[gtk+/wip/wayland-tablet: 47/61] gtk-demo: Use GdkAxisUse instead of axis labels

[Carlos Garnacho <carlosg src gnome org>]

commit 6b2d0822732d3ae85d6ecdbfc4a91ea1f9514f40
Author: Stephen Chandler Paul <thatslyude gmail com>
Date:   Mon Feb 9 19:44:50 2015 -0500

    gtk-demo: Use GdkAxisUse instead of axis labels
    
    Axis labels are very X specific, and are not really possible to port to other
    backends such as Wayland. As such, it makes more sense to use GdkAxisUse and
    GdkAxisUseFlag in order to determine the axis capabilities of a device and draw
    their axes.
    
    Signed-off-by: Stephen Chandler Paul <thatslyude gmail com>

 demos/gtk-demo/event_axes.c |   83 ++++++++++++++----------------------------
 1 files changed, 28 insertions(+), 55 deletions(-)
---
diff --git a/demos/gtk-demo/event_axes.c b/demos/gtk-demo/event_axes.c
index bc31f53..555e299 100644
--- a/demos/gtk-demo/event_axes.c
+++ b/demos/gtk-demo/event_axes.c
@@ -24,7 +24,7 @@
 
 typedef struct {
   GdkDevice *last_source;
-  GHashTable *axes; /* axis label atom -> value */
+  gdouble *axes;
   GdkRGBA color;
   gdouble x;
   gdouble y;
@@ -59,8 +59,6 @@ axes_info_new (void)
 
   info = g_new0 (AxesInfo, 1);
   gdk_rgba_parse (&info->color, colors[cur_color]);
-  info->axes = g_hash_table_new_full (NULL, NULL, NULL,
-                                      (GDestroyNotify) g_free);
 
   cur_color = (cur_color + 1) % G_N_ELEMENTS (colors);
 
@@ -70,32 +68,9 @@ axes_info_new (void)
 static void
 axes_info_free (AxesInfo *info)
 {
-  g_hash_table_destroy (info->axes);
   g_free (info);
 }
 
-static gboolean
-axes_info_lookup (AxesInfo    *info,
-                  const gchar *axis_label,
-                  gdouble     *value)
-{
-  gdouble *val;
-  GdkAtom atom;
-
-  atom = gdk_atom_intern (axis_label, FALSE);
-
-  if (atom == GDK_NONE)
-    return FALSE;
-
-  val = g_hash_table_lookup (info->axes, GDK_ATOM_TO_POINTER (atom));
-
-  if (!val)
-    return FALSE;
-
-  *value = *val;
-  return TRUE;
-}
-
 static EventData *
 event_data_new (void)
 {
@@ -121,13 +96,11 @@ static void
 update_axes_from_event (GdkEvent  *event,
                         EventData *data)
 {
-  GdkDevice *device, *source_device;
+  GdkDevice *source_device;
   GdkEventSequence *sequence;
-  gdouble x, y, value;
-  GList *l, *axes;
+  gdouble x, y;
   AxesInfo *info;
 
-  device = gdk_event_get_device (event);
   source_device = gdk_event_get_source_device (event);
   sequence = gdk_event_get_event_sequence (event);
 
@@ -162,10 +135,7 @@ update_axes_from_event (GdkEvent  *event,
     }
 
   if (info->last_source != source_device)
-    {
-      g_hash_table_remove_all (info->axes);
-      info->last_source = source_device;
-    }
+    info->last_source = source_device;
 
   if (event->type == GDK_TOUCH_BEGIN ||
       event->type == GDK_TOUCH_UPDATE ||
@@ -173,8 +143,6 @@ update_axes_from_event (GdkEvent  *event,
       event->type == GDK_BUTTON_PRESS ||
       event->type == GDK_BUTTON_RELEASE)
     {
-      axes = gdk_device_list_axes (device);
-
       if (sequence && event->touch.emulating_pointer)
         {
           if (data->pointer_info)
@@ -182,21 +150,12 @@ update_axes_from_event (GdkEvent  *event,
           data->pointer_info = NULL;
         }
 
-      for (l = axes; l; l = l->next)
-        {
-          gdouble *ptr;
-
-          /* All those event types are compatible wrt axes position in the struct */
-          if (!gdk_device_get_axis_value (device, event->motion.axes,
-                                          l->data, &value))
-            continue;
-
-          ptr = g_new0 (gdouble, 1);
-          *ptr = value;
-          g_hash_table_insert (info->axes, GDK_ATOM_TO_POINTER (l->data), ptr);
-        }
+      if (info->axes)
+        g_free (info->axes);
 
-      g_list_free (axes);
+      info->axes =
+        g_memdup (event->motion.axes,
+                  sizeof(gdouble) * gdk_device_get_n_axes (source_device));
     }
 
   if (gdk_event_get_coords (event, &x, &y))
@@ -242,6 +201,7 @@ draw_axes_info (cairo_t       *cr,
                 GtkAllocation *allocation)
 {
   gdouble pressure, tilt_x, tilt_y, wheel;
+  GdkAxisFlags axes = gdk_device_get_axes (info->last_source);
 
   cairo_save (cr);
 
@@ -256,10 +216,13 @@ draw_axes_info (cairo_t       *cr,
 
   cairo_translate (cr, info->x, info->y);
 
-  if (axes_info_lookup (info, "Abs Pressure", &pressure))
+  if (axes & GDK_AXIS_FLAG_PRESSURE)
     {
       cairo_pattern_t *pattern;
 
+      gdk_device_get_axis (info->last_source, info->axes, GDK_AXIS_PRESSURE,
+                           &pressure);
+
       pattern = cairo_pattern_create_radial (0, 0, 0, 0, 0, 100);
       cairo_pattern_add_color_stop_rgba (pattern, pressure, 1, 0, 0, pressure);
       cairo_pattern_add_color_stop_rgba (pattern, 1, 0, 0, 1, 0);
@@ -272,12 +235,22 @@ draw_axes_info (cairo_t       *cr,
       cairo_pattern_destroy (pattern);
     }
 
-  if (axes_info_lookup (info, "Abs Tilt X", &tilt_x) &&
-      axes_info_lookup (info, "Abs Tilt Y", &tilt_y))
-    render_arrow (cr, tilt_x * 100, tilt_y * 100, "Tilt");
+  if (axes & GDK_AXIS_FLAG_XTILT &&
+      axes & GDK_AXIS_FLAG_YTILT)
+    {
+      gdk_device_get_axis (info->last_source, info->axes, GDK_AXIS_XTILT,
+                           &tilt_x);
+      gdk_device_get_axis (info->last_source, info->axes, GDK_AXIS_YTILT,
+                           &tilt_y);
 
-  if (axes_info_lookup (info, "Abs Wheel", &wheel))
+      render_arrow (cr, tilt_x * 100, tilt_y * 100, "Tilt");
+    }
+
+  if (axes & GDK_AXIS_FLAG_WHEEL)
     {
+      gdk_device_get_axis (info->last_source, info->axes, GDK_AXIS_WHEEL,
+                           &wheel);
+
       cairo_save (cr);
       cairo_set_line_width (cr, 10);
       cairo_set_source_rgba (cr, 0, 0, 0, 0.5);