tdf#144961 vcl: fix CJK matching in FindFontFamilyByAttributes

Whilst testing CJK matching, I uncovered an issue. The matching
algorithm detects that the font is a CJK font if there are any CJK
characters in the font name. However, if you searched for a CJK font
against a font that was not a CJK font (i.e. the family name had no
CJK characters) then it would still match against this font family.

We now check if the font being matched against was a CJK font family
or not, if not then I reduced the testMatch value by CJK_MATCH_VALUE.

The fix can be tested with:

    make CPPUNIT_TEST_NAME=testShouldNotFindCJKFamily -sr \
        CppunitTest_vcl_font

Without the fix in place, the test fails with:

Test name: VclPhysicalFontCollectionTest::testShouldNotFindCJKFamily
assertion failed
- Expression: !aFontCollection.FindFontFamilyByAttributes( ImplFontAttrs::CJK, WEIGHT_NORMAL, WIDTH_NORMAL, ITALIC_NONE, "")
- family found

Change-Id: I18b246f151b2174dc4ae0f5507630a4e8e4bb442
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/123309
Tested-by: Jenkins
Reviewed-by: Hossein <hossein@libreoffice.org>

2 files changed, 31 insertions, 7 deletions

diff --git a/vcl/qa/cppunit/physicalfontcollection.cxx b/vcl/qa/cppunit/physicalfontcollection.cxx
index a147fb1dea4f..7df20ce76b66 100644
--- a/vcl/qa/cppunit/physicalfontcollection.cxx
+++ b/vcl/qa/cppunit/physicalfontcollection.cxx
@@ -35,6 +35,7 @@ public:
     void testShouldFindFontFamilyByTokenNames();
     void testShouldFindNoFamilyWithWorthlessAttributes();
     void testShouldFindCJKFamily();
+    void testShouldNotFindCJKFamily();
     void testShouldFindStarsymbolFamily();
     void testShouldFindOpensymbolFamilyWithMultipleSymbolFamilies();
     void testShouldFindSymboltypeFamily();
@@ -65,6 +66,7 @@ public:
     CPPUNIT_TEST(testShouldFindFontFamilyByTokenNames);
     CPPUNIT_TEST(testShouldFindNoFamilyWithWorthlessAttributes);
     CPPUNIT_TEST(testShouldFindCJKFamily);
+    CPPUNIT_TEST(testShouldNotFindCJKFamily);
     CPPUNIT_TEST(testShouldFindStarsymbolFamily);
     CPPUNIT_TEST(testShouldFindOpensymbolFamilyWithMultipleSymbolFamilies);
     CPPUNIT_TEST(testShouldFindSymboltypeFamily);
@@ -186,6 +188,18 @@ void VclPhysicalFontCollectionTest::testShouldFindCJKFamily()
                                  pCJKFamily->GetSearchName());
 }
 
+void VclPhysicalFontCollectionTest::testShouldNotFindCJKFamily()
+{
+    vcl::font::PhysicalFontCollection aFontCollection;
+    vcl::font::PhysicalFontFamily* pFontFamily
+        = aFontCollection.FindOrCreateFontFamily(GetEnglishSearchFontName(u"No CJK characters"));
+    AddNormalFontFace(pFontFamily, "No CJK characters");
+
+    CPPUNIT_ASSERT_MESSAGE("family found",
+                           !aFontCollection.FindFontFamilyByAttributes(
+                               ImplFontAttrs::CJK, WEIGHT_NORMAL, WIDTH_NORMAL, ITALIC_NONE, ""));
+}
+
 void VclPhysicalFontCollectionTest::testShouldFindStarsymbolFamily()
 {
     vcl::font::PhysicalFontCollection aFontCollection;
diff --git a/vcl/source/font/PhysicalFontCollection.cxx b/vcl/source/font/PhysicalFontCollection.cxx
index 0cb503a7df54..211e4e65bd57 100644
--- a/vcl/source/font/PhysicalFontCollection.cxx
+++ b/vcl/source/font/PhysicalFontCollection.cxx
@@ -445,13 +445,23 @@ PhysicalFontFamily* PhysicalFontCollection::FindFontFamilyByAttributes(ImplFontA
         // test CJK script attributes
         if ( nSearchType & ImplFontAttrs::CJK )
         {
-            // Matching language
-            if( ImplFontAttrs::None == ((nSearchType ^ nMatchType) & ImplFontAttrs::CJK_AllLang) )
-                nTestMatch += 10000000*3;
-            if( nMatchType & ImplFontAttrs::CJK )
-                nTestMatch += 10000000*2;
-            if( nMatchType & ImplFontAttrs::Full )
-                nTestMatch += 10000000;
+            // if the matching font doesn't support any CJK languages, then
+            // it is not appropriate
+            if ( !(nMatchType & ImplFontAttrs::CJK_AllLang) )
+            {
+                nTestMatch -= 10000000;
+            }
+            else
+            {
+                // Matching language
+                if ( (nSearchType & ImplFontAttrs::CJK_AllLang)
+                    && (nMatchType & ImplFontAttrs::CJK_AllLang) )
+                    nTestMatch += 10000000*3;
+                if ( nMatchType & ImplFontAttrs::CJK )
+                    nTestMatch += 10000000*2;
+                if ( nMatchType & ImplFontAttrs::Full )
+                    nTestMatch += 10000000;
+            }
         }
         else if ( nMatchType & ImplFontAttrs::CJK )
         {