Avoid dublicate drawing.

7 files changed, 37 insertions, 21 deletions

diff --git a/doc/dw-stacking-context.doc b/doc/dw-stacking-context.doc
index 59d22f1c..47854546 100644
--- a/doc/dw-stacking-context.doc
+++ b/doc/dw-stacking-context.doc
@@ -31,12 +31,12 @@ The first is done from bottom to top, the latter from top to bottom.
 I'm here referring to the simplified description in
 <a href="http://www.w3.org/TR/CSS2/visuren.html#z-index">section
 9.9.1</a>. The table shows a recommended order for the implementations
-of dw::core::Widget::draw and dw::core::Widget::getWidgetAtPoint (for
-the latter, read from bottom to top):
+of dw::core::Widget::draw and dw::core::Widget::getWidgetAtPoint
+(for the latter, read from bottom to top)<sup>1</sup>:
  
 <table>
 <tr>
-<th> CSS specification <th> Drawing <th> Mouse events
+<th> CSS specification <th> Drawing <th> Mouse events<sup>2</sup>
 <tr>
 <td> *1. the background and borders of the element forming the
          stacking context.*
@@ -61,8 +61,8 @@ the latter, read from bottom to top):
 
                  This order differs from the specified order, but
                  since floats and in-flow elements do not overlap,
-                 this difference has no effect.
-<td rowspan="4"> ...
+                 this difference has no effect.<sup>3</sup>
+<td rowspan="4"> ...<sup>3</sup>
 <tr>
 <td> *4. the non-positioned floats.*
 <tr>
@@ -87,15 +87,19 @@ the latter, read from bottom to top):
 
 Notes:
 
-- Handling mouse events is, at this time, not implemented at all.
+<sup>1</sup>) This is not quite in conformance with the specification:
+              this description refers to any widget, not only widgets
+              establishing a stacking context. Does this make a
+              difference?
 
-- This is not quite in conformance with the specification: this
-  description refers to any widget, not only widgets establishing a
-  stacking context. Does this make a difference?
+<sup>2</sup>) Handling mouse events is, at this time, not implemented
+              at all.
 
-- Drawing (and handling mouse events, respectively) should avoid
-  dublicate calls: Widgets drawn by dw::core::StackingContextMgr::drawBottom
-  and by dw::core::StackingContextMgr::drawTop should be excluded
-  elsewhere.
+<sup>3</sup>) Drawing (and handling mouse events, respectively) should
+	      avoid dublicate calls: Widgets drawn by
+	      dw::core::StackingContextMgr::drawBottom and by
+	      dw::core::StackingContextMgr::drawTop should be excluded
+	      elsewhere. This can be tested with
+	      dw::core::StackingContextMgr::handledByStackingContextMgr.
 
 */
\ No newline at end of file
diff --git a/dw/ooffloatsmgr.cc b/dw/ooffloatsmgr.cc
index 7850b18f..eecd4faa 100644
--- a/dw/ooffloatsmgr.cc
+++ b/dw/ooffloatsmgr.cc
@@ -1284,10 +1284,11 @@ void OOFFloatsMgr::drawFloats (SortedFloatsVector *list, View *view,
    // first float fitting into the area, and iterate until one is
    // found below the area.
    for (int i = 0; i < list->size(); i++) {
-      Float *vloat = list->get(i);
+      Widget *childWidget = list->get(i)->getWidget ();
       Rectangle childArea;
-      if (vloat->getWidget()->intersects (area, &childArea))
-         vloat->getWidget()->draw (view, &childArea);
+      if (!StackingContextMgr::handledByStackingContextMgr (childWidget) &&
+          childWidget->intersects (area, &childArea))
+         childWidget->draw (view, &childArea);
    }
 }
 
diff --git a/dw/oofpositionedmgr.cc b/dw/oofpositionedmgr.cc
index 3efb5002..4799ec8c 100644
--- a/dw/oofpositionedmgr.cc
+++ b/dw/oofpositionedmgr.cc
@@ -176,7 +176,8 @@ void OOFPositionedMgr::draw (View *view, Rectangle *area)
    for (int i = 0; i < children->size(); i++) {
       Widget *childWidget = children->get(i)->widget;
       Rectangle childArea;
-      if (childWidget->intersects (area, &childArea))
+      if (!StackingContextMgr::handledByStackingContextMgr (childWidget) &&
+          childWidget->intersects (area, &childArea))
          childWidget->draw (view, &childArea);
    }
 
diff --git a/dw/stackingcontextmgr.cc b/dw/stackingcontextmgr.cc
index 333f0707..b3573a3f 100644
--- a/dw/stackingcontextmgr.cc
+++ b/dw/stackingcontextmgr.cc
@@ -67,7 +67,7 @@ void StackingContextMgr::drawBottom (View *view, Rectangle *area)
 
 void StackingContextMgr::drawTop (View *view, Rectangle *area)
 {
-   DBG_OBJ_ENTER ("draw", 0, "drawBottom", "%d, %d, %d * %d",
+   DBG_OBJ_ENTER ("draw", 0, "drawTop", "%d, %d, %d * %d",
                   area->x, area->y, area->width, area->height);
    draw (view, area, 0, INT_MAX);
    DBG_OBJ_LEAVE ();
diff --git a/dw/stackingcontextmgr.hh b/dw/stackingcontextmgr.hh
index 36acfb11..cbb59231 100644
--- a/dw/stackingcontextmgr.hh
+++ b/dw/stackingcontextmgr.hh
@@ -35,6 +35,14 @@ public:
          widget->getStyle()->zIndex != style::Z_INDEX_AUTO;
    }
 
+   inline static bool handledByStackingContextMgr  (Widget *widget) {
+      // Each widget establishing a stacking context is child of another
+      // stacking context, so drawn by StackingContextMgr::drawTop or
+      // StackingContextMgr::drawBottom etc.
+      return widget->getParent () != NULL
+         && isEstablishingStackingContext (widget);
+   }
+
    void addChildSCWidget (Widget *widget);
 
    void drawBottom (View *view, Rectangle *area);
diff --git a/dw/table.cc b/dw/table.cc
index d443327b..4259111a 100644
--- a/dw/table.cc
+++ b/dw/table.cc
@@ -382,7 +382,8 @@ void Table::draw (core::View *view, core::Rectangle *area)
       if (childDefined (i)) {
          Widget *child = children->get(i)->cell.widget;
          core::Rectangle childArea;
-         if (child->intersects (area, &childArea))
+         if (!core::StackingContextMgr::handledByStackingContextMgr (child) &&
+             child->intersects (area, &childArea))
             child->draw (view, &childArea);
       }
    }
diff --git a/dw/textblock.cc b/dw/textblock.cc
index 9bff14d7..df38a8e7 100644
--- a/dw/textblock.cc
+++ b/dw/textblock.cc
@@ -1447,8 +1447,9 @@ void Textblock::drawLine (Line *line, core::View *view, core::Rectangle *area)
                if (word->content.type == core::Content::WIDGET_IN_FLOW) {
                   core::Widget *child = word->content.widget;
                   core::Rectangle childArea;
-
-                  if (child->intersects (area, &childArea))
+                  if (!core::StackingContextMgr::handledByStackingContextMgr
+                          (child) &&
+                      child->intersects (area, &childArea))
                      child->draw (view, &childArea);
                } else {
                   int wordIndex2 = wordIndex;