tdf#88827 - double-thin border: MINGAPWIDTH is a valid width

double-thin borders are available in the UI starting from 0.5pt.
The actual minumum (as seen in a round-trip), is 1.10pt.
(Each thin line is ~ .50pt, the gap is ~ .05pt, and then some
approximations and rounding show it as 1.10 - at least that is how I
understood it). 1.15pt is the first point at which the gap is larger
than the minimum - and double_thins with a minimum gap were considered
invalid, and thus were not imported.

With this fix, double-thin borders created with a size less than 1.15pt
are valid and visible on import.

Change-Id: I6da2a40d13ed83281de403b22b3acbea4288ac60
Reviewed-on: https://gerrit.libreoffice.org/30857Reviewed-by: Justin Luth <justin_luth@sil.org>
Tested-by: Justin Luth <justin_luth@sil.org>

sc/qa/unit/subsequent_export-test.cxx

@@ -1949,8 +1949,8 @@ void ScExportTest::testBordersExchangeXLSX()
 /* 0,05 */   {{Solid   , Solid   ,  1,  1}, {Dotted  , Dotted  , 15, 15}, {Dotted  , Dotted  , 15, 15}, {FineDash, FineDash, 15, 15}, {FineDash, FineDash, 15, 15}, {FineDash, FineDash, 15, 15}, {None    , None    ,  0,  0}},
 /* 0,25 */   {{Solid   , Solid   ,  1,  1}, {Dotted  , Dotted  , 15, 15}, {Dotted  , Dotted  , 15, 15}, {FineDash, FineDash, 15, 15}, {FineDash, FineDash, 15, 15}, {FineDash, FineDash, 15, 15}, {None    , None    ,  0,  0}},
 /* 0,50 */   {{Solid   , Solid   ,  1,  1}, {Dotted  , Dotted  , 15, 15}, {Dotted  , Dotted  , 15, 15}, {FineDash, FineDash, 15, 15}, {FineDash, FineDash, 15, 15}, {FineDash, FineDash, 15, 15}, {None    , None    ,  0,  0}},
-/* 0,75 */   {{Solid   , Solid   , 15, 15}, {Dotted  , Dotted  , 15, 15}, {FineDash, FineDash, 15, 15}, {FineDash, FineDash, 15, 15}, {DashDot , DashDot , 15, 15}, {DashDoDo, DashDoDo, 15, 15}, {None    , None    ,  0,  0}},
-/* 1,00 */   {{Solid   , Solid   , 15, 15}, {Dotted  , Dotted  , 15, 15}, {FineDash, FineDash, 15, 15}, {FineDash, FineDash, 15, 15}, {DashDot , DashDot , 15, 15}, {DashDoDo, DashDoDo, 15, 15}, {None    , None    ,  0,  0}},
+/* 0,75 */   {{Solid   , Solid   , 15, 15}, {Dotted  , Dotted  , 15, 15}, {FineDash, FineDash, 15, 15}, {FineDash, FineDash, 15, 15}, {DashDot , DashDot , 15, 15}, {DashDoDo, DashDoDo, 15, 15}, {DoubThin, DoubThin, 35, 35}},
+/* 1,00 */   {{Solid   , Solid   , 15, 15}, {Dotted  , Dotted  , 15, 15}, {FineDash, FineDash, 15, 15}, {FineDash, FineDash, 15, 15}, {DashDot , DashDot , 15, 15}, {DashDoDo, DashDoDo, 15, 15}, {DoubThin, DoubThin, 35, 35}},
 /* 1,25 */   {{Solid   , Solid   , 15, 15}, {Dotted  , Dotted  , 15, 15}, {FineDash, FineDash, 15, 15}, {FineDash, FineDash, 15, 15}, {DashDot , DashDot , 15, 15}, {DashDoDo, DashDoDo, 15, 15}, {DoubThin, DoubThin, 35, 35}},
 /* 1,50 */   {{Solid   , Solid   , 15, 15}, {Dotted  , Dotted  , 15, 15}, {FineDash, FineDash, 15, 15}, {FineDash, FineDash, 15, 15}, {DashDot , DashDot , 15, 15}, {DashDoDo, DashDoDo, 15, 15}, {DoubThin, DoubThin, 35, 35}},
 
@@ -1982,8 +1982,8 @@ void ScExportTest::testBordersExchangeXLSX()
             const editeng::SvxBorderLine* pLineTop    = nullptr;
             const editeng::SvxBorderLine* pLineBottom = nullptr;
             rDoc.GetBorderLines(nCol + 2, (nRow * 2) + 8, 0, nullptr, &pLineTop, nullptr, &pLineBottom);
-            if((nCol < 5) && (nRow == 6))
-            {   // in this range no lines
+            if((nCol < 3) && (nRow == 6))
+            {   // in this range no lines since minimum size to create a double is 0.5
                 CPPUNIT_ASSERT(!pLineTop);
                 CPPUNIT_ASSERT(!pLineBottom);
                 continue;

sc/qa/unit/subsequent_filters-test.cxx

@@ -136,6 +136,7 @@ public:
     // void testFormatsXLSX();
     void testMatrixODS();
     void testMatrixXLS();
+    void testDoubleThinBorder();
     void testBorderODS();
     void testBordersOoo33();
     void testBugFixesODS();
@@ -262,6 +263,7 @@ public:
 //  CPPUNIT_TEST(testFormatsXLSX); TODO: Fix this
     CPPUNIT_TEST(testMatrixODS);
     CPPUNIT_TEST(testMatrixXLS);
+    CPPUNIT_TEST(testDoubleThinBorder);
     CPPUNIT_TEST(testBorderODS);
     CPPUNIT_TEST(testBordersOoo33);
     CPPUNIT_TEST(testBugFixesODS);
@@ -915,6 +917,25 @@ void ScFiltersTest::testMatrixXLS()
     xDocSh->DoClose();
 }
 
+void ScFiltersTest::testDoubleThinBorder()
+{
+// double-thin borders created with size less than 1.15 where invisible (and subsequently lost) on round-trips.
+    ScDocShellRef xDocSh = loadDoc("tdf88827_borderDoubleThin.", FORMAT_ODS);
+
+    CPPUNIT_ASSERT_MESSAGE("Failed to load tdf88827_borderDoubleThin.*", xDocSh.Is());
+    ScDocument& rDoc = xDocSh->GetDocument();
+
+    const editeng::SvxBorderLine* pLeft = nullptr;
+    const editeng::SvxBorderLine* pTop = nullptr;
+    const editeng::SvxBorderLine* pRight = nullptr;
+    const editeng::SvxBorderLine* pBottom = nullptr;
+
+    rDoc.GetBorderLines( 2, 2, 0, &pLeft, &pTop, &pRight, &pBottom );
+    CPPUNIT_ASSERT(pTop);
+    CPPUNIT_ASSERT(pRight);
+    CPPUNIT_ASSERT_EQUAL( table::BorderLineStyle::DOUBLE_THIN, pRight->GetBorderLineStyle() );
+}
+
 void ScFiltersTest::testBorderODS()
 {
     ScDocShellRef xDocSh = loadDoc("border.", FORMAT_ODS);

svtools/source/control/ctrlbox.cxx

@@ -170,7 +170,7 @@ long BorderWidthImpl::GuessWidth( long nLine1, long nLine2, long nGap )
 
     bool bGapChange = bool( m_nFlags & BorderWidthImplFlags::CHANGE_DIST );
     double nWidthGap = lcl_getGuessedWidth( nGap, m_nRateGap, bGapChange );
-    if ( bGapChange && nGap > MINGAPWIDTH )
+    if ( bGapChange && nGap >= MINGAPWIDTH )
         aToCompare.push_back( nWidthGap );
     else if ( !bGapChange && nWidthGap < 0 )
         bInvalid = true;