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>

0 files changed, 0 insertions, 0 deletions