From beb9d63a39b01fad2c4126b695a9935443634eab Mon Sep 17 00:00:00 2001
From: Rob Norris <rw_norris@hotmail.com>
Date: Fri, 6 Dec 2013 23:56:05 +0000
Subject: [PATCH] Enable double clicking as an optional way to control zooming
 in pan mode.

Double click of the left (primary) mouse will zoom in.
Double click of the right (secondary) mouse will zoom out.

Make use of a timeout function to wait and see if a double click event occurs.
If it hasn't then the timeout will action the single click request
 (to recenter the display to the clicked location).
---
 help/C/viking.xml |  5 +++
 src/vikwindow.c   | 81 +++++++++++++++++++++++++++++++++++++++++++----
 2 files changed, 79 insertions(+), 7 deletions(-)

diff --git a/help/C/viking.xml b/help/C/viking.xml
index 84d0736e..1baf61b1 100644
--- a/help/C/viking.xml
+++ b/help/C/viking.xml
@@ -1762,6 +1762,11 @@ This is the default tool.
 <para>
 This mode can also be entered by the keyboard shortcut <keycap>Ctrl+Shift+P</keycap>
 </para>
+<para>
+Double clicking the left mouse button will zoom the map in.
+<keycap>Shift</keycap> + double clicking the left mouse button will zoom the map out.
+Double clicking the right mouse button will also zoom the map out.
+</para>
 </section>
 
 <section><title>Zoom</title>
diff --git a/src/vikwindow.c b/src/vikwindow.c
index e2999d5b..a1f49abe 100644
--- a/src/vikwindow.c
+++ b/src/vikwindow.c
@@ -173,6 +173,8 @@ struct _VikWindow {
 
   gboolean pan_move;
   gint pan_x, pan_y;
+  gint delayed_pan_x, delayed_pan_y; // Temporary storage
+  gboolean single_click_pending;
 
   guint draw_image_width, draw_image_height;
   gboolean draw_image_save_as_png;
@@ -720,6 +722,7 @@ static void vik_window_init ( VikWindow *vw )
  
   vw->pan_move = FALSE; 
   vw->pan_x = vw->pan_y = -1;
+  vw->single_click_pending = FALSE;
 
   gint draw_image_width;
   if ( a_settings_get_integer ( VIK_SETTINGS_WIN_SAVE_IMAGE_WIDTH, &draw_image_width ) )
@@ -1222,16 +1225,61 @@ static void draw_mouse_motion (VikWindow *vw, GdkEventMotion *event)
   /* gdk_event_request_motions ( event ); */
 }
 
+/**
+ * Action the single click after a small timeout
+ * If a double click has occurred then this will do nothing
+ */
+static gboolean vik_window_pan_timeout (VikWindow *vw)
+{
+  if ( ! vw->single_click_pending ) {
+    // Double click happened, so don't do anything
+    return FALSE;
+  }
+
+  /* set panning origin */
+  vw->pan_move = FALSE;
+  vw->single_click_pending = FALSE;
+  vik_viewport_set_center_screen ( vw->viking_vvp, vw->delayed_pan_x, vw->delayed_pan_y );
+  draw_update ( vw );
+
+  // Really turn off the pan moving!!
+  vw->pan_x = vw->pan_y = -1;
+  return FALSE;
+}
+
 static void vik_window_pan_release ( VikWindow *vw, GdkEventButton *event )
 {
-  if ( vw->pan_move == FALSE )
-    vik_viewport_set_center_screen ( vw->viking_vvp, vw->pan_x, vw->pan_y );
-  else
+  if ( vw->pan_move == FALSE ) {
+    vw->single_click_pending = !vw->single_click_pending;
+
+    if ( vw->single_click_pending ) {
+      // Store offset to use
+      vw->delayed_pan_x = vw->pan_x;
+      vw->delayed_pan_y = vw->pan_y;
+      // Get double click time
+      GtkSettings *gs = gtk_widget_get_settings ( GTK_WIDGET(vw) );
+      GValue dct = G_VALUE_INIT;
+      g_value_init ( &dct, G_TYPE_INT );
+      g_object_get_property ( G_OBJECT(gs), "gtk-double-click-time", &dct );
+      // Give chance for a double click to occur
+      gint timer = g_value_get_int ( &dct ) + 50;
+      g_timeout_add ( timer, (GSourceFunc)vik_window_pan_timeout, vw );
+      goto skip_draw;
+    }
+    else {
+      vik_viewport_set_center_screen ( vw->viking_vvp, vw->pan_x, vw->pan_y );
+    }
+  }
+  else {
      vik_viewport_set_center_screen ( vw->viking_vvp, vik_viewport_get_width(vw->viking_vvp)/2 - event->x + vw->pan_x,
                                       vik_viewport_get_height(vw->viking_vvp)/2 - event->y + vw->pan_y );
+  }
+
+  draw_update ( vw );
+
+ skip_draw:
   vw->pan_move = FALSE;
   vw->pan_x = vw->pan_y = -1;
-  draw_update ( vw );
 }
 
 static void draw_release ( VikWindow *vw, GdkEventButton *event )
@@ -1864,12 +1912,31 @@ static gpointer pantool_create (VikWindow *vw, VikViewport *vvp)
   return vw;
 }
 
+// NB Double clicking means this gets called THREE times!!!
 static VikLayerToolFuncStatus pantool_click (VikLayer *vl, GdkEventButton *event, VikWindow *vw)
 {
   vw->modified = TRUE;
-  if ( event->button == 1 )
-    vik_window_pan_click ( vw, event );
-  draw_update ( vw );
+
+  if ( event->type == GDK_2BUTTON_PRESS ) {
+    // Zoom in / out on double click
+    // No need to change the center as that has already occurred in the first click of a double click occurrence
+    if ( event->button == 1 ) {
+      guint modifier = event->state & GDK_SHIFT_MASK;
+      if ( modifier )
+        vik_viewport_zoom_out ( vw->viking_vvp );
+      else
+        vik_viewport_zoom_in ( vw->viking_vvp );
+    }
+    else if ( event->button == 3 )
+      vik_viewport_zoom_out ( vw->viking_vvp );
+
+    draw_update ( vw );
+  }
+  else
+    // Standard pan click
+    if ( event->button == 1 )
+      vik_window_pan_click ( vw, event );
+
   return VIK_LAYER_TOOL_ACK;
 }
 
-- 
2.39.5