Canvas:onPaint() | LuaRT free and open source Windows programming framework for Lua

Canvas:onPaint() event

This event is fired continuously to redraw the Canvas. You can put all your drawing operations inside this event handler function.

Notes

This event is thrown asynchronously by a Task, so be sure to call sleep() if you use an ui.update() loop.
When drawing operations are executed inside an event or in a Task, Canvas.begin() and Canvas.flip() must be called to preserve the Direct2D drawing state across Tasks.

Return value

This event returns no value.

Example


local ui = require "ui"
require "canvas"

-- create a fixed Window
local win = ui.Window("Canvas:onPait() sample", "fixed", 320, 200)

-- create a Canvas
local canvas = ui.Canvas(win)
canvas.align = "all"

-- set the onPaint() event handler to draw on the canvas
function canvas:onPaint()
    self:begin()
    self:clear()
    self:print("Hello World !", 10, 10)
    self:flip()
end

-- shows the Window and wait for it to be closed
ui.run(win):wait()