Html5 Dynamically create Canvas

Setting the stage for dynamic canvas

Before we get to the fun part, let's configure our canvas properly. Besides the width and height, consider controlling canvas layering with the zIndex. Also, position your canvas with CSS styles.

canvas.id = 'myCanvas';   // Tag - you're it!
canvas.style.border = '1px solid #000'; // Outlining your artistic space
canvas.style.position = 'absolute';   // The world is not flat, your canvas should not be too!
canvas.style.zIndex = 10;    // Keeping the canvas on top of its game
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Always remember, the DOM needs to be fully loaded before you begin your art session. Wrap your setup inside a window.onload function:

window.onload = function() {
  let canvas = document.createElement('canvas');
  // more configurations...
  document.body.appendChild(canvas);
  // action continues...
};
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Basics of canvas drawing

After your canvas has found a cozy spot in your DOM, it's time to add some colors to it. Use the getContext('2d') method to begin. A good place to start is with a simple rectangle using fillRect:

ctx.fillRect(50, 50, 150, 100); // Oh, look! A rectangle.
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If needed, clear sections using clearRect, it's almost like having an eraser in your digital art toolkit:

ctx.clearRect(0, 0, canvas.width, canvas.height); // Oops! Let's start over, shall we?
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Canvas maintains its cool by using save() and restore() to remember settings between drawing frames. These methods reset styles and transformations, saving you the headache of undoing every change manually:

ctx.save();  // Don't worry, I got your back!
ctx.fillStyle = 'red'; // Roses are red,
ctx.fillRect(10, 10, 50, 50); // this rectangle is also red.
ctx.restore(); // And we're back to square one! Get it, square, rectangle? Ha!
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For creatives looking to add images, the Image constructor and the drawImage method are your go-to tools:

let img = new Image();
img.onload = function() {
  ctx.drawImage(img, 0, 0); // Unleashing the picasso within!
};
img.src = 'path/to/your/image.png';
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Next level canvas operations and things to remember

Creating animations with canvas

Achieving smooth animations is as easy as requestAnimationFrame. This beauty optimizes the animation loop ensuring best performance and buttery smooth visuals:

function animate() {
  requestAnimationFrame(animate); // And the cycle continues
  ctx.clearRect(0, 0, canvas.width, canvas.height); // New day, new canvas
  // your masterpiece in the making...
}
animate();  // Lights, Camera, Action!
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Transformations on canvas

Canvas transformations, such as rotation, add a dynamic flare to your artwork. The rotate method is your turntable:

ctx.rotate(angle); // WARNING: Objects in the canvas are literally turning!
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If your canvas objects' world is spinning around the wrong point, use translate to set the right pivot point. Because after all, the world doesn’t revolve around the origin, does it?

Tackling cross-browser issues

jQuery might be your savior when dealing with older browsers or when you need to deal with browser idiosyncrasies. Native JavaScript is now much more consistent, but jQuery still offers a fairly neat syntax:

$('body').append($(canvas)); // jQuery handling the heavy lifting
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Squashing bugs in your canvas code

When canvas drawing plays hide and seek

Not seeing your drawings on the canvas? Check whether the canvas context was acquired properly using getContext('2d') and if canvas dimensions are set right. No dimension settings? Well, you just got a very petite canvas worth 300x150 pixels!

Resize massacres

Every canvas comes with a self-destruct button during resize – it clears itself! Handle resize events smartly by redrawing your contents. And just as squirrels store nuts for winter, save your necessary state outside of your canvas element in JS variables.

Performance jitters

Complex drawings slowing down your webpage? Time to meet the offscreen canvas – create your art backstage and only unveil it on the live canvas when ready!