Optimizing web drawing, layout and rendering: finding the best solution

Redraw, reflow and reflow: find the most effective optimization solution

In web development, performance optimization is an eternal topic. Improving web page loading speed is one of the key points of optimization. In order to understand how to optimize web page loading speed, we need to understand the browser's rendering process.

When the browser receives a web page, it converts the web page into a DOM tree. The DOM tree is the logical representation of a web page. Next, the browser needs to build a rendering tree based on the DOM tree and calculate the position and size of each node.

In the process of building the rendering tree, the browser needs to perform two important operations: redraw and reflow. Redrawing means that when the appearance of an element changes, the browser needs to redraw the element. Reflow means that when the position of an element changes, the browser needs to recalculate the position and size of this element and its descendants.

Redrawing and reflowing are very time-consuming operations, so we need to minimize the number of times they occur. However, sometimes we can't prevent them from happening, such as when the user interacts or the page content changes. At this time, we can use some optimization techniques to reduce the impact of redrawing and reflowing.

First of all, we can use the CSS transform attribute to replace the modification of the element position. Because transform does not trigger reflow, it can help us reduce the number of reflows. In addition, we can use the requestAnimationFrame method to perform redrawing and reordering operations. requestAnimationFrame will call the specified function before the next frame starts, so that multiple redrawing and reordering operations can be merged into one to improve performance.

Secondly, we can find out the performance bottleneck by analyzing the rendering performance of the web page. The browser provides some tools to help us analyze the rendering performance of web pages, such as the performance panel of Chrome developer tools. By using these tools, we can find out what causes redraws and reflows and take appropriate steps to optimize them.

In addition, we can use the caching mechanism to reduce the number of requests to the server. The browser will cache frequently accessed resources. When the resource is requested again, the browser can read it directly from the cache without re-downloading. This can reduce the number of network requests and improve web page loading speed.

Finally, we can use some tools to help us automate the optimization process. For example, webpack can help us merge multiple JavaScript files into one file and compress it to reduce the file size. In addition, tools such as Gzip can compress files and reduce network transmission time.

In the process of optimizing web page performance, we need to weigh various factors. Sometimes, optimizing one aspect can lead to performance degradation in other aspects. So we need to consider it comprehensively and find the most effective optimization solution.

In short, redrawing, reflowing and reflowing are important factors affecting web page performance. In order to improve the performance of web pages, we can adopt some optimization techniques, such as using the CSS transform attribute, requestAnimationFrame method and caching mechanism. At the same time, with the help of browser tools and some automation tools, we can perform performance optimization more conveniently. By comprehensively considering various factors, we can find the most effective optimization solution to improve the loading speed of web pages.

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