tdf#155321 sc: fix color of the highest value on percentile color scale

if the highest value occurs multiple times in the data set.

Also for coloring based on the percentile, use always the end
of the color scale for the highest values, like other spreadsheets
do, i.e. not the first possible color in the case of repeating
values. For example, the corner case in the test document is not
a red and two yellow cells any more, but a red and two green cells.

Note: color of the other repeating values still differs from
MSO, but the same as in Google Sheets.

Change-Id: I1d7eacec6e442c1112a9568e64dd6461e2ff2fbd
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/152117
Reviewed-by: László Németh <nemeth@numbertext.org>
Tested-by: László Németh <nemeth@numbertext.org>

4 files changed, 18 insertions, 3 deletions

diff --git a/sc/inc/conditio.hxx b/sc/inc/conditio.hxx
index 51786d3dc712..47f5fdb3addb 100644
--- a/sc/inc/conditio.hxx
+++ b/sc/inc/conditio.hxx
@@ -208,7 +208,7 @@ class ScConditionalFormat;
 struct ScDataBarInfo;
 struct ScIconSetInfo;
 
-struct ScCondFormatData
+struct SC_DLLPUBLIC ScCondFormatData
 {
     ScCondFormatData();
     ScCondFormatData(ScCondFormatData&&);
diff --git a/sc/qa/unit/data/xlsx/tdf155321.xlsx b/sc/qa/unit/data/xlsx/tdf155321.xlsx
new file mode 100644
index 000000000000..42299ff746cb
--- /dev/null
+++ b/sc/qa/unit/data/xlsx/tdf155321.xlsx
diff --git a/sc/qa/unit/subsequent_filters_test.cxx b/sc/qa/unit/subsequent_filters_test.cxx
index 535afe72d818..d206ce2cbf69 100644
--- a/sc/qa/unit/subsequent_filters_test.cxx
+++ b/sc/qa/unit/subsequent_filters_test.cxx
@@ -123,6 +123,17 @@ void testContentImpl(ScDocument& rDoc, bool bCheckMergedCells)
 }
 }
 
+CPPUNIT_TEST_FIXTURE(ScFiltersTest, testTdf155321_CondFormatColor_XLSX)
+{
+    createScDoc("xlsx/tdf155321.xlsx");
+
+    ScDocument* pDoc = getScDoc();
+    ScConditionalFormat* pCondFormat = pDoc->GetCondFormat(0, 0, 0);
+    ScRefCellValue aCellB1(*pDoc, ScAddress(1, 0, 0));
+    Color aColor = pCondFormat->GetData(aCellB1, ScAddress(1, 0, 0)).mxColorScale.value();
+    CPPUNIT_ASSERT_EQUAL(Color(99, 190, 123), aColor);
+}
+
 CPPUNIT_TEST_FIXTURE(ScFiltersTest, testTdf138601_CondFormatXLSX)
 {
     createScDoc("xlsx/tdf138601.xlsx");
diff --git a/sc/source/core/data/colorscale.cxx b/sc/source/core/data/colorscale.cxx
index 1d713c447c5b..4e61dbdbc228 100644
--- a/sc/source/core/data/colorscale.cxx
+++ b/sc/source/core/data/colorscale.cxx
@@ -657,11 +657,15 @@ std::optional<Color> ScColorScaleFormat::GetColor( const ScAddress& rAddr ) cons
     double nValMax = CalcValue(nMin, nMax, itr);
     Color rColMax = (*itr)->GetColor();
 
+    // tdf#155321 for the last percentile value, use always the end of the color scale,
+    // i.e. not the first possible color in the case of repeating values
+    bool bEqual = COLORSCALE_PERCENTILE == (*itr)->GetType() && nVal == nMax && nVal == nValMax;
+
     ++itr;
-    while(itr != end() && nVal > nValMax)
+    while(itr != end() && (nVal > nValMax || bEqual))
     {
         rColMin = rColMax;
-        nValMin = nValMax;
+        nValMin = !bEqual ? nValMax : nValMax - 1;
         rColMax = (*itr)->GetColor();
         nValMax = CalcValue(nMin, nMax, itr);
         ++itr;