/* cairo - a vector graphics library with display and print output * * Copyright © 2003 University of Southern California * * This library is free software; you can redistribute it and/or * modify it either under the terms of the GNU Lesser General Public * License version 2.1 as published by the Free Software Foundation * (the "LGPL") or, at your option, under the terms of the Mozilla * Public License Version 1.1 (the "MPL"). If you do not alter this * notice, a recipient may use your version of this file under either * the MPL or the LGPL. * * You should have received a copy of the LGPL along with this library * in the file COPYING-LGPL-2.1; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA * You should have received a copy of the MPL along with this library * in the file COPYING-MPL-1.1 * * The contents of this file are subject to the Mozilla Public License * Version 1.1 (the "License"); you may not use this file except in * compliance with the License. You may obtain a copy of the License at * http://www.mozilla.org/MPL/ * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY * OF ANY KIND, either express or implied. See the LGPL or the MPL for * the specific language governing rights and limitations. * * The Original Code is the cairo graphics library. * * The Initial Developer of the Original Code is University of Southern * California. * * Contributor(s): * Carl D. Worth * Kristian Høgsberg * Chris Wilson */ #include "cairoint.h" #include "cairo-error-private.h" #include "cairo-image-surface-private.h" #include "cairo-output-stream-private.h" #include "cairo-ttrace.h" #include #include #include /** * SECTION:cairo-png * @Title: PNG Support * @Short_Description: Reading and writing PNG images * @See_Also: #cairo_surface_t * * The PNG functions allow reading PNG images into image surfaces, and writing * any surface to a PNG file. * * It is a toy API. It only offers very simple support for reading and * writing PNG files, which is sufficient for testing and * demonstration purposes. Applications which need more control over * the generated PNG file should access the pixel data directly, using * cairo_image_surface_get_data() or a backend-specific access * function, and process it with another library, e.g. gdk-pixbuf or * libpng. **/ /** * CAIRO_HAS_PNG_FUNCTIONS: * * Defined if the PNG functions are available. * This macro can be used to conditionally compile code using the cairo * PNG functions. * * Since: 1.0 **/ struct png_read_closure_t { cairo_read_func_t read_func; void *closure; cairo_output_stream_t *png_data; }; /* Unpremultiplies data and converts native endian ARGB => RGBA bytes */ static void unpremultiply_data (png_structp png, png_row_infop row_info, png_bytep data) { unsigned int i; for (i = 0; i < row_info->rowbytes; i += 4) { uint8_t *b = &data[i]; uint32_t pixel; uint8_t alpha; memcpy (&pixel, b, sizeof (uint32_t)); alpha = (pixel & 0xff000000) >> 24; if (alpha == 0) { b[0] = b[1] = b[2] = b[3] = 0; } else { b[0] = (((pixel & 0xff0000) >> 16) * 255 + alpha / 2) / alpha; b[1] = (((pixel & 0x00ff00) >> 8) * 255 + alpha / 2) / alpha; b[2] = (((pixel & 0x0000ff) >> 0) * 255 + alpha / 2) / alpha; b[3] = alpha; } } } /* Converts native endian xRGB => RGBx bytes */ static void convert_data_to_bytes (png_structp png, png_row_infop row_info, png_bytep data) { unsigned int i; for (i = 0; i < row_info->rowbytes; i += 4) { uint8_t *b = &data[i]; uint32_t pixel; memcpy (&pixel, b, sizeof (uint32_t)); b[0] = (pixel & 0xff0000) >> 16; b[1] = (pixel & 0x00ff00) >> 8; b[2] = (pixel & 0x0000ff) >> 0; b[3] = 0; } } /* Use a couple of simple error callbacks that do not print anything to * stderr and rely on the user to check for errors via the #cairo_status_t * return. */ static void png_simple_error_callback (png_structp png, png_const_charp error_msg) { cairo_status_t *error = png_get_error_ptr (png); /* default to the most likely error */ if (*error == CAIRO_STATUS_SUCCESS) *error = _cairo_error (CAIRO_STATUS_NO_MEMORY); #ifdef PNG_SETJMP_SUPPORTED longjmp (png_jmpbuf (png), 1); #endif /* if we get here, then we have to choice but to abort ... */ } static void png_simple_warning_callback (png_structp png, png_const_charp error_msg) { /* png does not expect to abort and will try to tidy up and continue * loading the image after a warning. So we also want to return the * (incorrect?) surface. * * We use our own warning callback to squelch any attempts by libpng * to write to stderr as we may not be in control of that output. */ } /* Starting with libpng-1.2.30, we must explicitly specify an output_flush_fn. * Otherwise, we will segfault if we are writing to a stream. */ static void png_simple_output_flush_fn (png_structp png_ptr) { } static cairo_status_t write_png (cairo_surface_t *surface, png_rw_ptr write_func, void *closure) { CAIRO_TRACE_BEGIN (__func__); int i; cairo_int_status_t status; cairo_image_surface_t *image; cairo_image_surface_t * volatile clone; void *image_extra; png_struct *png; png_info *info; png_byte **volatile rows = NULL; png_color_16 white; int png_color_type; int bpc; status = _cairo_surface_acquire_source_image (surface, &image, &image_extra); if (status == CAIRO_INT_STATUS_UNSUPPORTED) { CAIRO_TRACE_END (__func__); return _cairo_error (CAIRO_STATUS_SURFACE_TYPE_MISMATCH); } else if (unlikely (status)) { CAIRO_TRACE_END (__func__); return status; } /* PNG complains about "Image width or height is zero in IHDR" */ if (image->width == 0 || image->height == 0) { status = _cairo_error (CAIRO_STATUS_WRITE_ERROR); goto BAIL1; } /* Handle the various fallback formats (e.g. low bit-depth XServers) * by coercing them to a simpler format using pixman. */ clone = _cairo_image_surface_coerce (image); status = clone->base.status; if (unlikely (status)) goto BAIL1; rows = _cairo_malloc_ab (clone->height, sizeof (png_byte*)); if (unlikely (rows == NULL)) { status = _cairo_error (CAIRO_STATUS_NO_MEMORY); goto BAIL2; } for (i = 0; i < clone->height; i++) rows[i] = (png_byte *) clone->data + i * clone->stride; png = png_create_write_struct (PNG_LIBPNG_VER_STRING, &status, png_simple_error_callback, png_simple_warning_callback); if (unlikely (png == NULL)) { status = _cairo_error (CAIRO_STATUS_NO_MEMORY); goto BAIL3; } info = png_create_info_struct (png); if (unlikely (info == NULL)) { status = _cairo_error (CAIRO_STATUS_NO_MEMORY); goto BAIL4; } #ifdef PNG_SETJMP_SUPPORTED if (setjmp (png_jmpbuf (png))) goto BAIL4; #endif png_set_write_fn (png, closure, write_func, png_simple_output_flush_fn); switch (clone->format) { case CAIRO_FORMAT_ARGB32: bpc = 8; if (_cairo_image_analyze_transparency (clone) == CAIRO_IMAGE_IS_OPAQUE) png_color_type = PNG_COLOR_TYPE_RGB; else png_color_type = PNG_COLOR_TYPE_RGB_ALPHA; break; case CAIRO_FORMAT_RGB30: bpc = 10; png_color_type = PNG_COLOR_TYPE_RGB; break; case CAIRO_FORMAT_RGB24: bpc = 8; png_color_type = PNG_COLOR_TYPE_RGB; break; case CAIRO_FORMAT_A8: bpc = 8; png_color_type = PNG_COLOR_TYPE_GRAY; break; case CAIRO_FORMAT_A1: bpc = 1; png_color_type = PNG_COLOR_TYPE_GRAY; #ifndef WORDS_BIGENDIAN png_set_packswap (png); #endif break; case CAIRO_FORMAT_INVALID: case CAIRO_FORMAT_RGB16_565: default: status = _cairo_error (CAIRO_STATUS_INVALID_FORMAT); goto BAIL4; } png_set_IHDR (png, info, clone->width, clone->height, bpc, png_color_type, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT); white.gray = (1 << bpc) - 1; white.red = white.blue = white.green = white.gray; png_set_bKGD (png, info, &white); if (0) { /* XXX extract meta-data from surface (i.e. creation date) */ png_time pt; png_convert_from_time_t (&pt, time (NULL)); png_set_tIME (png, info, &pt); } /* We have to call png_write_info() before setting up the write * transformation, since it stores data internally in 'png' * that is needed for the write transformation functions to work. */ png_write_info (png, info); if (png_color_type == PNG_COLOR_TYPE_RGB_ALPHA) { png_set_write_user_transform_fn (png, unpremultiply_data); } else if (png_color_type == PNG_COLOR_TYPE_RGB) { png_set_write_user_transform_fn (png, convert_data_to_bytes); png_set_filler (png, 0, PNG_FILLER_AFTER); } png_write_image (png, rows); png_write_end (png, info); BAIL4: png_destroy_write_struct (&png, &info); BAIL3: free (rows); BAIL2: cairo_surface_destroy (&clone->base); BAIL1: _cairo_surface_release_source_image (surface, image, image_extra); CAIRO_TRACE_END (__func__); return status; } static void stdio_write_func (png_structp png, png_bytep data, png_size_t size) { FILE *fp; fp = png_get_io_ptr (png); while (size) { size_t ret = fwrite (data, 1, size, fp); size -= ret; data += ret; if (size && ferror (fp)) { cairo_status_t *error = png_get_error_ptr (png); if (*error == CAIRO_STATUS_SUCCESS) *error = _cairo_error (CAIRO_STATUS_WRITE_ERROR); png_error (png, NULL); } } } /** * cairo_surface_write_to_png: * @surface: a #cairo_surface_t with pixel contents * @filename: the name of a file to write to * * Writes the contents of @surface to a new file @filename as a PNG * image. * * Return value: %CAIRO_STATUS_SUCCESS if the PNG file was written * successfully. Otherwise, %CAIRO_STATUS_NO_MEMORY if memory could not * be allocated for the operation or * %CAIRO_STATUS_SURFACE_TYPE_MISMATCH if the surface does not have * pixel contents, or %CAIRO_STATUS_WRITE_ERROR if an I/O error occurs * while attempting to write the file. * * Since: 1.0 **/ cairo_status_t cairo_surface_write_to_png (cairo_surface_t *surface, const char *filename) { FILE *fp; cairo_status_t status; if (surface->status) return surface->status; if (surface->finished) return _cairo_error (CAIRO_STATUS_SURFACE_FINISHED); fp = fopen (filename, "wb"); if (fp == NULL) { switch (errno) { case ENOMEM: return _cairo_error (CAIRO_STATUS_NO_MEMORY); default: return _cairo_error (CAIRO_STATUS_WRITE_ERROR); } } status = write_png (surface, stdio_write_func, fp); if (fclose (fp) && status == CAIRO_STATUS_SUCCESS) status = _cairo_error (CAIRO_STATUS_WRITE_ERROR); return status; } struct png_write_closure_t { cairo_write_func_t write_func; void *closure; }; static void stream_write_func (png_structp png, png_bytep data, png_size_t size) { cairo_status_t status; struct png_write_closure_t *png_closure; png_closure = png_get_io_ptr (png); status = png_closure->write_func (png_closure->closure, data, size); if (unlikely (status)) { cairo_status_t *error = png_get_error_ptr (png); if (*error == CAIRO_STATUS_SUCCESS) *error = status; png_error (png, NULL); } } /** * cairo_surface_write_to_png_stream: * @surface: a #cairo_surface_t with pixel contents * @write_func: a #cairo_write_func_t * @closure: closure data for the write function * * Writes the image surface to the write function. * * Return value: %CAIRO_STATUS_SUCCESS if the PNG file was written * successfully. Otherwise, %CAIRO_STATUS_NO_MEMORY is returned if * memory could not be allocated for the operation, * %CAIRO_STATUS_SURFACE_TYPE_MISMATCH if the surface does not have * pixel contents. * * Since: 1.0 **/ cairo_status_t cairo_surface_write_to_png_stream (cairo_surface_t *surface, cairo_write_func_t write_func, void *closure) { CAIRO_TRACE_BEGIN (__func__); struct png_write_closure_t png_closure; if (surface->status) { CAIRO_TRACE_END (__func__); return surface->status; } if (surface->finished) { CAIRO_TRACE_END (__func__); return _cairo_error (CAIRO_STATUS_SURFACE_FINISHED); } png_closure.write_func = write_func; png_closure.closure = closure; CAIRO_TRACE_END (__func__); return write_png (surface, stream_write_func, &png_closure); } slim_hidden_def (cairo_surface_write_to_png_stream); static inline int multiply_alpha (int alpha, int color) { int temp = (alpha * color) + 0x80; return ((temp + (temp >> 8)) >> 8); } /* Premultiplies data and converts RGBA bytes => native endian */ static void premultiply_data (png_structp png, png_row_infop row_info, png_bytep data) { unsigned int i; for (i = 0; i < row_info->rowbytes; i += 4) { uint8_t *base = &data[i]; uint8_t alpha = base[3]; uint32_t p; if (alpha == 0) { p = 0; } else { uint8_t red = base[0]; uint8_t green = base[1]; uint8_t blue = base[2]; if (alpha != 0xff) { red = multiply_alpha (alpha, red); green = multiply_alpha (alpha, green); blue = multiply_alpha (alpha, blue); } p = (alpha << 24) | (red << 16) | (green << 8) | (blue << 0); } memcpy (base, &p, sizeof (uint32_t)); } } /* Converts RGBx bytes to native endian xRGB */ static void convert_bytes_to_data (png_structp png, png_row_infop row_info, png_bytep data) { unsigned int i; for (i = 0; i < row_info->rowbytes; i += 4) { uint8_t *base = &data[i]; uint8_t red = base[0]; uint8_t green = base[1]; uint8_t blue = base[2]; uint32_t pixel; pixel = (0xff << 24) | (red << 16) | (green << 8) | (blue << 0); memcpy (base, &pixel, sizeof (uint32_t)); } } static cairo_status_t stdio_read_func (void *closure, unsigned char *data, unsigned int size) { FILE *file = closure; while (size) { size_t ret; ret = fread (data, 1, size, file); size -= ret; data += ret; if (size && (feof (file) || ferror (file))) return _cairo_error (CAIRO_STATUS_READ_ERROR); } return CAIRO_STATUS_SUCCESS; } static void stream_read_func (png_structp png, png_bytep data, png_size_t size) { cairo_status_t status; struct png_read_closure_t *png_closure; png_closure = png_get_io_ptr (png); status = png_closure->read_func (png_closure->closure, data, size); if (unlikely (status)) { cairo_status_t *error = png_get_error_ptr (png); if (*error == CAIRO_STATUS_SUCCESS) *error = status; png_error (png, NULL); } _cairo_output_stream_write (png_closure->png_data, data, size); } static cairo_surface_t * read_png (struct png_read_closure_t *png_closure) { cairo_surface_t *surface; png_struct *png = NULL; png_info *info; png_byte *data = NULL; png_byte **row_pointers = NULL; png_uint_32 png_width, png_height; int depth, color_type, interlace, stride; unsigned int i; cairo_format_t format; cairo_status_t status; unsigned char *mime_data; unsigned long mime_data_length; png_closure->png_data = _cairo_memory_stream_create (); /* XXX: Perhaps we'll want some other error handlers? */ png = png_create_read_struct (PNG_LIBPNG_VER_STRING, &status, png_simple_error_callback, png_simple_warning_callback); if (unlikely (png == NULL)) { surface = _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY)); goto BAIL; } info = png_create_info_struct (png); if (unlikely (info == NULL)) { surface = _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY)); goto BAIL; } png_set_read_fn (png, png_closure, stream_read_func); status = CAIRO_STATUS_SUCCESS; #ifdef PNG_SETJMP_SUPPORTED if (setjmp (png_jmpbuf (png))) { surface = _cairo_surface_create_in_error (status); goto BAIL; } #endif png_read_info (png, info); png_get_IHDR (png, info, &png_width, &png_height, &depth, &color_type, &interlace, NULL, NULL); if (unlikely (status)) { /* catch any early warnings */ surface = _cairo_surface_create_in_error (status); goto BAIL; } /* convert palette/gray image to rgb */ if (color_type == PNG_COLOR_TYPE_PALETTE) png_set_palette_to_rgb (png); /* expand gray bit depth if needed */ if (color_type == PNG_COLOR_TYPE_GRAY) { #if PNG_LIBPNG_VER >= 10209 png_set_expand_gray_1_2_4_to_8 (png); #else png_set_gray_1_2_4_to_8 (png); #endif } /* transform transparency to alpha */ if (png_get_valid (png, info, PNG_INFO_tRNS)) png_set_tRNS_to_alpha (png); if (depth == 16) png_set_strip_16 (png); if (depth < 8) png_set_packing (png); /* convert grayscale to RGB */ if (color_type == PNG_COLOR_TYPE_GRAY || color_type == PNG_COLOR_TYPE_GRAY_ALPHA) { png_set_gray_to_rgb (png); } if (interlace != PNG_INTERLACE_NONE) png_set_interlace_handling (png); png_set_filler (png, 0xff, PNG_FILLER_AFTER); /* recheck header after setting EXPAND options */ png_read_update_info (png, info); png_get_IHDR (png, info, &png_width, &png_height, &depth, &color_type, &interlace, NULL, NULL); if (depth != 8 || ! (color_type == PNG_COLOR_TYPE_RGB || color_type == PNG_COLOR_TYPE_RGB_ALPHA)) { surface = _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_READ_ERROR)); goto BAIL; } switch (color_type) { default: ASSERT_NOT_REACHED; /* fall-through just in case ;-) */ case PNG_COLOR_TYPE_RGB_ALPHA: format = CAIRO_FORMAT_ARGB32; png_set_read_user_transform_fn (png, premultiply_data); break; case PNG_COLOR_TYPE_RGB: format = CAIRO_FORMAT_RGB24; png_set_read_user_transform_fn (png, convert_bytes_to_data); break; } stride = cairo_format_stride_for_width (format, png_width); if (stride < 0) { surface = _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_INVALID_STRIDE)); goto BAIL; } data = _cairo_malloc_ab (png_height, stride); if (unlikely (data == NULL)) { surface = _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY)); goto BAIL; } row_pointers = _cairo_malloc_ab (png_height, sizeof (char *)); if (unlikely (row_pointers == NULL)) { surface = _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY)); goto BAIL; } for (i = 0; i < png_height; i++) row_pointers[i] = &data[i * stride]; png_read_image (png, row_pointers); png_read_end (png, info); if (unlikely (status)) { /* catch any late warnings - probably hit an error already */ surface = _cairo_surface_create_in_error (status); goto BAIL; } surface = cairo_image_surface_create_for_data (data, format, png_width, png_height, stride); if (surface->status) goto BAIL; _cairo_image_surface_assume_ownership_of_data ((cairo_image_surface_t*)surface); data = NULL; _cairo_debug_check_image_surface_is_defined (surface); status = _cairo_memory_stream_destroy (png_closure->png_data, &mime_data, &mime_data_length); png_closure->png_data = NULL; if (unlikely (status)) { cairo_surface_destroy (surface); surface = _cairo_surface_create_in_error (status); goto BAIL; } status = cairo_surface_set_mime_data (surface, CAIRO_MIME_TYPE_PNG, mime_data, mime_data_length, free, mime_data); if (unlikely (status)) { free (mime_data); cairo_surface_destroy (surface); surface = _cairo_surface_create_in_error (status); goto BAIL; } BAIL: free (row_pointers); free (data); if (png != NULL) png_destroy_read_struct (&png, &info, NULL); if (png_closure->png_data != NULL) { cairo_status_t status_ignored; status_ignored = _cairo_output_stream_destroy (png_closure->png_data); } return surface; } /** * cairo_image_surface_create_from_png: * @filename: name of PNG file to load * * Creates a new image surface and initializes the contents to the * given PNG file. * * Return value: a new #cairo_surface_t initialized with the contents * of the PNG file, or a "nil" surface if any error occurred. A nil * surface can be checked for with cairo_surface_status(surface) which * may return one of the following values: * * %CAIRO_STATUS_NO_MEMORY * %CAIRO_STATUS_FILE_NOT_FOUND * %CAIRO_STATUS_READ_ERROR * * Alternatively, you can allow errors to propagate through the drawing * operations and check the status on the context upon completion * using cairo_status(). * * Since: 1.0 **/ cairo_surface_t * cairo_image_surface_create_from_png (const char *filename) { struct png_read_closure_t png_closure; cairo_surface_t *surface; png_closure.closure = fopen (filename, "rb"); if (png_closure.closure == NULL) { cairo_status_t status; switch (errno) { case ENOMEM: status = _cairo_error (CAIRO_STATUS_NO_MEMORY); break; case ENOENT: status = _cairo_error (CAIRO_STATUS_FILE_NOT_FOUND); break; default: status = _cairo_error (CAIRO_STATUS_READ_ERROR); break; } return _cairo_surface_create_in_error (status); } png_closure.read_func = stdio_read_func; surface = read_png (&png_closure); fclose (png_closure.closure); return surface; } /** * cairo_image_surface_create_from_png_stream: * @read_func: function called to read the data of the file * @closure: data to pass to @read_func. * * Creates a new image surface from PNG data read incrementally * via the @read_func function. * * Return value: a new #cairo_surface_t initialized with the contents * of the PNG file or a "nil" surface if the data read is not a valid PNG image * or memory could not be allocated for the operation. A nil * surface can be checked for with cairo_surface_status(surface) which * may return one of the following values: * * %CAIRO_STATUS_NO_MEMORY * %CAIRO_STATUS_READ_ERROR * * Alternatively, you can allow errors to propagate through the drawing * operations and check the status on the context upon completion * using cairo_status(). * * Since: 1.0 **/ cairo_surface_t * cairo_image_surface_create_from_png_stream (cairo_read_func_t read_func, void *closure) { struct png_read_closure_t png_closure; png_closure.read_func = read_func; png_closure.closure = closure; return read_png (&png_closure); }