vcl: stack blur implementation + basic test & performance test

Change-Id: I793ed80a07d9488c5f75b3abdca6db344d80d3d8

include/vcl/BitmapFilterStackBlur.hxx

+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ */
+
+#ifndef INCLUDED_VCL_BITMAPFILTERSTACKBLUR_HXX
+#define INCLUDED_VCL_BITMAPFILTERSTACKBLUR_HXX
+
+#include <vcl/bitmap.hxx>
+#include <vcl/bitmapex.hxx>
+#include <vcl/bitmapfilter.hxx>
+
+class VCL_DLLPUBLIC BitmapFilterStackBlur : BitmapFilter
+{
+    sal_Int32 mnRadius;
+    bool mbExtend;
+
+public:
+    BitmapFilterStackBlur(sal_Int32 nRadius, bool bExtend = true);
+    virtual ~BitmapFilterStackBlur();
+
+    virtual bool filter(Bitmap& rBitmap) SAL_OVERRIDE;
+
+    bool filter(BitmapEx& rBitmap);
+};
+
+#endif // INCLUDED_VCL_BITMAPFILTERSTACKBLUR_HXX
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */

vcl/CppunitTest_vcl_bitmap_test.mk

@@ -11,6 +11,7 @@ $(eval $(call gb_CppunitTest_CppunitTest,vcl_bitmap_test))
 
 $(eval $(call gb_CppunitTest_add_exception_objects,vcl_bitmap_test, \
     vcl/qa/cppunit/BitmapTest \
+    vcl/qa/cppunit/BitmapFilterTest \
 ))
 
 $(eval $(call gb_CppunitTest_use_externals,vcl_bitmap_test,\

vcl/Library_vcl.mk

@@ -316,6 +316,7 @@ $(eval $(call gb_Library_add_exception_objects,vcl,\
     vcl/source/bitmap/bitmapfilter \
     vcl/source/bitmap/bitmapscalesuper \
     vcl/source/bitmap/BitmapSymmetryCheck \
+    vcl/source/bitmap/BitmapFilterStackBlur \
     vcl/source/helper/canvasbitmap \
     vcl/source/helper/canvastools \
     vcl/source/helper/evntpost \

vcl/qa/cppunit/BitmapFilterTest.cxx

+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#include <cppunit/TestAssert.h>
+#include <cppunit/TestFixture.h>
+#include <cppunit/extensions/HelperMacros.h>
+#include <cppunit/plugin/TestPlugIn.h>
+
+#include <vcl/bitmap.hxx>
+#include <vcl/bmpacc.hxx>
+
+#include <tools/stream.hxx>
+#include <vcl/graphicfilter.hxx>
+
+#include <vcl/BitmapFilterStackBlur.hxx>
+#include "BitmapSymmetryCheck.hxx"
+
+#include <chrono>
+
+namespace
+{
+
+const bool constWriteResultBitmap(false);
+const bool constEnablePerformanceTest(false);
+
+class BitmapFilterTest : public CppUnit::TestFixture
+{
+
+    void testBlurCorrectness();
+    void testPerformance();
+
+    CPPUNIT_TEST_SUITE(BitmapFilterTest);
+    CPPUNIT_TEST(testBlurCorrectness);
+    CPPUNIT_TEST(testPerformance);
+    CPPUNIT_TEST_SUITE_END();
+};
+
+void BitmapFilterTest::testBlurCorrectness()
+{
+    // Setup test bitmap
+    Size aSize(41, 31);
+    Bitmap aBitmap24Bit(aSize, 24);
+
+    sal_uLong nScanlineFormat = 0;
+    sal_uInt16 nBPP = aBitmap24Bit.GetBitCount();
+
+    {
+        long aMargin1 = 1;
+        long aMargin2 = 3;
+        Bitmap::ScopedWriteAccess aWriteAccess(aBitmap24Bit);
+        nScanlineFormat = aWriteAccess->GetScanlineFormat();
+        aWriteAccess->Erase(COL_WHITE);
+        aWriteAccess->SetLineColor(COL_BLACK);
+
+        Rectangle aRectangle1(
+                    aMargin1,
+                    aMargin1,
+                    aSize.Width() - 1 - aMargin1,
+                    aSize.Height() - 1 - aMargin1);
+
+        Rectangle aRectangle2(
+                    aMargin2,
+                    aMargin2,
+                    aSize.Width() - 1 - aMargin2,
+                    aSize.Height() - 1 - aMargin2);
+
+        Rectangle aRectangle3(
+                    aSize.Width()  / 2,
+                    aSize.Height() / 2,
+                    aSize.Width()  / 2,
+                    aSize.Height() / 2);
+
+        aWriteAccess->DrawRect(aRectangle1);
+        aWriteAccess->DrawRect(aRectangle2);
+        aWriteAccess->DrawRect(aRectangle3);
+    }
+
+    if (constWriteResultBitmap)
+    {
+        SvFileStream aStream(OUString("~/blurBefore.png"), StreamMode::WRITE | StreamMode::TRUNC);
+        GraphicFilter& rFilter = GraphicFilter::GetGraphicFilter();
+        rFilter.compressAsPNG(aBitmap24Bit, aStream, 1);
+    }
+
+    // Perform blur
+    BitmapFilterStackBlur aBlurFilter(2);
+    aBlurFilter.filter(aBitmap24Bit);
+
+    // Check the result
+
+    if (constWriteResultBitmap)
+    {
+        SvFileStream aStream(OUString("~/blurAfter.png"), StreamMode::WRITE | StreamMode::TRUNC);
+        GraphicFilter& rFilter = GraphicFilter::GetGraphicFilter();
+        rFilter.compressAsPNG(aBitmap24Bit, aStream, 1);
+    }
+
+    // Check blurred bitmap parameters
+    CPPUNIT_ASSERT_EQUAL(static_cast<long>(45), aBitmap24Bit.GetSizePixel().Width());
+    CPPUNIT_ASSERT_EQUAL(static_cast<long>(35), aBitmap24Bit.GetSizePixel().Height());
+
+    CPPUNIT_ASSERT_EQUAL(nBPP, aBitmap24Bit.GetBitCount());
+
+    // Check that the bitmap is horizontally and vertically symmetrical
+    BitmapSymmetryCheck symmetryCheck;
+    CPPUNIT_ASSERT(symmetryCheck.check(aBitmap24Bit));
+
+    {
+        Bitmap::ScopedReadAccess aReadAccess(aBitmap24Bit);
+        CPPUNIT_ASSERT_EQUAL(nScanlineFormat, aReadAccess->GetScanlineFormat());
+    }
+}
+
+void BitmapFilterTest::testPerformance()
+{
+    if (!constEnablePerformanceTest)
+        return;
+
+    Size aSize(4000, 3000); // A rather common picture size
+
+    // Prepare bitmap
+    Bitmap aBigBitmap(aSize, 24);
+    {
+        long aMargin = 500;
+        Bitmap::ScopedWriteAccess aWriteAccess(aBigBitmap);
+        aWriteAccess->Erase(COL_WHITE);
+        aWriteAccess->SetLineColor(COL_BLACK);
+        aWriteAccess->SetFillColor(COL_BLACK);
+        Rectangle aRectangle(
+                    aMargin,
+                    aMargin,
+                    aSize.Width() - 1 - aMargin,
+                    aSize.Height() - 1 - aMargin);
+
+        aWriteAccess->DrawRect(aRectangle);
+    }
+
+    int nIterations = 10;
+    auto start = std::chrono::high_resolution_clock::now();
+    for (int i = 0; i < nIterations; i++)
+    {
+        {
+            BitmapFilterStackBlur aBlurFilter(250, false); // don't extend the image
+            aBlurFilter.filter(aBigBitmap);
+        }
+    }
+    auto end = std::chrono::high_resolution_clock::now();
+    auto elapsed = (end - start) / nIterations;
+
+    if (constWriteResultBitmap)
+    {
+        std::unique_ptr<SvFileStream> pStream(
+            new SvFileStream(OUString("~/BlurBigPerformance.png"), StreamMode::WRITE | StreamMode::TRUNC));
+        GraphicFilter& rFilter = GraphicFilter::GetGraphicFilter();
+        rFilter.compressAsPNG(aBigBitmap, *pStream, 1);
+
+        pStream.reset(
+            new SvFileStream(OUString("~/BlurBigPerformance.txt"), StreamMode::WRITE));
+        pStream->WriteOString(OString("Blur average time: "));
+        pStream->WriteOString(OString::number(std::chrono::duration_cast<std::chrono::milliseconds>(elapsed).count()));
+        pStream->WriteOString(OString("\n"));
+    }
+}
+
+} // namespace
+
+CPPUNIT_TEST_SUITE_REGISTRATION(BitmapFilterTest);
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */