50projects50days/drawing-app/script.js
2020-11-12 15:04:57 -05:00

86 lines
1.6 KiB
JavaScript

const canvas = document.getElementById('canvas');
const increaseBtn = document.getElementById('increase');
const decreaseBtn = document.getElementById('decrease');
const sizeEL = document.getElementById('size');
const colorEl = document.getElementById('color');
const clearEl = document.getElementById('clear');
const ctx = canvas.getContext('2d');
let size = 10
let isPressed = false
let color = 'black'
let x
let y
canvas.addEventListener('mousedown', (e) => {
isPressed = true
x = e.offsetX
y = e.offsetY
})
canvas.addEventListener('mouseup', (e) => {
isPressed = false
x = undefined
y = undefined
})
canvas.addEventListener('mousemove', (e) => {
if(isPressed) {
const x2 = e.offsetX
const y2 = e.offsetY
drawCircle(x2, y2)
drawLine(x, y, x2, y2)
x = x2
y = y2
}
})
function drawCircle(x, y) {
ctx.beginPath();
ctx.arc(x, y, size, 0, Math.PI * 2)
ctx.fillStyle = color
ctx.fill()
}
function drawLine(x1, y1, x2, y2) {
ctx.beginPath()
ctx.moveTo(x1, y1)
ctx.lineTo(x2, y2)
ctx.strokeStyle = color
ctx.lineWidth = size * 2
ctx.stroke()
}
function updateSizeOnScreen() {
sizeEL.innerText = size
}
increaseBtn.addEventListener('click', () => {
size += 5
if(size > 50) {
size = 50
}
updateSizeOnScreen()
})
decreaseBtn.addEventListener('click', () => {
size -= 5
if(size < 5) {
size = 5
}
updateSizeOnScreen()
})
colorEl.addEventListener('change', (e) => color = e.target.value)
clearEl.addEventListener('click', () => ctx.clearRect(0,0, canvas.width, canvas.height))