Make HarfBuzz-NG the default shaper on Mac

For AAT shaping support, we need either the pre-QPA shaping trick
or the new HarfBuzz on Mac; prefer the latter.
Disable some test cases aimed to test the HB-old behavior; enable ones
that should guarantee shaping-unaware behavior.

[ChangeLog][OS X] Use CoreText text shaping engine for support of
complex scripts. If required, the shaping engine used in previous
versions can be preferred by configuring Qt with -no-harfbuzz.
Alternatively, the QT_HARFBUZZ environment variable could be set to "old".

Task-number: QTBUG-18980 (relates)
Task-number: QTBUG-38246
Change-Id: Iee6fe4f5bc047e77259182b8585385c5febd02b3
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>

configure

@@ -616,7 +616,7 @@ CFG_EGL=auto
 CFG_EGL_X=auto
 CFG_FONTCONFIG=auto
 CFG_FREETYPE=auto
-CFG_HARFBUZZ=no
+CFG_HARFBUZZ=auto
 CFG_SQL_AVAILABLE=
 QT_ALL_BUILD_PARTS=" libs tools examples tests "
 QT_DEFAULT_BUILD_PARTS="libs tools examples"
@@ -5233,8 +5233,8 @@ if [ "$CFG_FREETYPE" = "auto" ]; then
 fi
 
 # harfbuzz support
-[ "$XPLATFORM_MINGW" = "yes" ] && [ "$CFG_HARFBUZZ" = "auto" ] && CFG_HARFBUZZ=no
 [ "$XPLATFORM_MAC" = "yes" ] && [ "$CFG_HARFBUZZ" = "auto" ] && CFG_HARFBUZZ=yes
+[ "$CFG_HARFBUZZ" = "auto" ] && CFG_HARFBUZZ=no # disable auto-detection on non-Mac for now
 if [ "$CFG_HARFBUZZ" = "auto" ]; then
     if compileTest unix/harfbuzz "HarfBuzz"; then
         CFG_HARFBUZZ=system

src/gui/text/qtextengine.cpp

@@ -1556,8 +1556,10 @@ void QTextEngine::itemize() const
 #ifdef QT_ENABLE_HARFBUZZ_NG
     analysis = scriptAnalysis.data();
     if (useHarfbuzzNG) {
+        // ### pretend HB-old behavior for now
         for (int i = 0; i < length; ++i) {
             switch (analysis[i].script) {
+            case QChar::Script_Latin:
             case QChar::Script_Han:
             case QChar::Script_Hiragana:
             case QChar::Script_Katakana:

tests/auto/gui/text/qtextlayout/tst_qtextlayout.cpp

@@ -309,9 +309,6 @@ void tst_QTextLayout::simpleBoundingRect()
 
 void tst_QTextLayout::threeLineBoundingRect()
 {
-#if defined(Q_OS_MAC)
-    QSKIP("QTestFontEngine on the mac does not support logclusters at the moment");
-#endif
     /* stricter check. break text into three lines */
 
     QString firstWord("hello");
@@ -430,9 +427,6 @@ void tst_QTextLayout::forcedBreaks()
 
 void tst_QTextLayout::breakAny()
 {
-#if defined(Q_OS_MAC)
-    QSKIP("QTestFontEngine on the mac does not support logclusters at the moment");
-#endif
     QString text = "ABCD";
 
     QTextLayout layout(text, testFont);
@@ -473,9 +467,6 @@ void tst_QTextLayout::breakAny()
 
 void tst_QTextLayout::noWrap()
 {
-#if defined(Q_OS_MAC)
-    QSKIP("QTestFontEngine on the mac does not support logclusters at the moment");
-#endif
     QString text = "AB CD";
 
     QTextLayout layout(text, testFont);
@@ -1048,9 +1039,6 @@ void tst_QTextLayout::charWordStopOnLineSeparator()
 
 void tst_QTextLayout::xToCursorAtEndOfLine()
 {
-#if defined(Q_OS_MAC)
-    QSKIP("QTestFontEngine on the mac does not support logclusters at the moment");
-#endif
     QString text = "FirstLine SecondLine";
     text.replace('\n', QChar::LineSeparator);
 
@@ -1112,9 +1100,6 @@ void tst_QTextLayout::graphemeBoundaryForSurrogatePairs()
 
 void tst_QTextLayout::tabStops()
 {
-#if defined(Q_OS_MAC)
-    QSKIP("QTestFontEngine on the mac does not support logclusters at the moment");
-#endif
     QString txt("Hello there\tworld");
     QTextLayout layout(txt, testFont);
     layout.beginLayout();
@@ -1931,13 +1916,16 @@ void tst_QTextLayout::textWithSurrogates_qtbug15679()
 void tst_QTextLayout::textWidthWithStackedTextEngine()
 {
     QString text = QString::fromUtf8("คลิก ถัดไป เพื่อดำเนินการต่อ");
+
     QTextLayout layout(text);
     layout.setCacheEnabled(true);
     layout.beginLayout();
     QTextLine line = layout.createLine();
     layout.endLayout();
-    QFontMetricsF fm(layout.font());
-    QCOMPARE(line.naturalTextWidth(), fm.width(text));
+
+    QStackTextEngine layout2(text, layout.font());
+
+    QVERIFY(layout2.width(0, text.size()).toReal() >= line.naturalTextWidth());
 }
 
 void tst_QTextLayout::textWidthWithLineSeparator()
@@ -1958,27 +1946,24 @@ void tst_QTextLayout::textWidthWithLineSeparator()
 
 void tst_QTextLayout::cursorInLigatureWithMultipleLines()
 {
-#if !defined(Q_OS_MAC)
-    QSKIP("This test can only be run on Mac");
-#endif
     QTextLayout layout("first line finish", QFont("Times", 20));
     layout.setCacheEnabled(true);
     layout.beginLayout();
     QTextLine line = layout.createLine();
-    line.setLineWidth(70);
-    line = layout.createLine();
+    line.setNumColumns(10);
+    QTextLine line2 = layout.createLine();
     layout.endLayout();
 
-    // The second line will be "finish", with "fi" as a ligature
-    QEXPECT_FAIL("", "QTBUG-26403", Abort);
-    QVERIFY(line.cursorToX(0) != line.cursorToX(1));
+    // The second line will be "finish"
+    QCOMPARE(layout.text().mid(line2.textStart(), line2.textLength()), QString::fromLatin1("finish"));
+
+    QVERIFY(line.cursorToX(1) != line.cursorToX(0));
+    QCOMPARE(line2.cursorToX(line2.textStart()), line.cursorToX(0));
+    QCOMPARE(line2.cursorToX(line2.textStart() + 1), line.cursorToX(1));
 }
 
 void tst_QTextLayout::xToCursorForLigatures()
 {
-#if !defined(Q_OS_MAC)
-    QSKIP("This test can only be run on Mac");
-#endif
     QTextLayout layout("fi", QFont("Times", 20));
     layout.setCacheEnabled(true);
     layout.beginLayout();
@@ -2001,9 +1986,6 @@ void tst_QTextLayout::xToCursorForLigatures()
 
 void tst_QTextLayout::cursorInNonStopChars()
 {
-#if defined(Q_OS_MAC)
-    QSKIP("This test can not be run on Mac");
-#endif
     QTextLayout layout(QString::fromUtf8("\xE0\xA4\xA4\xE0\xA5\x8D\xE0\xA4\xA8"));
     layout.setCacheEnabled(true);
     layout.beginLayout();

tests/auto/gui/text/qtextscriptengine/tst_qtextscriptengine.cpp

@@ -1105,6 +1105,9 @@ void tst_QTextScriptEngine::mirroredChars()
 
 void tst_QTextScriptEngine::controlInSyllable_qtbug14204()
 {
+#ifdef Q_OS_MAC
+    QSKIP("Result differs for HarfBuzz-NG, skip test.");
+#endif
     QFontDatabase db;
     if (!db.families().contains(QStringLiteral("Aparajita")))
         QSKIP("couldn't find 'Aparajita' font");
@@ -1143,6 +1146,10 @@ void tst_QTextScriptEngine::combiningMarks_qtbug15675_data()
     QTest::addColumn<QFont>("font");
     QTest::addColumn<QString>("string");
 
+#ifdef Q_OS_MAC
+    QSKIP("Result differs for HarfBuzz-NG, skip test.");
+#endif
+
     bool hasTests = false;
 
     QStringList families;
@@ -1274,13 +1281,22 @@ void tst_QTextScriptEngine::thaiWithZWJ()
         QCOMPARE(logClusters[i], ushort(i));
     for (int i = 0; i < 10; i++)
         QCOMPARE(logClusters[i+7], ushort(0));
+#ifndef Q_OS_MAC
+    // ### Result differs for HarfBuzz-NG
     QCOMPARE(logClusters[17], ushort(1));
+#endif
 
     // A thai implementation could either remove the ZWJ and ZWNJ characters, or hide them.
     // The current implementation hides them, so we test for that.
     // The only characters that we should be hiding are the ZWJ and ZWNJ characters in position 1 and 3.
     const QGlyphLayout glyphLayout = e->layoutData->glyphLayout;
     for (int i = 0; i < 18; i++) {
+#ifdef Q_OS_MAC
+        // ### Result differs for HarfBuzz-NG
+        if (i == 17)
+            QCOMPARE(glyphLayout.advances[i].toInt(), 0);
+        else
+#endif
         if (i == 1 || i == 3)
             QCOMPARE(glyphLayout.advances[i].toInt(), 0);
         else