Re: reading a png picture from memory

[Tristan Van Berkom <vantr touchtunes com>]

this is the first few lines of gdk_pixbuf_new_from_file
in gdk-pixbuf-io.c. 

as you can see... it reads 128 bytes from the beginning of
the file to read the header and choose a image loader
to do the rest.

you could easily change this function prototype
and first few lines to suit your needs.

happy hacking!
        -Tristan.
===================================================
GdkPixbuf *
gdk_pixbuf_new_from_file (const char *filename,
                          GError    **error)
{
        GdkPixbuf *pixbuf;
        int size;
        FILE *f;
        guchar buffer [128];
        GdkPixbufModule *image_module;

        g_return_val_if_fail (filename != NULL, NULL);

        f = fopen (filename, "rb");
        if (!f) {
                g_set_error (error,
                             G_FILE_ERROR,
                             g_file_error_from_errno (errno),
                             _("Failed to open file '%s': %s"),
                             filename, g_strerror (errno));
                return NULL;
        }

        size = fread (&buffer, 1, sizeof (buffer), f);
        if (size == 0) {
                g_set_error (error,
                             GDK_PIXBUF_ERROR,
                             GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
                             _("Image file '%s' contains no data"),
                             filename);
                
                fclose (f);
                return NULL;
        }

        image_module = _gdk_pixbuf_get_module (buffer, size, filename, error);
        if (image_module == NULL) {
                fclose (f);
                return NULL;
        }
================================================


Stephane Pontier wrote:
> Hi everyone,
>
> I'm trying to display a picture from a zipped file into a GTK+(1.2)
> application.
> I can already display this picture if it's stored on the hard drive (in
> png format) using the gdk_pixbuf_new_from_file function, now I can read
> a zip file containing png pictures, use zlib to inflate the picture file
> in a buffer in memory but I don't know how to put it into a pixbuf.
> Do I need to:
>  - save the buffer in a temporary file then load it with
> gdk_pixbuf_new_from_file
>  - use another librairy to transform this png in memory into a
> "8-bit/sample packed format" as specified in the
> gdk_pixbuf_new_from_data function manual
> or
>  - can I use something simpler ?
>
> thank to reply to my email as I'm not subscribed to this list.
>
> Stephane Pontier
>
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