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Fix 2nd part of STR #2520: added Fl_PNG_Image in-memory constructor.

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This constructor has a 3rd argument, the size of the array holding the in-memory PNG image.
This allows the constructor to check for errors in the image.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@8287 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
This commit is contained in:
Manolo Gouy 2011-01-17 20:51:12 +00:00
parent 5af1531cd2
commit 0ae1054d07
2 changed files with 69 additions and 20 deletions
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5
FL/Fl_PNG_Image.H
View File

@ -40,9 +40,12 @@
*/
class FL_EXPORT Fl_PNG_Image : public Fl_RGB_Image {
public:
public:
Fl_PNG_Image(const char* filename);
Fl_PNG_Image (const char *name_png, const unsigned char *buffer, int datasize);
private:
void load_png_(const char *name_png, const unsigned char *buffer_png, int datasize);
};
#endif

84
src/Fl_PNG_Image.cxx
View File

@ -42,37 +42,76 @@
#include <stdlib.h>
#include <FL/fl_utf8.h>
#if defined(HAVE_LIBPNG) && defined(HAVE_LIBZ)
extern "C"
{
#if defined(HAVE_LIBPNG) && defined(HAVE_LIBZ)
# include <zlib.h>
# ifdef HAVE_PNG_H
# include <png.h>
# else
# include <libpng/png.h>
# endif // HAVE_PNG_H
#endif // HAVE_LIBPNG && HAVE_LIBZ
}
typedef struct {
png_structp pp;
const unsigned char *current;
const unsigned char *last;
} fl_png_memory;
static void png_read_data_from_mem( png_structp png_ptr, //pointer to our data
png_bytep data, // where to copy the image data for libpng computing
png_size_t length) // length of data to copy
{
fl_png_memory *png_mem_data = (fl_png_memory*)png_get_io_ptr(png_ptr); // get the pointer to our struct
if (png_mem_data->current + length > png_mem_data->last) {
png_error(png_mem_data->pp, "Invalid attempt to read row data");
return;
}
/* copy data from image buffer */
memcpy (data, png_mem_data->current, length);
/* advance in the memory data */
png_mem_data->current += length;
}
#endif // HAVE_LIBPNG && HAVE_LIBZ
/**
The constructor loads the named PNG image from the given png filename.
<P>The destructor free all memory and server resources that are used by
<P>The destructor frees all memory and server resources that are used by
the image.
*/
Fl_PNG_Image::Fl_PNG_Image(const char *png) // I - File to read
: Fl_RGB_Image(0,0,0) {
Fl_PNG_Image::Fl_PNG_Image (const char *filename): Fl_RGB_Image(0,0,0)
{
load_png_(filename, NULL, 0);
}
/** Constructor that reads a PNG image from memory.
\param name_png A name given to this image
\param buffer Pointer to the start of the PNG image in memory
\param maxsize Size in bytes of the memory buffer containing the PNG image
*/
Fl_PNG_Image::Fl_PNG_Image (
const char *name_png, const unsigned char *buffer, int maxsize): Fl_RGB_Image(0,0,0)
{
load_png_(name_png, buffer, maxsize);
}
void Fl_PNG_Image::load_png_(const char *name_png, const unsigned char *buffer_png, int maxsize)
{
#if defined(HAVE_LIBPNG) && defined(HAVE_LIBZ)
int i; // Looping var
FILE *fp; // File pointer
int channels; // Number of color channels
png_structp pp; // PNG read pointer
png_infop info; // PNG info pointers
png_bytep *rows; // PNG row pointers
int i; // Looping var
FILE *fp; // File pointer
int channels; // Number of color channels
png_structp pp; // PNG read pointer
png_infop info; // PNG info pointers
png_bytep *rows;// PNG row pointers
fl_png_memory png_mem_data;
int from_memory = (buffer_png != NULL); // true iff reading image from memory
// Open the PNG file...
if ((fp = fl_fopen(png, "rb")) == NULL) return;
if (!from_memory) {
if ((fp = fl_fopen(name_png, "rb")) == NULL) return;
}
// Setup the PNG data structures...
pp = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
@ -80,12 +119,19 @@ Fl_PNG_Image::Fl_PNG_Image(const char *png) // I - File to read
if (setjmp(png_jmpbuf(pp)))
{
Fl::warning("PNG file \"%s\" contains errors!\n", png);
Fl::warning("PNG file \"%s\" contains errors!\n", name_png);
return;
}
// Initialize the PNG read "engine"...
png_init_io(pp, fp);
if (from_memory) {
png_mem_data.current = buffer_png;
png_mem_data.last = buffer_png + maxsize;
png_mem_data.pp = pp;
// Initialize the function pointer to the PNG read "engine"...
png_set_read_fn (pp, (png_voidp) &png_mem_data, png_read_data_from_mem);
} else {
png_init_io(pp, fp); // Initialize the PNG file read "engine"...
}
// Get the image dimensions and convert to grayscale or RGB...
png_read_info(pp, info);
@ -101,7 +147,7 @@ Fl_PNG_Image::Fl_PNG_Image(const char *png) // I - File to read
int num_trans = 0;
png_get_tRNS(pp, info, 0, &num_trans, 0);
if ((png_get_color_type(pp, info) & PNG_COLOR_MASK_ALPHA) || (num_trans != 0))
channels ++;
channels ++;
w((int)(png_get_image_width(pp, info)));
h((int)(png_get_image_height(pp, info)));
@ -150,7 +196,7 @@ Fl_PNG_Image::Fl_PNG_Image(const char *png) // I - File to read
png_read_end(pp, info);
png_destroy_read_struct(&pp, &info, NULL);
fclose(fp);
if (!from_memory) fclose(fp);
#endif // HAVE_LIBPNG && HAVE_LIBZ
}