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, 46 insertions, 0 deletions

diff --git a/drawinglayer/source/processor2d/vclpixelprocessor2d.cxx b/drawinglayer/source/processor2d/vclpixelprocessor2d.cxx
index 2fa5a7d47a44..4bd490dcfe78 100644
--- a/drawinglayer/source/processor2d/vclpixelprocessor2d.cxx
+++ b/drawinglayer/source/processor2d/vclpixelprocessor2d.cxx
@@ -18,6 +18,8 @@
  */
 
 #include "vclpixelprocessor2d.hxx"
+#include "vclhelperbufferdevice.hxx"
+#include <vcl/BitmapFilterStackBlur.hxx>
 #include <vcl/outdev.hxx>
 #include <drawinglayer/primitive2d/drawinglayer_primitivetypes2d.hxx>
 #include <drawinglayer/primitive2d/Tools.hxx>
@@ -48,6 +50,9 @@
 #include <drawinglayer/primitive2d/epsprimitive2d.hxx>
 #include <drawinglayer/primitive2d/svggradientprimitive2d.hxx>
 
+#include <vcl/dibtools.hxx>
+#include <tools/stream.hxx>
+
 using namespace com::sun::star;
 
 namespace drawinglayer::processor2d
@@ -361,6 +366,47 @@ namespace drawinglayer::processor2d
                     processBorderLinePrimitive2D(static_cast<const drawinglayer::primitive2d::BorderLinePrimitive2D&>(rCandidate));
                     break;
                 }
+                case PRIMITIVE2D_ID_GLOWPRIMITIVE2D:
+                {
+                    basegfx::B2DRange aRange(rCandidate.getB2DRange(getViewInformation2D()));
+                    aRange.transform(maCurrentTransformation);
+                    aRange.grow(10.0);
+                    impBufferDevice aBufferDevice(*mpOutputDevice, aRange);
+                    if(aBufferDevice.isVisible())
+                    {
+                        // remember last OutDev and set to content
+                        OutputDevice* pLastOutputDevice = mpOutputDevice;
+                        mpOutputDevice = &aBufferDevice.getTransparence();
+                        // paint content to virtual device
+                        mpOutputDevice->Erase();
+                        process(rCandidate);
+
+                        // obtain result as a bitmap
+                        auto bitmap = mpOutputDevice->GetBitmapEx(Point(aRange.getMinX(), aRange.getMinY()), Size(aRange.getWidth(), aRange.getHeight()));
+                        constexpr sal_Int32 nRadius = 5;
+                        bitmap.Scale(Size(aRange.getWidth()-nRadius, aRange.getHeight()-nRadius));
+                        // use bitmap later as mask
+                        auto mask = bitmap.GetBitmap();
+
+                        mpOutputDevice = &aBufferDevice.getContent();
+                        process(rCandidate);
+                        bitmap = mpOutputDevice->GetBitmapEx(Point(aRange.getMinX(), aRange.getMinY()), Size(aRange.getWidth(), aRange.getHeight()));
+                        bitmap.Scale(Size(aRange.getWidth()-nRadius, aRange.getHeight()-nRadius));
+
+                        // calculate blurry effect
+                        BitmapFilterStackBlur glowFilter(nRadius);
+                        BitmapFilter::Filter(bitmap, glowFilter);
+                        // back to old OutDev
+                        mpOutputDevice = pLastOutputDevice;
+                        mpOutputDevice->DrawBitmapEx(Point(aRange.getMinX()-nRadius/2, aRange.getMinY()-nRadius/2), BitmapEx(bitmap.GetBitmap(), mask));
+
+                        // paint result
+                        //aBufferDevice.paint();
+                    }
+                    else
+                        SAL_WARN("drawinglayer", "Temporary buffered virtual device is not visible");
+                    break;
+                }
                 default :
                 {
                     SAL_INFO("drawinglayer", "default case for " << drawinglayer::primitive2d::idToString(rCandidate.getPrimitive2DID()));