How to implement the image interception function in html (two methods)

With the continuous development of the Internet, pictures have become one of the indispensable and important elements in web design. In HTML, we can use various techniques to display and capture images to make web pages more beautiful and attractive. This article will introduce HTML image interception technology to help readers better master this skill.

1. Basic knowledge of HTML images

In HTML, we often use the tag to display images. The following is a piece of HTML code that displays an image:

<img src="example.jpg" alt="演示图">

Among them, the src attribute specifies the path of the image to be displayed, and the alt attribute specifies the alternative text of the image. If the image cannot be loaded, the browser will display alternative text based on the alt attribute. In addition to the tag, there are some other HTML tags that can also be used for image display, such as

and .

2. HTML image interception technology

1. CSS3 clip-path attribute

CSS3 clip-path attribute can crop and intercept images to create Various shapes and effects. The following is a piece of HTML code and CSS code that shows how to use the clip-path attribute to circularly intercept an image:

<img class="round" src="example.jpg" alt="演示图">

.round {
  -webkit-clip-path: circle(50%);
  clip-path: circle(50%);
}

Among them, both the -webkit-clip-path and clip-path attributes can be used to intercept images. , the performance in different browsers is slightly different. In the above code, circle(50%) specifies the size of the circle to be intercepted.

2. HTML5 canvas

HTML5 canvas is a programmable graphics engine that can be used to create a variety of dynamic images and effects. The following is a piece of HTML code and JavaScript code that shows how to use the drawImage() method of canvas to intercept an image:

<canvas id="canvas" width="400" height="400"></canvas>

var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
var img = new Image();
img.src = "example.jpg";
img.onload = function() {
  ctx.drawImage(img, 0, 0, 400, 400, 0, 0, 200, 200);
};

In the above code, the drawImage() method can accept 8 parameters, and the first 4 parameters are specified The original image to be intercepted is specified, and the last four parameters specify the target image to be drawn on the canvas. In the above code, we intercept the original image to a size of 400x400, then adjust it to a size of 200x200 and draw it on the canvas.

3. Summary

Image interception is an important skill in web design, which can make the page more vivid and attractive. In HTML, we can use some techniques to capture images, such as the clip-path attribute of CSS3 and the canvas technology of HTML5. I hope this article will be helpful to readers, and everyone is welcome to explore more HTML technologies.

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