X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/75b6e0a0aba793c6b739689b4414c1a2d8fcb041..6811c2f3e3e8afc1872280dfd1464565a3ddb306:/src/png/example.c diff --git a/src/png/example.c b/src/png/example.c index 088aad3a76..7956cf7abd 100644 --- a/src/png/example.c +++ b/src/png/example.c @@ -1,20 +1,33 @@ +#if 0 /* in case someone actually tries to compile this */ + /* 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. + * implementation. This is not officially part of libpng, is hereby placed + * in the public domain, 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. + * working PNG reader/writer, see pngtest.c, included in this distribution; + * see also the programs in the contrib directory. */ #include "png.h" + /* The png_jmpbuf() macro, used in error handling, became available in + * libpng version 1.0.6. If you want to be able to run your code with older + * versions of libpng, you must define the macro yourself (but only if it + * is not already defined by libpng!). + */ + +#ifndef png_jmpbuf +# define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf) +#endif + /* 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. * @@ -41,7 +54,7 @@ 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); + if ((*fp = fopen(file_name, "rb")) == NULL) return 0; /* Read in some of the signature bytes */ @@ -71,7 +84,7 @@ void read_png(char *file_name) /* We need to open the file */ FILE *fp; if ((fp = fopen(file_name, "rb")) == NULL) - return; + return (ERROR); #else no_open_file /* prototype 2 */ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */ { @@ -93,7 +106,7 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */ if (png_ptr == NULL) { fclose(fp); - return; + return (ERROR); } /* Allocate/initialize the memory for image information. REQUIRED. */ @@ -101,21 +114,22 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */ if (info_ptr == NULL) { fclose(fp); - png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL); - return; + png_destroy_read_struct(&png_ptr, png_infopp_NULL, png_infopp_NULL); + return (ERROR); } /* 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)) + + if (setjmp(png_jmpbuf(png_ptr))) { /* Free all of the memory associated with the png_ptr and info_ptr */ - png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL); + 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; + return (ERROR); } /* One of the following I/O initialization methods is REQUIRED */ @@ -134,24 +148,37 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */ /* If we have already read some of the signature */ png_set_sig_bytes(png_ptr, sig_read); +#ifdef hilevel + /* + * If you have enough memory to read in the entire image at once, + * and you need to specify only transforms that can be controlled + * with one of the PNG_TRANSFORM_* bits (this presently excludes + * dithering, filling, setting background, and doing gamma + * adjustment), then you can read the entire image (including + * pixels) into the info structure with this call: + */ + png_read_png(png_ptr, info_ptr, png_transforms, png_voidp_NULL); +#else + /* OK, you're doing it the hard way, with the lower-level functions */ + /* 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); + &interlace_type, int_p_NULL, int_p_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. - ****/ +/* 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 + /* Strip alpha bytes from the input data without combining with the * background (not recommended). */ png_set_strip_alpha(png_ptr); @@ -167,17 +194,17 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */ /* Expand paletted colors into true RGB triplets */ if (color_type == PNG_COLOR_TYPE_PALETTE) - png_set_expand(png_ptr); + png_set_palette_rgb(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); + png_set_gray_1_2_4_to_8(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); + png_set_tRNS_to_alpha(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 @@ -197,7 +224,8 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */ /* Some suggestions as to how to get a screen gamma value */ - /* Note that screen gamma is (display_gamma/viewing_gamma) */ + /* Note that screen gamma is the display_exponent, which includes + * the CRT_exponent and any correction for viewing conditions */ if (/* We have a user-defined screen gamma value */) { screen_gamma = user-defined screen_gamma; @@ -215,7 +243,7 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */ 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 + /* Tell libpng to handle the gamma conversion for you. The final 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. @@ -224,7 +252,7 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */ int intent; if (png_get_sRGB(png_ptr, info_ptr, &intent)) - png_set_sRGB(png_ptr, intent, 0); + png_set_gamma(png_ptr, screen_gamma, 0.45455); else { double image_gamma; @@ -239,7 +267,7 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */ */ if (color_type & PNG_COLOR_MASK_COLOR) { - png_uint_32 num_palette; + int num_palette; png_colorp palette; /* This reduces the image to the application supplied palette */ @@ -249,12 +277,12 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */ png_color std_color_cube[MAX_SCREEN_COLORS]; png_set_dither(png_ptr, std_color_cube, MAX_SCREEN_COLORS, - MAX_SCREEN_COLORS, NULL, 0); + MAX_SCREEN_COLORS, png_uint_16p_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_uint_16p histogram = NULL; png_get_hIST(png_ptr, info_ptr, &histogram); @@ -263,7 +291,7 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */ } } - /* invert monocrome files to have 0 as white and 1 as black */ + /* invert monochrome 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 @@ -272,14 +300,15 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */ */ if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT)) { - png_color8p sig_bit; + png_color_8p 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); + if (color_type & PNG_COLOR_MASK_COLOR) + 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); @@ -309,7 +338,8 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */ for (row = 0; row < height; row++) { - row_pointers[row] = malloc(png_get_rowbytes(png_ptr, info_ptr)); + row_pointers[row] = png_malloc(png_ptr, png_get_rowbytes(png_ptr, + info_ptr)); } /* Now it's time to read the image. One of these methods is REQUIRED */ @@ -324,18 +354,18 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */ #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); + png_read_rows(png_ptr, &row_pointers[y], png_bytepp_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); + png_read_rows(png_ptr, &row_pointers[y], png_bytepp_NULL, + 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); + png_read_rows(png_ptr, png_bytepp_NULL, &row_pointers[y], + number_of_rows); #endif no_sparkle /* use only one of these two methods */ } @@ -347,15 +377,18 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */ /* read rest of file, and get additional chunks in info_ptr - REQUIRED */ png_read_end(png_ptr, info_ptr); +#endif hilevel + + /* At this point you have read the entire image */ /* clean up after the read, and free any memory allocated - REQUIRED */ - png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL); + png_destroy_read_struct(&png_ptr, &info_ptr, png_infopp_NULL); /* close the file */ fclose(fp); /* that's it */ - return; + return (OK); } /* progressively read a file */ @@ -375,21 +408,21 @@ initialize_png_reader(png_structp *png_ptr, png_infop *info_ptr) if (*png_ptr == NULL) { *info_ptr = NULL; - return ERROR; + 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; + png_destroy_read_struct(png_ptr, info_ptr, png_infopp_NULL); + return (ERROR); } - if (setjmp((*png_ptr)->jmpbuf)) + if (setjmp(png_jmpbuf((*png_ptr)))) { - png_destroy_read_struct(png_ptr, info_ptr, (png_infopp)NULL); - return ERROR; + png_destroy_read_struct(png_ptr, info_ptr, png_infopp_NULL); + return (ERROR); } /* This one's new. You will need to provide all three @@ -407,18 +440,18 @@ initialize_png_reader(png_structp *png_ptr, png_infop *info_ptr) png_set_progressive_read_fn(*png_ptr, (void *)stream_data, info_callback, row_callback, end_callback); - return OK; + 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)) + if (setjmp(png_jmpbuf((*png_ptr)))) { /* Free the png_ptr and info_ptr memory on error */ - png_destroy_read_struct(png_ptr, info_ptr, (png_infopp)NULL); - return 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 @@ -432,7 +465,7 @@ process_data(png_structp *png_ptr, png_infop *info_ptr, * callback, if you aren't already displaying them there. */ png_process_data(*png_ptr, *info_ptr, buffer, length); - return OK; + return (OK); } info_callback(png_structp png_ptr, png_infop info) @@ -449,21 +482,47 @@ info_callback(png_structp png_ptr, png_infop info) 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 is called for every row in the image. If the + * image is interlaced, 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. + * + * In this function you will receive a pointer to new row data from + * libpng called new_row that is to replace a corresponding row (of + * the same data format) in a buffer allocated by your application. + * + * The new row data pointer new_row may be NULL, indicating there is + * no new data to be replaced (in cases of interlace loading). + * + * If new_row is not NULL then you need to call + * png_progressive_combine_row() to replace the corresponding row as + * shown below: + */ + /* Check if row_num is in bounds. */ + if((row_num >= 0) && (row_num < height)) + { + /* Get pointer to corresponding row in our + * PNG read buffer. + */ + png_bytep old_row = ((png_bytep *)our_data)[row_num]; + + /* If both rows are allocated then copy the new row + * data to the corresponding row data. + */ + if((old_row != NULL) && (new_row != NULL)) + png_progressive_combine_row(png_ptr, old_row, new_row); + } +/* * 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() passing in the new row and the + * old row, as demonstrated above. You can call this function for + * NULL rows (it will just return) and for non-interlaced images + * (it just does the png_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); @@ -472,8 +531,8 @@ row_callback(png_structp png_ptr, png_bytep new_row, * 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. + * to pass the current row as new_row, and the function will combine + * the old row and the new row. */ } @@ -496,11 +555,12 @@ void write_png(char *file_name /* , ... other image information ... */) FILE *fp; png_structp png_ptr; png_infop info_ptr; + png_colorp palette; /* open the file */ fp = fopen(file_name, "wb"); if (fp == NULL) - return; + return (ERROR); /* Create and initialize the png_struct with the desired error handler * functions. If you want to use the default stderr and longjump method, @@ -514,7 +574,7 @@ void write_png(char *file_name /* , ... other image information ... */) if (png_ptr == NULL) { fclose(fp); - return; + return (ERROR); } /* Allocate/initialize the image information data. REQUIRED */ @@ -522,19 +582,19 @@ void write_png(char *file_name /* , ... other image information ... */) if (info_ptr == NULL) { fclose(fp); - png_destroy_write_struct(&png_ptr, (png_infopp)NULL); - return; + png_destroy_write_struct(&png_ptr, png_infopp_NULL); + return (ERROR); } /* Set error handling. REQUIRED if you aren't supplying your own - * error hadnling functions in the png_create_write_struct() call. + * error handling functions in the png_create_write_struct() call. */ - if (setjmp(png_ptr->jmpbuf)) + if (setjmp(png_jmpbuf(png_ptr))) { /* If we get here, we had a problem reading the file */ fclose(fp); - png_destroy_write_struct(&png_ptr, (png_infopp)NULL); - return; + png_destroy_write_struct(&png_ptr, &info_ptr); + return (ERROR); } /* One of the following I/O initialization functions is REQUIRED */ @@ -549,6 +609,15 @@ void write_png(char *file_name /* , ... other image information ... */) /* where user_io_ptr is a structure you want available to the callbacks */ #endif no_streams /* only use one initialization method */ +#ifdef hilevel + /* This is the easy way. Use it if you already have all the + * image info living info in the structure. You could "|" many + * PNG_TRANSFORM flags into the png_transforms integer here. + */ + png_write_png(png_ptr, info_ptr, png_transforms, png_voidp_NULL); +#else + /* This is the hard way */ + /* 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, @@ -561,9 +630,13 @@ void write_png(char *file_name /* , ... other image information ... */) 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)); + palette = (png_colorp)png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH + * sizeof (png_color)); /* ... set palette colors ... */ - png_set_PLTE(png_ptr, info_ptr, palette, 256); + png_set_PLTE(png_ptr, info_ptr, palette, PNG_MAX_PALETTE_LENGTH); + /* You must not free palette here, because png_set_PLTE only makes a link to + the palette that you malloced. Wait until you are about to destroy + the png structure. */ /* optional significant bit chunk */ /* if we are dealing with a grayscale image then */ @@ -592,15 +665,31 @@ void write_png(char *file_name /* , ... other image information ... */) text_ptr[2].key = "Description"; text_ptr[2].text = ""; text_ptr[2].compression = PNG_TEXT_COMPRESSION_zTXt; +#ifdef PNG_iTXt_SUPPORTED + text_ptr[0].lang = NULL; + text_ptr[1].lang = NULL; + text_ptr[2].lang = NULL; +#endif 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 + /* note that if sRGB is present the gAMA and cHRM chunks 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); + /* If you want, you can write the info in two steps, in case you need to + * write your private chunk ahead of PLTE: + * + * png_write_info_before_PLTE(write_ptr, write_info_ptr); + * write_my_chunk(); + * png_write_info(png_ptr, info_ptr); + * + * However, given the level of known- and unknown-chunk support in 1.1.0 + * and up, this should no longer be necessary. + */ + /* 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 @@ -611,7 +700,7 @@ void write_png(char *file_name /* , ... other image information ... */) * all optional. Only call them if you want them. */ - /* invert monocrome pixels */ + /* invert monochrome pixels */ png_set_invert_mono(png_ptr); /* Shift the pixels up to a legal bit depth and fill in @@ -650,10 +739,10 @@ void write_png(char *file_name /* , ... other image information ... */) * use the first method if you aren't handling interlacing yourself. */ png_uint_32 k, height, width; - png_byte image[height][width]; + png_byte image[height][width*bytes_per_pixel]; png_bytep row_pointers[height]; for (k = 0; k < height; k++) - row_pointers[k] = image + k*width; + row_pointers[k] = image + k*width*bytes_per_pixel; /* One of the following output methods is REQUIRED */ #ifdef entire /* write out the entire image data in one call */ @@ -679,24 +768,37 @@ void write_png(char *file_name /* , ... other image information ... */) #endif no_entire /* use only one output method */ /* You can write optional chunks like tEXt, zTXt, and tIME at the end - * as well. + * as well. Shouldn't be necessary in 1.1.0 and up as all the public + * chunks are supported and you can use png_set_unknown_chunks() to + * register unknown chunks into the info structure to be written out. */ /* 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 */ +#endif hilevel + + /* If you png_malloced a palette, free it here (don't free info_ptr->palette, + as recommended in versions 1.0.5m and earlier of this example; if + libpng mallocs info_ptr->palette, libpng will free it). If you + allocated it with malloc() instead of png_malloc(), use free() instead + of png_free(). */ + png_free(png_ptr, palette); + palette=NULL; + + /* Similarly, if you png_malloced any data that you passed in with + png_set_something(), such as a hist or trans array, free it here, + when you can be sure that libpng is through with it. */ + png_free(png_ptr, trans); + trans=NULL; /* clean up after the write, and free any memory allocated */ - png_destroy_write_struct(&png_ptr, (png_infopp)NULL); + png_destroy_write_struct(&png_ptr, &info_ptr); /* close the file */ fclose(fp); /* that's it */ - return; + return (OK); } +#endif /* if 0 */