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Clean up config, scripts, examples, etc.

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This commit is contained in:
Cosmin Truta 2018-11-25 20:27:04 -05:00
parent 702a07e716
commit 81a65de25d
9 changed files with 219 additions and 246 deletions
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example.c
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@ -14,8 +14,8 @@
*/
/* This is an example of how to use libpng to read and write PNG files.
* The file libpng-manual.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
* The file libpng-manual.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, is hereby placed
* in the public domain, and therefore does not require a copyright notice.
*
@ -26,16 +26,17 @@
* see also the programs in the contrib directory.
*/
/* The simple, but restricted, approach to reading a PNG file or data stream
* just requires two function calls, as in the following complete program.
* Writing a file just needs one function call, so long as the data has an
/* The simple, but restricted approach to reading a PNG file or data stream
* requires just two function calls, as in the following complete program.
* Writing a file needs just one function call, so long as the data has an
* appropriate layout.
*
* The following code reads PNG image data from a file and writes it, in a
* potentially new format, to a new file. While this code will compile there is
* minimal (insufficient) error checking; for a more realistic version look at
* contrib/examples/pngtopng.c
* potentially new format, to a new file. While this code will compile, there
* is minimal (insufficient) error checking. For a more realistic version,
* see contrib/examples/pngtopng.c
*/
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
@ -70,28 +71,28 @@ int main(int argc, const char **argv)
*/
buffer = malloc(PNG_IMAGE_SIZE(image));
/* If enough memory was available read the image in the desired format
* then write the result out to the new file. 'background' is not
* necessary when reading the image because the alpha channel is
/* If enough memory was available, read the image in the desired
* format, then write the result out to the new file. 'background' is
* not necessary when reading the image, because the alpha channel is
* preserved; if it were to be removed, for example if we requested
* PNG_FORMAT_RGB, then either a solid background color would have to
* be supplied or the output buffer would have to be initialized to the
* actual background of the image.
* be supplied, or the output buffer would have to be initialized to
* the actual background of the image.
*
* The fourth argument to png_image_finish_read is the 'row_stride' -
* this is the number of components allocated for the image in each
* row. It has to be at least as big as the value returned by
* PNG_IMAGE_ROW_STRIDE, but if you just allocate space for the
* default, minimum, size using PNG_IMAGE_SIZE as above you can pass
* default, minimum size, using PNG_IMAGE_SIZE as above, you can pass
* zero.
*
* The final argument is a pointer to a buffer for the colormap;
* colormaps have exactly the same format as a row of image pixels (so
* you choose what format to make the colormap by setting
* colormaps have exactly the same format as a row of image pixels
* (so you choose what format to make the colormap by setting
* image.format). A colormap is only returned if
* PNG_FORMAT_FLAG_COLORMAP is also set in image.format, so in this
* case NULL is passed as the final argument. If you do want to force
* all images into an index/color-mapped format then you can use:
* all images into an index/color-mapped format, then you can use:
*
* PNG_IMAGE_COLORMAP_SIZE(image)
*
@ -113,17 +114,15 @@ int main(int argc, const char **argv)
exit(0);
}
}
else
{
/* Calling png_image_free is optional unless the simplified API was
* not run to completion. In this case if there wasn't enough
* memory for 'buffer' we didn't complete the read, so we must free
* the image:
* not run to completion. In this case, if there wasn't enough
* memory for 'buffer', we didn't complete the read, so we must
* free the image:
*/
if (buffer == NULL)
png_image_free(&image);
else
free(buffer);
}
@ -132,65 +131,67 @@ int main(int argc, const char **argv)
* textual message in the 'png_image' structure:
*/
fprintf(stderr, "pngtopng: error: %s\n", image.message);
exit (1);
exit(1);
}
fprintf(stderr, "pngtopng: usage: pngtopng input-file output-file\n");
exit(1);
exit(2);
}
/* That's it ;-) Of course you probably want to do more with PNG files than
* just converting them all to 32-bit RGBA PNG files; you can do that between
* the call to png_image_finish_read and png_image_write_to_file. You can also
* ask for the image data to be presented in a number of different formats. You
* do this by simply changing the 'format' parameter set before allocating the
* buffer.
* ask for the image data to be presented in a number of different formats.
* You do this by simply changing the 'format' parameter set before allocating
* the buffer.
*
* The format parameter consists of five flags that define various aspects of
* the image, you can simply add these together to get the format or you can use
* one of the predefined macros from png.h (as above):
* the image. You can simply add these together to get the format, or you can
* use one of the predefined macros from png.h (as above):
*
* PNG_FORMAT_FLAG_COLOR: if set the image will have three color components per
* pixel (red, green and blue), if not set the image will just have one
* PNG_FORMAT_FLAG_COLOR: if set, the image will have three color components
* per pixel (red, green and blue); if not set, the image will just have one
* luminance (grayscale) component.
*
* PNG_FORMAT_FLAG_ALPHA: if set each pixel in the image will have an additional
* alpha value; a linear value that describes the degree the image pixel
* covers (overwrites) the contents of the existing pixel on the display.
* PNG_FORMAT_FLAG_ALPHA: if set, each pixel in the image will have an
* additional alpha value; a linear value that describes the degree the
* image pixel covers (overwrites) the contents of the existing pixel on the
* display.
*
* PNG_FORMAT_FLAG_LINEAR: if set the components of each pixel will be returned
* as a series of 16-bit linear values, if not set the components will be
* returned as a series of 8-bit values encoded according to the 'sRGB'
* standard. The 8-bit format is the normal format for images intended for
* direct display, because almost all display devices do the inverse of the
* sRGB transformation to the data they receive. The 16-bit format is more
* common for scientific data and image data that must be further processed;
* because it is linear simple math can be done on the component values.
* Regardless of the setting of this flag the alpha channel is always linear,
* although it will be 8 bits or 16 bits wide as specified by the flag.
* PNG_FORMAT_FLAG_LINEAR: if set, the components of each pixel will be
* returned as a series of 16-bit linear values; if not set, the components
* will be returned as a series of 8-bit values encoded according to the
* sRGB standard. The 8-bit format is the normal format for images intended
* for direct display, because almost all display devices do the inverse of
* the sRGB transformation to the data they receive. The 16-bit format is
* more common for scientific data and image data that must be further
* processed; because it is linear, simple math can be done on the component
* values. Regardless of the setting of this flag, the alpha channel is
* always linear, although it will be 8 bits or 16 bits wide as specified by
* the flag.
*
* PNG_FORMAT_FLAG_BGR: if set the components of a color pixel will be returned
* in the order blue, then green, then red. If not set the pixel components
* are in the order red, then green, then blue.
* PNG_FORMAT_FLAG_BGR: if set, the components of a color pixel will be
* returned in the order blue, then green, then red. If not set, the pixel
* components are in the order red, then green, then blue.
*
* PNG_FORMAT_FLAG_AFIRST: if set the alpha channel (if present) precedes the
* color or grayscale components. If not set the alpha channel follows the
* PNG_FORMAT_FLAG_AFIRST: if set, the alpha channel (if present) precedes the
* color or grayscale components. If not set, the alpha channel follows the
* components.
*
* You do not have to read directly from a file. You can read from memory or,
* on systems that support it, from a <stdio.h> FILE*. This is controlled by
* the particular png_image_read_from_ function you call at the start. Likewise
* on write you can write to a FILE* if your system supports it. Check the
* macro PNG_STDIO_SUPPORTED to see if stdio support has been included in your
* libpng build.
* the particular png_image_read_from_ function you call at the start.
* Likewise, on write, you can write to a FILE* if your system supports it.
* Check the macro PNG_STDIO_SUPPORTED to see if stdio support has been
* included in your libpng build.
*
* If you read 16-bit (PNG_FORMAT_FLAG_LINEAR) data you may need to write it in
* the 8-bit format for display. You do this by setting the convert_to_8bit
* If you read 16-bit (PNG_FORMAT_FLAG_LINEAR) data, you may need to write it
* in the 8-bit format for display. You do this by setting the convert_to_8bit
* flag to 'true'.
*
* Don't repeatedly convert between the 8-bit and 16-bit forms. There is
* significant data loss when 16-bit data is converted to the 8-bit encoding and
* the current libpng implementation of conversion to 16-bit is also
* significant data loss when 16-bit data is converted to the 8-bit encoding,
* and the current libpng implementation of conversion to 16-bit is also
* significantly lossy. The latter will be fixed in the future, but the former
* is unavoidable - the 8-bit format just doesn't have enough resolution.
*/
@ -201,10 +202,10 @@ int main(int argc, const char **argv)
* interfaces.
*
* All these interfaces require that you do your own error handling - your
* program must be able to arrange for control to return to your own code any
* time libpng encounters a problem. There are several ways to do this, but the
* standard way is to use the ANSI-C (C90) <setjmp.h> interface to establish a
* return point within your own code. You must do this if you do not use the
* program must be able to arrange for control to return to your own code, any
* time libpng encounters a problem. There are several ways to do this, but
* the standard way is to use the <setjmp.h> interface to establish a return
* point within your own code. You must do this if you do not use the
* simplified interface (above).
*
* The first step is to include the header files you need, including the libpng
@ -216,7 +217,7 @@ int main(int argc, const char **argv)
/* 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!).
* is not already defined by libpng!)
*/
#ifndef png_jmpbuf
@ -224,10 +225,10 @@ int main(int argc, const char **argv)
#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.
* returns zero if the image is a PNG, and nonzero otherwise.
*
* 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 the file can be opened and is a PNG, and 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
@ -240,7 +241,7 @@ int main(int argc, const char **argv)
*
* 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
* 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
@ -252,13 +253,13 @@ int check_if_png(char *file_name, FILE **fp)
if ((*fp = fopen(file_name, "rb")) == NULL)
return 0;
/* Read in some of the signature bytes */
/* 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 nonzero (true) if they match.
*/
return(!png_sig_cmp(buf, 0, PNG_BYTES_TO_CHECK));
}
@ -294,7 +295,7 @@ void read_png(FILE *fp, int sig_read) /* File is already open */
* 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
* 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);
@ -318,35 +319,33 @@ void read_png(FILE *fp, int sig_read) /* File is already open */
* 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_jmpbuf(png_ptr)))
{
/* Free all of the memory associated with the png_ptr and info_ptr */
/* Free all of the memory associated with the png_ptr and info_ptr. */
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
fclose(fp);
/* If we get here, we had a problem reading the file */
/* If we get here, we had a problem reading the file. */
return (ERROR);
}
/* One of the following I/O initialization methods is REQUIRED */
/* 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 */
/* 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_init_io(), 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 */
/* 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);
#ifdef hilevel
/*
* If you have enough memory to read in the entire image at once,
/* 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
* quantizing, filling, setting background, and doing gamma
@ -356,10 +355,10 @@ void read_png(FILE *fp, int sig_read) /* File is already open */
png_read_png(png_ptr, info_ptr, png_transforms, NULL);
#else
/* OK, you're doing it the hard way, with the lower-level functions */
/* 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 file before the first IDAT (image data chunk). REQUIRED.
*/
png_read_info(png_ptr, info_ptr);
@ -387,20 +386,21 @@ void read_png(FILE *fp, int sig_read) /* File is already open */
*/
png_set_strip_alpha(png_ptr);
/* Extract multiple pixels with bit depths of 1, 2, and 4 from a single
/* Extract multiple pixels with bit depths of 1, 2 or 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). */
* (not useful if you are using png_set_packing).
*/
png_set_packswap(png_ptr);
/* Expand paletted colors into true RGB triplets */
/* Expand paletted colors into true RGB triplets. */
if (color_type == PNG_COLOR_TYPE_PALETTE)
png_set_palette_to_rgb(png_ptr);
/* Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel */
/* 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_gray_1_2_4_to_8(png_ptr);
@ -411,12 +411,11 @@ void read_png(FILE *fp, int sig_read) /* File is already open */
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
* for paletted images instead of supplying a palette index. Note that
* 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) != 0)
@ -426,32 +425,29 @@ void read_png(FILE *fp, int sig_read) /* File is already open */
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
/* Some suggestions as to how to get a screen gamma value.
*
* Note that screen gamma is the display_exponent, which includes
* the CRT_exponent and any correction for viewing conditions
* the CRT_exponent and any correction for viewing conditions.
*/
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 */
/* 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 = PNG_DEFAULT_sRGB; /* A good guess for a PC monitor
in a dimly lit room */
screen_gamma = PNG_GAMMA_MAC_18 or 1.0; /* Good guesses for Mac systems */
screen_gamma = PNG_GAMMA_MAC_18 or 1.0; /* Good guesses for Mac
systems */
}
/* 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.
* by the user at run time. Gamma correction support in your application
* is strongly recommended.
*/
int intent;
@ -468,7 +464,7 @@ void read_png(FILE *fp, int sig_read) /* File is already open */
}
#ifdef PNG_READ_QUANTIZE_SUPPORTED
/* Quantize RGB files down to 8-bit palette or reduce palettes
/* Quantize 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) != 0)
@ -476,29 +472,26 @@ void read_png(FILE *fp, int sig_read) /* File is already open */
int num_palette;
png_colorp palette;
/* This reduces the image to the application supplied 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 quantized */
/* An array of colors to which the image should be quantized. */
png_color std_color_cube[MAX_SCREEN_COLORS];
png_set_quantize(png_ptr, std_color_cube, MAX_SCREEN_COLORS,
MAX_SCREEN_COLORS, NULL, 0);
}
/* This reduces the image to the palette supplied in the file */
/* This reduces the image to the palette supplied in the file. */
else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette) != 0)
{
png_uint_16p histogram = NULL;
png_get_hIST(png_ptr, info_ptr, &histogram);
png_set_quantize(png_ptr, palette, num_palette,
max_screen_colors, histogram, 0);
}
}
#endif /* READ_QUANTIZE */
/* Invert monochrome 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
@ -508,22 +501,21 @@ void read_png(FILE *fp, int sig_read) /* File is already open */
if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT) != 0)
{
png_color_8p sig_bit_p;
png_get_sBIT(png_ptr, info_ptr, &sig_bit_p);
png_set_shift(png_ptr, sig_bit_p);
}
/* Flip the RGB pixels to BGR (or RGBA to BGRA) */
/* Flip the RGB pixels to BGR (or RGBA to BGRA). */
if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
png_set_bgr(png_ptr);
/* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
/* 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 */
/* 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) */
/* Add filler (or alpha) byte (before/after each RGB triplet). */
png_set_filler(png_ptr, 0xffff, PNG_FILLER_AFTER);
#ifdef PNG_READ_INTERLACING_SUPPORTED
@ -536,40 +528,31 @@ void read_png(FILE *fp, int sig_read) /* File is already open */
number_passes = 1;
#endif /* READ_INTERLACING */
/* 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).
* update the palette for you (i.e. 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];
/* Clear the pointer array */
for (row = 0; row < height; row++)
row_pointers[row] = NULL;
row_pointers[row] = NULL; /* Clear the pointer array */
for (row = 0; row < height; row++)
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 */
/* 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)
@ -583,24 +566,24 @@ void read_png(FILE *fp, int sig_read) /* File is already open */
#endif no_sparkle /* Use only one of these two methods */
}
/* If you want to display the image after every pass, do so here */
/* 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 */
/* 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 */
/* At this point you have read the entire image. */
/* Clean up after the read, and free any memory allocated - REQUIRED */
/* Clean up after the read, and free any memory allocated. REQUIRED. */
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
/* Close the file */
/* Close the file. */
fclose(fp);
/* That's it */
/* That's it! */
return (OK);
}
@ -612,34 +595,30 @@ 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
* 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, NULL);
return (ERROR);
}
if (setjmp(png_jmpbuf((*png_ptr))))
{
png_destroy_read_struct(png_ptr, info_ptr, NULL);
return (ERROR);
}
/* This one's new. You will need to provide all three
* function callbacks, even if you aren't using them all.
/* You will need to provide all three function callbacks,
* even if you aren't using all of them.
* 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().
@ -652,7 +631,6 @@ 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);
}
@ -662,18 +640,18 @@ process_data(png_structp *png_ptr, png_infop *info_ptr,
{
if (setjmp(png_jmpbuf((*png_ptr))))
{
/* Free the png_ptr and info_ptr memory on error */
/* Free the png_ptr and info_ptr memory on error. */
png_destroy_read_struct(png_ptr, info_ptr, 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).
/* Give 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
* 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
* 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.
*/
@ -695,8 +673,7 @@ 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
/* 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.
*
@ -707,25 +684,22 @@ row_callback(png_structp png_ptr, png_bytep new_row,
* 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
* If new_row is not NULL, then you need to call
* png_progressive_combine_row(), to replace the corresponding row as
* shown below:
*/
/* Get pointer to corresponding row in our
* PNG read buffer.
*/
/* Get pointer to corresponding row in our PNG read buffer. */
png_bytep old_row = ((png_bytep *)our_data)[row_num];
#ifdef PNG_READ_INTERLACING_SUPPORTED
/* If both rows are allocated then copy the new row
/* If both rows are allocated, then copy the new row
* data to the corresponding row data.
*/
if ((old_row != NULL) && (new_row != NULL))
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
/* 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.
*
@ -736,7 +710,6 @@ row_callback(png_structp png_ptr, png_bytep new_row,
* (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
@ -783,14 +756,13 @@ void write_png(char *file_name /* , ... other image information ... */)
*/
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 (ERROR);
}
/* Allocate/initialize the image information data. REQUIRED */
/* Allocate/initialize the image information data. REQUIRED. */
info_ptr = png_create_info_struct(png_ptr);
if (info_ptr == NULL)
{
@ -799,30 +771,30 @@ void write_png(char *file_name /* , ... other image information ... */)
return (ERROR);
}
/* Set error handling. REQUIRED if you aren't supplying your own
/* Set up error handling. REQUIRED if you aren't supplying your own
* error handling functions in the png_create_write_struct() call.
*/
if (setjmp(png_jmpbuf(png_ptr)))
{
/* If we get here, we had a problem writing the file */
/* If we get here, we had a problem writing the file. */
fclose(fp);
png_destroy_write_struct(&png_ptr, &info_ptr);
return (ERROR);
}
/* One of the following I/O initialization functions is REQUIRED */
/* 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 */
/* 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 write functions, instead of calling
* png_init_io() here you would call
* png_init_io(), 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 */
/* where user_io_ptr is a structure you want available to the callbacks. */
#endif no_streams /* Only use one initialization method */
#ifdef hilevel
@ -833,30 +805,32 @@ void write_png(char *file_name /* , ... other image information ... */)
png_write_png(png_ptr, info_ptr, png_transforms, NULL);
#else
/* This is the hard way */
/* 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
* 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
* 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);
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, PNG_MAX_PALETTE_LENGTH
* (sizeof (png_color)));
/* Set the palette if there is one. REQUIRED for indexed-color images. */
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, 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
/* You must not free palette here, because png_set_PLTE only makes a link
* to the palette that you allocated. Wait until you are about to destroy
* the png structure.
*/
/* Optional significant bit (sBIT) chunk */
/* Optional significant bit (sBIT) chunk. */
png_color_8 sig_bit;
/* If we are dealing with a grayscale image then */
@ -872,18 +846,17 @@ void write_png(char *file_name /* , ... other image information ... */)
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 */
/* Optionally write comments into the image. */
{
png_text text_ptr[3];
char key0[]="Title";
char text0[]="Mona Lisa";
char key0[] = "Title";
char text0[] = "Mona Lisa";
text_ptr[0].key = key0;
text_ptr[0].text = text0;
text_ptr[0].compression = PNG_TEXT_COMPRESSION_NONE;
@ -891,8 +864,8 @@ void write_png(char *file_name /* , ... other image information ... */)
text_ptr[0].lang = NULL;
text_ptr[0].lang_key = NULL;
char key1[]="Author";
char text1[]="Leonardo DaVinci";
char key1[] = "Author";
char text1[] = "Leonardo DaVinci";
text_ptr[1].key = key1;
text_ptr[1].text = text1;
text_ptr[1].compression = PNG_TEXT_COMPRESSION_NONE;
@ -900,8 +873,8 @@ void write_png(char *file_name /* , ... other image information ... */)
text_ptr[1].lang = NULL;
text_ptr[1].lang_key = NULL;
char key2[]="Description";
char text2[]="<long text>";
char key2[] = "Description";
char text2[] = "<long text>";
text_ptr[2].key = key2;
text_ptr[2].text = text2;
text_ptr[2].compression = PNG_TEXT_COMPRESSION_zTXt;
@ -912,14 +885,14 @@ void write_png(char *file_name /* , ... other image information ... */)
png_set_text(write_ptr, write_info_ptr, text_ptr, 3);
}
/* Other optional chunks like cHRM, bKGD, tRNS, tIME, oFFs, pHYs */
/* Other optional chunks like cHRM, bKGD, tRNS, tIME, oFFs, pHYs. */
/* Note that if sRGB is present the gAMA and cHRM chunks must be ignored
/* Note that if sRGB is present, the gAMA and cHRM chunks must be ignored
* on read and, if your application chooses to write them, they must
* be written in accordance with the sRGB profile
* be written in accordance with the sRGB profile.
*/
/* Write the file header information. REQUIRED */
/* 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
@ -943,7 +916,7 @@ void write_png(char *file_name /* , ... other image information ... */)
* all optional. Only call them if you want them.
*/
/* Invert monochrome pixels */
/* Invert monochrome pixels. */
png_set_invert_mono(png_ptr);
/* Shift the pixels up to a legal bit depth and fill in
@ -951,10 +924,10 @@ void write_png(char *file_name /* , ... other image information ... */)
*/
png_set_shift(png_ptr, &sig_bit);
/* Pack pixels into bytes */
/* Pack pixels into bytes. */
png_set_packing(png_ptr);
/* Swap location of alpha bytes from ARGB to RGBA */
/* 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
@ -962,19 +935,18 @@ void write_png(char *file_name /* , ... other image information ... */)
*/
png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
/* Flip BGR pixels to RGB */
/* Flip BGR pixels to RGB. */
png_set_bgr(png_ptr);
/* Swap bytes of 16-bit files to most significant byte first */
/* Swap bytes of 16-bit files to most significant byte first. */
png_set_swap(png_ptr);
/* Swap bits of 1-bit, 2-bit, 4-bit packed pixel formats */
/* Swap bits of 1-bit, 2-bit, 4-bit packed pixel formats. */
png_set_packswap(png_ptr);
/* Turn on interlace handling if you are not using png_write_image() */
/* Turn on interlace handling if you are not using png_write_image(). */
if (interlacing != 0)
number_passes = png_set_interlace_handling(png_ptr);
else
number_passes = 1;
@ -984,29 +956,28 @@ void write_png(char *file_name /* , ... other image information ... */)
*/
png_uint_32 k, height, width;
/* In this example, "image" is a one-dimensional array of bytes */
/* In this example, "image" is a one-dimensional array of bytes. */
/* Guard against integer overflow */
if (height > PNG_SIZE_MAX/(width*bytes_per_pixel)) {
png_error(png_ptr, "Image_data buffer would be too large");
}
png_byte image[height*width*bytes_per_pixel];
/* Guard against integer overflow. */
if (height > PNG_SIZE_MAX / (width * bytes_per_pixel))
png_error(png_ptr, "Image data buffer would be too large");
png_byte image[height * width * bytes_per_pixel];
png_bytep row_pointers[height];
if (height > PNG_UINT_32_MAX/(sizeof (png_bytep)))
png_error (png_ptr, "Image is too tall to process in memory");
if (height > PNG_UINT_32_MAX / (sizeof (png_bytep)))
png_error(png_ptr, "Image is too tall to process in memory");
/* Set up pointers into your "image" byte array */
/* Set up pointers into your "image" byte array. */
for (k = 0; k < height; k++)
row_pointers[k] = image + k*width*bytes_per_pixel;
row_pointers[k] = image + k * width * bytes_per_pixel;
/* One of the following output methods is REQUIRED */
/* 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 */
/* The other way to write the image - deal with interlacing. */
#else no_entire /* Write out the image data by one or more scanlines */
@ -1018,27 +989,27 @@ void write_png(char *file_name /* , ... other image information ... */)
/* 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 */
/* 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. Shouldn't be necessary in 1.2.0 and up as all the public
* chunks are supported and you can use png_set_unknown_chunks() to
* as well. Shouldn't be necessary in 1.2.0 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 */
/* It is REQUIRED to call this to finish writing the rest of the file. */
png_write_end(png_ptr, info_ptr);
#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().
/* If you png_malloced a palette, free it here.
* (Don't free info_ptr->palette, as shown 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;
@ -1049,19 +1020,20 @@ void write_png(char *file_name /* , ... other image information ... */)
*/
png_free(png_ptr, trans);
trans = NULL;
/* Whenever you use png_free() it is a good idea to set the pointer to
/* Whenever you use png_free(), it is a good idea to set the pointer to
* NULL in case your application inadvertently tries to png_free() it
* again. When png_free() sees a NULL it returns without action, thus
* avoiding the double-free security problem.
* again. When png_free() sees a NULL it returns without action, avoiding
* the double-free problem.
*/
/* Clean up after the write, and free any memory allocated */
/* Clean up after the write, and free any allocated memory. */
png_destroy_write_struct(&png_ptr, &info_ptr);
/* Close the file */
/* Close the file. */
fclose(fp);
/* That's it */
/* That's it! */
return (OK);
}

16
png.c
View File

@ -3128,11 +3128,11 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, size_t size,
/* The total output count (max) is now 4+precision */
/* Check for an exponent, if we don't need one we are
* done and just need to terminate the string. At
* this point exp_b10==(-1) is effectively a flag - it got
* to '-1' because of the decrement after outputting
* the decimal point above (the exponent required is
* *not* -1!)
* done and just need to terminate the string. At this
* point, exp_b10==(-1) is effectively a flag: it got
* to '-1' because of the decrement, after outputting
* the decimal point above. (The exponent required is
* *not* -1.)
*/
if (exp_b10 >= (-1) && exp_b10 <= 2)
{
@ -3978,10 +3978,10 @@ png_build_16bit_table(png_structrp png_ptr, png_uint_16pp *ptable,
/* CSE the division and work round wacky GCC warnings (see the comments
* in png_gamma_8bit_correct for where these come from.)
*/
const double fmax = 1./(((png_int_32)1 << (16U - shift))-1);
double fmax = 1.0 / (((png_int_32)1 << (16U - shift)) - 1);
#endif
unsigned int max = (1U << (16U - shift))-1U;
unsigned int max_by_2 = 1U << (15U-shift);
unsigned int max = (1U << (16U - shift)) - 1U;
unsigned int max_by_2 = 1U << (15U - shift);
unsigned int i;
png_uint_16pp table = *ptable =

4
pngconf.h
View File

@ -63,8 +63,8 @@
*/
#define PNG_CONST const /* backward compatibility only */
/* This controls optimization of the reading of 16-bit and 32-bit values
* from PNG files. It can be set on a per-app-file basis - it
/* This controls optimization of the reading of 16-bit and 32-bit
* values from PNG files. It can be set on a per-app-file basis: it
* just changes whether a macro is used when the function is called.
* The library builder sets the default; if read functions are not
* built into the library the macro implementation is forced on.

2
scripts/descrip.mms
View File

@ -19,7 +19,7 @@ all : pngtest.exe libpng.olb
@ write sys$output " pngtest available"
libpng.olb : libpng.olb($(OBJS))
@ write sys$output " Libpng available"
@ write sys$output " libpng available"
pngtest.exe : pngtest.obj libpng.olb

2
scripts/makefile.hp64
View File

@ -1,7 +1,7 @@
# makefile for libpng, HPUX (10.20 and 11.00) using the ANSI/C product.
# Copyright (C) 1999-2002, 2006, 2009, 2010-2014 Glenn Randers-Pehrson
# Copyright (C) 1995 Guy Eric Schalnat, Group 42
# contributed by Jim Rice and updated by Chris Schleicher, Hewlett Packard
# Contributed by Jim Rice and updated by Chris Schleicher, Hewlett Packard
#
# This code is released under the libpng license.
# For conditions of distribution and use, see the disclaimer

2
scripts/makefile.hpux
View File

@ -1,7 +1,7 @@
# makefile for libpng, HPUX (10.20 and 11.00) using the ANSI/C product.
# Copyright (C) 1999-2002, 2006, 2010-2014 Glenn Randers-Pehrson
# Copyright (C) 1995 Guy Eric Schalnat, Group 42
# contributed by Jim Rice and updated by Chris Schleicher, Hewlett Packard
# Contributed by Jim Rice and updated by Chris Schleicher, Hewlett Packard
#
# This code is released under the libpng license.
# For conditions of distribution and use, see the disclaimer

2
scripts/makefile.std
View File

@ -122,6 +122,7 @@ pngwio.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.
pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
@ -129,6 +130,5 @@ pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebu
pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
pngtest.o: png.h pngconf.h pnglibconf.h

3
scripts/pnglibconf.dfa
View File

@ -8,7 +8,8 @@ com pnglibconf.h - library build configuration
com
version
com
com Copyright (c) 1998-2017 Glenn Randers-Pehrson
com Copyright (c) 2018 Cosmin Truta
com Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
com
com This code is released under the libpng license.
com For conditions of distribution and use, see the disclaimer

8
scripts/pnglibconf.h.prebuilt
View File

@ -2,10 +2,10 @@
/* pnglibconf.h - library build configuration */
/* Libpng version 1.6.36.git */
/* libpng version 1.6.36.git */
/* Copyright (c) 2018 Cosmin Truta */
/* Copyright (c) 1998-2018 Glenn Randers-Pehrson */
/* Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson */
/* This code is released under the libpng license. */
/* For conditions of distribution and use, see the disclaimer */
@ -21,8 +21,6 @@
#define PNG_ALIGNED_MEMORY_SUPPORTED
/*#undef PNG_ARM_NEON_API_SUPPORTED*/
/*#undef PNG_ARM_NEON_CHECK_SUPPORTED*/
/*#undef PNG_POWERPC_VSX_API_SUPPORTED*/
/*#undef PNG_POWERPC_VSX_CHECK_SUPPORTED*/
#define PNG_BENIGN_ERRORS_SUPPORTED
#define PNG_BENIGN_READ_ERRORS_SUPPORTED
/*#undef PNG_BENIGN_WRITE_ERRORS_SUPPORTED*/
@ -47,6 +45,8 @@
#define PNG_IO_STATE_SUPPORTED
#define PNG_MNG_FEATURES_SUPPORTED
#define PNG_POINTER_INDEXING_SUPPORTED
/*#undef PNG_POWERPC_VSX_API_SUPPORTED*/
/*#undef PNG_POWERPC_VSX_CHECK_SUPPORTED*/
#define PNG_PROGRESSIVE_READ_SUPPORTED
#define PNG_READ_16BIT_SUPPORTED
#define PNG_READ_ALPHA_MODE_SUPPORTED