Fix implicitHeight for Text items bindings dependent on implicitWidth.

Recalculate the implicitHeight on the second layout if the width
changes after setting the implicitWidth, and potentially do another
layout if the updating the implicitHeight changes the height.

Change-Id: Ib6a637452013b56dba7ae8a6862cd92156386578
Task-number: QTBUG-45546
Reviewed-by: Michael Brasser <michael.brasser@live.com>
Reviewed-by: Albert Astals Cid <albert.astals@canonical.com>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@theqtcompany.com>

3 files changed, 191 insertions, 0 deletions

diff --git a/src/quick/items/qquicktext.cpp b/src/quick/items/qquicktext.cpp
index c1794697a5..456ec25edd 100644
--- a/src/quick/items/qquicktext.cpp
+++ b/src/quick/items/qquicktext.cpp
@@ -749,6 +749,7 @@ QRectF QQuickTextPrivate::setupTextLayout(qreal *const baseline)
             : largeFont;
     int scaledFontSize = largeFont;
 
+    bool widthChanged = false;
     widthExceeded = q->width() <= 0 && (singlelineElide || canWrap || horizontalFit);
     heightExceeded = q->height() <= 0 && (multilineElide || verticalFit);
 
@@ -945,6 +946,7 @@ QRectF QQuickTextPrivate::setupTextLayout(qreal *const baseline)
             if ((lineWidth < qMin(oldWidth, naturalWidth) || (widthExceeded && lineWidth > oldWidth))
                     && (singlelineElide || multilineElide || canWrap || horizontalFit
                         || q->effectiveHAlign() != QQuickText::AlignLeft)) {
+                widthChanged = true;
                 widthExceeded = false;
                 heightExceeded = false;
                 continue;
@@ -966,6 +968,39 @@ QRectF QQuickTextPrivate::setupTextLayout(qreal *const baseline)
                 heightExceeded = false;
                 continue;
             }
+        } else if (widthChanged) {
+            widthChanged = false;
+            if (line.isValid()) {
+                for (int lineCount = layout.lineCount(); lineCount < maxLineCount; ++lineCount) {
+                    line = layout.createLine();
+                    if (!line.isValid())
+                        break;
+                    setLineGeometry(line, lineWidth, naturalHeight);
+                }
+            }
+            layout.endLayout();
+
+            bool wasInLayout = internalWidthUpdate;
+            internalWidthUpdate = true;
+            q->setImplicitHeight(naturalHeight);
+            internalWidthUpdate = wasInLayout;
+
+            multilineElide = elideMode == QQuickText::ElideRight
+                    && q->widthValid()
+                    && (q->heightValid() || maximumLineCountValid);
+            verticalFit = fontSizeMode() & QQuickText::VerticalFit
+                    && (q->heightValid() || (maximumLineCountValid && canWrap));
+
+            const qreal oldHeight = maxHeight;
+            maxHeight = q->heightValid() ? q->height() : FLT_MAX;
+            // If the height of the item has changed and it's possible the result of eliding,
+            // line count truncation or scaling has changed, do another layout.
+            if ((maxHeight < qMin(oldHeight, naturalHeight) || (heightExceeded && maxHeight > oldHeight))
+                    && (multilineElide || (canWrap && maximumLineCountValid))) {
+                widthExceeded = false;
+                heightExceeded = false;
+                continue;
+            }
         } else {
             layout.endLayout();
         }
diff --git a/tests/auto/quick/qquicktext/data/implicitSizes.qml b/tests/auto/quick/qquicktext/data/implicitSizes.qml
new file mode 100644
index 0000000000..fae67c0273
--- /dev/null
+++ b/tests/auto/quick/qquicktext/data/implicitSizes.qml
@@ -0,0 +1,99 @@
+import QtQuick 2.0
+
+Rectangle {
+    width: 200
+    height: column.height
+
+    Column {
+        id: column
+        Text {
+            id: reference
+            objectName: "reference"
+
+            wrapMode: Text.Wrap
+            elide: Text.ElideRight
+
+            text: "Lorem ipsum dolor sit amet, consectetur adipiscing elit.
+Integer at ante dui Curabitur ante est, pulvinar quis adipiscing a, iaculis id ipsum. Nunc blandit
+condimentum odio vel egestas. in ipsum lacinia sit amet
+mattis orci interdum. Quisque vitae accumsan lectus. Ut nisi turpis,
+sollicitudin ut dignissim id, fermentum ac est. Maecenas nec libero leo. Sed ac
+mattis orci interdum. Quisque vitae accumsan lectus. Ut nisi turpis,
+sollicitudin ut dignissim id, fermentum ac est. Maecenas nec libero leo. Sed ac
+leo eget ipsum ultricies viverra sit amet eu orci. Praesent et tortor risus,
+viverra accumsan sapien. Sed faucibus eleifend lectus, sed euismod urna porta
+eu. Quisque vitae accumsan lectus."
+        }
+        Text {
+            id: fixedWidthAndHeight
+            objectName: "fixedWidthAndHeight"
+
+            width: 100
+            height: 100
+
+            wrapMode: Text.Wrap
+            elide: Text.ElideRight
+
+            text: reference.text
+        }
+
+        Text {
+            id: implicitWidthFixedHeight
+            objectName: "implicitWidthFixedHeight"
+
+            height: 100
+
+            wrapMode: Text.Wrap
+            elide: Text.ElideRight
+
+            text: reference.text
+        }
+        Text {
+            id: fixedWidthImplicitHeight
+            objectName: "fixedWidthImplicitHeight"
+
+            width: 100
+
+            wrapMode: Text.Wrap
+            elide: Text.ElideRight
+
+            text: reference.text
+        }
+        Text {
+            id: cappedWidthAndHeight
+            objectName: "cappedWidthAndHeight"
+
+            width: Math.min(100, implicitWidth)
+            height: Math.min(100, implicitHeight)
+
+            wrapMode: Text.Wrap
+            elide: Text.ElideRight
+
+            text: reference.text
+        }
+        Text {
+            id: cappedWidthFixedHeight
+            objectName: "cappedWidthFixedHeight"
+
+            width: Math.min(100, implicitWidth)
+            height: 100
+
+            wrapMode: Text.Wrap
+            elide: Text.ElideRight
+
+            text: reference.text
+        }
+        Text {
+            id: fixedWidthCappedHeight
+            objectName: "fixedWidthCappedHeight"
+
+            width: 100
+            height: Math.min(100, implicitHeight)
+
+            wrapMode: Text.Wrap
+            elide: Text.ElideRight
+
+            text: reference.text
+        }
+    }
+}
diff --git a/tests/auto/quick/qquicktext/tst_qquicktext.cpp b/tests/auto/quick/qquicktext/tst_qquicktext.cpp
index f25c09fcd1..eb9f7529fe 100644
--- a/tests/auto/quick/qquicktext/tst_qquicktext.cpp
+++ b/tests/auto/quick/qquicktext/tst_qquicktext.cpp
@@ -106,6 +106,7 @@ private slots:
 
     void implicitSize_data();
     void implicitSize();
+    void dependentImplicitSizes();
     void contentSize();
     void implicitSizeBinding_data();
     void implicitSizeBinding();
@@ -2206,6 +2207,62 @@ void tst_qquicktext::implicitSize()
     delete textObject;
 }
 
+void tst_qquicktext::dependentImplicitSizes()
+{
+    QQmlComponent component(&engine, testFile("implicitSizes.qml"));
+    QScopedPointer<QObject> object(component.create());
+    QVERIFY(object.data());
+
+    QQuickText *reference = object->findChild<QQuickText *>("reference");
+    QQuickText *fixedWidthAndHeight = object->findChild<QQuickText *>("fixedWidthAndHeight");
+    QQuickText *implicitWidthFixedHeight = object->findChild<QQuickText *>("implicitWidthFixedHeight");
+    QQuickText *fixedWidthImplicitHeight = object->findChild<QQuickText *>("fixedWidthImplicitHeight");
+    QQuickText *cappedWidthAndHeight = object->findChild<QQuickText *>("cappedWidthAndHeight");
+    QQuickText *cappedWidthFixedHeight = object->findChild<QQuickText *>("cappedWidthFixedHeight");
+    QQuickText *fixedWidthCappedHeight = object->findChild<QQuickText *>("fixedWidthCappedHeight");
+
+    QVERIFY(reference);
+    QVERIFY(fixedWidthAndHeight);
+    QVERIFY(implicitWidthFixedHeight);
+    QVERIFY(fixedWidthImplicitHeight);
+    QVERIFY(cappedWidthAndHeight);
+    QVERIFY(cappedWidthFixedHeight);
+    QVERIFY(fixedWidthCappedHeight);
+
+    QCOMPARE(reference->width(), reference->implicitWidth());
+    QCOMPARE(reference->height(), reference->implicitHeight());
+
+    QVERIFY(fixedWidthAndHeight->width() < fixedWidthAndHeight->implicitWidth());
+    QVERIFY(fixedWidthAndHeight->height() < fixedWidthAndHeight->implicitHeight());
+    QCOMPARE(fixedWidthAndHeight->implicitWidth(), reference->implicitWidth());
+    QVERIFY(fixedWidthAndHeight->implicitHeight() > reference->implicitHeight());
+
+    QCOMPARE(implicitWidthFixedHeight->width(), implicitWidthFixedHeight->implicitWidth());
+    QVERIFY(implicitWidthFixedHeight->height() < implicitWidthFixedHeight->implicitHeight());
+    QCOMPARE(implicitWidthFixedHeight->implicitWidth(), reference->implicitWidth());
+    QCOMPARE(implicitWidthFixedHeight->implicitHeight(), reference->implicitHeight());
+
+    QVERIFY(fixedWidthImplicitHeight->width() < fixedWidthImplicitHeight->implicitWidth());
+    QCOMPARE(fixedWidthImplicitHeight->height(), fixedWidthImplicitHeight->implicitHeight());
+    QCOMPARE(fixedWidthImplicitHeight->implicitWidth(), reference->implicitWidth());
+    QCOMPARE(fixedWidthImplicitHeight->implicitHeight(), fixedWidthAndHeight->implicitHeight());
+
+    QVERIFY(cappedWidthAndHeight->width() < cappedWidthAndHeight->implicitWidth());
+    QVERIFY(cappedWidthAndHeight->height() < cappedWidthAndHeight->implicitHeight());
+    QCOMPARE(cappedWidthAndHeight->implicitWidth(), reference->implicitWidth());
+    QCOMPARE(cappedWidthAndHeight->implicitHeight(), fixedWidthAndHeight->implicitHeight());
+
+    QVERIFY(cappedWidthFixedHeight->width() < cappedWidthAndHeight->implicitWidth());
+    QVERIFY(cappedWidthFixedHeight->height() < cappedWidthFixedHeight->implicitHeight());
+    QCOMPARE(cappedWidthFixedHeight->implicitWidth(), reference->implicitWidth());
+    QCOMPARE(cappedWidthFixedHeight->implicitHeight(), fixedWidthAndHeight->implicitHeight());
+
+    QVERIFY(fixedWidthCappedHeight->width() < fixedWidthCappedHeight->implicitWidth());
+    QVERIFY(fixedWidthCappedHeight->height() < fixedWidthCappedHeight->implicitHeight());
+    QCOMPARE(fixedWidthCappedHeight->implicitWidth(), reference->implicitWidth());
+    QCOMPARE(fixedWidthCappedHeight->implicitHeight(), fixedWidthAndHeight->implicitHeight());
+}
+
 void tst_qquicktext::contentSize()
 {
     QString componentStr = "import QtQuick 2.0\nText { width: 75; height: 16; font.pixelSize: 10 }";