MCGR: Model data changes for ColorSteps (II)

The biggest change here is to allow multiple ColorStops
with the same Offset. That allows to define gradients
with 'hard' color changes at any place using two
ColorStops with the same Offset and different Colors.
This required quite some adaptions, but works well.

Also removed in this context checking for all Colors
being the same to not mix up things. Also works well.

Also changed the need for having Start/EndColors AKA
ColorStops for 0.0 and 1.0 in place, instead 'imply'
the 1st ColorStop to also define the StartColor and
the last one the EndColor. This allows e.g. Gradient
definitions with two GradientStops at the same
Offset e.g. 0.5 with different colors to already
define a full Gradient.

Also added a tooling method to reverse ColorSteps,
which changes the order and mirrors the Offsets
(what even keeps an existing sort valid).
This is useful e.g. for GradientAxial which is the
only one where for decomposition the Gradient had
to be interpreted 'reverse' since it's defined
from center to edge, but for creating correct filled
polygons to represent this the inverse order had to
be used, creating polygons from edge to center.
This led to 'wild' code for this one of six cases
and prevented unifications with the other cases
(also made your brain flip).
Thus I adapted this now to use the reversed
ColorSteps consequently, and the same principle
loops than the other implementations to make things
easier for the future and to use common tooling.

Change-Id: If2943348d17d5b9cd165f4d78f22638a1dff5237
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/149208
Tested-by: Jenkins
Reviewed-by: Armin Le Grand <Armin.Le.Grand@me.com>

1 files changed, 67 insertions, 8 deletions

diff --git a/svx/source/sdr/primitive2d/sdrattributecreator.cxx b/svx/source/sdr/primitive2d/sdrattributecreator.cxx
index 7409c4017202..475a0916f444 100644
--- a/svx/source/sdr/primitive2d/sdrattributecreator.cxx
+++ b/svx/source/sdr/primitive2d/sdrattributecreator.cxx
@@ -494,28 +494,39 @@ namespace drawinglayer::primitive2d
                                 case 2:
                                 {
                                     // single added in-between, no change of start/end
+                                    aColorStops.clear();
+                                    aColorStops.emplace_back(0.0, basegfx::BColor(1.0, 0.0, 0.0)); // red
                                     aColorStops.emplace_back(0.5, basegfx::BColor(1.0, 1.0, 0.0)); // yellow@50%
+                                    aColorStops.emplace_back(1.0, basegfx::BColor(0.0, 0.0, 1.0)); // blue
                                     break;
                                 }
 
                                 case 3:
                                 {
-                                    // check additional StartColor, the one given directly has to win
+                                    // check additional StartColor, the second one has to win
+                                    aColorStops.clear();
+                                    aColorStops.emplace_back(0.0, basegfx::BColor(1.0, 0.0, 0.0)); // red
                                     aColorStops.emplace_back(0.0, basegfx::BColor(1.0, 1.0, 0.0)); // yellow@50%
+                                    aColorStops.emplace_back(1.0, basegfx::BColor(0.0, 0.0, 1.0)); // blue
                                     break;
                                 }
 
                                 case 4:
                                 {
-                                    // check additional EndColor, the one given directly has to win
-                                    // due this one being added *after* the original one
+                                    // check additional EndColor, the first one has to win
+                                    aColorStops.clear();
+                                    aColorStops.emplace_back(0.0, basegfx::BColor(1.0, 0.0, 0.0)); // red
                                     aColorStops.emplace_back(1.0, basegfx::BColor(1.0, 1.0, 0.0)); // yellow@50%
+                                    aColorStops.emplace_back(1.0, basegfx::BColor(0.0, 0.0, 1.0)); // blue
                                     break;
                                 }
 
                                 case 5:
                                 {
                                     // check invalid color (too low index), has to be ignored
+                                    aColorStops.clear();
+                                    aColorStops.emplace_back(0.0, basegfx::BColor(1.0, 0.0, 0.0)); // red
+                                    aColorStops.emplace_back(1.0, basegfx::BColor(0.0, 0.0, 1.0)); // blue
                                     aColorStops.emplace_back(-1.0, basegfx::BColor(1.0, 1.0, 0.0)); // yellow@50%
                                     break;
                                 }
@@ -523,6 +534,9 @@ namespace drawinglayer::primitive2d
                                 case 6:
                                 {
                                     // check invalid color (too high index), has to be ignored
+                                    aColorStops.clear();
+                                    aColorStops.emplace_back(0.0, basegfx::BColor(1.0, 0.0, 0.0)); // red
+                                    aColorStops.emplace_back(1.0, basegfx::BColor(0.0, 0.0, 1.0)); // blue
                                     aColorStops.emplace_back(2.0, basegfx::BColor(1.0, 1.0, 0.0)); // yellow@50%
                                     break;
                                 }
@@ -530,33 +544,45 @@ namespace drawinglayer::primitive2d
                                 case 7:
                                 {
                                     // check in-between single-color section
+                                    aColorStops.clear();
+                                    aColorStops.emplace_back(0.0, basegfx::BColor(1.0, 0.0, 0.0)); // red
                                     aColorStops.emplace_back(0.3, basegfx::BColor(1.0, 1.0, 0.0)); // yellow@50%
                                     aColorStops.emplace_back(0.7, basegfx::BColor(1.0, 1.0, 0.0)); // yellow@50%
+                                    aColorStops.emplace_back(1.0, basegfx::BColor(0.0, 0.0, 1.0)); // blue
                                     break;
                                 }
 
                                 case 8:
                                 {
                                     // check in-between single-color sections
+                                    aColorStops.clear();
+                                    aColorStops.emplace_back(0.0, basegfx::BColor(1.0, 0.0, 0.0)); // red
                                     aColorStops.emplace_back(0.2, basegfx::BColor(1.0, 1.0, 0.0)); // yellow@50%
                                     aColorStops.emplace_back(0.4, basegfx::BColor(1.0, 1.0, 0.0)); // yellow@50%
-                                    aColorStops.emplace_back(0.5, aXGradient.GetColorStops().front().getStopColor());
+                                    aColorStops.emplace_back(0.5, basegfx::BColor(1.0, 0.0, 0.0)); // red
                                     aColorStops.emplace_back(0.6, basegfx::BColor(1.0, 1.0, 0.0)); // yellow@50%
                                     aColorStops.emplace_back(0.8, basegfx::BColor(1.0, 1.0, 0.0)); // yellow@50%
+                                    aColorStops.emplace_back(1.0, basegfx::BColor(0.0, 0.0, 1.0)); // blue
                                     break;
                                 }
 
                                 case 9:
                                 {
                                     // check single-color start area
-                                    aColorStops.emplace_back(0.6, aXGradient.GetColorStops().front().getStopColor());
+                                    aColorStops.clear();
+                                    aColorStops.emplace_back(0.0, basegfx::BColor(1.0, 0.0, 0.0)); // red
+                                    aColorStops.emplace_back(0.6, basegfx::BColor(1.0, 0.0, 0.0)); // red
+                                    aColorStops.emplace_back(1.0, basegfx::BColor(0.0, 0.0, 1.0)); // blue
                                     break;
                                 }
 
                                 case 10:
                                 {
                                     // check single-color end area
-                                    aColorStops.emplace_back(0.4, aXGradient.GetColorStops().back().getStopColor());
+                                    aColorStops.clear();
+                                    aColorStops.emplace_back(0.0, basegfx::BColor(1.0, 0.0, 0.0)); // red
+                                    aColorStops.emplace_back(0.4, basegfx::BColor(0.0, 0.0, 1.0)); // blue
+                                    aColorStops.emplace_back(1.0, basegfx::BColor(0.0, 0.0, 1.0)); // blue
                                     break;
                                 }
 
@@ -564,8 +590,41 @@ namespace drawinglayer::primitive2d
                                 {
                                     // check case without direct Start/EndColor
                                     aColorStops.clear();
-                                    aColorStops.emplace_back(0.4, aXGradient.GetColorStops().back().getStopColor());
-                                    aColorStops.emplace_back(0.6, aXGradient.GetColorStops().front().getStopColor());
+                                    aColorStops.emplace_back(0.4, basegfx::BColor(1.0, 0.0, 0.0)); // red
+                                    aColorStops.emplace_back(0.6, basegfx::BColor(0.0, 0.0, 1.0)); // blue
+                                    break;
+                                }
+
+                                case 12:
+                                {
+                                    // check case without colors at all
+                                    aColorStops.clear();
+                                    break;
+                                }
+
+                                case 13:
+                                {
+                                    // check case with single stop
+                                    aColorStops.clear();
+                                    aColorStops.emplace_back(0.5, basegfx::BColor(1.0, 0.0, 0.0)); // red
+                                    break;
+                                }
+
+                                case 14:
+                                {
+                                    // check case with single-double stop
+                                    aColorStops.clear();
+                                    aColorStops.emplace_back(0.5, basegfx::BColor(1.0, 0.0, 0.0)); // red
+                                    aColorStops.emplace_back(0.5, basegfx::BColor(1.0, 0.0, 0.0)); // red
+                                    break;
+                                }
+
+                                case 15:
+                                {
+                                    // check case with single stop diff colors
+                                    aColorStops.clear();
+                                    aColorStops.emplace_back(0.5, basegfx::BColor(1.0, 0.0, 0.0)); // red
+                                    aColorStops.emplace_back(0.5, basegfx::BColor(0.0, 0.0, 1.0)); // blue
                                     break;
                                 }