HTML Canvas cheat sheet

<!-- Create a canvas element -->
<canvas id="myCanvas"></canvas>

<!-- Get the canvas element in JavaScript -->
var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");

// Draw a rectangle
ctx.beginPath();
ctx.rect(x, y, width, height);
ctx.fillStyle = "color";
ctx.fill();
ctx.closePath();

// Draw a circle
ctx.beginPath();
ctx.arc(x, y, radius, startAngle, endAngle, anticlockwise);
ctx.fillStyle = "color";
ctx.fill();
ctx.closePath();

// Draw a line
ctx.beginPath();
ctx.moveTo(x1, y1);
ctx.lineTo(x2, y2);
ctx.strokeStyle = "color";
ctx.stroke();
ctx.closePath();

ctx.font = "fontStyle fontSize fontFamily";
ctx.fillStyle = "color";
ctx.fillText("Text", x, y);
ctx.strokeText("Text", x, y);

// Set fill color
ctx.fillStyle = "color";

// Set stroke color
ctx.strokeStyle = "color";

// Set line width
ctx.lineWidth = width;

// Set line join style
ctx.lineJoin = "style";

// Set line cap style
ctx.lineCap = "style";

// Set shadow
ctx.shadowColor = "color";
ctx.shadowBlur = value;
ctx.shadowOffsetX = value;
ctx.shadowOffsetY = value;

// Translate the canvas origin
ctx.translate(x, y);

// Scale the canvas
ctx.scale(scaleX, scaleY);

// Rotate the canvas
ctx.rotate(angle);

// Reset transformations
ctx.setTransform(1, 0, 0, 1, 0, 0);

// Draw an image
var img = new Image();
img.src = "imageURL";
img.onload = function() {
    ctx.drawImage(img, x, y, width, height);
}

// Draw a portion of an image
ctx.drawImage(img, sx, sy, sWidth, sHeight, dx, dy, dWidth, dHeight);

// Create a pattern with an image
var pattern = ctx.createPattern(image, "repeat/repeat-x/repeat-y/no-repeat");
ctx.fillStyle = pattern;
ctx.fill();