check that jpeg export of 8bit non-grayscale works

This checks what I fixed in 1893024c54ab173ec6262d77a05cad285c17a617
(related to tdf#116888).

Change-Id: I721017fd037d62ba75cbc962fdd9316e02085624
Reviewed-on: https://gerrit.libreoffice.org/69819
Tested-by: Jenkins
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>

vcl/CppunitTest_vcl_jpeg_read_write_test.mk

@@ -11,6 +11,7 @@ $(eval $(call gb_CppunitTest_CppunitTest,vcl_jpeg_read_write_test))
 
 $(eval $(call gb_CppunitTest_add_exception_objects,vcl_jpeg_read_write_test, \
     vcl/qa/cppunit/jpeg/JpegReaderTest \
+    vcl/qa/cppunit/jpeg/JpegWriterTest \
 ))
 
 $(eval $(call gb_CppunitTest_use_external,vcl_jpeg_read_write_test,boost_headers))

vcl/qa/cppunit/jpeg/JpegWriterTest.cxx

@@ -0,0 +1,88 @@
+/* -*- 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 <test/setupvcl.hxx>
+#include <unotest/bootstrapfixturebase.hxx>
+#include <vcl/graphicfilter.hxx>
+#include <vcl/bitmapaccess.hxx>
+#include <bitmapwriteaccess.hxx>
+#include <tools/stream.hxx>
+
+static OUString const gaDataUrl("/vcl/qa/cppunit/jpeg/data/");
+
+class JpegWriterTest : public test::BootstrapFixtureBase
+{
+    OUString getFullUrl(const OUString& sFileName)
+    {
+        return m_directories.getURLFromSrc(gaDataUrl) + sFileName;
+    }
+
+    BitmapEx load(const OUString& aURL);
+    BitmapEx roundtripJPG(const BitmapEx& bitmap);
+    BitmapEx roundtripJPG(const OUString& aURL);
+
+public:
+    void testWrite8BitNonGrayscale();
+
+    CPPUNIT_TEST_SUITE(JpegWriterTest);
+    CPPUNIT_TEST(testWrite8BitNonGrayscale);
+    CPPUNIT_TEST_SUITE_END();
+};
+
+BitmapEx JpegWriterTest::load(const OUString& aURL)
+{
+    GraphicFilter& rFilter = GraphicFilter::GetGraphicFilter();
+    Graphic aGraphic;
+    SvFileStream aFileStream(aURL, StreamMode::READ);
+    ErrCode bResult = rFilter.ImportGraphic(aGraphic, aURL, aFileStream);
+    CPPUNIT_ASSERT_EQUAL(ERRCODE_NONE, bResult);
+    return aGraphic.GetBitmapEx();
+}
+
+BitmapEx JpegWriterTest::roundtripJPG(const OUString& aURL) { return roundtripJPG(load(aURL)); }
+
+BitmapEx JpegWriterTest::roundtripJPG(const BitmapEx& bitmap)
+{
+    SvMemoryStream stream;
+    GraphicFilter& rFilter = GraphicFilter::GetGraphicFilter();
+    sal_uInt16 exportFormatJPG = rFilter.GetExportFormatNumberForShortName(JPG_SHORTNAME);
+    Graphic aExportGraphic(bitmap);
+    ErrCode bResult = rFilter.ExportGraphic(aExportGraphic, "memory", stream, exportFormatJPG);
+    CPPUNIT_ASSERT_EQUAL(ERRCODE_NONE, bResult);
+    stream.Seek(0);
+    Graphic aImportGraphic;
+    sal_uInt16 importFormatJPG = rFilter.GetImportFormatNumberForShortName(JPG_SHORTNAME);
+    bResult = rFilter.ImportGraphic(aImportGraphic, "memory", stream, importFormatJPG);
+    CPPUNIT_ASSERT_EQUAL(ERRCODE_NONE, bResult);
+    return aImportGraphic.GetBitmapEx();
+}
+
+void JpegWriterTest::testWrite8BitNonGrayscale()
+{
+    Bitmap bitmap = roundtripJPG(getFullUrl("8BitNonGrayscale.gif")).GetBitmap();
+    Bitmap::ScopedReadAccess access(bitmap);
+    const ScanlineFormat format = access->GetScanlineFormat();
+    // Check that it's still 8bit grayscale.
+    CPPUNIT_ASSERT_EQUAL(ScanlineFormat::N8BitPal, format);
+    // The original image has grayscale palette, just with entries in a different order,
+    // so do not check for non-grayscale, the roundtrip apparently fixes that. What's important
+    // is the content.
+    // CPPUNIT_ASSERT(!bitmap.HasGreyPalette());
+    // Check that the content is valid.
+    CPPUNIT_ASSERT_EQUAL(BitmapColor(COL_WHITE), access->GetColor(0, 0));
+    CPPUNIT_ASSERT_EQUAL(BitmapColor(COL_WHITE), access->GetColor(0, access->Width() - 1));
+    CPPUNIT_ASSERT_EQUAL(BitmapColor(COL_WHITE), access->GetColor(access->Height() - 1, 0));
+    CPPUNIT_ASSERT_EQUAL(BitmapColor(COL_BLACK),
+                         access->GetColor(access->Height() - 1, access->Width() - 1));
+}
+
+CPPUNIT_TEST_SUITE_REGISTRATION(JpegWriterTest);
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */