MCGR: ColorSteps handling moved to tooling

Due to the fact that handling of a vector GradientSteps
will get used more often with ongoing changes I moved
some handling to tooling, see sortAndCorrectColorSteps.
That method sorts and corrects a vector of ColorSteps
so that only valid entreis remain in a sorted order,
for details please refer to the docu at function
definition. I took the occasion to rearrange that to
work on the single provided vector which is better for
speed & ressources.

Also changed the ColorStep constructor to not
automatically correct constructed entries: While that
is formally correct, it moves an invalid entry to 0.0
or 1.0, thus creating additional wrong Start/EndColor
entries. Those may then 'overlay' the correct entry
when corrections are applied to the vector of entries
which leads to getting the wanted Start/EndColor to be
factically deleted, what is an error.

Also rearranged FillGradientAttribute to now work
initially with ColorSteps, no longer requires the
Start/EndColor, also adapted all usages. This securely
allows start/end and in-between single-color sections
in gradients.

Also needed to re-formulate GradientRect &
GradientElliptical ::appendTransformationsAndColors
method for correct 2D mapping(s) - always incrementing
from the start to end conflicts with the adaption of
the start value for the inner loop mainly because
increment is at start of inner loop (pre-increment).

Corrected errors from clang plugin, but also some
wrong initialiations for basegfx::ColorSteps.

Change-Id: I292592ed9abcfa591f68a680479f4fcdda46cbeb
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/148196
Tested-by: Jenkins
Reviewed-by: Armin Le Grand <Armin.Le.Grand@me.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/drawinglayer/source/primitive3d/textureprimitive3d.cxx b/drawinglayer/source/primitive3d/textureprimitive3d.cxx
index ba998c7f50bb..549932e93049 100644
--- a/drawinglayer/source/primitive3d/textureprimitive3d.cxx
+++ b/drawinglayer/source/primitive3d/textureprimitive3d.cxx
@@ -20,6 +20,7 @@
 #include <primitive3d/textureprimitive3d.hxx>
 #include <drawinglayer/primitive3d/drawinglayer_primitivetypes3d.hxx>
 #include <basegfx/color/bcolor.hxx>
+#include <basegfx/utils/gradienttools.hxx>
 #include <utility>
 
 
@@ -92,7 +93,13 @@ namespace drawinglayer::primitive3d
             {
                 // create TransparenceTexturePrimitive3D with fixed transparence as replacement
                 const basegfx::BColor aGray(getTransparence(), getTransparence(), getTransparence());
-                const attribute::FillGradientAttribute aFillGradient(attribute::GradientStyle::Linear, 0.0, 0.0, 0.0, 0.0, aGray, aGray);
+
+                // create ColorSteps with StartColor == EndCoOlor == aGray
+                const basegfx::ColorSteps aColorSteps {
+                    basegfx::ColorStep(0.0, aGray),
+                    basegfx::ColorStep(1.0, aGray) };
+
+                const attribute::FillGradientAttribute aFillGradient(attribute::GradientStyle::Linear, 0.0, 0.0, 0.0, 0.0, aColorSteps);
                 const Primitive3DReference xRef(new TransparenceTexturePrimitive3D(aFillGradient, getChildren(), getTextureSize()));
                 return { xRef };
             }