Fun with canvas

Justin Ramel · Justin Ramel · commit 4fd3c67b2da3 · 2016-12-14T13:47:04.000Z
diff --git a/08 - Fun with HTML5 Canvas/index-START.html b/08 - Fun with HTML5 Canvas/index-START.html
@@ -7,6 +7,48 @@
 <body>
 <canvas id="draw" width="800" height="800"></canvas>
 <script>
+  const canvas = document.querySelector('#draw')
+  const ctx = canvas.getContext('2d')
+  ctx.width = window.innerWidth
+  ctx.height = window.innerHeight
+  ctx.strokeStyle = '#BADA55'
+  ctx.lineJoin = 'round'
+  ctx.lineCap = 'round'
+
+  let drawing = false
+  let lastX = 0
+  let lastY = 0
+  let hue = 0
+  let lineWidthInc = 1
+
+  canvas.addEventListener('mousemove', draw)
+  canvas.addEventListener('mousedown', (e) => {
+    drawing = true
+    lastX = e.offsetX
+    lastY = e.offsetY
+  })
+  canvas.addEventListener('mouseup', () => drawing = false)
+  canvas.addEventListener('mouseout', () => drawing = false)
+
+
+  function draw(e) {
+    if (!drawing) return
+    ctx.strokeStyle = `hsl(${hue}, 100%, 50%)`
+    ctx.beginPath()
+    ctx.moveTo(lastX, lastY)
+    ctx.lineTo(e.offsetX, e.offsetY)
+    ctx.stroke()
+    lastX = e.offsetX
+    lastY = e.offsetY
+    hue++
+    if (hue > 360) hue = 0
+    if (ctx.lineWidth >= 100) lineWidthInc = -1
+    if (ctx.lineWidth <= 1) lineWidthInc = 1
+    ctx.lineWidth = ctx.lineWidth + lineWidthInc
+    console.log(ctx.lineWidth)
+  }
+
+
 </script>
 
 <style>
