restore unit test code accidentally deleted

in c05680bd27f0f9fc9d5371f4ef97fd45184de1c6

Change-Id: I8d35ed9411c51b8bfffc2ca67d9d8de94ba067dc
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/88355
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

1 files changed, 42 insertions, 0 deletions

diff --git a/vcl/qa/cppunit/ScanlineToolsTest.cxx b/vcl/qa/cppunit/ScanlineToolsTest.cxx
index 9a0ad213e7cc..bf053d3bc890 100644
--- a/vcl/qa/cppunit/ScanlineToolsTest.cxx
+++ b/vcl/qa/cppunit/ScanlineToolsTest.cxx
@@ -20,12 +20,14 @@ class ScanlineToolsTest : public CppUnit::TestFixture
     void ScanlineTransformer_32_ARGB();
     void ScanlineTransformer_24_BGR();
     void ScanlineTransformer_8bit_Palette();
+    void ScanlineTransformer_4bit_Palette();
     void ScanlineTransformer_1bit_Palette();
 
     CPPUNIT_TEST_SUITE(ScanlineToolsTest);
     CPPUNIT_TEST(ScanlineTransformer_32_ARGB);
     CPPUNIT_TEST(ScanlineTransformer_24_BGR);
     CPPUNIT_TEST(ScanlineTransformer_8bit_Palette);
+    CPPUNIT_TEST(ScanlineTransformer_4bit_Palette);
     CPPUNIT_TEST(ScanlineTransformer_1bit_Palette);
     CPPUNIT_TEST_SUITE_END();
 };
@@ -124,6 +126,46 @@ void ScanlineToolsTest::ScanlineTransformer_8bit_Palette()
     }
 }
 
+void ScanlineToolsTest::ScanlineTransformer_4bit_Palette()
+{
+    std::vector<Color> aColors{
+        Color(10, 250, 120), Color(30, 230, 110), Color(50, 210, 100),
+        Color(70, 190, 90),  Color(90, 170, 80),  Color(110, 150, 70),
+    };
+
+    BitmapPalette aPalette(16);
+    for (size_t i = 0; i < aColors.size(); ++i)
+    {
+        aPalette[i] = aColors[i];
+    }
+
+    std::unique_ptr<vcl::bitmap::ScanlineTransformer> pScanlineTransformer
+        = vcl::bitmap::getScanlineTransformer(4, aPalette);
+
+    std::vector<sal_uInt8> aScanLine(3, 0); // 6 * 0.5 BytesPerPixel
+    pScanlineTransformer->startLine(aScanLine.data());
+
+    for (Color const& aColor : aColors)
+    {
+        pScanlineTransformer->writePixel(aColor);
+    }
+
+    std::vector<sal_uInt8> aExpectedBytes{ 0x01, 0x23, 0x45 };
+
+    for (size_t i = 0; i < aScanLine.size(); ++i)
+    {
+        CPPUNIT_ASSERT_EQUAL(int(aExpectedBytes[i]), int(aScanLine[i]));
+    }
+
+    pScanlineTransformer->startLine(aScanLine.data());
+
+    for (size_t i = 0; i < aColors.size(); ++i)
+    {
+        Color aColor = pScanlineTransformer->readPixel();
+        CPPUNIT_ASSERT_EQUAL(aColors[i], aColor);
+    }
+}
+
 void ScanlineToolsTest::ScanlineTransformer_1bit_Palette()
 {
     std::vector<Color> aColors{