tdf#121120 vcl opengl: handle 8-bit palette bitmap as 24 bit RGB texture

This fixes the black rectangle instead of actual image content in the
bugdoc.

An alternative would be to handle this in the PNG import, but commit
66dbd4da3afcadb1393daf9be9cecff71b86509a (tdf#113918: Workaround: Load
1bpp indexed PNG as 8bpp indexed Bitmap, 2017-11-20) already tried
something similar and failed, leading to the revert in commit
25cd843664919974f0d21ca7a0b02cc43e9eeabb (tdf#115297: alternative fix
for displaying 1bit images, 2018-02-27).

The test is especially useful with SAL_FORCEGL=1 SAL_USE_VCLPLUGIN=gen
specified on Linux, so the GL codepath is triggered.

Change-Id: Ia9d049d09dce2ac34826ee427f74616a96a35c88
Reviewed-on: https://gerrit.libreoffice.org/68925
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
Tested-by: Jenkins

2 files changed, 84 insertions, 0 deletions

diff --git a/vcl/qa/cppunit/gen/data/tdf121120.png b/vcl/qa/cppunit/gen/data/tdf121120.png
new file mode 100644
index 000000000000..8e48fba385f9
--- /dev/null
+++ b/vcl/qa/cppunit/gen/data/tdf121120.png
diff --git a/vcl/qa/cppunit/gen/gen.cxx b/vcl/qa/cppunit/gen/gen.cxx
new file mode 100644
index 000000000000..f5d1c1c6769c
--- /dev/null
+++ b/vcl/qa/cppunit/gen/gen.cxx
@@ -0,0 +1,84 @@
+/* -*- 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 <com/sun/star/frame/Desktop.hpp>
+
+#include <comphelper/processfactory.hxx>
+#include <sfx2/app.hxx>
+#include <sfx2/objsh.hxx>
+#include <sfx2/sfxbasemodel.hxx>
+#include <test/unoapi_test.hxx>
+#include <vcl/bitmapaccess.hxx>
+#include <vcl/pngwrite.hxx>
+#include <vcl/gdimtf.hxx>
+#include <tools/stream.hxx>
+
+using namespace com::sun::star;
+
+/// This test uses the gen backend (i.e. intentionally not the svp one, which is the default.)
+class GenTest : public UnoApiTest
+{
+public:
+    GenTest()
+        : UnoApiTest("/vcl/qa/cppunit/gen/data/")
+    {
+    }
+
+    virtual void setUp() override
+    {
+        UnoApiTest::setUp();
+        mxDesktop.set(
+            frame::Desktop::create(comphelper::getComponentContext(getMultiServiceFactory())));
+        SfxApplication::GetOrCreate();
+    };
+
+    virtual void tearDown() override
+    {
+        if (mxComponent.is())
+        {
+            closeDocument(mxComponent);
+            mxComponent->dispose();
+        }
+        UnoApiTest::tearDown();
+    };
+
+    Bitmap load(const char* pName)
+    {
+        OUString aFileURL;
+        createFileURL(OUString::createFromAscii(pName), aFileURL);
+        mxComponent = loadFromDesktop(aFileURL, "com.sun.star.drawing.DrawingDocument");
+        SfxBaseModel* pModel = dynamic_cast<SfxBaseModel*>(mxComponent.get());
+        CPPUNIT_ASSERT(pModel);
+        SfxObjectShell* pShell = pModel->GetObjectShell();
+        std::shared_ptr<GDIMetaFile> xMetaFile = pShell->GetPreviewMetaFile();
+        BitmapEx aResultBitmap;
+        CPPUNIT_ASSERT(xMetaFile->CreateThumbnail(aResultBitmap));
+        return aResultBitmap.GetBitmap();
+    }
+
+    uno::Reference<lang::XComponent> mxComponent;
+};
+
+CPPUNIT_TEST_FIXTURE(GenTest, testTdf121120)
+{
+    Bitmap aBitmap = load("tdf121120.png");
+    Bitmap::ScopedReadAccess pAccess(aBitmap);
+    const Size& rSize = aBitmap.GetPrefSize();
+    Color aColor(pAccess->GetPixel(rSize.getWidth() / 2, rSize.getHeight() / 2).GetColor());
+    // Without the accompanying fix in place, this test would have failed with 'Expected: 255;
+    // Actual  : 1'. I.e. center if the preview (which has the background color) was ~black, not
+    // white.
+    CPPUNIT_ASSERT_EQUAL(0xff, int(aColor.GetRed()));
+    CPPUNIT_ASSERT_EQUAL(0xff, int(aColor.GetBlue()));
+    CPPUNIT_ASSERT_EQUAL(0xff, int(aColor.GetGreen()));
+}
+
+CPPUNIT_PLUGIN_IMPLEMENT();
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */