sBIT value");
}
static void
insert_sBIT(png_structp png_ptr, png_infop info_ptr, int nparams,
png_charpp params)
{
const int ct = png_get_color_type(png_ptr, info_ptr);
const int c = (ct & PNG_COLOR_MASK_COLOR ? 3 : 1) +
(ct & PNG_COLOR_MASK_ALPHA ? 1 : 0);
const unsigned int maxval =
ct & PNG_COLOR_MASK_PALETTE ? 8U : png_get_bit_depth(png_ptr, info_ptr);
png_color_8 sBIT;
if (nparams != c)
png_error(png_ptr, "sBIT: incorrect parameter count");
if (ct & PNG_COLOR_MASK_COLOR)
{
sBIT.red = bval(png_ptr, params[0], maxval);
sBIT.green = bval(png_ptr, params[1], maxval);
sBIT.blue = bval(png_ptr, params[2], maxval);
sBIT.gray = 42;
}
else
{
sBIT.red = sBIT.green = sBIT.blue = 42;
sBIT.gray = bval(png_ptr, params[0], maxval);
}
if (ct & PNG_COLOR_MASK_ALPHA)
sBIT.alpha = bval(png_ptr, params[nparams-1], maxval);
else
sBIT.alpha = 42;
png_set_sBIT(png_ptr, info_ptr, &sBIT);
}
#if 0
static void
insert_sPLT(png_structp png_ptr, png_infop info_ptr, int nparams, png_charpp params)
{
fprintf(stderr, "insert sPLT: NYI\n");
}
#endif
static int
find_parameters(png_const_charp what, png_charp param, png_charp *list,
int nparams)
{
/* Parameters are separated by '\n' or ':' characters, up to nparams are
* accepted (more is an error) and the number found is returned.
*/
int i;
for (i=0; *param && i<nparams; ++i)
{
list[i] = param;
while (*++param) if (*param == '\n' || *param == ':')
{
*param++ = 0; /* Terminate last parameter */
break; /* And start a new one. */
}
}
if (*param)
{
fprintf(stderr, "--insert %s: too many parameters (%s)\n", what, param);
exit(1);
}
list[i] = NULL; /* terminates list */
return i; /* number of parameters filled in */
}
static void
bad_parameter_count(png_const_charp what, int nparams)
{
fprintf(stderr, "--insert %s: bad parameter count %d\n", what, nparams);
exit(1);
}
static chunk_insert *
make_insert(png_const_charp what,
void (*insert)(png_structp, png_infop, int, png_charpp),
int nparams, png_charpp list)
{
int i;
chunk_insert *cip;
cip = malloc(offsetof(chunk_insert,parameters) +
nparams * sizeof (png_charp));
if (cip == NULL)
{
fprintf(stderr, "--insert %s: out of memory allocating %d parameters\n",
what, nparams);
exit(1);
}
cip->next = NULL;
cip->insert = insert;
cip->nparams = nparams;
for (i=0; i<nparams; ++i)
cip->parameters[i] = list[i];
return cip;
}
static chunk_insert *
find_insert(png_const_charp what, png_charp param)
{
png_uint_32 chunk = 0;
png_charp parameter_list[1024];
int i, nparams;
/* Assemble the chunk name */
for (i=0; i<4; ++i)
{
char ch = what[i];
if ((ch >= 65 && ch <= 90) || (ch >= 97 && ch <= 122))
chunk = (chunk << 8) + what[i];
else
break;
}
if (i < 4 || what[4] != 0)
{
fprintf(stderr, "makepng --insert \"%s\": invalid chunk name\n", what);
exit(1);
}
/* Assemble the parameter list. */
nparams = find_parameters(what, param, parameter_list, 1024);
# define CHUNK(a,b,c,d) (((a)<<24)+((b)<<16)+((c)<<8)+(d))
switch (chunk)
{
case CHUNK(105,67,67,80): /* iCCP */
if (nparams == 2)
return make_insert(what, insert_iCCP, nparams, parameter_list);
break;
case CHUNK(116,69,88,116): /* tEXt */
if (nparams == 2)
return make_insert(what, insert_tEXt, nparams, parameter_list);
break;
case CHUNK(122,84,88,116): /* zTXt */
if (nparams == 2)
return make_insert(what, insert_zTXt, nparams, parameter_list);
break;
case CHUNK(105,84,88,116): /* iTXt */
if (nparams == 4)
return make_insert(what, insert_iTXt, nparams, parameter_list);
break;
case CHUNK(104,73,83,84): /* hIST */
if (nparams <= 256)
return make_insert(what, insert_hIST, nparams, parameter_list);
break;
case CHUNK(115,66,73,84): /* sBIT */
if (nparams <= 4)
return make_insert(what, insert_sBIT, nparams, parameter_list);
break;
#if 0
case CHUNK(115,80,76,84): /* sPLT */
return make_insert(what, insert_sPLT, nparams, parameter_list);
#endif
default:
fprintf(stderr, "makepng --insert \"%s\": unrecognized chunk name\n",
what);
exit(1);
}
bad_parameter_count(what, nparams);
return NULL;
}
/* This is necessary because libpng expects writeable strings for things like
* text chunks (maybe this should be fixed...)
*/
static png_charp
strstash(png_const_charp foo)
{
/* The program indicates a memory allocation error by crashing, this is by
* design.
*/
if (foo != NULL)
{
png_charp bar = malloc(strlen(foo)+1);
return strcpy(bar, foo);
}
return NULL;
}
static png_charp
strstash_list(const png_const_charp *text)
{
size_t foo = 0;
png_charp result, bar;
const png_const_charp *line = text;
while (*line != NULL)
foo += strlen(*line++);
result = bar = malloc(foo+1);
line = text;
while (*line != NULL)
{
foo = strlen(*line);
memcpy(bar, *line++, foo);
bar += foo;
}
*bar = 0;
return result;
}
/* These are used to insert Copyright and Licence fields, they allow the text to
* have \n unlike the --insert option.
*/
static chunk_insert *
add_tEXt(const char *key, const png_const_charp *text)
{
static char what[5] = { 116, 69, 88, 116, 0 };
png_charp parameter_list[3];
parameter_list[0] = strstash(key);
parameter_list[1] = strstash_list(text);
parameter_list[2] = NULL;
return make_insert(what, insert_tEXt, 2, parameter_list);
}
static chunk_insert *
add_iTXt(const char *key, const char *language, const char *language_key,
const png_const_charp *text)
{
static char what[5] = { 105, 84, 88, 116, 0 };
png_charp parameter_list[5];
parameter_list[0] = strstash(key);
parameter_list[1] = strstash(language);
parameter_list[2] = strstash(language_key);
parameter_list[3] = strstash_list(text);
parameter_list[4] = NULL;
return make_insert(what, insert_iTXt, 4, parameter_list);
}
/* This is a not-very-good parser for a sequence of numbers (including 0). It
* doesn't accept some apparently valid things, but it accepts all the sensible
* combinations.
*/
static void
parse_color(char *arg, unsigned int *colors)
{
unsigned int ncolors = 0;
while (*arg && ncolors < 4)
{
char *ep = arg;
unsigned long ul = strtoul(arg, &ep, 0);
if (ul > 65535)
{
fprintf(stderr, "makepng --color=...'%s': too big\n", arg);
exit(1);
}
if (ep == arg)
{
fprintf(stderr, "makepng --color=...'%s': not a valid color\n", arg);
exit(1);
}
if (*ep) ++ep; /* skip a separator */
arg = ep;
colors[++ncolors] = (unsigned int)ul; /* checked above */
}
if (*arg)
{
fprintf(stderr, "makepng --color=...'%s': too many values\n", arg);
exit(1);
}
*colors = ncolors;
}
int
main(int argc, char **argv)
{
FILE *fp = stdout;
const char *file_name = NULL;
int color_type = 8; /* invalid */
int bit_depth = 32; /* invalid */
int small = 0; /* make full size images */
int tRNS = 0; /* don't output a tRNS chunk */
unsigned int colors[5];
unsigned int filters = PNG_ALL_FILTERS;
png_fixed_point gamma = 0; /* not set */
chunk_insert *head_insert = NULL;
chunk_insert **insert_ptr = &head_insert;
memset(colors, 0, sizeof colors);
while (--argc > 0)
{
char *arg = *++argv;
if (strcmp(arg, "--small") == 0)
{
small = 1;
continue;
}
if (strcmp(arg, "--tRNS") == 0)
{
tRNS = 1;
continue;
}
if (strcmp(arg, "--sRGB") == 0)
{
gamma = PNG_DEFAULT_sRGB;
continue;
}
if (strcmp(arg, "--linear") == 0)
{
gamma = PNG_FP_1;
continue;
}
if (strcmp(arg, "--1.8") == 0)
{
gamma = PNG_GAMMA_MAC_18;
continue;
}
if (strcmp(arg, "--nofilters") == 0)
{
filters = PNG_FILTER_NONE;
continue;
}
if (strncmp(arg, "--color=", 8) == 0)
{
parse_color(arg+8, colors);
continue;
}
if (argc >= 3 && strcmp(arg, "--insert") == 0)
{
png_const_charp what = *++argv;
png_charp param = *++argv;
chunk_insert *new_insert;
argc -= 2;
new_insert = find_insert(what, param);
if (new_insert != NULL)
{
*insert_ptr = new_insert;
insert_ptr = &new_insert->next;
}
continue;
}
if (arg[0] == '-')
{
fprintf(stderr, "makepng: %s: invalid option\n", arg);
exit(1);
}
if (strcmp(arg, "palette") == 0)
{
color_type = PNG_COLOR_TYPE_PALETTE;
continue;
}
if (strncmp(arg, "gray", 4) == 0)
{
if (arg[4] == 0)
{
color_type = PNG_COLOR_TYPE_GRAY;
continue;
}
else if (strcmp(arg+4, "a") == 0 ||
strcmp(arg+4, "alpha") == 0 ||
strcmp(arg+4, "-alpha") == 0)
{
color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
continue;
}
}
if (strncmp(arg, "rgb", 3) == 0)
{
if (arg[3] == 0)
{
color_type = PNG_COLOR_TYPE_RGB;
continue;
}
else if (strcmp(arg+3, "a") == 0 ||
strcmp(arg+3, "alpha") == 0 ||
strcmp(arg+3, "-alpha") == 0)
{
color_type = PNG_COLOR_TYPE_RGB_ALPHA;
continue;
}
}
if (color_type == 8 && isdigit(arg[0]))
{
color_type = atoi(arg);
if (color_type < 0 || color_type > 6 || color_type == 1 ||
color_type == 5)
{
fprintf(stderr, "makepng: %s: not a valid color type\n", arg);
exit(1);
}
continue;
}
if (bit_depth == 32 && isdigit(arg[0]))
{
bit_depth = atoi(arg);
if (bit_depth <= 0 || bit_depth > 16 ||
(bit_depth & -bit_depth) != bit_depth)
{
fprintf(stderr, "makepng: %s: not a valid bit depth\n", arg);
exit(1);
}
continue;
}
if (argc == 1) /* It's the file name */
{
fp = fopen(arg, "wb");
if (fp == NULL)
{
fprintf(stderr, "%s: %s: could not open\n", arg, strerror(errno));
exit(1);
}
file_name = arg;
continue;
}
fprintf(stderr, "makepng: %s: unknown argument\n", arg);
exit(1);
} /* argument while loop */
if (color_type == 8 || bit_depth == 32)
{
fprintf(stderr, "usage: makepng [--small] [--sRGB|--linear|--1.8] "
"[--color=...] color-type bit-depth [file-name]\n"
" Make a test PNG file, by default writes to stdout.\n"
" Other options are available, UTSL.\n");
exit(1);
}
/* Check the colors */
{
const unsigned int lim = (color_type == PNG_COLOR_TYPE_PALETTE ? 255U :
(1U<<bit_depth)-1);
unsigned int i;
for (i=1; i<=colors[0]; ++i)
if (colors[i] > lim)
{
fprintf(stderr, "makepng: --color=...: %u out of range [0..%u]\n",
colors[i], lim);
exit(1);
}
}
/* small and colors are incomparible (will probably crash if both are used at
* the same time!)
*/
if (small && colors[0] != 0)
{
fprintf(stderr, "makepng: --color --small: only one at a time!\n");
exit(1);
}
/* Restrict the filters for more speed to those we know are used for the
* generated images.
*/
if (filters == PNG_ALL_FILTERS && !small/*small provides defaults*/)
{
if ((color_type & PNG_COLOR_MASK_PALETTE) != 0 || bit_depth < 8)
filters = PNG_FILTER_NONE;
else if (color_type & PNG_COLOR_MASK_COLOR) /* rgb */
{
if (bit_depth == 8)
filters &= ~(PNG_FILTER_NONE | PNG_FILTER_AVG);
else
filters = PNG_FILTER_SUB | PNG_FILTER_PAETH;
}
else /* gray 8 or 16-bit */
filters &= ~PNG_FILTER_NONE;
}
/* Insert standard copyright and licence text. */
{
static png_const_charp copyright[] =
{
COPYRIGHT, /* ISO-Latin-1 */
NULL
};
static png_const_charp licensing[] =
{
IMAGE_LICENSING, /* UTF-8 */
NULL
};
chunk_insert *new_insert;
new_insert = add_tEXt("Copyright", copyright);
if (new_insert != NULL)
{
*insert_ptr = new_insert;
insert_ptr = &new_insert->next;
}
new_insert = add_iTXt("Licensing", "en", NULL, licensing);
if (new_insert != NULL)
{
*insert_ptr = new_insert;
insert_ptr = &new_insert->next;
}
}
{
int ret = write_png(&file_name, fp, color_type, bit_depth, gamma,
head_insert, filters, colors, small, tRNS);
if (ret != 0 && file_name != NULL)
remove(file_name);
return ret;
}
}