X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/5fea3204c9e6d3c28ffabecca54d971b8205abe2..8237875c04209b72a531faec70b3127e2cda2f36:/src/png/example.c diff --git a/src/png/example.c b/src/png/example.c deleted file mode 100644 index 088aad3a76..0000000000 --- a/src/png/example.c +++ /dev/null @@ -1,702 +0,0 @@ - -/* example.c - an example of using libpng */ - -/* This is an example of how to use libpng to read and write PNG files. - * The file libpng.txt is much more verbose then this. If you have not - * read it, do so first. This was designed to be a starting point of an - * implementation. This is not officially part of libpng, and therefore - * does not require a copyright notice. - * - * This file does not currently compile, because it is missing certain - * parts, like allocating memory to hold an image. You will have to - * supply these parts to get it to compile. For an example of a minimal - * working PNG reader/writer, see pngtest.c, included in this distribution. - */ - -#include "png.h" - -/* Check to see if a file is a PNG file using png_sig_cmp(). png_sig_cmp() - * returns zero if the image is a PNG and nonzero if it isn't a PNG. - * - * The function check_if_png() shown here, but not used, returns nonzero (true) - * if the file can be opened and is a PNG, 0 (false) otherwise. - * - * If this call is successful, and you are going to keep the file open, - * you should call png_set_sig_bytes(png_ptr, PNG_BYTES_TO_CHECK); once - * you have created the png_ptr, so that libpng knows your application - * has read that many bytes from the start of the file. Make sure you - * don't call png_set_sig_bytes() with more than 8 bytes read or give it - * an incorrect number of bytes read, or you will either have read too - * many bytes (your fault), or you are telling libpng to read the wrong - * number of magic bytes (also your fault). - * - * Many applications already read the first 2 or 4 bytes from the start - * of the image to determine the file type, so it would be easiest just - * to pass the bytes to png_sig_cmp() or even skip that if you know - * you have a PNG file, and call png_set_sig_bytes(). - */ -#define PNG_BYTES_TO_CHECK 4 -int check_if_png(char *file_name, FILE **fp) -{ - char buf[PNG_BYTES_TO_CHECK]; - - /* Open the prospective PNG file. */ - if ((*fp = fopen(file_name, "rb")) != NULL); - return 0; - - /* Read in some of the signature bytes */ - if (fread(buf, 1, PNG_BYTES_TO_CHECK, *fp) != PNG_BYTES_TO_CHECK) - return 0; - - /* Compare the first PNG_BYTES_TO_CHECK bytes of the signature. - Return nonzero (true) if they match */ - - return(!png_sig_cmp(buf, (png_size_t)0, PNG_BYTES_TO_CHECK)); -} - -/* Read a PNG file. You may want to return an error code if the read - * fails (depending upon the failure). There are two "prototypes" given - * here - one where we are given the filename, and we need to open the - * file, and the other where we are given an open file (possibly with - * some or all of the magic bytes read - see comments above). - */ -#ifdef open_file /* prototype 1 */ -void read_png(char *file_name) /* We need to open the file */ -{ - png_structp png_ptr; - png_infop info_ptr; - unsigned int sig_read = 0; - png_uint_32 width, height; - int bit_depth, color_type, interlace_type; - FILE *fp; - - if ((fp = fopen(file_name, "rb")) == NULL) - return; -#else no_open_file /* prototype 2 */ -void read_png(FILE *fp, unsigned int sig_read) /* file is already open */ -{ - png_structp png_ptr; - png_infop info_ptr; - png_uint_32 width, height; - int bit_depth, color_type, interlace_type; -#endif no_open_file /* only use one prototype! */ - - /* Create and initialize the png_struct with the desired error handler - * functions. If you want to use the default stderr and longjump method, - * you can supply NULL for the last three parameters. We also supply the - * the compiler header file version, so that we know if the application - * was compiled with a compatible version of the library. REQUIRED - */ - png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, - png_voidp user_error_ptr, user_error_fn, user_warning_fn); - - if (png_ptr == NULL) - { - fclose(fp); - return; - } - - /* Allocate/initialize the memory for image information. REQUIRED. */ - info_ptr = png_create_info_struct(png_ptr); - if (info_ptr == NULL) - { - fclose(fp); - png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL); - return; - } - - /* Set error handling if you are using the setjmp/longjmp method (this is - * the normal method of doing things with libpng). REQUIRED unless you - * set up your own error handlers in the png_create_read_struct() earlier. - */ - if (setjmp(png_ptr->jmpbuf)) - { - /* Free all of the memory associated with the png_ptr and info_ptr */ - png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL); - fclose(fp); - /* If we get here, we had a problem reading the file */ - return; - } - - /* One of the following I/O initialization methods is REQUIRED */ -#ifdef streams /* PNG file I/O method 1 */ - /* Set up the input control if you are using standard C streams */ - png_init_io(png_ptr, fp); - -#else no_streams /* PNG file I/O method 2 */ - /* If you are using replacement read functions, instead of calling - * png_init_io() here you would call: - */ - png_set_read_fn(png_ptr, (void *)user_io_ptr, user_read_fn); - /* where user_io_ptr is a structure you want available to the callbacks */ -#endif no_streams /* Use only one I/O method! */ - - /* If we have already read some of the signature */ - png_set_sig_bytes(png_ptr, sig_read); - - /* The call to png_read_info() gives us all of the information from the - * PNG file before the first IDAT (image data chunk). REQUIRED - */ - png_read_info(png_ptr, info_ptr); - - png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, - &interlace_type, NULL, NULL); - -/**** Set up the data transformations you want. Note that these are all - **** optional. Only call them if you want/need them. Many of the - **** transformations only work on specific types of images, and many - **** are mutually exclusive. - ****/ - - /* tell libpng to strip 16 bit/color files down to 8 bits/color */ - png_set_strip_16(png_ptr); - - /* Strip alpha bytes from the input data without combining with th - * background (not recommended). - */ - png_set_strip_alpha(png_ptr); - - /* Extract multiple pixels with bit depths of 1, 2, and 4 from a single - * byte into separate bytes (useful for paletted and grayscale images). - */ - png_set_packing(png_ptr); - - /* Change the order of packed pixels to least significant bit first - * (not useful if you are using png_set_packing). */ - png_set_packswap(png_ptr); - - /* Expand paletted colors into true RGB triplets */ - if (color_type == PNG_COLOR_TYPE_PALETTE) - png_set_expand(png_ptr); - - /* Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel */ - if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) - png_set_expand(png_ptr); - - /* Expand paletted or RGB images with transparency to full alpha channels - * so the data will be available as RGBA quartets. - */ - if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) - png_set_expand(png_ptr); - - /* Set the background color to draw transparent and alpha images over. - * It is possible to set the red, green, and blue components directly - * for paletted images instead of supplying a palette index. Note that - * even if the PNG file supplies a background, you are not required to - * use it - you should use the (solid) application background if it has one. - */ - - png_color_16 my_background, *image_background; - - if (png_get_bKGD(png_ptr, info_ptr, &image_background)) - png_set_background(png_ptr, image_background, - PNG_BACKGROUND_GAMMA_FILE, 1, 1.0); - else - png_set_background(png_ptr, &my_background, - PNG_BACKGROUND_GAMMA_SCREEN, 0, 1.0); - - /* Some suggestions as to how to get a screen gamma value */ - - /* Note that screen gamma is (display_gamma/viewing_gamma) */ - if (/* We have a user-defined screen gamma value */) - { - screen_gamma = user-defined screen_gamma; - } - /* This is one way that applications share the same screen gamma value */ - else if ((gamma_str = getenv("SCREEN_GAMMA")) != NULL) - { - screen_gamma = atof(gamma_str); - } - /* If we don't have another value */ - else - { - screen_gamma = 2.2; /* A good guess for a PC monitors in a dimly - lit room */ - screen_gamma = 1.7 or 1.0; /* A good guess for Mac systems */ - } - - /* Tell libpng to handle the gamma conversion for you. The second call - * is a good guess for PC generated images, but it should be configurable - * by the user at run time by the user. It is strongly suggested that - * your application support gamma correction. - */ - - int intent; - - if (png_get_sRGB(png_ptr, info_ptr, &intent)) - png_set_sRGB(png_ptr, intent, 0); - else - { - double image_gamma; - if (png_get_gAMA(png_ptr, info_ptr, &image_gamma)) - png_set_gamma(png_ptr, screen_gamma, image_gamma); - else - png_set_gamma(png_ptr, screen_gamma, 0.45455); - } - - /* Dither RGB files down to 8 bit palette or reduce palettes - * to the number of colors available on your screen. - */ - if (color_type & PNG_COLOR_MASK_COLOR) - { - png_uint_32 num_palette; - png_colorp palette; - - /* This reduces the image to the application supplied palette */ - if (/* we have our own palette */) - { - /* An array of colors to which the image should be dithered */ - png_color std_color_cube[MAX_SCREEN_COLORS]; - - png_set_dither(png_ptr, std_color_cube, MAX_SCREEN_COLORS, - MAX_SCREEN_COLORS, NULL, 0); - } - /* This reduces the image to the palette supplied in the file */ - else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette)) - { - png_color16p histogram; - - png_get_hIST(png_ptr, info_ptr, &histogram); - - png_set_dither(png_ptr, palette, num_palette, - max_screen_colors, histogram, 0); - } - } - - /* invert monocrome files to have 0 as white and 1 as black */ - png_set_invert_mono(png_ptr); - - /* If you want to shift the pixel values from the range [0,255] or - * [0,65535] to the original [0,7] or [0,31], or whatever range the - * colors were originally in: - */ - if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT)) - { - png_color8p sig_bit; - - png_get_sBIT(png_ptr, info_ptr, &sig_bit); - png_set_shift(png_ptr, sig_bit); - } - - /* flip the RGB pixels to BGR (or RGBA to BGRA) */ - png_set_bgr(png_ptr); - - /* swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */ - png_set_swap_alpha(png_ptr); - - /* swap bytes of 16 bit files to least significant byte first */ - png_set_swap(png_ptr); - - /* Add filler (or alpha) byte (before/after each RGB triplet) */ - png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER); - - /* Turn on interlace handling. REQUIRED if you are not using - * png_read_image(). To see how to handle interlacing passes, - * see the png_read_row() method below: - */ - number_passes = png_set_interlace_handling(png_ptr); - - /* Optional call to gamma correct and add the background to the palette - * and update info structure. REQUIRED if you are expecting libpng to - * update the palette for you (ie you selected such a transform above). - */ - png_read_update_info(png_ptr, info_ptr); - - /* Allocate the memory to hold the image using the fields of info_ptr. */ - - /* The easiest way to read the image: */ - png_bytep row_pointers[height]; - - for (row = 0; row < height; row++) - { - row_pointers[row] = malloc(png_get_rowbytes(png_ptr, info_ptr)); - } - - /* Now it's time to read the image. One of these methods is REQUIRED */ -#ifdef entire /* Read the entire image in one go */ - png_read_image(png_ptr, row_pointers); - -#else no_entire /* Read the image one or more scanlines at a time */ - /* The other way to read images - deal with interlacing: */ - - for (pass = 0; pass < number_passes; pass++) - { -#ifdef single /* Read the image a single row at a time */ - for (y = 0; y < height; y++) - { - png_read_rows(png_ptr, &row_pointers[y], NULL, 1); - } - -#else no_single /* Read the image several rows at a time */ - for (y = 0; y < height; y += number_of_rows) - { -#ifdef sparkle /* Read the image using the "sparkle" effect. */ - png_read_rows(png_ptr, &row_pointers[y], NULL, number_of_rows); - - png_read_rows(png_ptr, NULL, row_pointers[y], number_of_rows); -#else no_sparkle /* Read the image using the "rectangle" effect */ - png_read_rows(png_ptr, NULL, &row_pointers[y], number_of_rows); -#endif no_sparkle /* use only one of these two methods */ - } - - /* if you want to display the image after every pass, do - so here */ -#endif no_single /* use only one of these two methods */ - } -#endif no_entire /* use only one of these two methods */ - - /* read rest of file, and get additional chunks in info_ptr - REQUIRED */ - png_read_end(png_ptr, info_ptr); - - /* clean up after the read, and free any memory allocated - REQUIRED */ - png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL); - - /* close the file */ - fclose(fp); - - /* that's it */ - return; -} - -/* progressively read a file */ - -int -initialize_png_reader(png_structp *png_ptr, png_infop *info_ptr) -{ - /* Create and initialize the png_struct with the desired error handler - * functions. If you want to use the default stderr and longjump method, - * you can supply NULL for the last three parameters. We also check that - * the library version is compatible in case we are using dynamically - * linked libraries. - */ - *png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, - png_voidp user_error_ptr, user_error_fn, user_warning_fn); - - if (*png_ptr == NULL) - { - *info_ptr = NULL; - return ERROR; - } - - *info_ptr = png_create_info_struct(png_ptr); - - if (*info_ptr == NULL) - { - png_destroy_read_struct(png_ptr, info_ptr, (png_infopp)NULL); - return ERROR; - } - - if (setjmp((*png_ptr)->jmpbuf)) - { - png_destroy_read_struct(png_ptr, info_ptr, (png_infopp)NULL); - return ERROR; - } - - /* This one's new. You will need to provide all three - * function callbacks, even if you aren't using them all. - * If you aren't using all functions, you can specify NULL - * parameters. Even when all three functions are NULL, - * you need to call png_set_progressive_read_fn(). - * These functions shouldn't be dependent on global or - * static variables if you are decoding several images - * simultaneously. You should store stream specific data - * in a separate struct, given as the second parameter, - * and retrieve the pointer from inside the callbacks using - * the function png_get_progressive_ptr(png_ptr). - */ - png_set_progressive_read_fn(*png_ptr, (void *)stream_data, - info_callback, row_callback, end_callback); - - return OK; -} - -int -process_data(png_structp *png_ptr, png_infop *info_ptr, - png_bytep buffer, png_uint_32 length) -{ - if (setjmp((*png_ptr)->jmpbuf)) - { - /* Free the png_ptr and info_ptr memory on error */ - png_destroy_read_struct(png_ptr, info_ptr, (png_infopp)NULL); - return ERROR; - } - - /* This one's new also. Simply give it chunks of data as - * they arrive from the data stream (in order, of course). - * On Segmented machines, don't give it any more than 64K. - * The library seems to run fine with sizes of 4K, although - * you can give it much less if necessary (I assume you can - * give it chunks of 1 byte, but I haven't tried with less - * than 256 bytes yet). When this function returns, you may - * want to display any rows that were generated in the row - * callback, if you aren't already displaying them there. - */ - png_process_data(*png_ptr, *info_ptr, buffer, length); - return OK; -} - -info_callback(png_structp png_ptr, png_infop info) -{ -/* do any setup here, including setting any of the transformations - * mentioned in the Reading PNG files section. For now, you _must_ - * call either png_start_read_image() or png_read_update_info() - * after all the transformations are set (even if you don't set - * any). You may start getting rows before png_process_data() - * returns, so this is your last chance to prepare for that. - */ -} - -row_callback(png_structp png_ptr, png_bytep new_row, - png_uint_32 row_num, int pass) -{ -/* this function is called for every row in the image. If the - * image is interlacing, and you turned on the interlace handler, - * this function will be called for every row in every pass. - * Some of these rows will not be changed from the previous pass. - * When the row is not changed, the new_row variable will be NULL. - * The rows and passes are called in order, so you don't really - * need the row_num and pass, but I'm supplying them because it - * may make your life easier. - * - * For the non-NULL rows of interlaced images, you must call - * png_progressive_combine_row() passing in the row and the - * old row. You can call this function for NULL rows (it will - * just return) and for non-interlaced images (it just does the - * memcpy for you) if it will make the code easier. Thus, you - * can just do this for all cases: - */ - - png_progressive_combine_row(png_ptr, old_row, new_row); - -/* where old_row is what was displayed for previous rows. Note - * that the first pass (pass == 0 really) will completely cover - * the old row, so the rows do not have to be initialized. After - * the first pass (and only for interlaced images), you will have - * to pass the current row, and the function will combine the - * old row and the new row. - */ -} - -end_callback(png_structp png_ptr, png_infop info) -{ -/* this function is called when the whole image has been read, - * including any chunks after the image (up to and including - * the IEND). You will usually have the same info chunk as you - * had in the header, although some data may have been added - * to the comments and time fields. - * - * Most people won't do much here, perhaps setting a flag that - * marks the image as finished. - */ -} - -/* write a png file */ -void write_png(char *file_name /* , ... other image information ... */) -{ - FILE *fp; - png_structp png_ptr; - png_infop info_ptr; - - /* open the file */ - fp = fopen(file_name, "wb"); - if (fp == NULL) - return; - - /* Create and initialize the png_struct with the desired error handler - * functions. If you want to use the default stderr and longjump method, - * you can supply NULL for the last three parameters. We also check that - * the library version is compatible with the one used at compile time, - * in case we are using dynamically linked libraries. REQUIRED. - */ - png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, - png_voidp user_error_ptr, user_error_fn, user_warning_fn); - - if (png_ptr == NULL) - { - fclose(fp); - return; - } - - /* Allocate/initialize the image information data. REQUIRED */ - info_ptr = png_create_info_struct(png_ptr); - if (info_ptr == NULL) - { - fclose(fp); - png_destroy_write_struct(&png_ptr, (png_infopp)NULL); - return; - } - - /* Set error handling. REQUIRED if you aren't supplying your own - * error hadnling functions in the png_create_write_struct() call. - */ - if (setjmp(png_ptr->jmpbuf)) - { - /* If we get here, we had a problem reading the file */ - fclose(fp); - png_destroy_write_struct(&png_ptr, (png_infopp)NULL); - return; - } - - /* One of the following I/O initialization functions is REQUIRED */ -#ifdef streams /* I/O initialization method 1 */ - /* set up the output control if you are using standard C streams */ - png_init_io(png_ptr, fp); -#else no_streams /* I/O initialization method 2 */ - /* If you are using replacement read functions, instead of calling - * png_init_io() here you would call */ - png_set_write_fn(png_ptr, (void *)user_io_ptr, user_write_fn, - user_IO_flush_function); - /* where user_io_ptr is a structure you want available to the callbacks */ -#endif no_streams /* only use one initialization method */ - - /* Set the image information here. Width and height are up to 2^31, - * bit_depth is one of 1, 2, 4, 8, or 16, but valid values also depend on - * the color_type selected. color_type is one of PNG_COLOR_TYPE_GRAY, - * PNG_COLOR_TYPE_GRAY_ALPHA, PNG_COLOR_TYPE_PALETTE, PNG_COLOR_TYPE_RGB, - * or PNG_COLOR_TYPE_RGB_ALPHA. interlace is either PNG_INTERLACE_NONE or - * PNG_INTERLACE_ADAM7, and the compression_type and filter_type MUST - * currently be PNG_COMPRESSION_TYPE_BASE and PNG_FILTER_TYPE_BASE. REQUIRED - */ - png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth, PNG_COLOR_TYPE_???, - PNG_INTERLACE_????, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE); - - /* set the palette if there is one. REQUIRED for indexed-color images */ - palette = (png_colorp)png_malloc(png_ptr, 256 * sizeof (png_color)); - /* ... set palette colors ... */ - png_set_PLTE(png_ptr, info_ptr, palette, 256); - - /* optional significant bit chunk */ - /* if we are dealing with a grayscale image then */ - sig_bit.gray = true_bit_depth; - /* otherwise, if we are dealing with a color image then */ - sig_bit.red = true_red_bit_depth; - sig_bit.green = true_green_bit_depth; - sig_bit.blue = true_blue_bit_depth; - /* if the image has an alpha channel then */ - sig_bit.alpha = true_alpha_bit_depth; - png_set_sBIT(png_ptr, info_ptr, sig_bit); - - - /* Optional gamma chunk is strongly suggested if you have any guess - * as to the correct gamma of the image. - */ - png_set_gAMA(png_ptr, info_ptr, gamma); - - /* Optionally write comments into the image */ - text_ptr[0].key = "Title"; - text_ptr[0].text = "Mona Lisa"; - text_ptr[0].compression = PNG_TEXT_COMPRESSION_NONE; - text_ptr[1].key = "Author"; - text_ptr[1].text = "Leonardo DaVinci"; - text_ptr[1].compression = PNG_TEXT_COMPRESSION_NONE; - text_ptr[2].key = "Description"; - text_ptr[2].text = ""; - text_ptr[2].compression = PNG_TEXT_COMPRESSION_zTXt; - png_set_text(png_ptr, info_ptr, text_ptr, 3); - - /* other optional chunks like cHRM, bKGD, tRNS, tIME, oFFs, pHYs, */ - /* note that if sRGB is present the cHRM chunk must be ignored - * on read and must be written in accordance with the sRGB profile */ - - /* Write the file header information. REQUIRED */ - png_write_info(png_ptr, info_ptr); - - /* Once we write out the header, the compression type on the text - * chunks gets changed to PNG_TEXT_COMPRESSION_NONE_WR or - * PNG_TEXT_COMPRESSION_zTXt_WR, so it doesn't get written out again - * at the end. - */ - - /* set up the transformations you want. Note that these are - * all optional. Only call them if you want them. - */ - - /* invert monocrome pixels */ - png_set_invert_mono(png_ptr); - - /* Shift the pixels up to a legal bit depth and fill in - * as appropriate to correctly scale the image. - */ - png_set_shift(png_ptr, &sig_bit); - - /* pack pixels into bytes */ - png_set_packing(png_ptr); - - /* swap location of alpha bytes from ARGB to RGBA */ - png_set_swap_alpha(png_ptr); - - /* Get rid of filler (OR ALPHA) bytes, pack XRGB/RGBX/ARGB/RGBA into - * RGB (4 channels -> 3 channels). The second parameter is not used. - */ - png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE); - - /* flip BGR pixels to RGB */ - png_set_bgr(png_ptr); - - /* swap bytes of 16-bit files to most significant byte first */ - png_set_swap(png_ptr); - - /* swap bits of 1, 2, 4 bit packed pixel formats */ - png_set_packswap(png_ptr); - - /* turn on interlace handling if you are not using png_write_image() */ - if (interlacing) - number_passes = png_set_interlace_handling(png_ptr); - else - number_passes = 1; - - /* The easiest way to write the image (you may have a different memory - * layout, however, so choose what fits your needs best). You need to - * use the first method if you aren't handling interlacing yourself. - */ - png_uint_32 k, height, width; - png_byte image[height][width]; - png_bytep row_pointers[height]; - for (k = 0; k < height; k++) - row_pointers[k] = image + k*width; - - /* One of the following output methods is REQUIRED */ -#ifdef entire /* write out the entire image data in one call */ - png_write_image(png_ptr, row_pointers); - - /* the other way to write the image - deal with interlacing */ - -#else no_entire /* write out the image data by one or more scanlines */ - /* The number of passes is either 1 for non-interlaced images, - * or 7 for interlaced images. - */ - for (pass = 0; pass < number_passes; pass++) - { - /* Write a few rows at a time. */ - png_write_rows(png_ptr, &row_pointers[first_row], number_of_rows); - - /* If you are only writing one row at a time, this works */ - for (y = 0; y < height; y++) - { - png_write_rows(png_ptr, &row_pointers[y], 1); - } - } -#endif no_entire /* use only one output method */ - - /* You can write optional chunks like tEXt, zTXt, and tIME at the end - * as well. - */ - - /* It is REQUIRED to call this to finish writing the rest of the file */ - png_write_end(png_ptr, info_ptr); - - /* if you malloced the palette, free it here */ - free(info_ptr->palette); - - /* if you allocated any text comments, free them here */ - - /* clean up after the write, and free any memory allocated */ - png_destroy_write_struct(&png_ptr, (png_infopp)NULL); - - /* close the file */ - fclose(fp); - - /* that's it */ - return; -} -