Canvas MessageBox

This article describes content/features that may not yet be available in the latest stable version of FlightGear (2020.3). You may need to install some extra components, use the latest development (Git) version or even rebuild FlightGear from source, possibly from a custom topic branch using special build settings: . This feature is scheduled for FlightGear 3.2. If you'd like to learn more about getting your own ideas into FlightGear, check out Implementing new features for FlightGear.

Canvas - the FlightGear 2D drawing API
Canvas - Main Page Canvas News - for the latest developments Shiva Alternatives - ongoing work for Core Profile support Canvas Efforts - projects using the Canvas system Canvas FAQs - frequently asked questions Canvas - Getting started Canvas Development (core) Canvas Troubleshooting (core) Canvas Sandbox (core) PUI2Canvas (PUI/XML Parser) Canvas GUI Canvas Widgets Canvas Maps Canvas Snippets
RFC
Canvas Instancing Howto:New Canvas Execution Model Canvas SVG Canvas Popout Windows Canvas Scenery Overlays
Frameworks
Canvas Map API (soon deprecated!) Canvas MapStructure Canvas MapStructure Layers MapStructure Snippets Canvas Radar Canvas Animation Framework (WIP) Canvas Plotting Framework (WIP) Canvas MFD Framework Canvas ND Framework Canvas PFD Framework Canvas MCDU Framework Canvas EFB Framework Canvas Wrappers Canvas Glass Cockpit Efforts
Tutorials
Howto:Getting started with Canvas Howto: Canvas Troubleshooting Howto:Adding a canvas to a GUI dialog (PUI!) Howto:Creating a Canvas GUI dialog file (New) Howto:Dynamic Liveries via Canvas (new) Howto:Creating a Canvas GUI Widget Howto:Add a 2D canvas instrument to your aircraft Howto:Parsing 2D Instruments using the Canvas Howto:Creating fullscreen Canvas applications Howto:Use SVG inside a Canvas Howto:Extend the Canvas SVG module Howto:Serializing a Canvas to SVG Howto:Canvas applications as Nasal submodules Howto:Using raster images and nested canvases Canvas HUD Howto:Project 3D to 2D coordinates on desktop canvas
Reference
Canvas Element Group Image Map Path Text Canvas Nasal API MessageBox Layout System Canvas GUI API Canvas draw library Event Handling
Related
Canvas Properties Unifying the 2D rendering backend via canvas Howto:Use a Camera View in an Instrument Howto:Extending Canvas to support rendering 3D models Howto:Extending Canvas to support MathGL
To be ported
Navigation display Map FGCanvas Canvas Nasal/JavaScript Subset
Deprecated by Canvas
Complex Glass Cockpit Avionics
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Message boxes provide a simple way to report information and warnings or ask questions. In FlightGear 3.1+ using canvas.MessageBox with the Nasal scripting language, allows showing standard message boxes to the user.

Predefined Severity Levels/Icons

Icon	Icon Name	Standard MessageBox	Description
	"dialog-question"	canvas.MessageBox.question( <title>, <text>, cb = nil, buttons = canvas.MessageBox.Yes | canvas.MessageBox.No );	Ask the user a (yes/no) question.
	"dialog-info"	canvas.MessageBox.information( <title>, <text>, cb = nil, buttons = canvas.MessageBox.Ok );	Show the user some information, with only the possiblity to close the dialog.
	"dialog-warning"	canvas.MessageBox.warning( <title>, <text>, cb = nil, buttons = canvas.MessageBox.Ok );	Show the user a non critical warning, with only the possiblity to close the dialog.
	"dialog-error"	canvas.MessageBox.critical( <title>, <text>, cb = nil, buttons = canvas.MessageBox.Ok );	Notify the user of a critical error or failure, with only the possiblity to close the dialog.

Examples

	canvas.MessageBox.info("Success", "The operation has successfully completed.");
	canvas.MessageBox.question( "Do you want it?", "The question is: Do you want to get a real question?.", func(sel) { if( sel == canvas.MessageBox.Yes ) print("I only know that the answer is 42."); else print("Ok, I will not give you a real question."); } );
	canvas.MessageBox.warning( "Warning...", "Have you read this warning? If you want it will not be shown again.", func(sel) { if( sel != canvas.MessageBox.Ok ) return; print("You have been warned. Let the games begin..."); }, canvas.MessageBox.Ok | canvas.MessageBox.Cancel | canvas.MessageBox.DontShowAgain );