web front end unit conversion

When doing web front-end development, it often involves the conversion of units, such as pixels (px), percentages (%), window units (vw, vh, etc.), etc. Master the use of these units and how to do it. Unit conversion is very important for web front-end engineers.

Pixel (px)

Pixel (px) is one of the most common units and the base unit for most device resolutions. In web development, style attributes such as the size and margin of elements are usually set in px units. For example, if we define a div element with a width of 300px and a height of 200px, then this div element will cover a 300*200 rectangle on the screen.

In addition, another unit of pixels is often used during the development process - device independent pixels (dip or dp). This unit appears to adapt to different device pixel densities. On a high-resolution screen, the display size of a pixel may be much larger than on a low-resolution screen, and using dip can ensure that the same size looks the same on devices with different resolutions.

Percentage (%)

Percentage is calculated based on the width of the containing block. Usually, setting attributes such as width or height to percentages can achieve better responsive layout effects. For example, if we define a box with a width of 50%, it will be displayed adaptively at half the width of its parent element.

View window units (vw, vh, etc.)

View window units are usually calculated based on the size of the browser window. By using these units, we can better implement responsive design. When we use vw units, it divides the viewport width into 100 units, and in CSS, vw is equal to 1/100 viewport width. For example, if we set the width of an element to 50vw, then it will occupy half of the entire viewport width.

Also, when we use vh units, it will divide the viewport height into 100 units, similar to vw, vh is equal to 1/100 viewport height.

Unit conversion

In web front-end development, it is often necessary to convert between different units. The following are some common unit conversion methods:

1. px -> rem

rem is the unit calculated relative to the font size of the root element (html element). If we want to convert px to rem, we need to first divide the pixel size of that element by the font size of the root element. For example, if the root element's font size is 16px and an element's width is 160px, then its rem value is 10rem.

2. px -> em

em is the unit calculated relative to the font size of the current element. You can usually set the overall font size of the web page to 1em and then size the elements as a percentage of the web page's font size. For example, if the web font size is 16px and the width of an element is 80px, then its em value is 5em.

3. px -> Percent (%)

If we want to convert the pixel size of an element to a percentage, we need to first divide the pixel size of the element by its Contains the pixel size of the block and then multiplies the resulting value by 100%. For example, if an element is 400px wide and its containing block is 800px wide, then its width percentage is 50%.

Summary

This article briefly introduces the commonly used units (px, %, vw/vh) in web front-end development, and how to perform unit conversion. When developing web front-end, understanding the usage and conversion methods of these units can better implement responsive design and improve the user experience of web pages.

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