From f2c47d12386bf9edcbdc79ea31682a60f9d119a4 Mon Sep 17 00:00:00 2001
From: Peter Penz <peter.penz19@gmail.com>
Date: Sun, 21 Sep 2008 21:24:54 +0000
Subject: Experimental patch provided by Fredrik Höglund: Use Xrender to scale
 the preview pixmaps in the X server. This is accelerated in HW by the latest
 version of the NVidia driver and by the open source ATI, Intel and Nouveau
 drivers when they're using the EXA acceleration architecture. EXA will be the
 default in the upcoming 1.6 release of the server, which is scheduled for
 December.
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CCMAIL: fredrik@kde.org

svn path=/trunk/KDE/kdebase/apps/; revision=863342
---
 src/kfilepreviewgenerator.cpp | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

(limited to 'src/kfilepreviewgenerator.cpp')

diff --git a/src/kfilepreviewgenerator.cpp b/src/kfilepreviewgenerator.cpp
index f614aae63..cbbb861ec 100644
--- a/src/kfilepreviewgenerator.cpp
+++ b/src/kfilepreviewgenerator.cpp
@@ -36,6 +36,12 @@
 #include <QScrollBar>
 #include <QIcon>
 
+#ifdef Q_WS_X11
+#  include <QX11Info>
+#  include <X11/Xlib.h>
+#  include <X11/extensions/Xrender.h>
+#endif
+
 /**
  * If the passed item view is an instance of QListView, expensive
  * layout operations are blocked in the constructor and are unblocked
@@ -575,7 +581,35 @@ bool KFilePreviewGenerator::Private::applyImageFrame(QPixmap& icon)
 void KFilePreviewGenerator::Private::limitToSize(QPixmap& icon, const QSize& maxSize)
 {
     if ((icon.width() > maxSize.width()) || (icon.height() > maxSize.height())) {
+#ifdef Q_WS_X11
+        // Assume that the texture size limit is 2048x2048
+        if ((icon.width() <= 2048) && (icon.height() <= 2048)) {
+            QSize size = icon.size();
+            size.scale(maxSize, Qt::KeepAspectRatio);
+
+            const qreal factor = size.width() / qreal(icon.width());
+
+            XTransform xform = {{
+                { XDoubleToFixed(1 / factor), 0, 0 },
+                { 0, XDoubleToFixed(1 / factor), 0 },
+                { 0, 0, XDoubleToFixed(1) }
+            }};
+
+            QPixmap pixmap(size);
+            pixmap.fill(Qt::transparent);
+
+            Display *dpy = QX11Info::display();
+            XRenderSetPictureFilter(dpy, icon.x11PictureHandle(), FilterBilinear, 0, 0);
+            XRenderSetPictureTransform(dpy, icon.x11PictureHandle(), &xform);
+            XRenderComposite(dpy, PictOpOver, icon.x11PictureHandle(), None, pixmap.x11PictureHandle(),
+                             0, 0, 0, 0, 0, 0, pixmap.width(), pixmap.height());
+            icon = pixmap;
+        } else {
+            icon = icon.scaled(maxSize, Qt::KeepAspectRatio, Qt::FastTransformation);
+        }
+#else
         icon = icon.scaled(maxSize, Qt::KeepAspectRatio, Qt::FastTransformation);
+#endif
     }
 }
 
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