main.lua

function love.load()
	image = love.graphics.newImage('images//image.png')
	love.window.setTitle("Red/Green Inverse")
	newHeight = 300
	newWidth = (newHeight * image:getWidth())/image:getHeight()
	love.window.setMode(newWidth, newHeight*2)
	factor = (newHeight/newWidth)*(newWidth/newHeight)
  myShader = love.graphics.newShader[[
		vec4 effect( vec4 color, Image texture, vec2 texture_coords, vec2 screen_coords ){
		vec4 pixel = Texel(texture, texture_coords );//This is the current pixel color
		number r = pixel.r;
		pixel.r = pixel.g;
		pixel.g = r;
		return pixel;
		}
  ]]
end

function love.update(dt)
	if love.keyboard.isDown('up') then 
		factor = factor +.001
	end 
	if love.keyboard.isDown('down') then 
		factor = factor -.001
	end 
end
function love.draw()
  love.graphics.setShader() --draw something here
	love.graphics.draw(image, 0, 0, 0, factor, factor)
	love.graphics.print("Factor: "..factor, 10, 5)
	love.graphics.print("WH: "..newWidth/newHeight, 10, 15)
	love.graphics.print("WH/HW: "..(newWidth/newHeight)/(newHeight/newWidth), 10, 25)
	love.graphics.print("HW: "..newHeight/newWidth, 10, 35)
	love.graphics.print("HW/WH: "..(newHeight/newWidth)/(newWidth/newHeight), 10, 45)
	love.graphics.print("Width: "..newWidth, 10, 55)
	love.graphics.print("Height: "..newHeight, 10, 65)
	love.graphics.setShader(myShader)
	love.graphics.draw(image, 0, newHeight, 0, factor, factor)
end