add code for snapping windows to screen edges

openbox/Makefile.am

@@ -20,11 +20,11 @@ ob3_LDADD=@LIBINTL@ ../render/librender.a
 ob3_LDFLAGS=-export-dynamic
 ob3_SOURCES=client.c event.c extensions.c focus.c frame.c openbox.c prop.c \
 	screen.c stacking.c xerror.c themerc.c timer.c dispatch.c \
-	engine.c plugin.c action.c grab.c
+	engine.c plugin.c action.c grab.c snap.c
 
 noinst_HEADERS=client.h event.h extensions.h focus.h frame.h geom.h gettext.h \
 	openbox.h prop.h screen.h stacking.h xerror.h themerc.h dispatch.h \
-	timer.h engine.h plugin.h action.h grab.h
+	timer.h engine.h plugin.h action.h grab.h snap.h
 
 MAINTAINERCLEANFILES= Makefile.in
 

openbox/snap.c

@@ -0,0 +1,48 @@
+#include "client.h"
+#include "frame.h"
+#include "stacking.h"
+#include "screen.h"
+
+static int resistance = 10;
+
+void snap_move(Client *c, int *x, int *y, int w, int h)
+{
+    GList *it;
+    Rect *area;
+    int l, t, r, b; /* requested edges */
+    int al, at, ar, ab; /* screen area edges */
+    int cl, ct, cr, cb; /* current edges */
+
+    /* add the frame to the dimensions */
+    l = *x;
+    t = *y;
+    r = l + w - 1;
+    b = t + h - 1;
+
+    cl = c->frame->area.x;
+    ct = c->frame->area.y;
+    cr = cl + c->frame->area.width - 1;
+    cb = ct + c->frame->area.height - 1;
+    
+    /* snap to other clients */
+    for (it = stacking_list; it != NULL; it = it->next) {
+        /* XXX foo */
+    }
+
+    /* get the screen boundaries */
+    area = screen_area(c->desktop);
+    al = area->x;
+    at = area->y;
+    ar = al + area->width - 1;
+    ab = at + area->height - 1;
+
+    /* snap to screen edges */
+    if (cl >= al && l < al && l >= al - resistance)
+        *x = al;
+    else if (cr <= ar && r > ar && r <= ar + resistance)
+            *x = ar - w + 1;
+    if (ct >= at && t < at && t >= at - resistance)
+        *y = at;
+    else if (cb <= ab && b > ab && b < ab + resistance)
+        *y = ab - h + 1;
+}

openbox/snap.h

@@ -0,0 +1,8 @@
+#ifndef __snap_h
+#define __snap_h
+
+#include "client.h"
+
+void snap_move(Client *c, int *x, int *y, int w, int h);
+
+#endif