2001-02-07  Michael Natterer  <mitch@gimp.org>

	* app/gimppreview.[ch]: allocate less temp_bufs by removing the
	"create_preview" virtual function and adding a "render" one.

	Implementations have to call the new public function
	gimp_preview_render_and_flush() to render their temp_bufs.
	This way, e.g. the GimpPatternPreview can render the preview
	directly from the pattern's mask.

	* app/gimpdrawablepreview.c
	* app/gimpimagepreview.c
	* app/gimppatternpreview.c: changed accordingly.

	* app/gimpbrushpreview.[ch]: same as above and added BrushPipe
	popup animation.