From ffff5455b4559c9018e5db42b872f0a32e727b33 Mon Sep 17 00:00:00 2001
From: Ryan Cumming <ryan@kde.org>
Date: Thu, 4 Jul 2002 02:43:54 +0000
Subject: [PATCH] Dither the titlebar graident on 15 and 16bpp displays. Thanks
 to gallium for the Qt::OrderedDither tip.

svn path=/trunk/kdebase/kwin/; revision=164671
---
 clients/redmond/redmond.cpp | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/clients/redmond/redmond.cpp b/clients/redmond/redmond.cpp
index 5f92068ada..831ea9e073 100644
--- a/clients/redmond/redmond.cpp
+++ b/clients/redmond/redmond.cpp
@@ -18,6 +18,7 @@
 #include <qdrawutil.h>
 #include <qdatetime.h>
 #include <kpixmapeffect.h>
+#include <kimageeffect.h>
 #include <kdrawutil.h>
 #include <klocale.h>
 #include <qbitmap.h>
@@ -591,8 +592,20 @@ void GalliumClient::paintEvent( QPaintEvent* )
         KPixmap* titleBuffer = new KPixmap;
         titleBuffer->resize(w-8, titleHeight);
 
-        KPixmapEffect::gradient(*titleBuffer, c1, c2,
-                                KPixmapEffect::HorizontalGradient);
+        if (titleBuffer->depth() > 16)
+        {
+            KPixmapEffect::gradient(*titleBuffer, c1, c2,
+                                    KPixmapEffect::HorizontalGradient);
+        }
+        else
+        {
+            // This enables dithering on 15 and 16bit displays, preventing
+            // some pretty horrible banding effects
+            QImage image = KImageEffect::gradient(titleBuffer->size(), c1, c2,
+                                    KImageEffect::HorizontalGradient);
+
+            titleBuffer->convertFromImage(image, Qt::OrderedDither);
+        }
 
         QPainter p2( titleBuffer, this );