add demo volume code

demo/volume/include/x.h

@@ -0,0 +1,45 @@
+/*
+ * ALGO     : PROJ. : Volume
+ * RESEARCH : File  : x.h
+ *          : Date  : 20100531.0725UTC
+ *          : Email : mail@algoresearch.net
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <X11/Xutil.h> 
+
+extern Display *dpy;
+extern GC gc;
+extern Pixmap pixmap;
+extern Atom delWin;
+extern XEvent e;
+extern unsigned long gray[], colors[], spectrum[];
+
+typedef struct{
+	unsigned short int *image_16;
+	long *image_32;
+	XImage *screen;
+	int w, h, cx, cy;
+	unsigned long size;
+}IMG;
+
+int create_x(int, int, char*);
+int create_image(IMG *, int, int);
+
+void set_graymap();
+void set_colormap();
+void set_spectrum();
+
+void clear_image(IMG *img);
+void burn_image(IMG *img);
+void draw_buffer(int, int, int, int);
+
+void put_pixel(IMG *img, int, int, unsigned long);
+void put_apixel(IMG *img, int, int, unsigned long, float alpha);
+void draw_line (IMG *img, int x0, int y0, int x1, int y1, unsigned long c);
+
+void clear_buffer(int, int, int, int);
+void draw_image(IMG *img, int x, int y, int w, int h);
+