[英]How to get font of widget in Qt set by stylesheet?
I have Qt application with custom stylesheet applied to it (and for all widgets in general) with custom font included in this stylesheet. 我有一个Qt应用程序,该样式表中包括了自定义字体,并且该Qt应用程序已应用了自定义样式表(以及所有普通小部件)。 But when try to get font of some widget
font()
method return different font. 但是,当尝试获取某些小部件
font()
方法的字体时,将返回不同的字体。 I want to get the font of a QWidget
which is set by a stylesheet. 我想获取由样式表设置的
QWidget
的字体。 The font()
method always returns the global system font or the font set by setFont()
, but not the font which is set by setStyleSheet()
and is used for painting in the widget. font()
方法始终返回全局系统字体或setFont()
设置的字体,但不返回setStyleSheet()
设置的,用于在小部件中绘画的字体。 I need the font to do some calculations based on the font size. 我需要字体根据字体大小进行一些计算。 I use Qt 4.6.
我使用Qt 4.6。 How can I get real font of widget (that is showing when application run) set by stylesheet?
如何获得样式表设置的小部件的真实字体(在应用程序运行时显示)?
After some investigations I saw that if I apply defined stylesheet to some widget I can get proper font information (defined by stylesheet) with myWidget->font()
method. 经过一些调查,我发现如果将定义的样式表应用于某些小部件,则可以使用
myWidget->font()
方法获得正确的字体信息(由样式表定义myWidget->font()
。 Also when I set stylesheet to whole MainWindow
I can get proper font information with font()
method for all the widgets that MainWindow
contains. 同样,当我将样式表设置为整个
MainWindow
我可以通过font()
方法获取MainWindow
包含的所有小部件的正确字体信息。 But, when I set stylesheet to instance of QApplication
the font()
method for all the widgets return default font or the font previously set by setFont()
. 但是,当我将样式表设置为
QApplication
的实例时,所有小部件的font()
方法都将返回默认字体或先前由setFont()
设置的字体。 Why so? 为什么这样?
You can retrieve a font of a specific widget reading it's properties, as the following: 您可以读取特定窗口小部件的字体,读取其属性,如下所示:
//Get pushbutton font.
QFont font = ui->pushButton->property("font").value<QFont>();
qDebug() << font.family() << font.pointSize();
//Get MainWindow font.
QFont font2 = property("font").value<QFont>();
qDebug() << font2.family() << font2.pointSize();
To load values from Qt Stylesheet you should call this methods: 要从Qt样式表加载值,您应该调用以下方法:
widget->style()->unpolish(widget);
widget->style()->polish(widget);
widget->update();
After this all values of your widget will be updated according your stylesheet values specified. 此后,将根据指定的样式表值来更新小部件的所有值。
The best I can tell from QStyleSheetStyle::updateStyleSheetFont , the widget always contains the resolved font from the stylesheet. 我可以从QStyleSheetStyle :: updateStyleSheetFont看出来 ,最好的是,小部件始终包含样式表中已解析的字体。 I'd expect
QWidget::font()
to return the resolved font that you've set using the stylesheet - ie the font that is the merged application font, any parent widget fonts, and the stylesheet font. 我希望
QWidget::font()
返回使用样式表设置的已解析字体-即作为合并的应用程序字体,任何父窗口小部件字体和样式表字体的字体。
The widget must be polished first, of course, unless you're querying after the events have been delivered (ie from within the event loop). 当然,必须首先对窗口小部件进行打磨,除非您在事件交付后(即从事件循环内)进行查询。
// https://github.com/KubaO/stackoverflown/tree/master/questions/style-font-query-test-45422885
#include <QtWidgets>
int main(int argc, char ** argv) {
QApplication app{argc, argv};
QLabel label("Test");
auto font1 = label.font();
label.setStyleSheet("font-size: 49pt;");
label.show();
label.ensurePolished();
auto font2 = label.font();
Q_ASSERT(font1.pointSize() != 49);
Q_ASSERT(font2.pointSize() == 49);
Q_ASSERT(font1.family() == font2.family());
}
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