[gnome-builder/wip/slaf/colorpicker] gstyle-eyedropper: add keys to change zoom factor

[Sébastien Lafargue <slafargue src gnome org>]

commit 3f40e0ab52c4a64ce49dfcfa4132be6f390599a6
Author: Sebastien Lafargue <slafargue gnome org>
Date:   Sun Jul 17 16:16:11 2016 +0200

    gstyle-eyedropper: add keys to change zoom factor
    
    PgUp and keypad PgUp to increase the zoom factor
    PgDown and keypad PgDown to decrease the zoom factor

 contrib/gstyle/gstyle-eyedropper.c |   30 ++++++++++++++++++++++++++++--
 1 files changed, 28 insertions(+), 2 deletions(-)
---
diff --git a/contrib/gstyle/gstyle-eyedropper.c b/contrib/gstyle/gstyle-eyedropper.c
index f2d0983..6a03353 100644
--- a/contrib/gstyle/gstyle-eyedropper.c
+++ b/contrib/gstyle/gstyle-eyedropper.c
@@ -368,6 +368,22 @@ gstyle_eyedropper_pointer_pressed_cb (GstyleEyedropper *self,
   return GDK_EVENT_PROPAGATE;
 }
 
+static void
+decrease_zoom_factor (GstyleEyedropper *self)
+{
+  g_assert (GSTYLE_IS_EYEDROPPER (self));
+
+  self->zoom_factor = CLAMP (self->zoom_factor - 0.5, MIN_ZOOM_FACTOR, MAX_ZOOM_FACTOR);
+}
+
+static void
+increase_zoom_factor (GstyleEyedropper *self)
+{
+  g_assert (GSTYLE_IS_EYEDROPPER (self));
+
+  self->zoom_factor = CLAMP (self->zoom_factor + 0.5, MIN_ZOOM_FACTOR, MAX_ZOOM_FACTOR);
+}
+
 static gboolean
 gstyle_eyedropper_pointer_wheel_cb (GstyleEyedropper *self,
                                     GdkEventScroll   *event,
@@ -381,9 +397,9 @@ gstyle_eyedropper_pointer_wheel_cb (GstyleEyedropper *self,
   if (event->type == GDK_SCROLL)
     {
       if (event->direction == GDK_SCROLL_UP)
-        self->zoom_factor = CLAMP (self->zoom_factor + 0.5, MIN_ZOOM_FACTOR, MAX_ZOOM_FACTOR);
+        increase_zoom_factor (self);
       else if (event->direction == GDK_SCROLL_DOWN)
-        self->zoom_factor = CLAMP (self->zoom_factor - 0.5, MIN_ZOOM_FACTOR, MAX_ZOOM_FACTOR);
+        decrease_zoom_factor (self);
       else
         return GDK_EVENT_PROPAGATE;
     }
@@ -439,6 +455,16 @@ gstyle_eyedropper_key_pressed_cb (GstyleEyedropper *self,
       dx = (state == GDK_MOD1_MASK) ? CURSOR_ALT_STEP : 1;
       break;
 
+    case GDK_KEY_Page_Up:
+    case GDK_KEY_KP_Page_Up:
+      increase_zoom_factor (self);
+      break;
+
+    case GDK_KEY_Page_Down:
+    case GDK_KEY_KP_Page_Down:
+      decrease_zoom_factor (self);
+      break;
+
     default:
       return GDK_EVENT_PROPAGATE;
     }