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Diffstat (limited to 'Build/source/libs/libpng/libpng-src/contrib/examples')
5 files changed, 1323 insertions, 0 deletions
diff --git a/Build/source/libs/libpng/libpng-src/contrib/examples/README.txt b/Build/source/libs/libpng/libpng-src/contrib/examples/README.txt new file mode 100644 index 00000000000..0525c9d36b4 --- /dev/null +++ b/Build/source/libs/libpng/libpng-src/contrib/examples/README.txt @@ -0,0 +1,24 @@ + +This directory (contrib/examples) contains examples of libpng usage. + +NO COPYRIGHT RIGHTS ARE CLAIMED TO ANY OF THE FILES IN THIS DIRECTORY. + +To the extent possible under law, the authors have waived all copyright and +related or neighboring rights to this work. This work is published from: +United States. + +The files may be used freely in any way. The intention is that appropriate +parts of the files be used in other libpng-using programs without any need for +the authors of the using code to seek copyright or license from the original +authors. + +The source code and comments in this directory are the original work of the +people named below. No other person or organization has made contributions to +the work in this directory. + +ORIGINAL AUTHORS + The following people have contributed to the code in this directory. None + of the people below claim any rights with regard to the contents of this + directory. + + John Bowler <jbowler@acm.org> diff --git a/Build/source/libs/libpng/libpng-src/contrib/examples/iccfrompng.c b/Build/source/libs/libpng/libpng-src/contrib/examples/iccfrompng.c new file mode 100644 index 00000000000..603037e7097 --- /dev/null +++ b/Build/source/libs/libpng/libpng-src/contrib/examples/iccfrompng.c @@ -0,0 +1,185 @@ +/*- iccfrompng + * + * COPYRIGHT: Written by John Cunningham Bowler, 2011. + * To the extent possible under law, the author has waived all copyright and + * related or neighboring rights to this work. This work is published from: + * United States. + * + * Extract any icc profiles found in the given PNG files. This is a simple + * example of a program that extracts information from the header of a PNG file + * without processing the image. Notice that some header information may occur + * after the image data. Textual data and comments are an example; the approach + * in this file won't work reliably for such data because it only looks for the + * information in the section of the file that preceeds the image data. + * + * Compile and link against libpng and zlib, plus anything else required on the + * system you use. + * + * To use supply a list of PNG files containing iCCP chunks, the chunks will be + * extracted to a similarly named file with the extension replaced by 'icc', + * which will be overwritten without warning. + */ +#include <stdlib.h> +#include <setjmp.h> +#include <string.h> +#include <stdio.h> + +#include <png.h> + +#if defined(PNG_READ_SUPPORTED) && defined(PNG_STDIO_SUPPORTED) && \ + defined (PNG_iCCP_SUPPORTED) + + +static int verbose = 1; +static png_byte no_profile[] = "no profile"; + +static png_bytep +extract(FILE *fp, png_uint_32 *proflen) +{ + png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,0,0,0); + png_infop info_ptr = NULL; + png_bytep result = NULL; + + /* Initialize for error or no profile: */ + *proflen = 0; + + if (png_ptr == NULL) + { + fprintf(stderr, "iccfrompng: version library mismatch?\n"); + return 0; + } + + if (setjmp(png_jmpbuf(png_ptr))) + { + png_destroy_read_struct(&png_ptr, &info_ptr, NULL); + return 0; + } + + 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"); + + png_read_info(png_ptr, info_ptr); + + { + png_charp name; + int compression_type; + png_bytep profile; + + if (png_get_iCCP(png_ptr, info_ptr, &name, &compression_type, &profile, + proflen) & PNG_INFO_iCCP) + { + result = malloc(*proflen); + if (result != NULL) + memcpy(result, profile, *proflen); + + else + png_error(png_ptr, "OOM allocating profile buffer"); + } + + else + result = no_profile; + } + + png_destroy_read_struct(&png_ptr, &info_ptr, NULL); + return result; +} + +static int +extract_one_file(const char *filename) +{ + int result = 0; + FILE *fp = fopen(filename, "rb"); + + if (fp != NULL) + { + png_uint_32 proflen = 0; + png_bytep profile = extract(fp, &proflen); + + if (profile != NULL && profile != no_profile) + { + size_t len; + char *output; + + { + const char *ep = strrchr(filename, '.'); + + if (ep != NULL) + len = ep-filename; + + else + len = strlen(filename); + } + + output = malloc(len + 5); + if (output != NULL) + { + FILE *of; + + memcpy(output, filename, len); + strcpy(output+len, ".icc"); + + of = fopen(output, "wb"); + if (of != NULL) + { + if (fwrite(profile, proflen, 1, of) == 1 && + fflush(of) == 0 && + fclose(of) == 0) + { + if (verbose) + printf("%s -> %s\n", filename, output); + /* Success return */ + result = 1; + } + + else + { + fprintf(stderr, "%s: error writing profile\n", output); + if (remove(output)) + fprintf(stderr, "%s: could not remove file\n", output); + } + } + + else + fprintf(stderr, "%s: failed to open output file\n", output); + + free(output); + } + + else + fprintf(stderr, "%s: OOM allocating string!\n", filename); + + free(profile); + } + + else if (verbose && profile == no_profile) + printf("%s has no profile\n", filename); + } + + else + fprintf(stderr, "%s: could not open file\n", filename); + + return result; +} + +int +main(int argc, char **argv) +{ + int i; + int extracted = 0; + + for (i=1; i<argc; ++i) + { + if (strcmp(argv[i], "-q") == 0) + verbose = 0; + + else if (extract_one_file(argv[i])) + extracted = 1; + } + + /* Exit code is true if any extract succeeds */ + return extracted == 0; +} +#endif /* READ && STDIO && iCCP */ diff --git a/Build/source/libs/libpng/libpng-src/contrib/examples/pngpixel.c b/Build/source/libs/libpng/libpng-src/contrib/examples/pngpixel.c new file mode 100644 index 00000000000..f762379ed3c --- /dev/null +++ b/Build/source/libs/libpng/libpng-src/contrib/examples/pngpixel.c @@ -0,0 +1,371 @@ +/*- pngpixel + * + * COPYRIGHT: Written by John Cunningham Bowler, 2011. + * To the extent possible under law, the author has waived all copyright and + * related or neighboring rights to this work. This work is published from: + * United States. + * + * Read a single pixel value from a PNG file. + * + * This code illustrates basic 'by-row' reading of a PNG file using libpng. + * Rows are read until a particular pixel is found; the value of this pixel is + * then printed on stdout. + * + * The code illustrates how to do this on interlaced as well as non-interlaced + * images. Normally you would call png_set_interlace_handling() to have libpng + * deal with the interlace for you, but that obliges you to buffer half of the + * image to assemble the interlaced rows. In this code + * png_set_interlace_handling() is not called and, instead, the code handles the + * interlace passes directly looking for the required pixel. + */ +#include <stdlib.h> +#include <stdio.h> +#include <setjmp.h> /* required for error handling */ + +/* Normally use <png.h> here to get the installed libpng, but this is done to + * ensure the code picks up the local libpng implementation: + */ +#include "../../png.h" + +#if defined(PNG_READ_SUPPORTED) && defined(PNG_SEQUENTIAL_READ_SUPPORTED) + +/* Return component 'c' of pixel 'x' from the given row. */ +static unsigned int +component(png_const_bytep row, png_uint_32 x, unsigned int c, + unsigned int bit_depth, unsigned int channels) +{ + /* PNG images can be up to 2^31 pixels wide, but this means they can be up to + * 2^37 bits wide (for a 64-bit pixel - the largest possible) and hence 2^34 + * bytes wide. Since the row fitted into memory, however, the following must + * work: + */ + png_uint_32 bit_offset_hi = bit_depth * ((x >> 6) * channels); + png_uint_32 bit_offset_lo = bit_depth * ((x & 0x3f) * channels + c); + + row = (png_const_bytep)(((PNG_CONST png_byte (*)[8])row) + bit_offset_hi); + row += bit_offset_lo >> 3; + bit_offset_lo &= 0x07; + + /* PNG pixels are packed into bytes to put the first pixel in the highest + * bits of the byte and into two bytes for 16-bit values with the high 8 bits + * first, so: + */ + switch (bit_depth) + { + case 1: return (row[0] >> (7-bit_offset_lo)) & 0x01; + case 2: return (row[0] >> (6-bit_offset_lo)) & 0x03; + case 4: return (row[0] >> (4-bit_offset_lo)) & 0x0f; + case 8: return row[0]; + case 16: return (row[0] << 8) + row[1]; + default: + /* This should never happen; it indicates a bug in this program or in + * libpng itself: + */ + fprintf(stderr, "pngpixel: invalid bit depth %u\n", bit_depth); + exit(1); + } +} + +/* Print a pixel from a row returned by libpng; determine the row format, find + * the pixel, and print the relevant information to stdout. + */ +static void +print_pixel(png_structp png_ptr, png_infop info_ptr, png_const_bytep row, + png_uint_32 x) +{ + PNG_CONST unsigned int bit_depth = png_get_bit_depth(png_ptr, info_ptr); + + switch (png_get_color_type(png_ptr, info_ptr)) + { + case PNG_COLOR_TYPE_GRAY: + printf("GRAY %u\n", component(row, x, 0, bit_depth, 1)); + return; + + /* The palette case is slightly more difficult - the palette and, if + * present, the tRNS ('transparency', though the values are really + * opacity) data must be read to give the full picture: + */ + case PNG_COLOR_TYPE_PALETTE: + { + PNG_CONST int index = component(row, x, 0, bit_depth, 1); + png_colorp palette = NULL; + int num_palette = 0; + + if ((png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette) & + PNG_INFO_PLTE) && num_palette > 0 && palette != NULL) + { + png_bytep trans_alpha = NULL; + int num_trans = 0; + if ((png_get_tRNS(png_ptr, info_ptr, &trans_alpha, &num_trans, + NULL) & PNG_INFO_tRNS) && num_trans > 0 && + trans_alpha != NULL) + printf("INDEXED %u = %d %d %d %d\n", index, + palette[index].red, palette[index].green, + palette[index].blue, + index < num_trans ? trans_alpha[index] : 255); + + else /* no transparency */ + printf("INDEXED %u = %d %d %d\n", index, + palette[index].red, palette[index].green, + palette[index].blue); + } + + else + printf("INDEXED %u = invalid index\n", index); + } + return; + + case PNG_COLOR_TYPE_RGB: + printf("RGB %u %u %u\n", component(row, x, 0, bit_depth, 3), + component(row, x, 1, bit_depth, 3), + component(row, x, 2, bit_depth, 3)); + return; + + case PNG_COLOR_TYPE_GRAY_ALPHA: + printf("GRAY+ALPHA %u %u\n", component(row, x, 0, bit_depth, 2), + component(row, x, 1, bit_depth, 2)); + return; + + case PNG_COLOR_TYPE_RGB_ALPHA: + printf("RGBA %u %u %u %u\n", component(row, x, 0, bit_depth, 4), + component(row, x, 1, bit_depth, 4), + component(row, x, 2, bit_depth, 4), + component(row, x, 3, bit_depth, 4)); + return; + + default: + png_error(png_ptr, "pngpixel: invalid color type"); + } +} + +int main(int argc, const char **argv) +{ + /* This program uses the default, <setjmp.h> based, libpng error handling + * mechanism, therefore any local variable that exists before the call to + * setjmp and is changed after the call to setjmp returns successfully must + * be declared with 'volatile' to ensure that their values don't get + * destroyed by longjmp: + */ + volatile int result = 1/*fail*/; + + if (argc == 4) + { + long x = atol(argv[1]); + long y = atol(argv[2]); + FILE *f = fopen(argv[3], "rb"); + volatile png_bytep row = NULL; + + if (f != NULL) + { + /* libpng requires a callback function for handling errors; this + * callback must not return. The default callback function uses a + * stored <setjmp.h> style jmp_buf which is held in a png_struct and + * writes error messages to stderr. Creating the png_struct is a + * little tricky; just copy the following code. + */ + png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, + NULL, NULL, NULL); + + if (png_ptr != NULL) + { + png_infop info_ptr = png_create_info_struct(png_ptr); + + if (info_ptr != NULL) + { + /* Declare stack variables to hold pointers to locally allocated + * data. + */ + + /* Initialize the error control buffer: */ + if (setjmp(png_jmpbuf(png_ptr)) == 0) + { + png_uint_32 width, height; + int bit_depth, color_type, interlace_method, + compression_method, filter_method; + png_bytep row_tmp; + + /* Now associate the recently opened (FILE*) with the default + * libpng initialization functions. Sometimes libpng is + * compiled without stdio support (it can be difficult to do + * in some environments); in that case you will have to write + * your own read callback to read data from the (FILE*). + */ + png_init_io(png_ptr, f); + + /* And read the first part of the PNG file - the header and + * all the information up to the first pixel. + */ + png_read_info(png_ptr, info_ptr); + + /* This fills in enough information to tell us the width of + * each row in bytes, allocate the appropriate amount of + * space. In this case png_malloc is used - it will not + * return if memory isn't available. + */ + row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, + info_ptr)); + + /* To avoid the overhead of using a volatile auto copy row_tmp + * to a local here - just use row for the png_free below. + */ + row_tmp = row; + + /* All the information we need is in the header is returned by + * png_get_IHDR, if this fails we can now use 'png_error' to + * signal the error and return control to the setjmp above. + */ + if (png_get_IHDR(png_ptr, info_ptr, &width, &height, + &bit_depth, &color_type, &interlace_method, + &compression_method, &filter_method)) + { + int passes, pass; + + /* png_set_interlace_handling returns the number of + * passes required as well as turning on libpng's + * handling, but since we do it ourselves this is + * necessary: + */ + switch (interlace_method) + { + case PNG_INTERLACE_NONE: + passes = 1; + break; + + case PNG_INTERLACE_ADAM7: + passes = PNG_INTERLACE_ADAM7_PASSES; + break; + + default: + png_error(png_ptr, "pngpixel: unknown interlace"); + } + + /* Now read the pixels, pass-by-pass, row-by-row: */ + png_start_read_image(png_ptr); + + for (pass=0; pass<passes; ++pass) + { + png_uint_32 ystart, xstart, ystep, xstep; + png_uint_32 py; + + if (interlace_method == PNG_INTERLACE_ADAM7) + { + /* Sometimes the whole pass is empty because the + * image is too narrow or too short. libpng + * expects to be called for each row that is + * present in the pass, so it may be necessary to + * skip the loop below (over py) if the image is + * too narrow. + */ + if (PNG_PASS_COLS(width, pass) == 0) + continue; + + /* We need the starting pixel and the offset + * between each pixel in this pass; use the macros + * in png.h: + */ + xstart = PNG_PASS_START_COL(pass); + ystart = PNG_PASS_START_ROW(pass); + xstep = PNG_PASS_COL_OFFSET(pass); + ystep = PNG_PASS_ROW_OFFSET(pass); + } + + else + { + ystart = xstart = 0; + ystep = xstep = 1; + } + + /* To find the pixel, loop over 'py' for each pass + * reading a row and then checking to see if it + * contains the pixel. + */ + for (py = ystart; py < height; py += ystep) + { + png_uint_32 px, ppx; + + /* png_read_row takes two pointers. When libpng + * handles the interlace the first is filled in + * pixel-by-pixel, and the second receives the same + * pixels but they are replicated across the + * unwritten pixels so far for each pass. When we + * do the interlace, however, they just contain + * the pixels from the interlace pass - giving + * both is wasteful and pointless, so we pass a + * NULL pointer. + */ + png_read_row(png_ptr, row_tmp, NULL); + + /* Now find the pixel if it is in this row; there + * are, of course, much better ways of doing this + * than using a for loop: + */ + if (y == py) for (px = xstart, ppx = 0; + px < width; px += xstep, ++ppx) if (x == px) + { + /* 'ppx' is the index of the pixel in the row + * buffer. + */ + print_pixel(png_ptr, info_ptr, row_tmp, ppx); + + /* Now terminate the loops early - we have + * found and handled the required data. + */ + goto pass_loop_end; + } /* x loop */ + } /* y loop */ + } /* pass loop */ + + /* Finally free the temporary buffer: */ + pass_loop_end: + row = NULL; + png_free(png_ptr, row_tmp); + } + + else + png_error(png_ptr, "pngpixel: png_get_IHDR failed"); + + } + + else + { + /* Else libpng has raised an error. An error message has + * already been output, so it is only necessary to clean up + * locally allocated data: + */ + if (row != NULL) + { + /* The default implementation of png_free never errors out + * (it just crashes if something goes wrong), but the safe + * way of using it is still to clear 'row' before calling + * png_free: + */ + png_bytep row_tmp = row; + row = NULL; + png_free(png_ptr, row_tmp); + } + } + + png_destroy_info_struct(png_ptr, &info_ptr); + } + + else + fprintf(stderr, "pngpixel: out of memory allocating png_info\n"); + + png_destroy_read_struct(&png_ptr, NULL, NULL); + } + + else + fprintf(stderr, "pngpixel: out of memory allocating png_struct\n"); + } + + else + fprintf(stderr, "pngpixel: %s: could not open file\n", argv[3]); + } + + else + /* Wrong number of arguments */ + fprintf(stderr, "pngpixel: usage: pngpixel x y png-file\n"); + + return result; +} +#endif /* READ && SEQUENTIAL_READ */ diff --git a/Build/source/libs/libpng/libpng-src/contrib/examples/pngtopng.c b/Build/source/libs/libpng/libpng-src/contrib/examples/pngtopng.c new file mode 100644 index 00000000000..4acf6b3ad4d --- /dev/null +++ b/Build/source/libs/libpng/libpng-src/contrib/examples/pngtopng.c @@ -0,0 +1,95 @@ +/*- pngtopng + * + * COPYRIGHT: Written by John Cunningham Bowler, 2011. + * To the extent possible under law, the author has waived all copyright and + * related or neighboring rights to this work. This work is published from: + * United States. + * + * Read a PNG and write it out in a fixed format, using the 'simplified API' + * that was introduced in libpng-1.6.0. + * + * This sample code is just the code from the top of 'example.c' with some error + * handling added. See example.c for more comments. + */ +#include <stddef.h> +#include <stdlib.h> +#include <string.h> +#include <stdio.h> + +/* Normally use <png.h> here to get the installed libpng, but this is done to + * ensure the code picks up the local libpng implementation: + */ +#include "../../png.h" +#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) && \ + defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) + +int main(int argc, const char **argv) +{ + int result = 1; + + if (argc == 3) + { + png_image image; + + /* Only the image structure version number needs to be set. */ + memset(&image, 0, sizeof image); + image.version = PNG_IMAGE_VERSION; + + if (png_image_begin_read_from_file(&image, argv[1])) + { + png_bytep buffer; + + /* Change this to try different formats! If you set a colormap format + * then you must also supply a colormap below. + */ + image.format = PNG_FORMAT_RGBA; + + buffer = malloc(PNG_IMAGE_SIZE(image)); + + if (buffer != NULL) + { + if (png_image_finish_read(&image, NULL/*background*/, buffer, + 0/*row_stride*/, NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP */)) + { + if (png_image_write_to_file(&image, argv[2], + 0/*convert_to_8bit*/, buffer, 0/*row_stride*/, + NULL/*colormap*/)) + result = 0; + + else + fprintf(stderr, "pngtopng: write %s: %s\n", argv[2], + image.message); + + free(buffer); + } + + else + { + fprintf(stderr, "pngtopng: read %s: %s\n", argv[1], + image.message); + + /* This is the only place where a 'free' is required; libpng does + * the cleanup on error and success, but in this case we couldn't + * complete the read because of running out of memory. + */ + png_image_free(&image); + } + } + + else + fprintf(stderr, "pngtopng: out of memory: %lu bytes\n", + (unsigned long)PNG_IMAGE_SIZE(image)); + } + + else + /* Failed to read the first argument: */ + fprintf(stderr, "pngtopng: %s: %s\n", argv[1], image.message); + } + + else + /* Wrong number of arguments */ + fprintf(stderr, "pngtopng: usage: pngtopng input-file output-file\n"); + + return result; +} +#endif /* READ && WRITE */ diff --git a/Build/source/libs/libpng/libpng-src/contrib/examples/simpleover.c b/Build/source/libs/libpng/libpng-src/contrib/examples/simpleover.c new file mode 100644 index 00000000000..59dd313688c --- /dev/null +++ b/Build/source/libs/libpng/libpng-src/contrib/examples/simpleover.c @@ -0,0 +1,648 @@ +/*- simpleover + * + * COPYRIGHT: Written by John Cunningham Bowler, 2015. + * To the extent possible under law, the author has waived all copyright and + * related or neighboring rights to this work. This work is published from: + * United States. + * + * Read several PNG files, which should have an alpha channel or transparency + * information, and composite them together to produce one or more 16-bit linear + * RGBA intermediates. This involves doing the correct 'over' composition to + * combine the alpha channels and corresponding data. + * + * Finally read an output (background) PNG using the 24-bit RGB format (the + * PNG will be composited on green (#00ff00) by default if it has an alpha + * channel), and apply the intermediate image generated above to specified + * locations in the image. + * + * The command line has the general format: + * + * simpleover <background.png> [output.png] + * {--sprite=width,height,name {[--at=x,y] {sprite.png}}} + * {--add=name {x,y}} + * + * The --sprite and --add options may occur multiple times. They are executed + * in order. --add may refer to any sprite already read. + * + * This code is intended to show how to composite multiple images together + * correctly. Apart from the libpng Simplified API the only work done in here + * is to combine multiple input PNG images into a single sprite; this involves + * a Porter-Duff 'over' operation and the input PNG images may, as a result, + * be regarded as being layered one on top of the other with the first (leftmost + * on the command line) being at the bottom and the last on the top. + */ +#include <stddef.h> +#include <stdlib.h> +#include <string.h> +#include <stdio.h> +#include <errno.h> + +/* Normally use <png.h> here to get the installed libpng, but this is done to + * ensure the code picks up the local libpng implementation, so long as this + * file is linked against a sufficiently recent libpng (1.6+) it is ok to + * change this to <png.h>: + */ +#include "../../png.h" + +#ifdef PNG_SIMPLIFIED_READ_SUPPORTED + +#define sprite_name_chars 15 +struct sprite { + FILE *file; + png_uint_16p buffer; + unsigned int width; + unsigned int height; + char name[sprite_name_chars+1]; +}; + +#if 0 /* div by 65535 test program */ +#include <math.h> +#include <stdio.h> + +int main(void) { + double err = 0; + unsigned int xerr = 0; + unsigned int r = 32769; + { + unsigned int x = 0; + + do { + unsigned int t = x + (x >> 16) /*+ (x >> 31)*/ + r; + double v = x, errtest; + + if (t < x) { + fprintf(stderr, "overflow: %u+%u -> %u\n", x, r, t); + return 1; + } + + v /= 65535; + errtest = v; + t >>= 16; + errtest -= t; + + if (errtest > err) { + err = errtest; + xerr = x; + + if (errtest >= .5) { + fprintf(stderr, "error: %u/65535 = %f, not %u, error %f\n", + x, v, t, errtest); + return 0; + } + } + } while (++x <= 65535U*65535U); + } + + printf("error %f @ %u\n", err, xerr); + + return 0; +} +#endif /* div by 65535 test program */ + +static void +sprite_op(const struct sprite *sprite, int x_offset, int y_offset, + png_imagep image, const png_uint_16 *buffer) +{ + /* This is where the Porter-Duff 'Over' operator is evaluated; change this + * code to change the operator (this could be parameterized). Any other + * image processing operation could be used here. + */ + + + /* Check for an x or y offset that pushes any part of the image beyond the + * right or bottom of the sprite: + */ + if ((y_offset < 0 || (unsigned)/*SAFE*/y_offset < sprite->height) && + (x_offset < 0 || (unsigned)/*SAFE*/x_offset < sprite->width)) + { + unsigned int y = 0; + + if (y_offset < 0) + y = -y_offset; /* Skip to first visible row */ + + do + { + unsigned int x = 0; + + if (x_offset < 0) + x = -x_offset; + + do + { + /* In and out are RGBA values, so: */ + const png_uint_16 *in_pixel = buffer + (y * image->width + x)*4; + png_uint_32 in_alpha = in_pixel[3]; + + /* This is the optimized Porter-Duff 'Over' operation, when the + * input alpha is 0 the output is not changed. + */ + if (in_alpha > 0) + { + png_uint_16 *out_pixel = sprite->buffer + + ((y+y_offset) * sprite->width + (x+x_offset))*4; + + /* This is the weight to apply to the output: */ + in_alpha = 65535-in_alpha; + + if (in_alpha > 0) + { + /* The input must be composed onto the output. This means + * multiplying the current output pixel value by the inverse + * of the input alpha (1-alpha). A division is required but + * it is by the constant 65535. Approximate this as: + * + * (x + (x >> 16) + 32769) >> 16; + * + * This is exact (and does not overflow) for all values of + * x in the range 0..65535*65535. (Note that the calculation + * produces the closest integer; the maximum error is <0.5). + */ + png_uint_32 tmp; + +# define compose(c)\ + tmp = out_pixel[c] * in_alpha;\ + tmp = (tmp + (tmp >> 16) + 32769) >> 16;\ + out_pixel[c] = tmp + in_pixel[c] + + /* The following is very vectorizable... */ + compose(0); + compose(1); + compose(2); + compose(3); + } + + else + out_pixel[0] = in_pixel[0], + out_pixel[1] = in_pixel[1], + out_pixel[2] = in_pixel[2], + out_pixel[3] = in_pixel[3]; + } + } + while (++x < image->width); + } + while (++y < image->height); + } +} + +static int +create_sprite(struct sprite *sprite, int *argc, const char ***argv) +{ + /* Read the arguments and create this sprite. The sprite buffer has already + * been allocated. This reads the input PNGs one by one in linear format, + * composes them onto the sprite buffer (the code in the function above) + * then saves the result, converting it on the fly to PNG RGBA 8-bit format. + */ + while (*argc > 0) + { + char tombstone; + int x = 0, y = 0; + + if ((*argv)[0][0] == '-' && (*argv)[0][1] == '-') + { + /* The only supported option is --at. */ + if (sscanf((*argv)[0], "--at=%d,%d%c", &x, &y, &tombstone) != 2) + break; /* success; caller will parse this option */ + + ++*argv, --*argc; + } + + else + { + /* The argument has to be a file name */ + png_image image; + + image.version = PNG_IMAGE_VERSION; + image.opaque = NULL; + + if (png_image_begin_read_from_file(&image, (*argv)[0])) + { + png_uint_16p buffer; + + image.format = PNG_FORMAT_LINEAR_RGB_ALPHA; + + buffer = malloc(PNG_IMAGE_SIZE(image)); + + if (buffer != NULL) + { + if (png_image_finish_read(&image, NULL/*background*/, buffer, + 0/*row_stride*/, + NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP*/)) + { + /* This is the place where the Porter-Duff 'Over' operator + * needs to be done by this code. In fact, any image + * processing required can be done here; the data is in + * the correct format (linear, 16-bit) and source and + * destination are in memory. + */ + sprite_op(sprite, x, y, &image, buffer); + free(buffer); + ++*argv, --*argc; + /* And continue to the next argument */ + continue; + } + + else + { + free(buffer); + fprintf(stderr, "simpleover: read %s: %s\n", (*argv)[0], + image.message); + } + } + + else + { + fprintf(stderr, "simpleover: out of memory: %lu bytes\n", + (unsigned long)PNG_IMAGE_SIZE(image)); + + /* png_image_free must be called if we abort the Simplified API + * read because of a problem detected in this code. If problems + * are detected in the Simplified API it cleans up itself. + */ + png_image_free(&image); + } + } + + else + { + /* Failed to read the first argument: */ + fprintf(stderr, "simpleover: %s: %s\n", (*argv)[0], image.message); + } + + return 0; /* failure */ + } + } + + /* All the sprite operations have completed successfully. Save the RGBA + * buffer as a PNG using the simplified write API. + */ + sprite->file = tmpfile(); + + if (sprite->file != NULL) + { + png_image save; + + memset(&save, 0, sizeof save); + save.version = PNG_IMAGE_VERSION; + save.opaque = NULL; + save.width = sprite->width; + save.height = sprite->height; + save.format = PNG_FORMAT_LINEAR_RGB_ALPHA; + save.flags = PNG_IMAGE_FLAG_FAST; + save.colormap_entries = 0; + + if (png_image_write_to_stdio(&save, sprite->file, 1/*convert_to_8_bit*/, + sprite->buffer, 0/*row_stride*/, NULL/*colormap*/)) + { + /* Success; the buffer is no longer needed: */ + free(sprite->buffer); + sprite->buffer = NULL; + return 1; /* ok */ + } + + else + fprintf(stderr, "simpleover: write sprite %s: %s\n", sprite->name, + save.message); + } + + else + fprintf(stderr, "simpleover: sprite %s: could not allocate tmpfile: %s\n", + sprite->name, strerror(errno)); + + return 0; /* fail */ +} + +static int +add_sprite(png_imagep output, png_bytep out_buf, struct sprite *sprite, + int *argc, const char ***argv) +{ + /* Given a --add argument naming this sprite, perform the operations listed + * in the following arguments. The arguments are expected to have the form + * (x,y), which is just an offset at which to add the sprite to the + * output. + */ + while (*argc > 0) + { + char tombstone; + int x, y; + + if ((*argv)[0][0] == '-' && (*argv)[0][1] == '-') + return 1; /* success */ + + if (sscanf((*argv)[0], "%d,%d%c", &x, &y, &tombstone) == 2) + { + /* Now add the new image into the sprite data, but only if it + * will fit. + */ + if (x < 0 || y < 0 || + (unsigned)/*SAFE*/x >= output->width || + (unsigned)/*SAFE*/y >= output->height || + sprite->width > output->width-x || + sprite->height > output->height-y) + { + fprintf(stderr, "simpleover: sprite %s @ (%d,%d) outside image\n", + sprite->name, x, y); + /* Could just skip this, but for the moment it is an error */ + return 0; /* error */ + } + + else + { + /* Since we know the sprite fits we can just read it into the + * output using the simplified API. + */ + png_image in; + + in.version = PNG_IMAGE_VERSION; + rewind(sprite->file); + + if (png_image_begin_read_from_stdio(&in, sprite->file)) + { + in.format = PNG_FORMAT_RGB; /* force compose */ + + if (png_image_finish_read(&in, NULL/*background*/, + out_buf + (y*output->width + x)*3/*RGB*/, + output->width*3/*row_stride*/, + NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP*/)) + { + ++*argv, --*argc; + continue; + } + } + + /* The read failed: */ + fprintf(stderr, "simpleover: add sprite %s: %s\n", sprite->name, + in.message); + return 0; /* error */ + } + } + + else + { + fprintf(stderr, "simpleover: --add='%s': invalid position %s\n", + sprite->name, (*argv)[0]); + return 0; /* error */ + } + } + + return 1; /* ok */ +} + +static int +simpleover_process(png_imagep output, png_bytep out_buf, int argc, + const char **argv) +{ + int result = 1; /* success */ +# define csprites 10/*limit*/ +# define str(a) #a + int nsprites = 0; + struct sprite sprites[csprites]; + + while (argc > 0) + { + result = 0; /* fail */ + + if (strncmp(argv[0], "--sprite=", 9) == 0) + { + char tombstone; + + if (nsprites < csprites) + { + int n; + + sprites[nsprites].width = sprites[nsprites].height = 0; + sprites[nsprites].name[0] = 0; + + n = sscanf(argv[0], "--sprite=%u,%u,%" str(sprite_name_chars) "s%c", + &sprites[nsprites].width, &sprites[nsprites].height, + sprites[nsprites].name, &tombstone); + + if ((n == 2 || n == 3) && + sprites[nsprites].width > 0 && sprites[nsprites].height > 0) + { + size_t buf_size, tmp; + + /* Default a name if not given. */ + if (sprites[nsprites].name[0] == 0) + sprintf(sprites[nsprites].name, "sprite-%d", nsprites+1); + + /* Allocate a buffer for the sprite and calculate the buffer + * size: + */ + buf_size = sizeof (png_uint_16 [4]); + buf_size *= sprites[nsprites].width; + buf_size *= sprites[nsprites].height; + + /* This can overflow a (size_t); check for this: */ + tmp = buf_size; + tmp /= sprites[nsprites].width; + tmp /= sprites[nsprites].height; + + if (tmp == sizeof (png_uint_16 [4])) + { + sprites[nsprites].buffer = malloc(buf_size); + /* This buffer must be initialized to transparent: */ + memset(sprites[nsprites].buffer, 0, buf_size); + + if (sprites[nsprites].buffer != NULL) + { + sprites[nsprites].file = NULL; + ++argv, --argc; + + if (create_sprite(sprites+nsprites++, &argc, &argv)) + { + result = 1; /* still ok */ + continue; + } + + break; /* error */ + } + } + + /* Overflow, or OOM */ + fprintf(stderr, "simpleover: %s: sprite too large\n", argv[0]); + break; + } + + else + { + fprintf(stderr, "simpleover: %s: invalid sprite (%u,%u)\n", + argv[0], sprites[nsprites].width, sprites[nsprites].height); + break; + } + } + + else + { + fprintf(stderr, "simpleover: %s: too many sprites\n", argv[0]); + break; + } + } + + else if (strncmp(argv[0], "--add=", 6) == 0) + { + const char *name = argv[0]+6; + int isprite = nsprites; + + ++argv, --argc; + + while (--isprite >= 0) + { + if (strcmp(sprites[isprite].name, name) == 0) + { + if (!add_sprite(output, out_buf, sprites+isprite, &argc, &argv)) + goto out; /* error in add_sprite */ + + break; + } + } + + if (isprite < 0) /* sprite not found */ + { + fprintf(stderr, "simpleover: --add='%s': sprite not found\n", name); + break; + } + } + + else + { + fprintf(stderr, "simpleover: %s: unrecognized operation\n", argv[0]); + break; + } + + result = 1; /* ok */ + } + + /* Clean up the cache of sprites: */ +out: + while (--nsprites >= 0) + { + if (sprites[nsprites].buffer != NULL) + free(sprites[nsprites].buffer); + + if (sprites[nsprites].file != NULL) + (void)fclose(sprites[nsprites].file); + } + + return result; +} + +int main(int argc, const char **argv) +{ + int result = 1; /* default to fail */ + + if (argc >= 2) + { + int argi = 2; + const char *output = NULL; + png_image image; + + if (argc > 2 && argv[2][0] != '-'/*an operation*/) + { + output = argv[2]; + argi = 3; + } + + image.version = PNG_IMAGE_VERSION; + image.opaque = NULL; + + if (png_image_begin_read_from_file(&image, argv[1])) + { + png_bytep buffer; + + image.format = PNG_FORMAT_RGB; /* 24-bit RGB */ + + buffer = malloc(PNG_IMAGE_SIZE(image)); + + if (buffer != NULL) + { + png_color background = {0, 0xff, 0}; /* fully saturated green */ + + if (png_image_finish_read(&image, &background, buffer, + 0/*row_stride*/, NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP */)) + { + /* At this point png_image_finish_read has cleaned up the + * allocated data in png_image, and only the buffer needs to be + * freed. + * + * Perform the remaining operations: + */ + if (simpleover_process(&image, buffer, argc-argi, argv+argi)) + { + /* Write the output: */ + if ((output != NULL && + png_image_write_to_file(&image, output, + 0/*convert_to_8bit*/, buffer, 0/*row_stride*/, + NULL/*colormap*/)) || + (output == NULL && + png_image_write_to_stdio(&image, stdout, + 0/*convert_to_8bit*/, buffer, 0/*row_stride*/, + NULL/*colormap*/))) + result = 0; + + else + fprintf(stderr, "simpleover: write %s: %s\n", + output == NULL ? "stdout" : output, image.message); + } + + /* else simpleover_process writes an error message */ + } + + else + fprintf(stderr, "simpleover: read %s: %s\n", argv[1], + image.message); + + free(buffer); + } + + else + { + fprintf(stderr, "simpleover: out of memory: %lu bytes\n", + (unsigned long)PNG_IMAGE_SIZE(image)); + + /* This is the only place where a 'free' is required; libpng does + * the cleanup on error and success, but in this case we couldn't + * complete the read because of running out of memory. + */ + png_image_free(&image); + } + } + + else + { + /* Failed to read the first argument: */ + fprintf(stderr, "simpleover: %s: %s\n", argv[1], image.message); + } + } + + else + { + /* Usage message */ + fprintf(stderr, + "simpleover: usage: simpleover background.png [output.png]\n" + " Output 'background.png' as a 24-bit RGB PNG file in 'output.png'\n" + " or, if not given, stdout. 'background.png' will be composited\n" + " on fully saturated green.\n" + "\n" + " Optionally, before output, process additional PNG files:\n" + "\n" + " --sprite=width,height,name {[--at=x,y] {sprite.png}}\n" + " Produce a transparent sprite of size (width,height) and with\n" + " name 'name'.\n" + " For each sprite.png composite it using a Porter-Duff 'Over'\n" + " operation at offset (x,y) in the sprite (defaulting to (0,0)).\n" + " Input PNGs will be truncated to the area of the sprite.\n" + "\n" + " --add='name' {x,y}\n" + " Optionally, before output, composite a sprite, 'name', which\n" + " must have been previously produced using --sprite, at each\n" + " offset (x,y) in the output image. Each sprite must fit\n" + " completely within the output image.\n" + "\n" + " PNG files are processed in the order they occur on the command\n" + " line and thus the first PNG processed appears as the bottommost\n" + " in the output image.\n"); + } + + return result; +} +#endif /* SIMPLIFIED_READ */ |