Canvas.measure() | LuaRT free and open source Windows programming framework for Lua

Canvas:measure(text) method

Measure text size on the Canvas

Parameters

text

A string representing the text to be measured

Return value

This function returns the text size as a table with two numeric fields: width and height

Example


local ui = require "ui"
require "canvas"

-- create a simple Window
local win = ui.Window("Canvas.measure() sample - Move the mouse over the window", "fixed", 500, 400)

-- create a Canvas
local canvas = ui.Canvas(win)
canvas.align = "all"
canvas.font = "Impact"
canvas.fontsize = 40

-- create a RadialGradient 
local radial = canvas:RadialGradient { [0] = 0x00FFFFFF, [1] = 0x00008BFF }
radial.radius = { 400, 400 }

local text = "Hello LuaRT World !!!"

-- center the text
local size = canvas:measure(text)
local xpos = (canvas.width - size.width)/2
local ypos = (canvas.height - size.height)/2

function canvas:onPaint()
  canvas:clear() 
  canvas:print(text, xpos, ypos, radial)
end

function canvas:onHover(x, y)
  radial.center = { x, y }
end

win:show()

-- update user interface
repeat
  ui.update()
until not win.visible