From 445f8bbd9709b712fa253fe1833bbf9416429603 Mon Sep 17 00:00:00 2001
From: Richard Moe Gustavsen <richard.gustavsen@nokia.com>
Date: Wed, 9 Dec 2009 15:30:10 +0100
Subject: Cocoa: scrolling viewports containing many widgets is slow

One of the reasons is that [NSView resetCursorRects] is called
for each view, also the ones not actually visible. And the
function is slow. This patch does an early check, and bails out
if this is the case.

Reviewed-by: Prasanth
---
 src/gui/kernel/qcocoaview_mac.mm | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/gui/kernel/qcocoaview_mac.mm b/src/gui/kernel/qcocoaview_mac.mm
index 1039a75..311cf24 100644
--- a/src/gui/kernel/qcocoaview_mac.mm
+++ b/src/gui/kernel/qcocoaview_mac.mm
@@ -227,6 +227,10 @@ extern "C" {
 
 - (void)resetCursorRects
 {
+    // [NSView addCursorRect] is slow, so bail out early if we can:
+    if (NSIsEmptyRect([self visibleRect]))
+        return;
+
     QWidget *cursorWidget = qwidget;
 
     if (cursorWidget->testAttribute(Qt::WA_TransparentForMouseEvents))
-- 
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