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

Canvas:RadialGradient(colors) method

Creates an RadialGradient object instance to be used in any Canvas drawing operation.

Parameters

colors

A table where :

keys are a number : a relative gradient position (only positions between 0.0 to 1.0 are visible, but any other positions might impact the gradient).
values are a number : a color in RGBA format.

The color is represented by a number, an RGBA value (one byte per primary color and one byte for alpha channel).
A RGBA color can be represented as an hexadecimal number : 0xRRGGBBAA , RR meaning a 8bit hexadecimal red value, and so on.

Return value

This function returns an RadialGradient instance.

Example


local ui = require "ui"
require "canvas"

-- create a simple Window
local win = ui.Window("RadialGradient.constructor() sample", "fixed", 500, 400)

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

local logo = canvas:Image("LuaRT.png")

local gradient = canvas:RadialGradient { [0] = 0xffffe600, [1] = 0x000000FF }
gradient.radius = { canvas.width/4, canvas.height/4 }

function canvas:onPaint()
    self:begin()
    logo:draw(20, 100, 1, 1, "linear")
    self:fillrect(0, 0, canvas.width, canvas.height, gradient)
    self:flip()
end

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

ui.run(win):wait()