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>

1 files changed, 35 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();
         }