From 33f9591e378a2162378d8be5e75a47adf034536b Mon Sep 17 00:00:00 2001 From: Volker Hilsheimer Date: Fri, 16 Jul 2021 13:44:19 +0200 Subject: [PATCH] Implement missing support for 'em' and 'ex' lengths in style sheet The Qt style sheet reference claimed that Length properties can be specified in 'em' or 'ex' units, but that was never implemented. Add the missing implementation. Since the sizes depend on the size of the font of the current element, we cannot convert the units in the CSS parser, but have to do so in the QRenderRule constructor, where we can make a decision about which font to use if the style sheet itself doesn't specify a font. Fall back to the widget font if possible; otherwise it will be the application default font. The implementation translates em into QFontMetrics.height, identical to what is already done in the QCssParser. This is in line with the CSS specification, but contradicts our previous documentation which stated that 'em' means "width of M". Fix the documentation. Fixes: QTBUG-8096 Pick-to: 6.2 Change-Id: I145e2504ae3b19101a0d0dd63653466b6c2cec1d Done-with: Cristian Maureira-Fredes Reviewed-by: Cristian Maureira-Fredes Reviewed-by: Richard Moe Gustavsen --- .../src/widgets-and-layouts/stylesheet.qdoc | 3 +- src/widgets/styles/qstylesheetstyle.cpp | 72 +++++++++++++------ .../qstylesheetstyle/tst_qstylesheetstyle.cpp | 28 ++++++++ 3 files changed, 80 insertions(+), 23 deletions(-) diff --git a/src/widgets/doc/src/widgets-and-layouts/stylesheet.qdoc b/src/widgets/doc/src/widgets-and-layouts/stylesheet.qdoc index f4edfb92dc..44f20ca0ae 100644 --- a/src/widgets/doc/src/widgets-and-layouts/stylesheet.qdoc +++ b/src/widgets/doc/src/widgets-and-layouts/stylesheet.qdoc @@ -3027,7 +3027,8 @@ \list \li \c px: pixels \li \c pt: the size of one point (i.e., 1/72 of an inch) - \li \c em: the em width of the font (i.e., the width of 'M') + \li \c em: the size relative to the font size of the element + (e.g., 2em means 2 times the size of the font) \li \c ex: the x-height of the font (i.e., the height of 'x') \endlist diff --git a/src/widgets/styles/qstylesheetstyle.cpp b/src/widgets/styles/qstylesheetstyle.cpp index bc23dfd6ac..d5eafa2e9d 100644 --- a/src/widgets/styles/qstylesheetstyle.cpp +++ b/src/widgets/styles/qstylesheetstyle.cpp @@ -1051,31 +1051,59 @@ QRenderRule::QRenderRule(const QList &declarations, const QObject * for (int i = 0; i < numKnownStyleHints; i++) { QLatin1String styleHint(knownStyleHints[i]); if (decl.d->property.compare(styleHint) == 0) { - QString hintName = QString(styleHint); - QVariant hintValue; - if (hintName.endsWith(QLatin1String("alignment"))) { - hintValue = (int) decl.alignmentValue(); - } else if (hintName.endsWith(QLatin1String("color"))) { - hintValue = (int) decl.colorValue().rgba(); - } else if (hintName.endsWith(QLatin1String("size"))) { - hintValue = decl.sizeValue(); - } else if (hintName.endsWith(QLatin1String("icon"))) { - hintValue = decl.iconValue(); - } else if (hintName == QLatin1String("button-layout") - && decl.d->values.count() != 0 && decl.d->values.at(0).type == Value::String) { - hintValue = subControlLayout(decl.d->values.at(0).variant.toString()); - } else { - int integer; - decl.intValue(&integer); - hintValue = integer; - } - styleHints[decl.d->property] = hintValue; - knownStyleHint = true; - break; + QString hintName = QString(styleHint); + QVariant hintValue; + if (hintName.endsWith(QLatin1String("alignment"))) { + hintValue = (int) decl.alignmentValue(); + } else if (hintName.endsWith(QLatin1String("color"))) { + hintValue = (int) decl.colorValue().rgba(); + } else if (hintName.endsWith(QLatin1String("size"))) { + // Check only for the 'em' case + const QString valueString = decl.d->values.at(0).variant.toString(); + const bool isEmSize = valueString.endsWith(u"em", Qt::CaseInsensitive); + if (isEmSize || valueString.endsWith(u"ex", Qt::CaseInsensitive)) { + // 1em == size of font; 1ex == xHeight of font + // See lengthValueFromData helper in qcssparser.cpp + QFont fontForSize(font); + // if no font is specified, then use the widget font if possible + if (const QWidget *widget; !hasFont && (widget = qobject_cast(object))) + fontForSize = widget->font(); + + const QFontMetrics fontMetrics(fontForSize); + qreal pixelSize = isEmSize ? fontMetrics.height() : fontMetrics.xHeight(); + + // Transform size according to the 'em'/'ex' value + qreal emexSize = {}; + if (decl.realValue(&emexSize, isEmSize ? "em" : "ex") && emexSize > 0) { + pixelSize *= emexSize; + const QSizeF newSize(pixelSize, pixelSize); + decl.d->parsed = QVariant::fromValue(newSize); + hintValue = newSize; + } else { + qWarning("Invalid '%s' size for %s. Skipping.", + isEmSize ? "em" : "ex", qPrintable(valueString)); + } + } else { + // Normal case where we receive a 'px' or 'pt' unit + hintValue = decl.sizeValue(); + } + } else if (hintName.endsWith(QLatin1String("icon"))) { + hintValue = decl.iconValue(); + } else if (hintName == QLatin1String("button-layout") + && decl.d->values.count() != 0 && decl.d->values.at(0).type == Value::String) { + hintValue = subControlLayout(decl.d->values.at(0).variant.toString()); + } else { + int integer; + decl.intValue(&integer); + hintValue = integer; + } + styleHints[decl.d->property] = hintValue; + knownStyleHint = true; + break; } } if (!knownStyleHint) - qDebug("Unknown property %s", qPrintable(decl.d->property)); + qWarning("Unknown property %s", qPrintable(decl.d->property)); } } diff --git a/tests/auto/widgets/styles/qstylesheetstyle/tst_qstylesheetstyle.cpp b/tests/auto/widgets/styles/qstylesheetstyle/tst_qstylesheetstyle.cpp index 63db23f3b0..272c175042 100644 --- a/tests/auto/widgets/styles/qstylesheetstyle/tst_qstylesheetstyle.cpp +++ b/tests/auto/widgets/styles/qstylesheetstyle/tst_qstylesheetstyle.cpp @@ -2352,12 +2352,40 @@ void tst_QStyleSheetStyle::iconSizes_data() smallFont.setPointSizeF(9.0); QFont largeFont; largeFont.setPointSizeF(24.0); + QFont hugeFont; + hugeFont.setPointSizeF(40.0); QTest::addRow("default") << QString() << QFont() << QSize(defaultSize, defaultSize); QTest::addRow("pixels") << "icon-size: 50px" << QFont() << QSize(50, 50); QTest::addRow("points") << "icon-size: 20pt" << QFont() << QSize(15, 15); QTest::addRow("pixels with font") << "icon-size: 50px" << smallFont << QSize(50, 50); QTest::addRow("points with font") << "icon-size: 20pt" << largeFont << QSize(15, 15); + + const QFontMetrics defaultMetrics{QFont()}; + const QFontMetrics smallMetrics(smallFont); + const QFontMetrics largeMetrics(largeFont); + const QFontMetrics hugeMetrics(hugeFont); + QTest::addRow("1em, default font") << "icon-size: 1em" + << QFont() << QSize(defaultMetrics.height(), defaultMetrics.height()); + QTest::addRow("1em, small font") << "icon-size: 1em" + << smallFont << QSize(smallMetrics.height(), smallMetrics.height()); + QTest::addRow("1em, large font") << "icon-size: 1em" + << largeFont << QSize(largeMetrics.height(), largeMetrics.height()); + QTest::addRow("1.5em, lage font") << "icon-size: 1.5em" + << largeFont << QSize(largeMetrics.height(), largeMetrics.height()) * 1.5; + QTest::addRow("2em with styled font") << "font-size: 40pt; icon-size: 2em" + << QFont() << QSize(hugeMetrics.height(), hugeMetrics.height()) * 2; + + QTest::addRow("1ex, default font") << "icon-size: 1ex" + << QFont() << QSize(defaultMetrics.xHeight(), defaultMetrics.xHeight()); + QTest::addRow("1ex, small font") << "icon-size: 1ex" + << smallFont << QSize(smallMetrics.xHeight(), smallMetrics.xHeight()); + QTest::addRow("1ex, large font") << "icon-size: 1ex" + << largeFont << QSize(largeMetrics.xHeight(), largeMetrics.xHeight()); + QTest::addRow("1.5ex, lage font") << "icon-size: 1.5ex" + << largeFont << QSize(largeMetrics.xHeight(), largeMetrics.xHeight()) * 1.5; + QTest::addRow("2ex with styled font") << "font-size: 40pt; icon-size: 2ex" + << QFont() << QSize(hugeMetrics.xHeight(), hugeMetrics.xHeight()) * 2; } void tst_QStyleSheetStyle::iconSizes()