s = QString("(%1,%2)---------------------->(%3,%4)---------------------->(%5,%6)").arg(lx).arg(ly).arg(bx).arg(by).arg(rx).arg(ry);
时间: 2023-09-19 14:06:19 浏览: 42
这行代码是用来生成一个包含三个点坐标的字符串,格式为:
```
(lx,ly)---------------------->(bx,by)---------------------->(rx,ry)
```
其中,`lx`、`ly`、`bx`、`by`、`rx`、`ry` 分别代表三个点的横纵坐标。
可以看到,这个字符串中每个点之间用 `---------------------->` 进行连接,这个连接符可以根据需要进行修改。该字符串的生成方式是使用了 Qt 框架中的 QString 类的 `arg()` 函数,将每个点的坐标依次插入到字符串中。
相关问题
写出qt C++ 代码:QString UTF-8 转 QString UTF-8 with BOM
以下是将QString UTF-8转换为QString UTF-8 with BOM的Qt C++代码:
```cpp
QString utf8ToUtf8Bom(const QString& utf8Str)
{
QByteArray utf8Bom = QByteArray::fromHex("EFBBBF");
QByteArray utf8Data = utf8Str.toUtf8();
QByteArray utf8BomData = utf8Bom + utf8Data;
return QString::fromUtf8(utf8BomData);
}
```
使用方法:
```cpp
QString utf8Str = "Hello, world!";
QString utf8BomStr = utf8ToUtf8Bom(utf8Str);
```
其中,`toUtf8()`函数将QString转换为QByteArray,`fromUtf8()`函数将QByteArray转换为QString。`QByteArray::fromHex()`函数可以将16进制字符串转换为QByteArray。我们将UTF-8的BOM(Byte Order Mark)以16进制字符串的形式传递给了`fromHex()`函数,得到了一个QByteArray类型的BOM。然后将原UTF-8字符串和BOM拼接在一起,最后使用`fromUtf8()`函数将字节数组转换为带BOM的QString类型。
QString str = QString("C:/Qt/lei-muban.dot").arg(dir.absolutePath());
This line of code creates a QString object named "str" that contains a path to a file named "lei-muban.dot". The path is specified as "C:/Qt/lei-muban.dot", and the ".arg()" method is used to insert the absolute path of the directory specified by the "dir" object.
For example, if "dir.absolutePath()" returns "C:/users/johndoe/documents/", the resulting string stored in "str" would be "C:/Qt/lei-muban.dot/C:/users/johndoe/documents/".
Note that this may not be a valid file path, as it could result in a directory being treated as part of the filename. It would be more appropriate to use QString's "append()" method to add the directory path to the end of the file path, like so:
QString str = QString("C:/Qt/lei-muban.dot").append(dir.absolutePath());
This would result in "str" containing the string "C:/Qt/lei-muban.dot/C:/users/johndoe/documents/" (using the example directory path from earlier).
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