C++ 在 Qt 中测量文本宽度
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Measuring text width in Qt
提问by Tony the Pony
Using the Qt framework, how do I measure the width (in pixels) of a piece of text rendered with a given font/style?
使用 Qt 框架，如何测量使用给定字体/样式呈现的一段文本的宽度（以像素为单位）？
采纳答案by Sebastien247
Since Qt 5.11 you must use horizontalAdvance()method of QFontMetricsclass instead of width(). width()is now obselete.
从 Qt 5.11 开始，您必须使用类的horizontalAdvance()方法QFontMetrics而不是width(). width()现在已经过时了。
QFont myFont(fontName, fontSize);;
QString str("I wonder how wide this is?");
QFontMetrics fm(myFont);
int width=fm.horizontalAdvance(str);
回答by Paul Dixon
You can use QFontMetricsclass - see the width()method which can give you the width of a given QString.
您可以使用QFontMetrics类 - 请参阅width()方法，它可以为您提供给定 QString 的宽度。
QFont myFont(fontName, fontSize);;
QString str("I wonder how wide this is?");
QFontMetrics fm(myFont);
int width=fm.width(str);
回答by Alexander
In the paintEvent
在paintEvent中
QString text("text");
QFontMetrics fm = painter.fontMetrics();
int width = fm.width(text);
回答by Johannes Schaub - litb
As an addition to the answer by @Paul, I found that when painting text (Qt4.8 on linux), the width of an actually painted text compared to the width of what QFontMetrics::boundingRectreturns is often off. In my cases, the painting was often too wide.
作为@Paul 回答的补充，我发现在绘制文本时（Linux 上的 Qt4.8），实际绘制的文本的宽度与QFontMetrics::boundingRect返回的宽度相比通常是关闭的。就我而言，这幅画通常太宽了。
If you want accurate results when painting text (for example to dimension rectangles you draw around text), better use the boundingRectfunctions provided directly by QPainter.
如果您绘制时文本（例如到尺寸矩形绘制文本周围）要准确的结果，最好使用boundingRect由直接提供的功能QPainter。
