app: Allow for mypaint tool to differentiate extended and non-extended events

This adds a boolean to GimpCoords struct that is true for enabled
extended non-mouse devices and false for all the rest allowing
the mypaint brush to override the the pressure sent to the paint library.

app/core/core-types.h

@@ -248,16 +248,17 @@ typedef gint64   (* GimpMemsizeFunc)       (gpointer          instance,
 
 struct _GimpCoords
 {
-  gdouble x;
-  gdouble y;
-  gdouble pressure;
-  gdouble xtilt;
-  gdouble ytilt;
-  gdouble wheel;
-  gdouble velocity;
-  gdouble direction;
-  gdouble xscale; /* the view scale */
-  gdouble yscale;
+  gdouble  x;
+  gdouble  y;
+  gdouble  pressure;
+  gdouble  xtilt;
+  gdouble  ytilt;
+  gdouble  wheel;
+  gdouble  velocity;
+  gdouble  direction;
+  gdouble  xscale; /* the view scale */
+  gdouble  yscale;
+  gboolean extended;
 };
 
 /*  temp hack as replacement for GdkSegment  */

app/core/gimpcoords-interpolate.c

@@ -265,7 +265,7 @@ gimp_coords_interpolate_catmull (const GimpCoords   catmul_pt1,
 
   for (n = 1; n <= num_points; n++)
     {
-      GimpCoords coords;
+      GimpCoords coords = past_coords; /*Make sure we carry over things we do not interpolate*/
       gdouble    velocity;
       gdouble    pressure;
       gdouble    p = (gdouble) n / num_points;

app/core/gimpcoords.c

@@ -51,6 +51,7 @@ gimp_coords_mix (const gdouble     amul,
       ret_val->wheel     = amul * a->wheel     + bmul * b->wheel;
       ret_val->velocity  = amul * a->velocity  + bmul * b->velocity;
       ret_val->direction = amul * a->direction + bmul * b->direction;
+      ret_val->extended  = b->extended || a->extended;
     }
   else
     {
@@ -62,6 +63,7 @@ gimp_coords_mix (const gdouble     amul,
       ret_val->wheel     = amul * a->wheel;
       ret_val->velocity  = amul * a->velocity;
       ret_val->direction = amul * a->direction;
+      ret_val->extended  = a->extended;
     }
 }
 
@@ -195,6 +197,8 @@ gimp_coords_equal (const GimpCoords *a,
           a->wheel     == b->wheel    &&
           a->velocity  == b->velocity &&
           a->direction == b->direction);
+  /* Extended attribute was omitted from this comparison deliberately
+     - it describes the events origin, not it's value*/
 }
 
 /* helper for calculating direction of two gimpcoords. */

app/paint/gimpmybrushcore.c

@@ -251,6 +251,7 @@ gimp_mybrush_core_motion (GimpPaintCore    *paint_core,
 {
   GimpMybrushCore  *mybrush = GIMP_MYBRUSH_CORE (paint_core);
   MyPaintRectangle  rect;
+  gdouble pressure = coords->pressure;
 
   mypaint_surface_begin_atomic ((MyPaintSurface *) mybrush->private->surface);
 
@@ -269,14 +270,20 @@ gimp_mybrush_core_motion (GimpPaintCore    *paint_core,
                                1.0f /* Pretend the cursor hasn't moved in a while */);
     }
 
+  if (!coords->extended)
+    {
+      pressure = 0.5f; /* Mypaint expects non-extended devices to default to half pressure*/
+    }
+
   mypaint_brush_stroke_to (mybrush->private->brush,
                            (MyPaintSurface *) mybrush->private->surface,
                            coords->x,
                            coords->y,
-                           coords->pressure,
+                           pressure,
                            coords->xtilt,
                            coords->ytilt,
                            (time - mybrush->private->last_time) * 0.001f);
+
   mybrush->private->last_time = time;
 
   mypaint_surface_end_atomic ((MyPaintSurface *) mybrush->private->surface,

app/widgets/gimpdeviceinfo-coords.c

@@ -101,6 +101,17 @@ gimp_device_info_get_event_coords (GimpDeviceInfo *info,
                                                      coords->wheel);
         }
 
+      if (gimp_device_info_get_mode (info)     != GDK_MODE_DISABLED &&
+          gdk_device_get_source (info->device) != GDK_SOURCE_MOUSE)
+        {
+          coords->extended = TRUE; /* The event was generated by an enabled extended non-mouse device */
+        }
+      else
+        {
+          coords->extended = FALSE; /* The event was generated by a not extended enabled device */
+        }
+
+
       return TRUE;
     }
 
@@ -154,6 +165,16 @@ gimp_device_info_get_device_coords (GimpDeviceInfo *info,
                                                  GDK_AXIS_WHEEL,
                                                  coords->wheel);
     }
+
+  if (gimp_device_info_get_mode (info)     != GDK_MODE_DISABLED &&
+      gdk_device_get_source (info->device) != GDK_SOURCE_MOUSE)
+    {
+      coords->extended = TRUE; /* The event was generated by an enabled extended non-mouse  device */
+    }
+  else
+    {
+      coords->extended = FALSE; /* The event was generated by a not extended enabled device */
+    }
 }
 
 void
@@ -201,6 +222,16 @@ gimp_device_info_get_time_coords (GimpDeviceInfo *info,
                                                  GDK_AXIS_WHEEL,
                                                  coords->wheel);
     }
+
+  if (gimp_device_info_get_mode (info)     != GDK_MODE_DISABLED &&
+      gdk_device_get_source (info->device) != GDK_SOURCE_MOUSE)
+    {
+      coords->extended = TRUE; /* The event was generated by an enabled extended non-mouse device */
+    }
+  else
+    {
+      coords->extended = FALSE; /* The event was generated by a not extended enabled device */
+    }
 }
 
 gboolean