Qt（PyQt） 显示 Markdown

引入

Markdown是一种轻量级标记语言，Qt 是支持 Html 的显示，那么支持 Markdown 吗？答案当然是支持的

效果图：

如何实现

注：Qt 是指 C++ Qt，PyQt 就是指 PyQt
在 Qt 和 PyQt 中的 QTextBrowser、QTextEdit等控件都有一个函数：

ui->XXX->setMarkdown("XXX");  // Qt

XXX.setMarkdown("XXX");  # PyQt

那么能不能用呢？当然是可以的，下面是一个示例：
就先以下面的 Markdown 为例：

**Hello** *World*~~!~~ 

Qt：

#include <QApplication>
#include <QMainWindow>
#include <QTextBrowser>
#include <QLabel>
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QMainWindow *w = new QMainWindow();
    QTextBrowser *br = new QTextBrowser(w);
    br->setMarkdown("**Hello** *World*~~!~~ ");
    w->show();
    return a.exec();
}

PyQt：

import sys
import PyQt5.QtWidgets as QtWidgets

app = QtWidgets.QApplication(sys.argv)
widget = QtWidgets.QWidget()
br = QtWidgets.QTextBrowser(widget)
br.setMarkdown("**Hello** *World*~~!~~")
widget.show()
sys.exit(app.exec_())

所以 Qt 是支持 Markdown

示例：一个实时显示 Markdown 结果的编辑器

注意：未完成打开、保存、另存为等高级功能，只有实时显示的功能

Qt

main.cpp

#include "mainwindow.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
    return a.exec();
}

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);/*
    ui->textBrowser->setMarkdown("```python\n"
                                 "import os\n"
                                 "```\n"
                                 "**b**\n");*/
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_textEdit_textChanged()
{
    if (ui->comboBox->currentIndex()==0){
        ui->textBrowser_2->setMarkdown(ui->textEdit->toPlainText());
        return;
    }
    ui->textBrowser_2->setHtml(ui->textEdit->toPlainText());
}

void MainWindow::on_comboBox_editTextChanged(const QString &arg1)
{

}

void MainWindow::on_comboBox_currentIndexChanged(int index)
{
    if (ui->comboBox->currentIndex()==0){
        ui->textBrowser_2->setMarkdown(ui->textEdit->toPlainText());
        return;
    }
    ui->textBrowser_2->setHtml(ui->textEdit->toPlainText());
}

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private slots:
    void on_textEdit_textChanged();

    void on_comboBox_editTextChanged(const QString &arg1);

    void on_comboBox_currentIndexChanged(int index);

private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

mainwindow.ui

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>MainWindow</class>
 <widget class="QMainWindow" name="MainWindow">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>400</width>
    <height>300</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>MainWindow</string>
  </property>
  <widget class="QWidget" name="centralWidget">
   <layout class="QHBoxLayout" name="horizontalLayout_2">
    <item>
     <widget class="QTextEdit" name="textEdit">
      <property name="html">
       <string>&lt;!DOCTYPE HTML PUBLIC &quot;-//W3C//DTD HTML 4.0//EN&quot; &quot;http://www.w3.org/TR/REC-html40/strict.dtd&quot;&gt;
&lt;html&gt;&lt;head&gt;&lt;meta name=&quot;qrichtext&quot; content=&quot;1&quot; /&gt;&lt;style type=&quot;text/css&quot;&gt;
p, li { white-space: pre-wrap; }
&lt;/style&gt;&lt;/head&gt;&lt;body style=&quot; font-family:'Noto Sans CJK SC'; font-size:10.5pt; font-weight:400; font-style:normal;&quot;&gt;
&lt;p style=&quot;-qt-paragraph-type:empty; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;&quot;&gt;&lt;br /&gt;&lt;/p&gt;&lt;/body&gt;&lt;/html&gt;</string>
      </property>
     </widget>
    </item>
    <item>
     <layout class="QVBoxLayout" name="verticalLayout">
      <item>
       <widget class="QComboBox" name="comboBox">
        <property name="currentText">
         <string>Markdown</string>
        </property>
        <item>
         <property name="text">
          <string>Markdown</string>
         </property>
        </item>
        <item>
         <property name="text">
          <string>Html</string>
         </property>
        </item>
       </widget>
      </item>
      <item>
       <widget class="QTextBrowser" name="textBrowser_2"/>
      </item>
     </layout>
    </item>
   </layout>
  </widget>
  <widget class="QMenuBar" name="menuBar">
   <property name="geometry">
    <rect>
     <x>0</x>
     <y>0</y>
     <width>400</width>
     <height>36</height>
    </rect>
   </property>
  </widget>
  <widget class="QToolBar" name="mainToolBar">
   <attribute name="toolBarArea">
    <enum>TopToolBarArea</enum>
   </attribute>
   <attribute name="toolBarBreak">
    <bool>false</bool>
   </attribute>
  </widget>
  <widget class="QStatusBar" name="statusBar"/>
  <widget class="QToolBar" name="toolBar">
   <property name="windowTitle">
    <string>toolBar</string>
   </property>
   <attribute name="toolBarArea">
    <enum>LeftToolBarArea</enum>
   </attribute>
   <attribute name="toolBarBreak">
    <bool>false</bool>
   </attribute>
  </widget>
  <widget class="QToolBar" name="toolBar_2">
   <property name="windowTitle">
    <string>toolBar_2</string>
   </property>
   <attribute name="toolBarArea">
    <enum>LeftToolBarArea</enum>
   </attribute>
   <attribute name="toolBarBreak">
    <bool>false</bool>
   </attribute>
  </widget>
 </widget>
 <layoutdefault spacing="6" margin="11"/>
 <resources/>
 <connections/>
</ui>

untitled.pro

#-------------------------------------------------
#
# Project created by QtCreator 2021-08-09T11:55:07
#
#-------------------------------------------------

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = untitled
TEMPLATE = app

# The following define makes your compiler emit warnings if you use
# any feature of Qt which has been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS

# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

CONFIG += c++11

SOURCES += \
        main.cpp \
        mainwindow.cpp

HEADERS += \
        mainwindow.h

FORMS += \
        mainwindow.ui

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

效果

截图：

PyQt

main.py

import sys
import PyQt5.QtWidgets as QtWidgets

def Change():
    textBrow.setMarkdown(textEdit.toPlainText())

app = QtWidgets.QApplication(sys.argv)
widget = QtWidgets.QWidget()
hbox = QtWidgets.QHBoxLayout()
textEdit = QtWidgets.QTextEdit()
textBrow = QtWidgets.QTextBrowser()
textEdit.textChanged.connect(Change)
hbox.addWidget(textEdit)
hbox.addWidget(textBrow)
widget.setLayout(hbox)
widget.show()
sys.exit(app.exec_())

效果

截图：

示例项目链接：

1. 蓝奏云：https://gfdgdxi.lanzoui.com/b01oibted，密码:4sqa