Cleanup and optimization of qimage smoothscale

Cleaning up smoothscale code. Upscaling is improved using existing
optimized interpolation methods, and downscale is given SSE4.1
optimized versions.

Change-Id: I7cdc256c26850948aef7dae26fda1622be6b8179
Reviewed-by: Gunnar Sletta <gunnar@sletta.org>

3 files changed, 145 insertions, 0 deletions

diff --git a/tests/benchmarks/gui/image/image.pro b/tests/benchmarks/gui/image/image.pro
index 71228f4499..89008290fc 100644
--- a/tests/benchmarks/gui/image/image.pro
+++ b/tests/benchmarks/gui/image/image.pro
@@ -3,6 +3,7 @@ SUBDIRS = \
         blendbench \
         qimageconversion \
         qimagereader \
+        qimagescale \
         qpixmap \
         qpixmapcache
 
diff --git a/tests/benchmarks/gui/image/qimagescale/qimagescale.pro b/tests/benchmarks/gui/image/qimagescale/qimagescale.pro
new file mode 100644
index 0000000000..a576e2c9aa
--- /dev/null
+++ b/tests/benchmarks/gui/image/qimagescale/qimagescale.pro
@@ -0,0 +1,4 @@
+TEMPLATE = app
+TARGET = tst_bench_imageScale
+QT += testlib
+SOURCES += tst_qimagescale.cpp
diff --git a/tests/benchmarks/gui/image/qimagescale/tst_qimagescale.cpp b/tests/benchmarks/gui/image/qimagescale/tst_qimagescale.cpp
new file mode 100644
index 0000000000..58abfdf4da
--- /dev/null
+++ b/tests/benchmarks/gui/image/qimagescale/tst_qimagescale.cpp
@@ -0,0 +1,140 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** As a special exception, The Qt Company gives you certain additional
+** rights. These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <qtest.h>
+#include <QImage>
+
+class tst_QImageScale : public QObject
+{
+    Q_OBJECT
+private slots:
+    void scaleRgb32_data();
+    void scaleRgb32();
+
+    void scaleArgb32pm_data();
+    void scaleArgb32pm();
+
+private:
+    QImage generateImageRgb32(int width, int height);
+    QImage generateImageArgb32(int width, int height);
+};
+
+void tst_QImageScale::scaleRgb32_data()
+{
+    QTest::addColumn<QImage>("inputImage");
+    QTest::addColumn<QSize>("outputSize");
+
+    QImage image = generateImageRgb32(1000, 1000);
+    QTest::newRow("1000x1000 -> 2000x2000") << image << QSize(2000, 2000);
+    QTest::newRow("1000x1000 -> 2000x1000") << image << QSize(2000, 1000);
+    QTest::newRow("1000x1000 -> 1000x2000") << image << QSize(1000, 2000);
+    QTest::newRow("1000x1000 -> 2000x500") << image << QSize(2000, 500);
+    QTest::newRow("1000x1000 -> 500x2000") << image << QSize(500, 2000);
+    QTest::newRow("1000x1000 -> 500x500") << image << QSize(500, 500);
+    QTest::newRow("1000x1000 -> 200x200") << image << QSize(200, 200);
+}
+
+void tst_QImageScale::scaleRgb32()
+{
+    QFETCH(QImage, inputImage);
+    QFETCH(QSize, outputSize);
+
+    QBENCHMARK {
+        volatile QImage output = inputImage.scaled(outputSize, Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
+        // we need the volatile and the following to make sure the compiler does not do
+        // anything stupid :)
+        (void)output;
+    }
+}
+
+void tst_QImageScale::scaleArgb32pm_data()
+{
+    QTest::addColumn<QImage>("inputImage");
+    QTest::addColumn<QSize>("outputSize");
+
+    QImage image = generateImageArgb32(1000, 1000).convertToFormat(QImage::Format_ARGB32_Premultiplied);
+    QTest::newRow("1000x1000 -> 2000x2000") << image << QSize(2000, 2000);
+    QTest::newRow("1000x1000 -> 2000x1000") << image << QSize(2000, 1000);
+    QTest::newRow("1000x1000 -> 1000x2000") << image << QSize(1000, 2000);
+    QTest::newRow("1000x1000 -> 2000x500") << image << QSize(2000, 500);
+    QTest::newRow("1000x1000 -> 500x2000") << image << QSize(500, 2000);
+    QTest::newRow("1000x1000 -> 500x500") << image << QSize(500, 500);
+    QTest::newRow("1000x1000 -> 200x200") << image << QSize(200, 200);
+}
+
+void tst_QImageScale::scaleArgb32pm()
+{
+    QFETCH(QImage, inputImage);
+    QFETCH(QSize, outputSize);
+
+    QBENCHMARK {
+        volatile QImage output = inputImage.scaled(outputSize, Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
+        // we need the volatile and the following to make sure the compiler does not do
+        // anything stupid :)
+        (void)output;
+    }
+}
+
+/*
+ Fill a RGB32 image with "random" pixel values.
+ */
+QImage tst_QImageScale::generateImageRgb32(int width, int height)
+{
+    QImage image(width, height, QImage::Format_RGB32);
+
+    for (int y = 0; y < image.height(); ++y) {
+        QRgb *scanline = (QRgb*)image.scanLine(y);
+        for (int x = 0; x < width; ++x)
+            scanline[x] = qRgb(x, y, x ^ y);
+    }
+    return image;
+}
+
+/*
+ Fill a ARGB32 image with "random" pixel values.
+ */
+QImage tst_QImageScale::generateImageArgb32(int width, int height)
+{
+    QImage image(width, height, QImage::Format_ARGB32);
+    const int byteWidth = width * 4;
+
+    for (int y = 0; y < image.height(); ++y) {
+        uchar *scanline = image.scanLine(y);
+        for (int x = 0; x < byteWidth; ++x)
+            scanline[x] = x ^ y;
+    }
+    return image;
+}
+
+QTEST_MAIN(tst_QImageScale)
+#include "tst_qimagescale.moc"