Plugin development overview

Here are some points concerning MuseScore plugin development:

Plugins are QML components.

MuseScore plugins are coded in QML. Each plugin is a QML component using which implements some logic inside its instance of MuseScore class and are capable to interact both with MuseScore API and with Qt itself (so MuseScore plugins can create their own windows, dialogs). Most of plugins are contained within a single .qml file though they may contain more items like resources and translation files.

Debugging plugins

MuseScore provides a simple plugin code editor which allows to develop and instantly test the developed plugin. This editor can be launched with Plugins → Plugin Creator menu item or by pressing Ctrl+Shift+P.

Clicking on a New button will create a sample plugin, you can also run your plugin with Run button and see some debugging output in the console window below the editing area. In order to print some debugging message to that console use console.log():

var e = newElement(Element.STAFF_TEXT);

console.log("the created element:", e, e.name);

Alternatively, you can edit your plugin's code with your favorite text editor and test it by launching it from MuseScore as long as the plugin is properly installed. See this Handbook page for the reference on plugins installation.

Hello World plugin

Here is an example of a simple plugin which prints "Hello World" to the debugging console:

import MuseScore 3.0
MuseScore {
    menuPath: "Plugins.pluginName"
    description: "Description goes here"
    version: "1.0"
    onRun: {
        console.log("Hello World!");
        Qt.quit();
    }
}

Here is what happens here.

import MuseScore 3.0 is necessary to use MuseScore API in QML code.
The MuseScore { ... } statement declares an object of MuseScore type (Ms::PluginAPI::PluginAPI is exposed to QML as MuseScore). This should be the root object of any QML plugin for MuseScore.
Statements like menuPath: "Plugins.pluginName" assign properties to that object, see the class reference for the meaning of those properties. Apart from the properties listed in that page, you can assign any other properties and/or declare other QML objects too.
onRun() is the function that is invoked when the plugin is executed (via a menu entry or via a shortcut). This is the entry point of your plugin.
Qt.quit() statement requests termination of the plugin's execution.

MuseScore is shipped with a set of simple plugins which can also be used as a reference while developing your own plugins.

Porting MuseScore 2 plugins

This documentation corresponds to the plugins API for MuseScore 3.X version. To see the information on its difference from MuseScore 2 plugins API as well as some instructions on adapting MuseScore 2 plugins code to work with MuseScore 3, please refer to the Porting MuseScore 2 plugins page.

Internationalization

For the questions related to making a plugin translatable to different languages please refer to Internationalization page.