Fix missing glyphs in selection

Change 198009db79a85d3cab7fe3a6432635d36123a2d6 revealed a bug in the
new selection algorithm which would occur sometimes
when a given run of text spanned several script items. Since we
are checking the glyph runs for overlaps in the actual text, we
need to report the exact characters spanned by the glyph run. We
use the new enabler for this in QGlyphRunPrivate.

Added a new test case which is an error case we did not yet cover,
which is when there is only a single script item, but several
font engines are used to produce it (fallback fonts).

Change-Id: Ie4c3e79ad98a033d5c75fd67ada4ae83df33435b
Task-number: QTBUG-41808
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

3 files changed, 77 insertions, 27 deletions

diff --git a/src/quick/items/qquicktextnodeengine.cpp b/src/quick/items/qquicktextnodeengine.cpp
index f746fe8b1b..67ff79d20f 100644
--- a/src/quick/items/qquicktextnodeengine.cpp
+++ b/src/quick/items/qquicktextnodeengine.cpp
@@ -46,12 +46,37 @@
 #include <private/qtextdocumentlayout_p.h>
 #include <private/qtextimagehandler_p.h>
 #include <private/qrawfont_p.h>
+#include <private/qglyphrun_p.h>
 
 QT_BEGIN_NAMESPACE
 
+QQuickTextNodeEngine::BinaryTreeNode::BinaryTreeNode(const QGlyphRun &g,
+                                                     SelectionState selState,
+                                                     const QRectF &brect,
+                                                     const QQuickTextNode::Decorations &decs,
+                                                     const QColor &c,
+                                                     const QColor &bc,
+                                                     const QPointF &pos, qreal a)
+    : glyphRun(g)
+    , boundingRect(brect)
+    , selectionState(selState)
+    , clipNode(0)
+    , decorations(decs)
+    , color(c)
+    , backgroundColor(bc)
+    , position(pos)
+    , ascent(a)
+    , leftChildIndex(-1)
+    , rightChildIndex(-1)
+{
+    QGlyphRunPrivate *d = QGlyphRunPrivate::get(g);
+    ranges.append(qMakePair(d->textRangeStart, d->textRangeEnd));
+}
+
+
 void QQuickTextNodeEngine::BinaryTreeNode::insert(QVarLengthArray<BinaryTreeNode, 16> *binaryTree, const QGlyphRun &glyphRun, SelectionState selectionState,
                                              QQuickTextNode::Decorations decorations, const QColor &textColor,
-                                             const QColor &backgroundColor, const QPointF &position, int rangeStart, int rangeEnd)
+                                             const QColor &backgroundColor, const QPointF &position)
 {
     QRectF searchRect = glyphRun.boundingRect();
     searchRect.translate(position);
@@ -65,8 +90,14 @@ void QQuickTextNodeEngine::BinaryTreeNode::insert(QVarLengthArray<BinaryTreeNode
     decorations |= (backgroundColor.isValid() ? QQuickTextNode::Background : QQuickTextNode::NoDecoration);
 
     qreal ascent = glyphRun.rawFont().ascent();
-    insert(binaryTree, BinaryTreeNode(glyphRun, selectionState, searchRect, decorations,
-                                      textColor, backgroundColor, position, ascent, rangeStart, rangeEnd));
+    insert(binaryTree, BinaryTreeNode(glyphRun,
+                                      selectionState,
+                                      searchRect,
+                                      decorations,
+                                      textColor,
+                                      backgroundColor,
+                                      position,
+                                      ascent));
 }
 
 void QQuickTextNodeEngine::BinaryTreeNode::insert(QVarLengthArray<BinaryTreeNode, 16> *binaryTree, const BinaryTreeNode &binaryTreeNode)
@@ -441,19 +472,27 @@ void QQuickTextNodeEngine::addTextObject(const QPointF &position, const QTextCha
     }
 }
 
-void QQuickTextNodeEngine::addUnselectedGlyphs(const QGlyphRun &glyphRun, int rangeStart, int rangeEnd)
+void QQuickTextNodeEngine::addUnselectedGlyphs(const QGlyphRun &glyphRun)
 {
-    BinaryTreeNode::insert(&m_currentLineTree, glyphRun, Unselected,
-                           QQuickTextNode::NoDecoration, m_textColor, m_backgroundColor, m_position,
-                           rangeStart, rangeEnd);
+    BinaryTreeNode::insert(&m_currentLineTree,
+                           glyphRun,
+                           Unselected,
+                           QQuickTextNode::NoDecoration,
+                           m_textColor,
+                           m_backgroundColor,
+                           m_position);
 }
 
-void QQuickTextNodeEngine::addSelectedGlyphs(const QGlyphRun &glyphRun, int rangeStart, int rangeEnd)
+void QQuickTextNodeEngine::addSelectedGlyphs(const QGlyphRun &glyphRun)
 {
     int currentSize = m_currentLineTree.size();
-    BinaryTreeNode::insert(&m_currentLineTree, glyphRun, Selected,
-                           QQuickTextNode::NoDecoration, m_textColor, m_backgroundColor, m_position,
-                           rangeStart, rangeEnd);
+    BinaryTreeNode::insert(&m_currentLineTree,
+                           glyphRun,
+                           Selected,
+                           QQuickTextNode::NoDecoration,
+                           m_textColor,
+                           m_backgroundColor,
+                           m_position);
     m_hasSelection = m_hasSelection || m_currentLineTree.size() > currentSize;
 }
 
@@ -526,7 +565,7 @@ void QQuickTextNodeEngine::addGlyphsInRange(int rangeStart, int rangeLength,
         QList<QGlyphRun> glyphRuns = line.glyphRuns(rangeStart, rangeLength);
         for (int j=0; j<glyphRuns.size(); ++j) {
             const QGlyphRun &glyphRun = glyphRuns.at(j);
-            addUnselectedGlyphs(glyphRun, rangeStart, rangeEnd - 1);
+            addUnselectedGlyphs(glyphRun);
         }
     } else {
         if (rangeStart < selectionStart) {
@@ -534,7 +573,7 @@ void QQuickTextNodeEngine::addGlyphsInRange(int rangeStart, int rangeLength,
             QList<QGlyphRun> glyphRuns = line.glyphRuns(rangeStart, length);
             for (int j=0; j<glyphRuns.size(); ++j) {
                 const QGlyphRun &glyphRun = glyphRuns.at(j);
-                addUnselectedGlyphs(glyphRun, rangeStart, rangeStart + length - 1);
+                addUnselectedGlyphs(glyphRun);
             }
         }
 
@@ -545,8 +584,8 @@ void QQuickTextNodeEngine::addGlyphsInRange(int rangeStart, int rangeLength,
 
             for (int j=0; j<glyphRuns.size(); ++j) {
                 const QGlyphRun &glyphRun = glyphRuns.at(j);
-                addSelectedGlyphs(glyphRun, start, start + length - 1);
-                addUnselectedGlyphs(glyphRun, start, start + length - 1);
+                addSelectedGlyphs(glyphRun);
+                addUnselectedGlyphs(glyphRun);
             }
         }
 
@@ -556,7 +595,7 @@ void QQuickTextNodeEngine::addGlyphsInRange(int rangeStart, int rangeLength,
             QList<QGlyphRun> glyphRuns = line.glyphRuns(start, length);
             for (int j=0; j<glyphRuns.size(); ++j) {
                 const QGlyphRun &glyphRun = glyphRuns.at(j);
-                addUnselectedGlyphs(glyphRun, start, start + length - 1);
+                addUnselectedGlyphs(glyphRun);
             }
         }
     }
@@ -927,7 +966,7 @@ void QQuickTextNodeEngine::addTextBlock(QTextDocument *textDocument, const QText
 
             QList<QGlyphRun> glyphRuns = layout.glyphRuns();
             for (int i=0; i<glyphRuns.size(); ++i)
-                addUnselectedGlyphs(glyphRuns.at(i), 0, layout.text().length() - 1);
+                addUnselectedGlyphs(glyphRuns.at(i));
         }
     }
 
diff --git a/src/quick/items/qquicktextnodeengine_p.h b/src/quick/items/qquicktextnodeengine_p.h
index 142375b5a3..f0d52683c6 100644
--- a/src/quick/items/qquicktextnodeengine_p.h
+++ b/src/quick/items/qquicktextnodeengine_p.h
@@ -75,12 +75,7 @@ public:
 
         BinaryTreeNode(const QGlyphRun &g, SelectionState selState, const QRectF &brect,
                        const QQuickTextNode::Decorations &decs, const QColor &c, const QColor &bc,
-                       const QPointF &pos, qreal a, int rangeStart, int rangeEnd)
-            : glyphRun(g), boundingRect(brect), selectionState(selState), clipNode(0), decorations(decs)
-            , color(c), backgroundColor(bc), position(pos), ascent(a), leftChildIndex(-1), rightChildIndex(-1)
-        {
-            ranges.append(qMakePair(rangeStart, rangeEnd));
-        }
+                       const QPointF &pos, qreal a);
 
         QGlyphRun glyphRun;
         QRectF boundingRect;
@@ -102,8 +97,7 @@ public:
         { insert(binaryTree, BinaryTreeNode(rect, image, selectionState, ascent)); }
 
         static void insert(QVarLengthArray<BinaryTreeNode, 16> *binaryTree, const QGlyphRun &glyphRun, SelectionState selectionState,
-                           QQuickTextNode::Decorations decorations, const QColor &textColor, const QColor &backgroundColor, const QPointF &position,
-                           int rangeStart, int rangeEnd);
+                           QQuickTextNode::Decorations decorations, const QColor &textColor, const QColor &backgroundColor, const QPointF &position);
         static void insert(QVarLengthArray<BinaryTreeNode, 16> *binaryTree, const BinaryTreeNode &binaryTreeNode);
         static void inOrder(const QVarLengthArray<BinaryTreeNode, 16> &binaryTree, QVarLengthArray<int> *sortedIndexes, int currentIndex = 0);
     };
@@ -138,8 +132,8 @@ public:
                        SelectionState selectionState,
                        QTextDocument *textDocument, int pos,
                        QTextFrameFormat::Position layoutPosition = QTextFrameFormat::InFlow);
-    void addSelectedGlyphs(const QGlyphRun &glyphRun, int rangeStart, int rangeEnd);
-    void addUnselectedGlyphs(const QGlyphRun &glyphRun, int rangeStart, int rangeEnd);
+    void addSelectedGlyphs(const QGlyphRun &glyphRun);
+    void addUnselectedGlyphs(const QGlyphRun &glyphRun);
     void addGlyphsInRange(int rangeStart, int rangeEnd,
                           const QColor &color, const QColor &backgroundColor,
                           int selectionStart, int selectionEnd);
diff --git a/tests/manual/scenegraph_lancelot/data/text/textinput_selected_fallback_font.qml b/tests/manual/scenegraph_lancelot/data/text/textinput_selected_fallback_font.qml
new file mode 100644
index 0000000000..2c5b152ea1
--- /dev/null
+++ b/tests/manual/scenegraph_lancelot/data/text/textinput_selected_fallback_font.qml
@@ -0,0 +1,17 @@
+import QtQuick 2.0
+
+Item {
+    width: 320
+    height: 480
+    TextInput {
+        anchors.centerIn: parent
+        id: textInput
+        font.family: "Arial"
+        font.pixelSize: 14
+        text: "∯AA≨"
+
+        Component.onCompleted: {
+            textInput.select(2, 4)
+        }
+    }
+}