first usable version of kernel and commands

After an year of hard work, this is a first "usable" version of Jehanne.

sys/src/lib/draw/allocimagemix.c

@@ -0,0 +1,52 @@
+/*
+ * This file is part of the UCB release of Plan 9. It is subject to the license
+ * terms in the LICENSE file found in the top-level directory of this
+ * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No
+ * part of the UCB release of Plan 9, including this file, may be copied,
+ * modified, propagated, or distributed except according to the terms contained
+ * in the LICENSE file.
+ */
+
+#include <u.h>
+#include <libc.h>
+#include <draw.h>
+
+Image*
+allocimagemix(Display *d, uint32_t color1, uint32_t color3)
+{
+	Image *t, *b;
+	static Image *qmask;
+
+	if(qmask == nil)
+		qmask = allocimage(d, Rect(0,0,1,1), GREY8, 1, 0x3F3F3FFF);
+		
+	if(d->screenimage->depth <= 8){	/* create a 2×2 texture */
+		t = allocimage(d, Rect(0,0,1,1), d->screenimage->chan, 0, color1);
+		if(t == nil)
+			return nil;
+
+		b = allocimage(d, Rect(0,0,2,2), d->screenimage->chan, 1, color3);
+		if(b == nil){
+			freeimage(t);
+			return nil;
+		}
+
+		draw(b, Rect(0,0,1,1), t, nil, ZP);
+		freeimage(t);
+		return b;
+	}else{	/* use a solid color, blended using alpha */
+		t = allocimage(d, Rect(0,0,1,1), d->screenimage->chan, 1, color1);
+		if(t == nil)
+			return nil;
+
+		b = allocimage(d, Rect(0,0,1,1), d->screenimage->chan, 1, color3);
+		if(b == nil){
+			freeimage(t);
+			return nil;
+		}
+
+		draw(b, b->r, t, qmask, ZP);
+		freeimage(t);
+		return b;
+	}
+}