What is the difference between px and pt in css

Difference: pt is an absolute unit and px is a relative unit. Use px to define text, and the size will not change no matter how the user sets it; use pt to define text, and when the user sets a value exceeding 96 DPI, the larger the value, the larger the font size.

The operating environment of this tutorial: Windows 7 system, CSS3 version, Dell G3 computer.

px and pt, one is device coordinates and the other is logical coordinates, they are different.

pt is an absolute unit, 1 pt =1/72 inch

px is a relative unit, the general reference value of pixels is: in a On a monitor with a pixel density of 90 pdi, the viewing angle for a normal person looking at one pixel from a distance of 28 inches from the monitor should be no less than 0.0227 degrees.

Use px to define text, no matter how the user sets it, the size will not change; use pt to define text, when the user sets a value exceeding 96DPI, the larger the value, the larger the font.

If you create web pages for browsing rather than printing, it is recommended that you use px to define the font size. The reasons are as follows:

1. As mentioned by Jet earlier, px refers to is the number of elephants. The concept of number of elephants itself is only used for display, and pt (point size) is largely for the purpose of printing without errors. There is a big difference between printing and display. I won’t go into details here. What Jiji said The situation mentioned is also a disadvantage caused by using pt.

2. Most of the default units in Html code, such as width=10, etc., are all in px. The total width and height of the screen are also in px. 800*600 is the width. 800px; height 600px; we define the font size as 12px; it can be easily calculated. For example, the width of 10 Chinese characters is 10*12=120. We can easily write a table with width=120 to frame them. , this is just an example.

3. Please do an experiment. The two definition methods of body { font-size:10.5pt; } and body { font-size:14.7px; } can make Netscape display the 10.5-point size. The more optimized font size can only be defined as 14.7px, otherwise only IE will recognize it.

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