[gtk+/wip/otte/snapshot: 10/30] snapshot: Add gtk_css_gadget_snapshot()

[Benjamin Otte <otte src gnome org>]

commit 02d0522ce2971f708a906a1a568275f330cc23d3
Author: Benjamin Otte <otte redhat com>
Date:   Sun Nov 13 20:47:34 2016 +0100

    snapshot: Add gtk_css_gadget_snapshot()
    
    Including a snpahsot() vfunc, wee!

 gtk/gtkcssgadget.c        |  142 +++++++++++++++++++++++++++++++++++++++++++++
 gtk/gtkcssgadgetprivate.h |    8 +++
 gtk/gtksnapshot.c         |    7 ++
 gtk/gtksnapshot.h         |    4 +
 4 files changed, 161 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkcssgadget.c b/gtk/gtkcssgadget.c
index 1559fac..5bc0e0f 100644
--- a/gtk/gtkcssgadget.c
+++ b/gtk/gtkcssgadget.c
@@ -122,6 +122,51 @@ gtk_css_gadget_real_draw (GtkCssGadget *gadget,
 }
 
 static void
+gtk_css_gadget_get_clip (GtkCssGadget    *gadget,
+                         graphene_rect_t *bounds)
+{
+  GtkCssGadgetPrivate *priv = gtk_css_gadget_get_instance_private (gadget);
+
+  if (priv->owner && !gtk_widget_get_has_window (priv->owner))
+    {
+      GtkAllocation widget_alloc;
+      gtk_widget_get_allocation (priv->owner, &widget_alloc);
+
+      graphene_rect_init (bounds,
+                          priv->clip.x - widget_alloc.x, priv->clip.y - widget_alloc.y,
+                          priv->clip.width, priv->clip.height);
+    }
+  else
+    {
+      graphene_rect_init (bounds,
+                          priv->clip.x, priv->clip.y,
+                          priv->clip.width, priv->clip.height);
+    }
+}
+
+static gboolean
+gtk_css_gadget_real_snapshot (GtkCssGadget *gadget,
+                              GtkSnapshot  *snapshot,
+                              int           x,
+                              int           y,
+                              int           width,
+                              int           height)
+{
+  graphene_rect_t bounds;
+  gboolean result;
+  cairo_t *cr;
+
+  gtk_css_gadget_get_clip (gadget, &bounds);
+  cr = gtk_snapshot_append_cairo_node (snapshot, &bounds, "Fallback<%s>", G_OBJECT_TYPE_NAME (gadget));
+
+  result = GTK_CSS_GADGET_GET_CLASS (gadget)->draw (gadget, cr, x, y, width, height);
+
+  cairo_destroy (cr);
+
+  return result;
+}
+
+static void
 gtk_css_gadget_real_style_changed (GtkCssGadget      *gadget,
                                    GtkCssStyleChange *change)
 {
@@ -277,6 +322,7 @@ gtk_css_gadget_class_init (GtkCssGadgetClass *klass)
   klass->get_preferred_size = gtk_css_gadget_real_get_preferred_size;
   klass->allocate = gtk_css_gadget_real_allocate;
   klass->draw = gtk_css_gadget_real_draw;
+  klass->snapshot = gtk_css_gadget_real_snapshot;
   klass->get_render_node = gtk_css_gadget_real_get_render_node;
   klass->style_changed = gtk_css_gadget_real_style_changed;
   klass->has_content = gtk_css_gadget_has_content;
@@ -1117,6 +1163,102 @@ gtk_css_gadget_draw (GtkCssGadget *gadget,
 #endif
 }
 
+/**
+ * gtk_css_gadget_snapshot:
+ * @gadget: The gadget to snapshot
+ * @snapshot: The snapshot to use
+ *
+ * Will draw the gadget at the position allocated via
+ * gtk_css_gadget_allocate(). It is your responsibility to make
+ * sure that those 2 coordinate systems match.
+ *
+ * The drawing virtual function will be passed an untransformed @cr.
+ * This is important because functions like
+ * gtk_container_propagate_draw() depend on that.
+ */
+void
+gtk_css_gadget_snapshot (GtkCssGadget *gadget,
+                         GtkSnapshot  *snapshot)
+{
+  GtkCssGadgetPrivate *priv = gtk_css_gadget_get_instance_private (gadget);
+  GtkBorder margin, border, padding;
+  gboolean draw_focus = FALSE;
+  GtkCssStyle *style;
+  int x, y, width, height;
+  int contents_x, contents_y, contents_width, contents_height;
+  GtkAllocation margin_box;
+  graphene_rect_t bounds;
+
+  if (!gtk_css_gadget_get_visible (gadget))
+    return;
+
+  gtk_css_gadget_get_clip (gadget, &bounds);
+  if (gtk_snapshot_clips_rect (snapshot, &bounds))
+    return;
+
+  gtk_css_gadget_get_margin_box (gadget, &margin_box);
+
+  x = margin_box.x;
+  y = margin_box.y;
+  width = margin_box.width;
+  height = margin_box.height;
+
+  if (width < 0 || height < 0)
+    {
+      g_warning ("Drawing a gadget with negative dimensions. "
+                 "Did you forget to allocate a size? (node %s owner %s)",
+                 gtk_css_node_get_name (gtk_css_gadget_get_node (gadget)),
+                 G_OBJECT_TYPE_NAME (gtk_css_gadget_get_owner (gadget)));
+      x = 0;
+      y = 0;
+      width = gtk_widget_get_allocated_width (priv->owner);
+      height = gtk_widget_get_allocated_height (priv->owner);
+    }
+
+  style = gtk_css_gadget_get_style (gadget);
+  get_box_margin (style, &margin);
+  get_box_border (style, &border);
+  get_box_padding (style, &padding);
+
+  gtk_snapshot_push (snapshot, &bounds, "%s<%s>", gtk_css_node_get_name (priv->node), G_OBJECT_TYPE_NAME 
(priv->owner));
+
+  gtk_snapshot_translate_2d (snapshot, x + margin.left, y + margin.top);
+  gtk_css_style_snapshot_background (style,
+                                     snapshot,
+                                     width - margin.left - margin.right,
+                                     height - margin.top - margin.bottom,
+                                     gtk_css_node_get_junction_sides (priv->node));
+  gtk_css_style_snapshot_border (style,
+                                 snapshot,
+                                 width - margin.left - margin.right,
+                                 height - margin.top - margin.bottom,
+                                 gtk_css_node_get_junction_sides (priv->node));
+  gtk_snapshot_translate_2d (snapshot, - x - margin.left, - y - margin.top);
+
+  contents_x = x + margin.left + border.left + padding.left;
+  contents_y = y + margin.top + border.top + padding.top;
+  contents_width = width - margin.left - margin.right - border.left - border.right - padding.left - 
padding.right;
+  contents_height = height - margin.top - margin.bottom - border.top - border.bottom - padding.top - 
padding.bottom;
+
+  if (contents_width > 0 && contents_height > 0)
+    draw_focus = GTK_CSS_GADGET_GET_CLASS (gadget)->snapshot (gadget,
+                                                              snapshot,
+                                                              contents_x, contents_y,
+                                                              contents_width, contents_height);
+
+  if (draw_focus)
+    {
+      gtk_snapshot_translate_2d (snapshot, x + margin.left, y + margin.top);
+      gtk_css_style_snapshot_outline (style,
+                                      snapshot,
+                                      width - margin.left - margin.right,
+                                      height - margin.top - margin.bottom);
+      gtk_snapshot_translate_2d (snapshot, - x - margin.left, - y - margin.top);
+  }
+
+  gtk_snapshot_pop (snapshot);
+}
+
 GskRenderNode *
 gtk_css_gadget_get_render_node (GtkCssGadget  *gadget,
                                 GskRenderer   *renderer,
diff --git a/gtk/gtkcssgadgetprivate.h b/gtk/gtkcssgadgetprivate.h
index 347920d..3542746 100644
--- a/gtk/gtkcssgadgetprivate.h
+++ b/gtk/gtkcssgadgetprivate.h
@@ -67,6 +67,12 @@ struct _GtkCssGadgetClass
                                                          int                     y,
                                                          int                     width,
                                                          int                     height);
+  gboolean      (* snapshot)                            (GtkCssGadget           *gadget,
+                                                         GtkSnapshot            *snapshot,
+                                                         int                     x,
+                                                         int                     y,
+                                                         int                     width,
+                                                         int                     height);
 
   GskRenderNode * (* get_render_node)                   (GtkCssGadget           *gadget,
                                                          GskRenderer            *renderer,
@@ -130,6 +136,8 @@ void            gtk_css_gadget_allocate                 (GtkCssGadget
                                                          GtkAllocation          *out_clip);
 void            gtk_css_gadget_draw                     (GtkCssGadget           *gadget,
                                                          cairo_t                *cr);
+void            gtk_css_gadget_snapshot                 (GtkCssGadget           *gadget,
+                                                         GtkSnapshot            *snapshot);
 
 GskRenderNode * gtk_css_gadget_get_render_node          (GtkCssGadget           *gadget,
                                                          GskRenderer            *renderer,
diff --git a/gtk/gtksnapshot.c b/gtk/gtksnapshot.c
index 2a0507a..26aef79 100644
--- a/gtk/gtksnapshot.c
+++ b/gtk/gtksnapshot.c
@@ -251,6 +251,13 @@ gtk_snapshot_push_cairo_node (GtkSnapshot            *state,
   return gsk_render_node_get_draw_context (node, state->renderer);
 }
 
+gboolean
+gtk_snapshot_clips_rect (GtkSnapshot           *snapshot,
+                         const graphene_rect_t *bounds)
+{
+  return FALSE;
+}
+
 void
 gtk_snapshot_render_background (GtkSnapshot     *state,
                                 GtkStyleContext *context,
diff --git a/gtk/gtksnapshot.h b/gtk/gtksnapshot.h
index 90ecef0..159c253 100644
--- a/gtk/gtksnapshot.h
+++ b/gtk/gtksnapshot.h
@@ -79,6 +79,10 @@ cairo_t *       gtk_snapshot_append_cairo_node          (GtkSnapshot
                                                          ...) G_GNUC_PRINTF(3, 4);
 
 GDK_AVAILABLE_IN_3_90
+gboolean        gtk_snapshot_clips_rect                 (GtkSnapshot            *snapshot,
+                                                         const graphene_rect_t  *bounds);
+
+GDK_AVAILABLE_IN_3_90
 void            gtk_snapshot_render_background          (GtkSnapshot            *state,
                                                          GtkStyleContext        *context,
                                                          gdouble                 x,