tdf#155901 MCGR: preserve first and last gradient stop too

Error was, that only the in-between gradient stops were preserve. First
stop was set with fixed offset 0, last stop with fixed offset 1. The
offsets of first and last gradient stop of the original gradient were
lost. Now in all cases (hopefully) the complete gradient stops vector is
preserved and the original offset is used, if e.g. the user changes the
color.

For calculating transparence the indirect way over Color is removed.
Instead percent is directly transformed to the 0..1 values of BColor.
That avoids rounding errors.

Change-Id: Icdf699a6c2e9c6289d2f77033858448e58396a60
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/153395
Tested-by: Jenkins
Reviewed-by: Regina Henschel <rb.henschel@t-online.de>

1 files changed, 16 insertions, 9 deletions

diff --git a/cui/source/tabpages/tpgradnt.cxx b/cui/source/tabpages/tpgradnt.cxx
index 7f6630747a42..d3d066236ae1 100644
--- a/cui/source/tabpages/tpgradnt.cxx
+++ b/cui/source/tabpages/tpgradnt.cxx
@@ -548,9 +548,11 @@ void SvxGradientTabPage::ChangeGradientHdl_Impl()
     m_xLbColorTo->SetNoSelection();
     m_xLbColorTo->SelectEntry(Color(pGradient->GetColorStops().back().getStopColor()));
 
-    // MCGR: preserve in-between ColorStops if given
-    if (pGradient->GetColorStops().size() > 2)
-        m_aColorStops = basegfx::BColorStops(pGradient->GetColorStops().begin() + 1, pGradient->GetColorStops().end() - 1);
+    // MCGR: preserve ColorStops if given.
+    // tdf#155901 We need offset of first and last stop, so include them.
+    if (pGradient->GetColorStops().size() >= 2)
+        m_aColorStops = basegfx::BColorStops(pGradient->GetColorStops().begin(),
+                                             pGradient->GetColorStops().end());
     else
         m_aColorStops.clear();
 
@@ -641,14 +643,19 @@ basegfx::BColorStops SvxGradientTabPage::createColorStops()
 {
     basegfx::BColorStops aColorStops;
 
-    aColorStops.emplace_back(0.0, m_xLbColorFrom->GetSelectEntryColor().getBColor());
-
-    if(!m_aColorStops.empty())
+    if(m_aColorStops.size() >= 2)
     {
-        aColorStops.insert(aColorStops.begin(), m_aColorStops.begin(), m_aColorStops.end());
+        aColorStops.emplace_back(m_aColorStops.front().getStopOffset(),
+                                 m_xLbColorFrom->GetSelectEntryColor().getBColor());
+        aColorStops.insert(aColorStops.begin(), m_aColorStops.begin() + 1, m_aColorStops.end() - 1);
+        aColorStops.emplace_back(m_aColorStops.back().getStopOffset(),
+                                 m_xLbColorTo->GetSelectEntryColor().getBColor());
+    }
+    else
+    {
+        aColorStops.emplace_back(0.0, m_xLbColorFrom->GetSelectEntryColor().getBColor());
+        aColorStops.emplace_back(1.0, m_xLbColorTo->GetSelectEntryColor().getBColor());
     }
-
-    aColorStops.emplace_back(1.0, m_xLbColorTo->GetSelectEntryColor().getBColor());
 
     return aColorStops;
 }