- 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.
Canvas:LinearGradient(colors) method
Creates an LinearGradient 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 between0.0to1.0are visible, but any other positions might impact the gradient). - values are a
number: a color inRGBAformat.
Return value
This function returns an LinearGradient instance.Example
local ui = require "ui"
require "canvas"
-- create a simple Window
local win = ui.Window("LinearGradient.constructor() sample", "fixed", 500, 400)
-- create a Canvas
local canvas = ui.Canvas(win)
canvas.align = "all"
canvas.bgcolor = 0x000000FF
canvas.fontsize = 37.5
canvas.fontstyle = "italic"
canvas.fontweight = 900
local gradient = canvas:LinearGradient { [0] = 0x00FFFFFF, [1] = 0x00008bFF }
gradient.start = { 0, 0 }
gradient.stop = { canvas.width, canvas.height }
local angle = 0
function canvas:onPaint()
canvas:clear()
canvas:rotate(angle)
angle = angle + 2
canvas:print("LuaRT Canvas", 150, 130, gradient)
end
-- update user interface
ui.run(win):wait()