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Imported from libpng-0.88.tar

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This commit is contained in:
Guy Schalnat
1996-01-26 01:38:47 -06:00
committed by Glenn Randers-Pehrson
parent 4ee97b0891
commit b2e01bd505
36 changed files with 3932 additions and 2578 deletions
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240
example.c
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@@ -40,7 +40,7 @@ int check_png(char * file_name)
void read_png(char *file_name)
{
FILE *fp;
png_structp png_ptr;
png_structp png_ptr;
png_infop info_ptr;
/* open the file */
@@ -82,18 +82,18 @@ void read_png(char *file_name)
/* set up the input control if you are using standard C streams */
png_init_io(png_ptr, fp);
/* if you are using replacement read functions, here you would call */
png_set_read_fn(png_ptr, (void *)io_ptr, user_read_fn);
/* where io_ptr is a structure you want available to the callbacks */
/* if you are using replacement read functions, here you would call */
png_set_read_fn(png_ptr, (void *)io_ptr, user_read_fn);
/* where io_ptr is a structure you want available to the callbacks */
/* if you are using replacement message functions, here you would call */
png_set_message_fn(png_ptr, (void *)msg_ptr, user_error_fn, user_warning_fn);
/* where msg_ptr is a structure you want available to the callbacks */
/* if you are using replacement message functions, here you would call */
png_set_message_fn(png_ptr, (void *)msg_ptr, user_error_fn, user_warning_fn);
/* where msg_ptr is a structure you want available to the callbacks */
/* read the file information */
png_read_info(png_ptr, info_ptr);
/* read the file information */
png_read_info(png_ptr, info_ptr);
/* set up the transformations you want. Note that these are
/* set up the transformations you want. Note that these are
all optional. Only call them if you want them */
/* expand paletted colors into true rgb */
@@ -110,14 +110,14 @@ void read_png(char *file_name)
png_set_expand(png_ptr);
/* Set the background color to draw transparent and alpha
images over */
images over */
png_color_16 my_background;
if (info_ptr->valid & PNG_INFO_bKGD)
png_set_background(png_ptr, &(info_ptr->background),
PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
else
png_set_background(png_ptr, &my_background,
PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
else
png_set_background(png_ptr, &my_background,
PNG_BACKGROUND_GAMMA_SCREEN, 0, 1.0);
/* tell libpng to handle the gamma conversion for you */
@@ -128,7 +128,7 @@ void read_png(char *file_name)
/* tell libpng to strip 16 bit depth files down to 8 bits */
if (info_ptr->bit_depth == 16)
png_set_strip_16(png_ptr);
png_set_strip_16(png_ptr);
/* dither rgb files down to 8 bit palettes & reduce palettes
to the number of colors available on your screen */
@@ -146,7 +146,7 @@ void read_png(char *file_name)
png_set_dither(png_ptr, std_color_cube, MAX_SCREEN_COLORS,
MAX_SCREEN_COLORS, NULL);
}
}
}
/* invert monocrome files */
if (info_ptr->bit_depth == 1 &&
@@ -164,7 +164,7 @@ void read_png(char *file_name)
/* flip the rgb pixels to bgr */
if (info_ptr->color_type == PNG_COLOR_TYPE_RGB ||
info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
png_set_bgr(png_ptr);
/* swap bytes of 16 bit files to least significant bit first */
@@ -182,7 +182,7 @@ void read_png(char *file_name)
else
number_passes = 1;
/* optional call to update palette with transformations */
/* optional call to update palette with transformations */
png_start_read_image(png_ptr);
/* optional call to update the info structure */
@@ -200,7 +200,7 @@ void read_png(char *file_name)
for (pass = 0; pass < number_passes; pass++)
{
/* Read the image using the "sparkle" effect. */
png_read_rows(png_ptr, row_pointers, NULL, number_of_rows);
png_read_rows(png_ptr, row_pointers, NULL, number_of_rows);
/* If you are only reading on row at a time, this works */
for (y = 0; y < height; y++)
@@ -218,7 +218,7 @@ void read_png(char *file_name)
/* read the rest of the file, getting any additional chunks
in info_ptr */
png_read_end(png_ptr, info_ptr);
png_read_end(png_ptr, info_ptr);
/* clean up after the read, and free any memory allocated */
png_read_destroy(png_ptr, info_ptr, (png_infop)0);
@@ -237,126 +237,126 @@ void read_png(char *file_name)
/* progressively read a file */
/* these will normally not be global unless you are only
reading in one image at a time */
reading in one image at a time */
png_structp png_ptr;
png_infop info_ptr;
int
initialize_png_reader()
{
png_ptr = malloc(sizeof (png_struct));
if (!png_ptr)
return -1;
info_ptr = malloc(sizeof (png_info));
if (!info_ptr)
{
free(png_ptr);
return -1;
}
png_ptr = malloc(sizeof (png_struct));
if (!png_ptr)
return -1;
info_ptr = malloc(sizeof (png_info));
if (!info_ptr)
{
free(png_ptr);
return -1;
}
if (setjmp(png_ptr->jmpbuf))
{
png_read_destroy(png_ptr, info_ptr, (png_info *)0);
/* free pointers before returning, if necessary */
free(png_ptr);
free(info_ptr);
return -1;
}
if (setjmp(png_ptr->jmpbuf))
{
png_read_destroy(png_ptr, info_ptr, (png_info *)0);
/* free pointers before returning, if necessary */
free(png_ptr);
free(info_ptr);
return -1;
}
png_info_init(info_ptr);
png_read_init(png_ptr);
png_info_init(info_ptr);
png_read_init(png_ptr);
/* this one's new. You will need to provide all three
function callbacks, even if you aren't using them all.
You can put a void pointer in place of the NULL, and
retrieve the pointer from inside the callbacks using
the function png_get_progressive_ptr(png_ptr); */
png_set_progressive_read_fn(png_ptr, NULL,
info_callback, row_callback, end_callback);
/* this one's new. You will need to provide all three
function callbacks, even if you aren't using them all.
You can put a void pointer in place of the NULL, and
retrieve the pointer from inside the callbacks using
the function png_get_progressive_ptr(png_ptr); */
png_set_progressive_read_fn(png_ptr, NULL,
info_callback, row_callback, end_callback);
return 0;
return 0;
}
int
process_data(png_bytep buffer, png_uint_32 length)
{
if (setjmp(png_ptr->jmpbuf))
{
png_read_destroy(png_ptr, info_ptr, (png_info *)0);
free(png_ptr);
free(info_ptr);
return -1;
}
if (setjmp(png_ptr->jmpbuf))
{
png_read_destroy(png_ptr, info_ptr, (png_info *)0);
free(png_ptr);
free(info_ptr);
return -1;
}
/* this one's new also. Simply give it a chunk of data
from the file stream (in order, of course). On Segmented
machines, don't give it any more then 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 less then 256 bytes yet).
When this function returns, you may want to display any
rows that were generated in the row callback. */
png_process_data(png_ptr, info_ptr, buffer, length);
return 0;
/* this one's new also. Simply give it a chunk of data
from the file stream (in order, of course). On Segmented
machines, don't give it any more then 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 less then 256 bytes yet).
When this function returns, you may want to display any
rows that were generated in the row callback. */
png_process_data(png_ptr, info_ptr, buffer, length);
return 0;
}
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. */
/* 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)
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.
/* 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: */
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);
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. */
/* 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.
/* 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. */
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;
png_structp png_ptr;
png_infop info_ptr;
/* open the file */
fp = fopen(file_name, "wb");
@@ -380,7 +380,7 @@ void write_png(char *file_name, ... other image information ...)
}
/* set error handling */
if (setjmp(png_ptr->jmpbuf))
if (setjmp(png_ptr->jmpbuf))
{
png_write_destroy(png_ptr);
fclose(fp);
@@ -397,15 +397,15 @@ void write_png(char *file_name, ... other image information ...)
/* set up the output control if you are using standard C streams */
png_init_io(png_ptr, fp);
/* if you are using replacement write functions, here you would call */
png_set_write_fn(png_ptr, (void *)io_ptr, user_write_fn, user_flush_fn);
/* where io_ptr is a structure you want available to the callbacks */
/* if you are using replacement write functions, here you would call */
png_set_write_fn(png_ptr, (void *)io_ptr, user_write_fn, user_flush_fn);
/* where io_ptr is a structure you want available to the callbacks */
/* if you are using replacement message functions, here you would call */
png_set_message_fn(png_ptr, (void *)msg_ptr, user_error_fn, user_warning_fn);
/* where msg_ptr is a structure you want available to the callbacks */
/* if you are using replacement message functions, here you would call */
png_set_message_fn(png_ptr, (void *)msg_ptr, user_error_fn, user_warning_fn);
/* where msg_ptr is a structure you want available to the callbacks */
/* set the file information here */
/* set the file information here */
info_ptr->width = ;
info_ptr->height = ;
etc.
@@ -418,18 +418,18 @@ void write_png(char *file_name, ... other image information ...)
/* optional significant bit chunk */
info_ptr->valid |= PNG_INFO_sBIT;
/* if we are dealing with a grayscale image then */
info_ptr->sig_bit.gray = true_bit_depth;
/* otherwise, if we are dealing with a color image then */
info_ptr->sig_bit.red = true_red_bit_depth;
info_ptr->sig_bit.green = true_green_bit_depth;
info_ptr->sig_bit.blue = true_blue_bit_depth;
/* if the image has an alpha channel then */
/* if we are dealing with a grayscale image then */
info_ptr->sig_bit.gray = true_bit_depth;
/* otherwise, if we are dealing with a color image then */
info_ptr->sig_bit.red = true_red_bit_depth;
info_ptr->sig_bit.green = true_green_bit_depth;
info_ptr->sig_bit.blue = true_blue_bit_depth;
/* if the image has an alpha channel then */
info_ptr->sig_bit.alpha = true_alpha_bit_depth;
/* optional gamma chunk is strongly suggested if you have any guess
as to the correct gamma of the image */
info_ptr->valid |= PNG_INFO_gAMA;
/* optional gamma chunk is strongly suggested if you have any guess
as to the correct gamma of the image */
info_ptr->valid |= PNG_INFO_gAMA;
info_ptr->gamma = gamma;
/* other optional chunks */