How to convert pixel Px to centimeter

 

How to convert pixel Px to centimeter
...... In course #01, we know the concept of pixels, but we need to understand that pixels, as a size of images, only exist in computers, it only exists in the computer as in the RGB color mode. Pixel is a virtual unit, which does not exist in real life.
In reality, if we see a person, how many pixels are there? No, we usually say that he is 1.82 tall, or 182 cm tall. The unit of traditional length is used.
The so-called traditional length unit refers to the unit of millimeters, centimeters, meters, meters, kilometers, and light years.

At this moment, a problem occurs. For example, how many pixels does a person with a height of 1.82 meters have in a computer?
This problem should be put down first. We have a reverse thinking to address this problem, that is, how many pixels of images in computer images are printed by a printer?

 

Px
The unit of relative length. Pixel (pixel ).
Pixels are relative to the display screen resolution. For example, wondows users generally use a 96-pixel/inch resolution. Mac users generally use 72 pixels/inch resolution.

Em
The unit of relative length. The font size relative to the text in the current object.
If the font size of the text in the current row is not set manually, the default font size is relative to that of the browser.

Ex
The unit of relative length. The height relative to the character "X. This height is usually half the font size.
If the font size of the text in the row is not set manually, the default font size is relative to that of the browser.

PT
Absolute length unit. Point ).
1In = 2.54 = 25.4 = 72pt = 6 PC

PC
Absolute length unit. Pica ). It is equivalent to the size of China's new 4.
1In = 2.54 = 25.4 = 72pt = 6 PC

In
Absolute length unit. Inch (inch ).
1In = 2.54 = 25.4 = 72pt = 6 PC

Mm
Absolute length unit. Mm (millimeter ).
1In = 2.54 = 25.4 = 72pt = 6 PC

Cm
Absolute length unit. Centimeter (centimeter ).
1In = 2.54 = 25.4 = 72pt = 6 PC
Respondent: jam_li-magician Level 4 12-14

It is different in different environments.
There is no absolute ratio.
Let me tell you this.

When the screen resolution of a Common Desktop is set to 800x600, the pixel of the display diagonal line is 1000, and the length of the ordinary 17' display diagonal line is about 43cm, according to the hook theorem.
That is to say, in this case,
1000px about = 43 cm,
That is, 1px = 0.4mm.

However, if you change the resolution, You have to calculate it again. For example, when you set the resolution to 1024 × 768, the diagonal pixel is 1280. If you still set the resolution to 17', then:
1280px = 43 cm
Calculate with a calculator --
1px = 0.3359375mm

 

 

From: http://blog.sina.com.cn/s/blog_587f4345010008jg.html