1:、打开字体对话框选择字体

//用到头文件：#include <QFontDialog>
void MainWindow::on_pushButton_font_clicked()
{bool ok;QFont f = QFontDialog::getFont(&ok, QFont("Consolas",9), this,"设置显示字体");if(ok){font = f;}
}

2、打开颜色对话框选择颜色

//用到头文件：#include <QColorDialog>
void MainWindow::on_pushButton_rxcolor_clicked()
{QColor c = QColorDialog::getColor();if (c.isValid()){color = c;int r = c.red();int g = c.green();int b = c.blue();QString style = QString("background-color:rgb(%1,%2,%3)").arg(r).arg(g).arg(b);ui->pushButton_rxcolor->setStyleSheet(style);}
}

3、设置需要插入的文本字体类别、大小和颜色

//用到头文件：#include <QTextCharFormat>
QTextCharFormat fmt;
fmt.setForeground(color);
fmt.setFont(font);
ui->textEdit->setCurrentCharFormat(fmt);
ui->textEdit->append(text);