tdf#101181 Implement glow effect on shapes

Glow effect is a color-blurred outline outside of the shape. In ooxml
document it is specified with the <a:glow> element.

The commit contains the following:
- Add support for importing and exporting <a:glow> from ooxml documents.
- Assign new properties to XShape which stores glow-related attributes.
- A new 2D primitive is introduced in module 'drawinglayer' which is
responsible for representing the glow primitive which is to be rendered.
+ A glow primitive is a clone of the original shape which has been
scaled up slightly and a new color has been assigned to it. The
radius of the glow effect and the color is defined in the <a:glow>
element being imported.
- A blur algorithm is introduced in module 'vcl', which is called during
rendering the primitive.
+ The blur algorithm works on a bitmap.
+ Since the algorithm is CPU-intensive, the result is cached in the
processor and it is recalculated only if needed.
- Add support for importing and exporting glow effect to ODF format. For
that, new attributes of element <style:graphic-properties> has been
added:
+ loext:glow, which can have the values "visible" or "hidden"
+ loext:glow-radius: which holds the radius of the glow effect in cm.
+ loext:glow-color: holds the color of the glow effect
- Tests have been added to assert properties after pptx import and
export.

Change-Id: I836aeb5e0f24e2c8d5725834c8c0f98083bc82e7
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/89125
Tested-by: Jenkins
Reviewed-by: Tamás Bunth <btomi96@gmail.com>

1 files changed, 80 insertions, 0 deletions

diff --git a/drawinglayer/source/attribute/sdrglowattribute.cxx b/drawinglayer/source/attribute/sdrglowattribute.cxx
new file mode 100644
index 000000000000..bc42b170a8e9
--- /dev/null
+++ b/drawinglayer/source/attribute/sdrglowattribute.cxx
@@ -0,0 +1,80 @@
+/* -*- 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 <drawinglayer/attribute/sdrglowattribute.hxx>
+#include <basegfx/vector/b2dvector.hxx>
+#include <basegfx/matrix/b2dhommatrixtools.hxx>
+#include <basegfx/color/bcolor.hxx>
+#include <rtl/instance.hxx>
+
+#include <utility>
+
+#include <sal/log.hxx>
+
+namespace drawinglayer
+{
+namespace attribute
+{
+SdrGlowAttribute::SdrGlowAttribute(sal_Int32 nRadius, const basegfx::BColor& rColor)
+    : m_nRadius(nRadius)
+    , m_color(rColor)
+{
+}
+
+SdrGlowAttribute::SdrGlowAttribute()
+    : m_nRadius(0)
+{
+}
+
+SdrGlowAttribute::SdrGlowAttribute(const SdrGlowAttribute&) = default;
+
+SdrGlowAttribute::SdrGlowAttribute(SdrGlowAttribute&&) = default;
+
+SdrGlowAttribute::~SdrGlowAttribute() = default;
+
+SdrGlowAttribute& SdrGlowAttribute::operator=(const SdrGlowAttribute&) = default;
+
+SdrGlowAttribute& SdrGlowAttribute::operator=(SdrGlowAttribute&&) = default;
+
+bool SdrGlowAttribute::operator==(const SdrGlowAttribute& rCandidate) const
+{
+    if (rCandidate.isDefault() != isDefault())
+        return false;
+    return m_nRadius == rCandidate.m_nRadius && m_color == rCandidate.m_color;
+}
+
+const basegfx::B2DHomMatrix& SdrGlowAttribute::GetTransfMatrix(basegfx::B2DRange nRange) const
+{
+    if (!m_oTransfCache)
+    {
+        double dRadius100mm = static_cast<double>(m_nRadius) / 360.0;
+        // Apply a scaling with the center point of the shape as origin.
+        // 1) translate shape to the origin
+        basegfx::B2DHomMatrix matrix = basegfx::utils::createCoordinateSystemTransform(
+            nRange.getCenter(), basegfx::B2DVector(-1, 0), basegfx::B2DVector(0, -1));
+
+        basegfx::B2DHomMatrix inverse(matrix);
+        inverse.invert();
+
+        // 2) Scale up
+        double scale_x = (nRange.getWidth() + dRadius100mm) / nRange.getWidth();
+        double scale_y = (nRange.getHeight() + dRadius100mm) / nRange.getHeight();
+        matrix *= basegfx::utils::createScaleB2DHomMatrix(scale_x, scale_y);
+
+        // 3) Translate shape back to its place
+        matrix *= inverse;
+        m_oTransfCache = std::move(matrix);
+    }
+    return *m_oTransfCache;
+}
+
+} // end of namespace attribute
+} // end of namespace drawinglayer
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */