--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/pkg-src/tree-x/dbl.h	Mon Aug 13 09:43:35 2007 +0200
@@ -0,0 +1,66 @@
+/* ----------------------------------------------------------------------------
+ *     Double buffering code
+ * ----------------------------------------------------------------------------
+ */
+
+#include <stdio.h>
+#include <X11/Xlib.h>
+
+#define DBL_MAX_SURFACES 2
+#define DBL_MIN_PLANES   2
+#define DBL_MAX_PLANES   6
+#define DBL_MAX_COLORS   (1 << (DBL_MAX_PLANES >> 1))
+
+typedef struct _surface {
+    int	         mask;          /* mask to use this surface           */
+    int	       offset;          /* offset within colormap             */
+    int	   num_colors;          /* number of colors in color array    */
+    XColor   color[1];          /* the actual color array             */
+} Surface;
+
+typedef struct _doublebuffer {
+    Display     *display;       /* X display for windows and pixmaps  */
+    Screen      *screen;	/* X screen                           */
+    Window	 window;	/* X window for this double buffer    */
+
+    int		 width;		/* width of window                    */
+    int          height;	/* height of window                   */
+
+    Pixmap	 frame;	        /* pixmap for frame buffer            */
+    Pixmap       backing;       /* pixmap for backing store           */
+    Drawable     drawable;      /* copy of window/pixmap we draw in   */
+
+    GC		 gc;		/* GC used to draw the drawable       */
+    Visual      *visual;	/* X visual                           */
+    Colormap     colormap;	/* X colormap identifier              */
+    int          depth;	        /* depth of screen in planes          */
+    int          num_planes;    /* number of planes used              */
+
+/* surface information is used to do double buffering                 */ 
+
+   int       num_surfaces;
+   int       current_surface;
+   Surface  *surface[DBL_MAX_SURFACES];
+
+/* we need to remember which pixels and planes we allocated           */
+
+   int       mask;
+   long      pixels[DBL_MAX_COLORS];                                  
+   long      planes[DBL_MAX_PLANES];
+
+/* the pixel values one should use when drawing to the viewports      */
+
+   int       num_colors; 
+   int       colors[DBL_MAX_COLORS];
+} DoubleBuffer;
+
+
+extern DoubleBuffer  *DBLcreate_double_buffer();
+extern void           DBLdelete_double_buffer();
+extern unsigned long  DBLinq_background();
+extern char          *getenv();
+
+
+
+
+