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Save work on libpng PNG loader (Issue #90)

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Michael R Sweet
2025-02-10 21:25:59 -05:00
parent 1e5cc6ffd5
commit e686669b9d
4 changed files with 290 additions and 20 deletions
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200
pdfio-content.c
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@@ -1,7 +1,7 @@
//
// Content helper functions for PDFio.
//
// Copyright © 2021-2024 by Michael R Sweet.
// Copyright © 2021-2025 by Michael R Sweet.
//
// Licensed under Apache License v2.0. See the file "LICENSE" for more
// information.
@@ -11,6 +11,9 @@
#include "pdfio-content.h"
#include "pdfio-base-font-widths.h"
#include "ttf.h"
#ifdef HAVE_LIBPNG
# include <png.h>
#endif // HAVE_LIBPNG
#include <math.h>
#ifndef M_PI
# define M_PI 3.14159265358979323846264338327950288
@@ -57,9 +60,15 @@ typedef pdfio_obj_t *(*_pdfio_image_func_t)(pdfio_dict_t *dict, int fd);
static pdfio_obj_t *copy_jpeg(pdfio_dict_t *dict, int fd);
static pdfio_obj_t *copy_png(pdfio_dict_t *dict, int fd);
static bool create_cp1252(pdfio_file_t *pdf);
static pdfio_obj_t *create_image(pdfio_file_t *pdf, pdfio_dict_t *dict, const unsigned char *data, size_t width, size_t height, size_t num_colors, bool alpha);
static pdfio_obj_t *create_image(pdfio_dict_t *dict, const unsigned char *data, size_t width, size_t height, size_t num_colors, bool alpha);
#ifdef HAVE_LIBPNG
static void png_error_func(png_structp pp, png_const_charp message);
static void png_read_func(png_structp png_ptr, png_bytep data, size_t length);
#endif // HAVE_LIBPNG
static void ttf_error_cb(pdfio_file_t *pdf, const char *message);
#ifndef HAVE_LIBPNG
static unsigned update_png_crc(unsigned crc, const unsigned char *buffer, size_t length);
#endif // !HAVE_LIBPNG
static bool write_string(pdfio_stream_t *st, bool unicode, const char *s, bool *newline);
@@ -103,6 +112,7 @@ static int _pdfio_cp1252[] = // CP1252-specific character mapping
0x0178
};
#ifndef HAVE_LIBPNG
static unsigned png_crc_table[256] = // CRC-32 table for PNG files
{
0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
@@ -149,6 +159,7 @@ static unsigned png_crc_table[256] = // CRC-32 table for PNG files
0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
};
#endif // !HAVE_LIBPNG
//
@@ -2016,7 +2027,7 @@ pdfioFileCreateImageObjFromData(
pdfioDictSetName(dict, "ColorSpace", defcolors[num_colors]);
// Create the image object(s)...
return (create_image(pdf, dict, data, width, height, num_colors, alpha));
return (create_image(dict, data, width, height, num_colors, alpha));
}
@@ -2469,8 +2480,145 @@ copy_png(pdfio_dict_t *dict, // I - Dictionary
int fd) // I - File descriptor
{
pdfio_obj_t *obj = NULL; // Object
pdfio_stream_t *st = NULL; // Stream for PNG data
#ifdef HAVE_LIBPNG
png_structp pp = NULL; // PNG read pointer
png_infop info = NULL; // PNG info pointers
png_bytep *rows = NULL; // PNG row pointers
unsigned char *pixels = NULL; // PNG image data
unsigned i, // Looping var
color_type, // PNG color mode
width, // Width in columns
height, // Height in lines
num_colors = 0, // Number of colors
bpp; // Bytes per pixel
bool alpha; // Alpha transparency?
// Allocate memory for PNG reader structures...
if ((pp = png_create_read_struct(PNG_LIBPNG_VER_STRING, (png_voidp)dict->pdf, png_error_func, png_error_func)) == NULL)
{
_pdfioFileError(dict->pdf, "Unable to allocate memory for PNG file: %s", strerror(errno));
goto finish_png;
}
if ((info = png_create_info_struct(pp)) == NULL)
{
_pdfioFileError(dict->pdf, "Unable to allocate memory for PNG file: %s", strerror(errno));
goto finish_png;
}
if (setjmp(png_jmpbuf(pp)))
{
// If we get here, PNG loading failed and any errors/warnings were logged
// via the corresponding callback functions...
goto finish_png;
}
// Set max image size to 16384x16384...
png_set_user_limits(pp, 16384, 16384);
// Read from the file descriptor...
png_set_read_fn(pp, &fd, png_read_func);
// Don't throw errors with "invalid" sRGB profiles produced by Adobe apps.
# if defined(PNG_SKIP_sRGB_CHECK_PROFILE) && defined(PNG_SET_OPTION_SUPPORTED)
png_set_option(pp, PNG_SKIP_sRGB_CHECK_PROFILE, PNG_OPTION_ON);
# endif // PNG_SKIP_sRGB_CHECK_PROFILE && PNG_SET_OPTION_SUPPORTED
// Get the image dimensions and depth...
png_read_info(pp, info);
width = png_get_image_width(pp, info);
height = png_get_image_height(pp, info);
color_type = png_get_color_type(pp, info);
if (color_type & PNG_COLOR_MASK_COLOR)
num_colors = 3;
else
num_colors = 1;
// Set decoding options...
if (png_get_valid(pp, info, PNG_INFO_tRNS))
{
// Map transparency to alpha
png_set_tRNS_to_alpha(pp);
color_type |= PNG_COLOR_MASK_ALPHA;
}
if (png_get_bit_depth(pp, info) > 8)
{
// Strip the bottom bits of 16-bit values
png_set_strip_16(pp);
}
else if (png_get_bit_depth(pp, info) < 8)
{
// Expand 1, 2, and 4-bit values to 8 bits
if (num_colors == 1)
png_set_expand_gray_1_2_4_to_8(pp);
else
png_set_packing(pp);
}
#if 1
if (color_type & PNG_COLOR_MASK_PALETTE)
{
// Convert indexed images to RGB...
png_set_palette_to_rgb(pp);
num_colors = 3;
}
#endif // 0
alpha = (color_type & PNG_COLOR_MASK_ALPHA) != 0;
bpp = num_colors + (alpha ? 1 : 0);
// Allocate memory for the image...
if ((pixels = (unsigned char *)calloc(height, width * bpp)) == NULL)
{
_pdfioFileError(dict->pdf, "Unable to allocate memory for PNG image: %s", strerror(errno));
goto finish_png;
}
if ((rows = (png_bytep *)calloc((size_t)height, sizeof(png_bytep))) == NULL)
{
_pdfioFileError(dict->pdf, "Unable to allocate memory for PNG image: %s", strerror(errno));
goto finish_png;
}
for (i = 0; i < height; i ++)
rows[i] = pixels + i * width * bpp;
// Read the image...
for (i = png_set_interlace_handling(pp); i > 0; i --)
png_read_rows(pp, rows, NULL, (png_uint_32)height);
// Grab any color space/palette information...
pdfioDictSetArray(dict, "ColorSpace", pdfioArrayCreateColorFromStandard(dict->pdf, num_colors, PDFIO_CS_SRGB));
// Create the image object...
obj = create_image(dict, pixels, width, height, num_colors, alpha);
finish_png:
if (pp && info)
{
png_read_end(pp, info);
png_destroy_read_struct(&pp, &info, NULL);
pp = NULL;
info = NULL;
}
free(pixels);
pixels = NULL;
free(rows);
rows = NULL;
return (obj);
#else
pdfio_dict_t *decode = NULL; // Parameters for PNG decode
pdfio_stream_t *st = NULL; // Stream for PNG data
ssize_t bytes; // Bytes read
unsigned char buffer[16384]; // Read buffer
unsigned i, // Looping var
@@ -2850,6 +2998,7 @@ copy_png(pdfio_dict_t *dict, // I - Dictionary
}
return (NULL);
#endif // HAVE_LIBPNG
}
@@ -3135,7 +3284,6 @@ create_cp1252(pdfio_file_t *pdf) // I - PDF file
static pdfio_obj_t * // O - PDF object or `NULL` on error
create_image(
pdfio_file_t *pdf, // I - PDF file
pdfio_dict_t *dict, // I - Image dictionary
const unsigned char *data, // I - Image data
size_t width, // I - Width in columns
@@ -3143,6 +3291,8 @@ create_image(
size_t num_colors, // I - Number of colors
bool alpha) // I - `true` if there is transparency
{
pdfio_file_t *pdf = dict->pdf;
// PDF file
pdfio_dict_t *mask_dict, // Mask image dictionary
*decode; // DecodeParms dictionary
pdfio_obj_t *obj, // Image object
@@ -3293,6 +3443,44 @@ create_image(
}
#ifdef HAVE_LIBPNG
//
// 'png_error_func()' - PNG error message function.
//
static void
png_error_func(
png_structp pp, // I - PNG pointer
png_const_charp message) // I - Error message
{
pdfio_file_t *pdf = (pdfio_file_t *)png_get_error_ptr(pp);
// PDF file
_pdfioFileError(pdf, "Unable to create image object from PNG file: %s", message);
}
//
// 'png_read_func()' - Read from a PNG file.
//
static void
png_read_func(png_structp pp, // I - PNG pointer
png_bytep data, // I - Read buffer
size_t length) // I - Number of bytes to read
{
int *fd = (int *)png_get_io_ptr(pp);
// Pointer to file descriptor
ssize_t bytes; // Bytes read
if ((bytes = read(*fd, data, length)) < (ssize_t)length)
png_error(pp, "Unable to read from PNG file.");
}
#endif // HAVE_LIBPNG
//
// 'ttf_error_cb()' - Relay a message from the TTF functions.
//
@@ -3305,6 +3493,7 @@ ttf_error_cb(pdfio_file_t *pdf, // I - PDF file
}
#ifndef HAVE_LIBPNG
//
// 'update_png_crc()' - Update the CRC-32 value for a PNG chunk.
//
@@ -3324,6 +3513,7 @@ update_png_crc(
return (crc);
}
#endif // !HAVE_LIBPNG
//