fdo#58029: replace quadratic child window loop with linear

... which should speed things up without introducing problems.

(Window::GetChild(n) is inefficient because the children are a linked
list)

Change-Id: I343d51a6866c5014cbca4c256b0c15f938958c39

1 files changed, 27 insertions, 0 deletions

diff --git a/svx/source/svdraw/sdrpaintwindow.cxx b/svx/source/svdraw/sdrpaintwindow.cxx
index a550c9e0bf68..6abacc5089ed 100644
--- a/svx/source/svdraw/sdrpaintwindow.cxx
+++ b/svx/source/svdraw/sdrpaintwindow.cxx
@@ -23,6 +23,33 @@
 #include <vcl/gdimtf.hxx>
 #include <vcl/svapp.hxx>
 
+
+void PaintTransparentChildren(Window & rWindow, Rectangle const& rPixelRect)
+{
+    if (rWindow.IsChildTransparentModeEnabled())
+    {
+        Window * pCandidate = rWindow.GetWindow( WINDOW_FIRSTCHILD );
+        while (pCandidate)
+        {
+            if (pCandidate->IsPaintTransparent())
+            {
+                const Rectangle aCandidatePosSizePixel(
+                                pCandidate->GetPosPixel(),
+                                pCandidate->GetSizePixel());
+
+                if (aCandidatePosSizePixel.IsOver(rPixelRect))
+                {
+                    pCandidate->Invalidate(
+                        INVALIDATE_NOTRANSPARENT|INVALIDATE_CHILDREN );
+                    // important: actually paint the child here!
+                    pCandidate->Update();
+                }
+            }
+            pCandidate = pCandidate->GetWindow( WINDOW_NEXT );
+        }
+    }
+}
+
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
 SdrPreRenderDevice::SdrPreRenderDevice(OutputDevice& rOriginal)