summaryrefslogtreecommitdiff
path: root/example.c
diff options
context:
space:
mode:
authorGlenn Randers-Pehrson <glennrp at users.sourceforge.net>2013-03-02 14:58:22 -0600
committerGlenn Randers-Pehrson <glennrp at users.sourceforge.net>2013-03-02 15:03:15 -0600
commit871b1d0fabee7995383cd6941362b68a03f86e25 (patch)
tree5b685f9d4c874b4e435db96b66cd20654b8b6ddf /example.c
parentf3af706c2a489333f816843bc986a6bafe47719b (diff)
downloadlibpng-871b1d0fabee7995383cd6941362b68a03f86e25.tar.gz
[libpng16] Bump version to 1.6.1beta05
Diffstat (limited to 'example.c')
-rw-r--r--example.c86
1 files changed, 58 insertions, 28 deletions
diff --git a/example.c b/example.c
index 61d9d74db..ee4e227bc 100644
--- a/example.c
+++ b/example.c
@@ -2,8 +2,8 @@
#if 0 /* in case someone actually tries to compile this */
/* example.c - an example of using libpng
- * Last changed in libpng 1.6.0 [(PENDING RELEASE)]
- * Maintained 1998-2012 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.0 [February 14, 2013]
+ * Maintained 1998-2013 Glenn Randers-Pehrson
* Maintained 1996, 1997 Andreas Dilger)
* Written 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
* To the extent possible under law, the authors have waived
@@ -48,7 +48,8 @@ int main(int argc, const char **argv)
png_image image; /* The control structure used by libpng */
/* Initialize the 'png_image' structure. */
- memset(&image, 0, sizeof image);
+ memset(&image, 0, (sizeof image));
+ image.version = PNG_IMAGE_VERSION;
/* The first argument is the file to read: */
if (png_image_begin_read_from_file(&image, argv[1]))
@@ -75,16 +76,28 @@ int main(int argc, const char **argv)
* be supplied or the output buffer would have to be initialized to the
* actual background of the image.
*
- * The final argument to png_image_finish_read is the 'row_stride' -
+ * 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
* 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
+ * 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:
+ *
+ * PNG_IMAGE_COLORMAP_SIZE(image)
+ *
+ * to find the maximum size of the colormap in bytes.
*/
if (buffer != NULL &&
png_image_finish_read(&image, NULL/*background*/, buffer,
- 0/*row_stride*/))
+ 0/*row_stride*/, NULL/*colormap*/))
{
/* Now write the image out to the second argument. In the write
* call 'convert_to_8bit' allows 16-bit data to be squashed down to
@@ -92,7 +105,7 @@ int main(int argc, const char **argv)
* to the 8-bit format.
*/
if (png_image_write_to_file(&image, argv[2], 0/*convert_to_8bit*/,
- buffer, 0/*row_stride*/))
+ buffer, 0/*row_stride*/, NULL/*colormap*/))
{
/* The image has been written successfully. */
exit(0);
@@ -833,7 +846,7 @@ void write_png(char *file_name /* , ... other image information ... */)
/* Set the palette if there is one. REQUIRED for indexed-color images */
palette = (png_colorp)png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH
- * png_sizeof(png_color));
+ * (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
@@ -864,25 +877,38 @@ void write_png(char *file_name /* , ... other image information ... */)
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[0].itxt_length = 0;
- text_ptr[0].lang = NULL;
- text_ptr[0].lang_key = NULL;
- text_ptr[1].key = "Author";
- text_ptr[1].text = "Leonardo DaVinci";
- text_ptr[1].compression = PNG_TEXT_COMPRESSION_NONE;
- text_ptr[1].itxt_length = 0;
- text_ptr[1].lang = NULL;
- text_ptr[1].lang_key = NULL;
- text_ptr[2].key = "Description";
- text_ptr[2].text = "<long text>";
- text_ptr[2].compression = PNG_TEXT_COMPRESSION_zTXt;
- text_ptr[2].itxt_length = 0;
- text_ptr[2].lang = NULL;
- text_ptr[2].lang_key = NULL;
- png_set_text(png_ptr, info_ptr, text_ptr, 3);
+ {
+ png_text text_ptr[3];
+
+ 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;
+ text_ptr[0].itxt_length = 0;
+ text_ptr[0].lang = NULL;
+ text_ptr[0].lang_key = NULL;
+
+ 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;
+ text_ptr[1].itxt_length = 0;
+ text_ptr[1].lang = NULL;
+ text_ptr[1].lang_key = NULL;
+
+ 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;
+ text_ptr[2].itxt_length = 0;
+ text_ptr[2].lang = NULL;
+ text_ptr[2].lang_key = NULL;
+
+ png_set_text(write_ptr, write_info_ptr, text_ptr, 3);
+ }
/* Other optional chunks like cHRM, bKGD, tRNS, tIME, oFFs, pHYs */
@@ -955,12 +981,16 @@ 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*bytes_per_pixel];
+
+ /* In this example, "image" is a one-dimensional array of bytes */
+ png_byte image[height*width*bytes_per_pixel];
+
png_bytep row_pointers[height];
- if (height > PNG_UINT_32_MAX/png_sizeof(png_bytep))
+ 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 */
for (k = 0; k < height; k++)
row_pointers[k] = image + k*width*bytes_per_pixel;