Make it possible to call gdk_pixbuf_loader_set_size (loader, 0, 0) by

Make it possible to call gdk_pixbuf_loader_set_size (loader, 0, 0) by

Wed Jan  7 01:17:36 2004  Matthias Clasen  <maclas@gmx.de>

	* gdk-pixbuf-loader.c (gdk_pixbuf_loader_size_func):
	* gdk-pixbuf-loader.c (gdk_pixbuf_loader_set_size):
	* gdk-pixbuf-loader.c (gdk_pixbuf_loader_init): Make it possible
	to call gdk_pixbuf_loader_set_size (loader, 0, 0) by changing
	the initial values of priv->width/height to -1.

	* io-tiff.c (tiff_image_parse):
	* io-ras.c (RAS2State):
	* io-pnm.c (gdk_pixbuf__pnm_image_load_increment):
	* io-pcx.c (gdk_pixbuf__pcx_load_increment):
	* io-jpeg.c (gdk_pixbuf__jpeg_image_load_increment):
	* io-png.c (png_info_callback):
	* io-ico.c (DecodeHeader):
	* io-bmp.c (DecodeHeader): Call size_func once the size is known,
	even if the module can't make use of the scaling information. If
	size_func returns 0, don't allocate a pixbuf and return, if
	necessary with an error.

	* gdk-pixbuf.h:
	* gdk-pixbuf-io.c (gdk_pixbuf_get_file_info): A new function
	to determine the type and size of an image file without loading
	it completely.  (#53725)