new feature: add focus{next,prev}screen ui_callback functions

this allows to switch focused screen in multi-head (zaphod) mode

awesomerc

@@ -70,6 +70,8 @@ awesome:
             (("Mod4"), "b", "togglebar"),
             (("Mod4"), "j", "focusnext"),
             (("Mod4"), "k", "focusprev"),
+            (("Mod4", "Control"), "j", "focusnextscreen"),
+            (("Mod4", "Control"), "k", "focusprevscreen"),
             (("Mod4"), "h", "setmwfact", "-0.05"),
             (("Mod4"), "l", "setmwfact", "+0.05"),
             (("Mod4"), "p", "setborder", "+1"),

config.c

@@ -33,6 +33,7 @@
 #include "draw.h"
 #include "util.h"
 #include "statusbar.h"
+#include "screen.h"
 #include "layouts/tile.h"
 #include "layouts/max.h"
 #include "layouts/floating.h"
@@ -109,6 +110,9 @@ static const NameFuncLink KeyfuncList[] = {
     {"setmwfact", uicb_setmwfact},
     {"setnmaster", uicb_setnmaster},
     {"setncols", uicb_setncols},
+    /* screen.c */
+    {"focusnextscreen", uicb_focusnextscreen},
+    {"focusprevscreen", uicb_focusprevscreen},
     /* awesome.c */
     {"quit", uicb_quit},
     /* statusbar.c */

screen.c

@@ -20,7 +20,12 @@
  */
 
 #include "util.h"
+#include "client.h"
 #include "screen.h"
+#include "tag.h"
+#include "layout.h"
+
+extern Client *sel, *clients;
 
 /** Get screens info
  * \param disp Display ref
@@ -85,3 +90,37 @@ get_display_info(Display *disp, int screen, Statusbar statusbar)
 
     return si;
 }
+
+void
+uicb_focusnextscreen(Display *disp,
+                     DC *drawcontext,
+                     awesome_config * awesomeconf,
+                     const char *arg __attribute__ ((unused)))
+{
+    Client *c;
+    int next_screen = awesomeconf->screen + 1 >= ScreenCount(disp) ? 0 : awesomeconf->screen + 1;
+
+    for(c = clients; c && !isvisible(c, next_screen, awesomeconf[next_screen - awesomeconf->screen].selected_tags, awesomeconf[next_screen - awesomeconf->screen].ntags); c = c->next);
+    if(c)
+    {
+        focus(c->display, &drawcontext[next_screen - awesomeconf->screen], c, True, &awesomeconf[next_screen - awesomeconf->screen]);
+        restack(c->display, &drawcontext[next_screen - awesomeconf->screen], &awesomeconf[next_screen - awesomeconf->screen]);
+    }
+}
+
+void
+uicb_focusprevscreen(Display *disp,
+                     DC *drawcontext,
+                     awesome_config * awesomeconf,
+                     const char *arg __attribute__ ((unused)))
+{
+    Client *c;
+    int prev_screen = awesomeconf->screen - 1 < 0 ? ScreenCount(disp) - 1 : awesomeconf->screen - 1;
+
+    for(c = clients; c && !isvisible(c, prev_screen, awesomeconf[prev_screen - awesomeconf->screen].selected_tags, awesomeconf[prev_screen - awesomeconf->screen].ntags); c = c->next);
+    if(c)
+    {
+        focus(c->display, &drawcontext[prev_screen - awesomeconf->screen], c, True, &awesomeconf[prev_screen - awesomeconf->screen]);
+        restack(c->display, &drawcontext[prev_screen - awesomeconf->screen], &awesomeconf[prev_screen - awesomeconf->screen]);
+    }
+}

screen.h

@@ -31,5 +31,7 @@ typedef XineramaScreenInfo ScreenInfo;
 
 ScreenInfo * get_screen_info(Display *, int, Statusbar, int *);
 ScreenInfo * get_display_info(Display *disp, int, Statusbar statusbar);
+void uicb_focusnextscreen(Display *, DC *, awesome_config *, const char *);
+void uicb_focusprevscreen(Display *, DC *, awesome_config *, const char *);
 
 #endif