QTextDocument 吃掉多个空格

发布于 2024-09-05 04:31:28 字数 2581 浏览 7 评论 0原文

有一个 Qt/C++ 代码：

#include <QtCore/QCoreApplication>
#include <QtGui/QTextDocument>
#include <QByteArray>
#include <QDebug>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    QTextDocument *doc = new QTextDocument();

    qDebug() << " === Document was: === ";
    qDebug() << doc->toHtml(QByteArray());

    doc->setHtml("<p>THIS       IS      SPARTA</p>");

    qDebug() << " === Document now: === ";
    qDebug() << doc->toHtml(QByteArray());

    return a.exec();
}

它输出：

 === Document was: ===  
"<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd">
<html><head><meta name="qrichtext" content="1" /><style type="text/css">
p, li { white-space: pre-wrap; }
</style></head><body style=" font-family:'Helvetica'; font-size:12pt; font-weight:400; font-style:normal;">
<table style="-qt-table-type: root; margin-top:4px; margin-bottom:4px; margin-left:4px; margin-right:4px;">
<tr>
<td style="border: none;">
<p style="-qt-paragraph-type:empty; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;"></p></td></tr></table></body></html>" 
 === Document now: ===  
"<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd">
<html><head><meta name="qrichtext" content="1" /><style type="text/css">
p, li { white-space: pre-wrap; }
</style></head><body style=" font-family:'Helvetica'; font-size:12pt; font-weight:400; font-style:normal;">
<table style="-qt-table-type: root; margin-top:4px; margin-bottom:4px; margin-left:4px; margin-right:4px;">
<tr>
<td style="border: none;">
<p style=" margin-top:12px; margin-bottom:12px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;">THIS IS SPARTA</p></td></tr></table></body></html>"

正如我所看到的，QTextDocument 中有类似默认 CSS 的内容：

<style type="text/css">p, li {white-space: pre-wrap;}</style>

但是，当我使用 p 标签和多个空格设置 HTML 时，它会删除空格。问题是——为什么？另一个问题是 - 为什么要为 p 标签添加边距？

PS 如果我在执行 setHtml 之前添加一行，它就可以正常工作

doc->setDefaultStyleSheet("p, li { white-space: pre-wrap; }");

- 它不会删除多个空格。但这个样式标签是什么？这不是默认样式表吗？为什么Qt会忽略它？

感谢您的回答。

原文

There is a Qt/C++ code:

#include <QtCore/QCoreApplication>
#include <QtGui/QTextDocument>
#include <QByteArray>
#include <QDebug>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    QTextDocument *doc = new QTextDocument();

    qDebug() << " === Document was: === ";
    qDebug() << doc->toHtml(QByteArray());

    doc->setHtml("<p>THIS       IS      SPARTA</p>");

    qDebug() << " === Document now: === ";
    qDebug() << doc->toHtml(QByteArray());

    return a.exec();
}

It outputs:

 === Document was: ===  
"<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd">
<html><head><meta name="qrichtext" content="1" /><style type="text/css">
p, li { white-space: pre-wrap; }
</style></head><body style=" font-family:'Helvetica'; font-size:12pt; font-weight:400; font-style:normal;">
<table style="-qt-table-type: root; margin-top:4px; margin-bottom:4px; margin-left:4px; margin-right:4px;">
<tr>
<td style="border: none;">
<p style="-qt-paragraph-type:empty; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;"></p></td></tr></table></body></html>" 
 === Document now: ===  
"<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd">
<html><head><meta name="qrichtext" content="1" /><style type="text/css">
p, li { white-space: pre-wrap; }
</style></head><body style=" font-family:'Helvetica'; font-size:12pt; font-weight:400; font-style:normal;">
<table style="-qt-table-type: root; margin-top:4px; margin-bottom:4px; margin-left:4px; margin-right:4px;">
<tr>
<td style="border: none;">
<p style=" margin-top:12px; margin-bottom:12px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;">THIS IS SPARTA</p></td></tr></table></body></html>"

As I can see, there is something like default CSS in QTextDocument:

<style type="text/css">p, li {white-space: pre-wrap;}</style>

But, when I'm setting HTML with p tag and multiple whitespaces, it removes whitespaces. The question is - why?
Another question is - why is it adding margins to p tag?

PS It works fine if I add a line

doc->setDefaultStyleSheet("p, li { white-space: pre-wrap; }");

before doing setHtml - it doesn't remove multiple whitespaces. But what is this style-tag then? Isn't it a default style sheet? Why Qt ignores it?

Thanks for the answer.

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以可爱出名 2024-09-12 04:31:28

这种行为来自 html，html 只是忽略标签内的多个空格..

尝试使用空格的特殊代码：

#include <QtCore/QCoreApplication>
#include <QtGui/QTextDocument>
#include <QByteArray>
#include <QDebug>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    QTextDocument *doc = new QTextDocument();
    qDebug() << " === Document was: === ";
    qDebug() << doc->toHtml(QByteArray());

    QByteArray myhtml ="<p>THIS       IS      SPARTA</p>";

    doc->setHtml(myhtml.replace(" "," "));

    qDebug() << " === Document now: === ";
    qDebug() << doc->toHtml(QByteArray());

    return a.exec();
}

this behavior is from html, html just ignore more than one spaces inside tags..

try to use the special code for space:

#include <QtCore/QCoreApplication>
#include <QtGui/QTextDocument>
#include <QByteArray>
#include <QDebug>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    QTextDocument *doc = new QTextDocument();
    qDebug() << " === Document was: === ";
    qDebug() << doc->toHtml(QByteArray());

    QByteArray myhtml ="<p>THIS       IS      SPARTA</p>";

    doc->setHtml(myhtml.replace(" "," "));

    qDebug() << " === Document now: === ";
    qDebug() << doc->toHtml(QByteArray());

    return a.exec();
}

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