From 7912caa1155ccfafae6d5171f3256ef82a19d3ce Mon Sep 17 00:00:00 2001
From: Arnaud Bienner <arnaud.bienner@gmail.com>
Date: Sun, 19 Feb 2012 21:43:55 +0100
Subject: [PATCH] Do not use QPainter::setOpacity because, as explained in
 http://techbase.kde.org/Development/Tutorials/Graphics/Performance#QPainter::setOpacity.28.29
 this deactivate hardware acceleration and make Clementine use 100% CPU when
 using a custom image as background.

---
 src/playlist/playlistview.cpp | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/playlist/playlistview.cpp b/src/playlist/playlistview.cpp
index 181cb4ef0..6366333cd 100644
--- a/src/playlist/playlistview.cpp
+++ b/src/playlist/playlistview.cpp
@@ -801,10 +801,21 @@ void PlaylistView::paintEvent(QPaintEvent* event) {
                                               width(), height(),
                                               Qt::KeepAspectRatioByExpanding,
                                               Qt::SmoothTransformation);
+        QPixmap temp(cached_scaled_background_image_.size());
+        temp.fill(Qt::transparent);
+
+        QPainter p(&temp);
+        p.setCompositionMode(QPainter::CompositionMode_Source);
+        p.drawPixmap(0, 0, cached_scaled_background_image_);
+        p.setCompositionMode(QPainter::CompositionMode_DestinationIn);
+        p.fillRect(temp.rect(), QColor(0, 0, 0, 127*kBackgroundOpacity));
+        p.end();
+
+        cached_scaled_background_image_ = temp;
+
         last_height_  = height();
         last_width_   = width();
       }
-      background_painter.setOpacity(kBackgroundOpacity);
       background_painter.drawPixmap((width() - cached_scaled_background_image_.width()) / 2,
                                     (height() - cached_scaled_background_image_.height()) / 2,
                                     cached_scaled_background_image_);