Learn how to use common properties of the canvas tag

To master the usage of common attributes of canvas tag, specific code examples are required

Overview:

The canvas tag in HTML5 is used to draw graphics, Powerful tool for animation and other visualization effects. It provides many properties and methods that give developers complete control over elements on the canvas. This article will introduce the common attributes of the canvas tag and how to use it, and give specific code examples to help readers better understand and use the canvas tag.

1. Basic attributes of the canvas tag:

1. width: Set the width of the canvas.
2. height: Set the height of the canvas.

Code example:

<canvas id="myCanvas" width="500" height="300"></canvas>

2. Get the canvas object and context:

1. Get the canvas object:

var canvas = document.getElementById("myCanvas");

2. Get the canvas context:

var context = canvas.getContext("2d");

3. Draw basic graphics:

1. Draw a rectangle:

context.fillStyle = "red";
context.fillRect(50, 50, 200, 100);

2. Draw a circle Shape:

context.beginPath();
context.arc(250, 150, 50, 0, 2 * Math.PI);
context.fillStyle = "blue";
context.fill();

3. Draw lines:

context.moveTo(100, 100);
context.lineTo(300, 200);
context.strokeStyle = "green";
context.lineWidth = 5;
context.stroke();

4. Draw text:

1. Draw filled text:

context.font = "30px Arial";
context.fillStyle = "purple";
context.fillText("Hello, Canvas!", 100, 100);

2. Draw stroked text:

context.font = "30px Arial";
context.strokeStyle = "orange";
context.lineWidth = 3;
context.strokeText("Hello, Canvas!", 100, 100);

5. Draw an image:

1. Draw a picture:

var img = new Image();
img.src = "image.png";
img.onload = function() {
    context.drawImage(img, 100, 100);
}

6. Clear the canvas:

context.clearRect(0, 0, canvas.width, canvas.height);

7. Implement animation effects:

function draw() {
    // 清空画布
    context.clearRect(0, 0, canvas.width, canvas.height);
  
    // 绘制动画元素
    // ...
  
    // 更新元素属性
  
    // 循环调用draw函数
    requestAnimationFrame(draw);
}

The above are specific code examples of common attributes of the canvas tag and their usage. By learning and mastering these examples, readers can better understand and use the canvas tag to achieve various cool drawing effects and animation effects.

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