[gtk+/wip/otte/rendernode] gsk: Add gsk_clip_node_new()

[Benjamin Otte <otte src gnome org>]

commit 029ff7b9576d2a24a5697f508e90b36fa93d3e3c
Author: Benjamin Otte <otte redhat com>
Date:   Tue Dec 13 09:37:51 2016 +0100

    gsk: Add gsk_clip_node_new()
    
    The node is a simple clipping node: It does a rectangular clip of its
    contents.

 docs/reference/gsk/gsk4-sections.txt   |    2 +
 gsk/gskenums.h                         |    4 +-
 gsk/gskrendernode.h                    |    6 ++
 gsk/gskrendernodeimpl.c                |  125 ++++++++++++++++++++++++++++++++
 gsk/gskrendernodeprivate.h             |    2 +
 gtk/inspector/gtktreemodelrendernode.c |    4 +
 6 files changed, 142 insertions(+), 1 deletions(-)
---
diff --git a/docs/reference/gsk/gsk4-sections.txt b/docs/reference/gsk/gsk4-sections.txt
index 486e31d..57b8657 100644
--- a/docs/reference/gsk/gsk4-sections.txt
+++ b/docs/reference/gsk/gsk4-sections.txt
@@ -45,6 +45,8 @@ gsk_transform_node_new
 gsk_transform_node_get_child
 gsk_opacity_node_new
 gsk_opacity_node_get_child
+gsk_clip_node_new
+gsk_clip_node_get_child
 <SUBSECTION Standard>
 GSK_IS_RENDER_NODE
 GSK_RENDER_NODE
diff --git a/gsk/gskenums.h b/gsk/gskenums.h
index caba77f..7b37715 100644
--- a/gsk/gskenums.h
+++ b/gsk/gskenums.h
@@ -32,6 +32,7 @@
  * @GSK_TRANSFORM_NODE: A node that renders its child after applying a
  *     matrix transform
  * @GSK_OPACITY_NODE: A node that changes the opacity of its child
+ * @GSK_CLIP_NODE: A node that clips its child to a rectangular area
  *
  * The type of a node determines what the node is rendering.
  *
@@ -44,7 +45,8 @@ typedef enum {
   GSK_COLOR_NODE,
   GSK_TEXTURE_NODE,
   GSK_TRANSFORM_NODE,
-  GSK_OPACITY_NODE
+  GSK_OPACITY_NODE,
+  GSK_CLIP_NODE
 } GskRenderNodeType;
 
 /**
diff --git a/gsk/gskrendernode.h b/gsk/gskrendernode.h
index 3be2503..cdd52b7 100644
--- a/gsk/gskrendernode.h
+++ b/gsk/gskrendernode.h
@@ -80,6 +80,12 @@ GDK_AVAILABLE_IN_3_90
 GskRenderNode *         gsk_opacity_node_get_child              (GskRenderNode            *node);
 
 GDK_AVAILABLE_IN_3_90
+GskRenderNode *         gsk_clip_node_new                       (GskRenderNode            *child,
+                                                                 const graphene_rect_t    *clip);
+GDK_AVAILABLE_IN_3_90
+GskRenderNode *         gsk_clip_node_get_child                 (GskRenderNode            *node);
+
+GDK_AVAILABLE_IN_3_90
 void                    gsk_render_node_set_blend_mode          (GskRenderNode *node,
                                                                  GskBlendMode   blend_mode);
 
diff --git a/gsk/gskrendernodeimpl.c b/gsk/gskrendernodeimpl.c
index 161fec5..25529ca 100644
--- a/gsk/gskrendernodeimpl.c
+++ b/gsk/gskrendernodeimpl.c
@@ -819,3 +819,128 @@ gsk_opacity_node_get_opacity (GskRenderNode *node)
   return self->opacity;
 }
 
+/*** GSK_CLIP_NODE ***/
+
+typedef struct _GskClipNode GskClipNode;
+
+struct _GskClipNode
+{
+  GskRenderNode render_node;
+
+  GskRenderNode *child;
+  graphene_rect_t clip;
+};
+
+static void
+gsk_clip_node_finalize (GskRenderNode *node)
+{
+  GskClipNode *self = (GskClipNode *) node;
+
+  gsk_render_node_unref (self->child);
+}
+
+static void
+gsk_clip_node_make_immutable (GskRenderNode *node)
+{
+  GskClipNode *self = (GskClipNode *) node;
+
+  gsk_render_node_make_immutable (self->child);
+}
+
+static void
+gsk_clip_node_draw (GskRenderNode *node,
+                    cairo_t       *cr)
+{
+  GskClipNode *self = (GskClipNode *) node;
+
+  cairo_save (cr);
+
+  cairo_rectangle (cr,
+                   self->clip.origin.x, self->clip.origin.y,
+                   self->clip.size.width, self->clip.size.height);
+  cairo_clip (cr);
+
+  gsk_render_node_draw (self->child, cr);
+
+  cairo_restore (cr);
+}
+
+static void
+gsk_clip_node_get_bounds (GskRenderNode   *node,
+                          graphene_rect_t *bounds)
+{
+  GskClipNode *self = (GskClipNode *) node;
+  graphene_rect_t child_bounds;
+
+  gsk_render_node_get_bounds (self->child, &child_bounds);
+
+  graphene_rect_intersection (&self->clip, &child_bounds, bounds);
+}
+
+static const GskRenderNodeClass GSK_CLIP_NODE_CLASS = {
+  GSK_CLIP_NODE,
+  sizeof (GskClipNode),
+  "GskClipNode",
+  gsk_clip_node_finalize,
+  gsk_clip_node_make_immutable,
+  gsk_clip_node_draw,
+  gsk_clip_node_get_bounds
+};
+
+/**
+ * gsk_clip_node_new:
+ * @child: The node to draw
+ * @clip: The clip to apply
+ *
+ * Creates a #GskRenderNode that will clip the @child to the area
+ * given by @clip.
+ *
+ * Returns: A new #GskRenderNode
+ *
+ * Since: 3.90
+ */
+GskRenderNode *
+gsk_clip_node_new (GskRenderNode         *child,
+                   const graphene_rect_t *clip)
+{
+  GskClipNode *self;
+
+  g_return_val_if_fail (GSK_IS_RENDER_NODE (child), NULL);
+  g_return_val_if_fail (clip != NULL, NULL);
+
+  self = (GskClipNode *) gsk_render_node_new (&GSK_CLIP_NODE_CLASS);
+
+  self->child = gsk_render_node_ref (child);
+  graphene_rect_normalize_r (clip, &self->clip);
+
+  return &self->render_node;
+}
+
+/**
+ * gsk_clip_node_get_child:
+ * @node: a clip @GskRenderNode
+ *
+ * Gets the child node that is getting clipped by the given @node.
+ *
+ * Returns: (transfer none): The child that is getting clipped
+ **/
+GskRenderNode *
+gsk_clip_node_get_child (GskRenderNode *node)
+{
+  GskClipNode *self = (GskClipNode *) node;
+
+  g_return_val_if_fail (GSK_IS_RENDER_NODE_TYPE (node, GSK_CLIP_NODE), NULL);
+
+  return self->child;
+}
+
+const graphene_rect_t *
+gsk_clip_node_peek_clip (GskRenderNode *node)
+{
+  GskClipNode *self = (GskClipNode *) node;
+
+  g_return_val_if_fail (GSK_IS_RENDER_NODE_TYPE (node, GSK_CLIP_NODE), NULL);
+
+  return &self->clip;
+}
+
diff --git a/gsk/gskrendernodeprivate.h b/gsk/gskrendernodeprivate.h
index 3ad5c43..1bb0639 100644
--- a/gsk/gskrendernodeprivate.h
+++ b/gsk/gskrendernodeprivate.h
@@ -60,6 +60,8 @@ GskTexture *gsk_texture_node_get_texture (GskRenderNode *node);
 
 const GdkRGBA *gsk_color_node_peek_color (GskRenderNode *node);
 
+const graphene_rect_t * gsk_clip_node_peek_clip (GskRenderNode *node);
+
 void gsk_transform_node_get_transform (GskRenderNode *node, graphene_matrix_t *transform);
 
 GskBlendMode gsk_render_node_get_blend_mode (GskRenderNode *node);
diff --git a/gtk/inspector/gtktreemodelrendernode.c b/gtk/inspector/gtktreemodelrendernode.c
index b25ae64..c44c4c7 100644
--- a/gtk/inspector/gtktreemodelrendernode.c
+++ b/gtk/inspector/gtktreemodelrendernode.c
@@ -534,6 +534,10 @@ append_node (GtkTreeModelRenderNode *nodemodel,
       append_node (nodemodel, gsk_opacity_node_get_child (node), priv->nodes->len - 1);
       break;
 
+    case GSK_CLIP_NODE:
+      append_node (nodemodel, gsk_clip_node_get_child (node), priv->nodes->len - 1);
+      break;
+
     case GSK_CONTAINER_NODE:
       {
         gint elt_index;