Add origin-shifting (Shift+cursors) and source-shifting (Ctrl+cursors) to Net.

(Adding modifier+cursors handling has had minor knock-on effects on the other
puzzles, so that they can continue to ignore modifiers.)

(An unfortunate side effect of this is some artifacts in exterior barrier
drawing; notably, a disconnected corner can now appear at the corner of the
grid under some circumstances. I haven't found a satisfactory way round
this yet.)

[originally from svn r5844]

1 files changed, 6 insertions, 4 deletions

diff --git a/gtk.c b/gtk.c
index ab10a11..3fdfc87 100644
--- a/gtk.c
+++ b/gtk.c
@@ -317,24 +317,26 @@ static gint key_event(GtkWidget *widget, GdkEventKey *event, gpointer data)
 {
     frontend *fe = (frontend *)data;
     int keyval;
+    int shift = (event->state & GDK_SHIFT_MASK) ? MOD_SHFT : 0;
+    int ctrl = (event->state & GDK_CONTROL_MASK) ? MOD_CTRL : 0;
 
     if (!fe->pixmap)
         return TRUE;
 
     if (event->keyval == GDK_Up)
-        keyval = CURSOR_UP;
+        keyval = shift | ctrl | CURSOR_UP;
     else if (event->keyval == GDK_KP_Up || event->keyval == GDK_KP_8)
 	keyval = MOD_NUM_KEYPAD | '8';
     else if (event->keyval == GDK_Down)
-        keyval = CURSOR_DOWN;
+        keyval = shift | ctrl | CURSOR_DOWN;
     else if (event->keyval == GDK_KP_Down || event->keyval == GDK_KP_2)
 	keyval = MOD_NUM_KEYPAD | '2';
     else if (event->keyval == GDK_Left)
-        keyval = CURSOR_LEFT;
+        keyval = shift | ctrl | CURSOR_LEFT;
     else if (event->keyval == GDK_KP_Left || event->keyval == GDK_KP_4)
 	keyval = MOD_NUM_KEYPAD | '4';
     else if (event->keyval == GDK_Right)
-        keyval = CURSOR_RIGHT;
+        keyval = shift | ctrl | CURSOR_RIGHT;
     else if (event->keyval == GDK_KP_Right || event->keyval == GDK_KP_6)
 	keyval = MOD_NUM_KEYPAD | '6';
     else if (event->keyval == GDK_KP_Home || event->keyval == GDK_KP_7)