From ece70ccba8718804bf8f42dafdcda00f8caa4d1a Mon Sep 17 00:00:00 2001
From: Andrew den Exter <andrew.den-exter@nokia.com>
Date: Wed, 15 Feb 2012 11:40:59 +1000
Subject: [PATCH] Avoid an unnecessary layout when eliding text.
Query the elided text from the initial layout rather than doing a
second layout of the line to be elided.
Change-Id: I399f99a11046013c0c51add2e2f2dd14b959831a
Reviewed-by: Martin Jones <martin.jones@nokia.com>
---
src/quick/items/qquicktext.cpp | 83 +++++++++++++++++++++++---------
src/quick/items/qquicktext_p_p.h | 1 +
2 files changed, 62 insertions(+), 22 deletions(-)
diff --git a/src/quick/items/qquicktext.cpp b/src/quick/items/qquicktext.cpp
index 241086cc83..ce030938a9 100644
--- a/src/quick/items/qquicktext.cpp
+++ b/src/quick/items/qquicktext.cpp
@@ -589,6 +589,28 @@ void QQuickTextPrivate::setupCustomLineGeometry(QTextLine &line, qreal &height,
#endif
}
+QString QQuickTextPrivate::elidedText(int lineWidth, const QTextLine &line, QTextLine *nextLine) const
+{
+ if (nextLine) {
+ nextLine->setLineWidth(INT_MAX);
+ return layout.engine()->elidedText(
+ Qt::TextElideMode(elideMode),
+ lineWidth,
+ 0,
+ line.textStart(),
+ line.textLength() + nextLine->textLength());
+ } else {
+ QString elideText = layout.text().mid(line.textStart(), line.textLength());
+ elideText[elideText.length() - 1] = elideChar;
+ // Appending the elide character may push the line over the maximum width
+ // in which case the elided text will need to be elided.
+ QFontMetricsF metrics(layout.font());
+ if (metrics.width(elideChar) + line.naturalTextWidth() >= lineWidth)
+ elideText = metrics.elidedText(elideText, Qt::TextElideMode(elideMode), lineWidth);
+ return elideText;
+ }
+}
+
/*!
Lays out the QQuickTextPrivate::layout QTextLayout in the constraints of the QQuickText.
@@ -677,6 +699,8 @@ QRect QQuickTextPrivate::setupTextLayout()
int eos = multilengthEos;
+ // Repeated layouts with reduced font sizes or abbreviated strings may be required if the text
+ // doesn't fit within the element dimensions.
for (;;) {
if (!once) {
if (pixelSize)
@@ -705,22 +729,25 @@ QRect QQuickTextPrivate::setupTextLayout()
setLineGeometry(line, lineWidth, height);
}
+ // Elide the previous line if the accumulated height of the text exceeds the height
+ // of the element.
if (multilineElide && height > q->height() && visibleCount > 1) {
+ elide = true;
+ if (eos != -1) // There's an abbreviated string available, skip the rest as it's
+ break; // all going to be discarded.
+
truncated = true;
truncateHeight = true;
height = preLayoutHeight;
- elide = true;
characterCount = line.textStart() + line.textLength();
QTextLine previousLine = layout.lineAt(visibleCount - 2);
- elideText = layoutText.mid(previousLine.textStart(), previousLine.textLength());
- if (layoutText.at(line.textStart() - 1) != QChar::LineSeparator) {
- line.setLineWidth(INT_MAX);
- elideText += layoutText.mid(line.textStart(), line.textLength());
- } else {
- elideText[elideText.length() - 1] = elideChar;
- }
+ elideText = layoutText.at(line.textStart() - 1) != QChar::LineSeparator
+ ? elidedText(lineWidth, previousLine, &line)
+ : elidedText(lineWidth, previousLine);
+ // The previous line is the last one visible so move the current one off somewhere
+ // out of the way and back everything up one line.
line.setLineWidth(0);
line.setPosition(QPointF(FLT_MAX, FLT_MAX));
line = previousLine;
@@ -733,10 +760,19 @@ QRect QQuickTextPrivate::setupTextLayout()
if (!nextLine.isValid()) {
characterCount = line.textStart() + line.textLength();
if (singlelineElide && visibleCount == 1 && line.naturalTextWidth() > lineWidth) {
+ // Elide a single line of text if its width exceeds the element width.
+ elide = true;
+ if (eos != -1) // There's an abbreviated string available.
+ break;
+
truncated = true;
height = preLayoutHeight;
- elide = true;
- elideText = layoutText.mid(line.textStart(), line.textLength());
+ elideText = layout.engine()->elidedText(
+ Qt::TextElideMode(elideMode),
+ lineWidth,
+ 0,
+ line.textStart(),
+ line.textLength());
} else {
br = br.united(line.naturalTextRect());
}
@@ -748,21 +784,20 @@ QRect QQuickTextPrivate::setupTextLayout()
if (!wrappedLine)
++unwrappedLineCount;
+ // Stop if the maximum number of lines has been reached and elide the last line
+ // if enabled.
if (visibleCount == maximumLineCount) {
truncated = true;
characterCount = nextLine.textStart() + nextLine.textLength();
if (multilineElide) {
- height = preLayoutHeight;
elide = true;
- elideText = layoutText.mid(line.textStart(), line.textLength());
- if (wrappedLine) {
- nextLine.setLineWidth(INT_MAX);
- elideText += layoutText.mid(nextLine.textStart(), nextLine.textLength());
- } else {
- elideText[elideText.length() - 1] = elideChar;
- }
- elideText += elideChar;
+ if (eos != -1) // There's an abbreviated string available
+ break;
+ height = preLayoutHeight;
+ elideText = wrappedLine
+ ? elidedText(lineWidth, line, &nextLine)
+ : elidedText(lineWidth, line);
} else {
br = br.united(line.naturalTextRect());
}
@@ -778,6 +813,7 @@ QRect QQuickTextPrivate::setupTextLayout()
layout.endLayout();
br.moveTop(0);
+ // Save the implicitWidth of the text on the first layout only.
if (once) {
naturalWidth = layout.maximumWidth();
once = false;
@@ -799,6 +835,8 @@ QRect QQuickTextPrivate::setupTextLayout()
}
}
+ // If the next needs to be elided and there's an abbreviated string available
+ // go back and do another layout with the abbreviated string.
if (eos != -1 && elide) {
int start = eos + 1;
eos = text.indexOf(QLatin1Char('\x9c'), start);
@@ -809,6 +847,10 @@ QRect QQuickTextPrivate::setupTextLayout()
continue;
}
+ if (!horizontalFit && !verticalFit)
+ break;
+
+ // Try and find a font size that better fits the dimensions of the element.
QRectF unelidedRect = br.united(line.naturalTextRect());
if (horizontalFit) {
@@ -840,8 +882,6 @@ QRect QQuickTextPrivate::setupTextLayout()
}
}
- if (!horizontalFit && !verticalFit)
- break;
}
if (eos != multilengthEos)
@@ -853,7 +893,6 @@ QRect QQuickTextPrivate::setupTextLayout()
elideLayout->setFont(layout.font());
elideLayout->setTextOption(layout.textOption());
elideLayout->setText(elideText);
- elideLayout->setText(elideLayout->engine()->elidedText(Qt::TextElideMode(elideMode), lineWidth));
elideLayout->beginLayout();
QTextLine elidedLine = elideLayout->createLine();
diff --git a/src/quick/items/qquicktext_p_p.h b/src/quick/items/qquicktext_p_p.h
index 0a7fc743b5..a03b403879 100644
--- a/src/quick/items/qquicktext_p_p.h
+++ b/src/quick/items/qquicktext_p_p.h
@@ -83,6 +83,7 @@ public:
QTextDocument *textDocument();
bool isLineLaidOutConnected();
void setLineGeometry(QTextLine &line, qreal lineWidth, qreal &height);
+ QString elidedText(int lineWidth, const QTextLine &line, QTextLine *nextLine = 0) const;
QString text;
QUrl baseUrl;
--
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