[libchamplain] Add dashed line drawing to path layers

[JiÅÃ Techet <jiritechet src gnome org>]

commit 68928ed16d4b078479f31895cf139abd027b70f9
Author: JiÅÃ Techet <techet gmail com>
Date:   Mon Nov 21 13:16:10 2011 +0100

    Add dashed line drawing to path layers

 champlain/champlain-path-layer.c |   71 ++++++++++++++++++++++++++++++++++++++
 champlain/champlain-path-layer.h |    4 ++
 demos/polygons.c                 |    7 +++-
 3 files changed, 81 insertions(+), 1 deletions(-)
---
diff --git a/champlain/champlain-path-layer.c b/champlain/champlain-path-layer.c
index 32c6976..172da8f 100644
--- a/champlain/champlain-path-layer.c
+++ b/champlain/champlain-path-layer.c
@@ -81,6 +81,8 @@ struct _ChamplainPathLayerPrivate
   gboolean stroke;
   gdouble stroke_width;
   gboolean visible;
+  gdouble *dash;
+  guint num_dashes;
 
   ClutterGroup *content_group;
   ClutterActor *path_actor;
@@ -315,6 +317,7 @@ champlain_path_layer_finalize (GObject *object)
 
   clutter_color_free (priv->stroke_color);
   clutter_color_free (priv->fill_color);
+  g_free (priv->dash);
 
   G_OBJECT_CLASS (champlain_path_layer_parent_class)->finalize (object);
 }
@@ -469,6 +472,8 @@ champlain_path_layer_init (ChamplainPathLayer *self)
   priv->stroke_width = 2.0;
   priv->nodes = NULL;
   priv->redraw_scheduled = FALSE;
+  priv->dash = NULL;
+  priv->num_dashes = 0;
 
   priv->fill_color = clutter_color_copy (&DEFAULT_FILL_COLOR);
   priv->stroke_color = clutter_color_copy (&DEFAULT_STROKE_COLOR);
@@ -728,6 +733,7 @@ redraw_path (ChamplainPathLayer *layer)
       priv->stroke_color->alpha / 255.0);
 
   cairo_set_line_width (cr, priv->stroke_width);
+  cairo_set_dash(cr, priv->dash, priv->num_dashes, 0);
 
   if (priv->stroke)
     cairo_stroke (cr);
@@ -1138,3 +1144,68 @@ champlain_path_layer_get_closed (ChamplainPathLayer *layer)
 
   return layer->priv->closed_path;
 }
+
+
+/**
+ * champlain_path_layer_set_dash:
+ * @layer: a #ChamplainPathLayer
+ * @dash_pattern: (element-type guint): list of integer values representing lengths
+ *     of dashes/spaces (see cairo documentation of cairo_set_dash())
+ *
+ * Sets dashed line pattern in a way similar to cairo_set_dash() of cairo. This 
+ * method supports only integer values for segment lengths. The values have to be
+ * passed inside the data pointer of the list (using the GUINT_TO_POINTER conversion)
+ * 
+ * Pass NULL to use solid line.
+ * 
+ * Since: 0.14
+ */
+void
+champlain_path_layer_set_dash (ChamplainPathLayer *layer,
+    GList *dash_pattern)
+{
+  g_return_if_fail (CHAMPLAIN_IS_PATH_LAYER (layer));
+
+  ChamplainPathLayerPrivate *priv = layer->priv;
+  GList *iter;
+  guint i;
+
+  if (priv->dash)
+    g_free (priv->dash);
+  priv->dash = NULL;  
+
+  priv->num_dashes = g_list_length (dash_pattern);
+
+  if (dash_pattern == NULL) 
+    return;
+
+  priv->dash = g_new (gdouble, priv->num_dashes);
+  for (iter = dash_pattern, i = 0; iter != NULL; iter = iter->next, i++)
+    (priv->dash)[i] = (gdouble) GPOINTER_TO_UINT (iter->data);
+}
+
+
+/**
+ * champlain_path_layer_get_dash:
+ * @layer: a #ChamplainPathLayer
+ *
+ * Returns the list of dash segment lengths.
+ * 
+ * Returns: (transfer container) (element-type guint): the list
+ *
+ * Since: 0.14
+ */
+GList *
+champlain_path_layer_get_dash (ChamplainPathLayer *layer)
+{
+  g_return_val_if_fail (CHAMPLAIN_IS_PATH_LAYER (layer), NULL);
+  
+  ChamplainPathLayerPrivate *priv = layer->priv;
+  GList *list = NULL;
+  guint i;
+  
+  for (i = 0; i < priv->num_dashes; i++)
+    list = g_list_append(list, GUINT_TO_POINTER((guint)(priv->dash)[i]));
+  
+  return list;
+}
diff --git a/champlain/champlain-path-layer.h b/champlain/champlain-path-layer.h
index 222ffb5..7181dbf 100644
--- a/champlain/champlain-path-layer.h
+++ b/champlain/champlain-path-layer.h
@@ -119,6 +119,10 @@ gboolean champlain_path_layer_get_closed (ChamplainPathLayer *layer);
 void champlain_path_layer_set_closed (ChamplainPathLayer *layer,
     gboolean value);
 
+GList *champlain_path_layer_get_dash (ChamplainPathLayer *layer);
+void champlain_path_layer_set_dash (ChamplainPathLayer *layer,
+    GList *dash_pattern);
+
 G_END_DECLS
 
 #endif
diff --git a/demos/polygons.c b/demos/polygons.c
index 0e82839..256d5cd 100644
--- a/demos/polygons.c
+++ b/demos/polygons.c
@@ -83,6 +83,7 @@ main (int argc,
   ClutterActor *actor, *stage, *buttons, *button;
   ChamplainPathLayer *layer;
   gfloat width, total_width = 0;;
+  GList *dash = NULL;
 
   if (clutter_init (&argc, &argv) != CLUTTER_INIT_SUCCESS)
     return 1;
@@ -131,9 +132,13 @@ main (int argc,
   append_point (layer, 45.3994, -73.1877);
   append_point (layer, 45.4000, -73.1815);
   append_point (layer, 45.4151, -73.1218);
-  champlain_path_layer_set_stroke_width (layer, 5.0);
+  champlain_path_layer_set_stroke_width (layer, 4.0);
   champlain_view_add_layer (CHAMPLAIN_VIEW (actor), CHAMPLAIN_LAYER (layer));
 
+  dash = g_list_append(dash, GUINT_TO_POINTER(6));
+  dash = g_list_append(dash, GUINT_TO_POINTER(2));
+  champlain_path_layer_set_dash (layer, dash);
+  
   /* draw a path */
   layer = champlain_path_layer_new ();
   append_point (layer, 45.1386, -73.9196);