Today I will tell you what these words we often deal with mean and what is the relationship between them. This article is a vernacular version that I extracted from more than N articles in an afternoon, and I promise you can understand it.
Let's start with the mobile phone. Let me show you some parameters about the screen of the mobile phone. The three parameters in the red box must be familiar to everyone, and I am not unfamiliar. But to be honest, not long ago, I didn't even know how the screen size of the phone was calculated. Let’s start talking slowly.
What is the screen (main screen) size and how to calculate it?
The picture below is the size of Huawei Honor 7. The picture is 5.2 inches. So how is this 5.2 inches calculated? Before talking about this issue, let's first convert the unit. We usually don’t use inches as a unit. We use millimeters, centimeters, and meters. So what is the conversion relationship between inches and millimeters and centimeters? I don't know, so I Baidu it.
1 inch (inch) = 2.54 centimeters (cm)
It turns out that one inch is equivalent to our 2.54 centimeters. Now let us return to the question of how to calculate 5.2 inches. At the beginning, I thought it might be that the screen area of the mobile phone was so large. Later, after I Baidu in inches, I realized how stupid I was. Because inches are a unit of length, the expression of area should be expressed in area units. Obviously, inches cannot express area. From this point, I denied my idea.
In fact, the 5.2 inches we are talking about is the diagonal length of the mobile phone screen.
When I say that, people with a little bit of mathematical knowledge know how to calculate the screen size of a mobile phone. That's right, it's the Pythagorean theorem. Know the length and width of the mobile phone screen, and then use the Pythagorean theorem to calculate the length of the hypotenuse. There is a simpler way, just use a ruler to measure how many centimeters its diagonal is, and then convert it to inches.
What the hell is the resolution?
The above figure shows that the resolution of Huawei Honor 7 is 1920PX*1080PX. So, what's the matter with this resolution? You may have noticed that both 1920 and 1080 are followed by the words PX. This PX is a pixel we are familiar with. Let's talk about this pixel later. Now you only need to understand that the pixel is a unit of resolution.
Before explaining the resolution, we need to understand a concept. A line, a surface, and an image presented on our mobile phones are all represented by the smallest unit pixel. You can also simply understand that it is composed of small squares. Look at the picture below and you will understand.
So, the resolution of 1920px*1080px means that on the 5.2-inch screen of Huawei Honor 7, there are 1920 pixel blocks in the vertical height and 1080 pixel blocks in the horizontal width.
Next, what is the resolution ratio?
You may have noticed that the screen of the phone is a rectangle with a height of 1920px and a width of 1080px. You will find that the ratio of height to width is 16:9. Speaking of the 16:9 ratio, students who often watch videos must be familiar with it. Mobile phone screens have various resolution ratios. This ratio can also be regarded as the size ratio of the mobile phone screen. According to Baidu Encyclopedia, the reason why the resolution of the mobile phone is expressed as 1920px*1080px is also for the convenience of expressing the size of the mobile phone screen. The size here should refer to the size of the mobile phone screen. In fact, telling you the resolution of a mobile phone, can you really calculate the size of the mobile phone screen? So, what are the conditions to calculate the size of the mobile phone screen?
What is the screen pixel density?
Screen pixel density, that is, the number of pixels per inch of screen, referred to as PPI in English. When reading this screen per inch, I was deeply puzzled, is this per inch short for per square inch? Facts have proved that I am still too young. This inch is the same size as the previous mobile phone screen, and it is also a diagonal length. Therefore, we can understand the screen pixel density as the number of pixels in a square with a diagonal of 1 inch. Speaking of this, everyone may still be a little confused, it's okay, then look at the following.
What is the relationship between screen pixel density, resolution, and screen size?
There is a very strict relationship between these three professional terms. Why is it rigorous, because there is a formula between these three.
This formula is really simple and clear, and has solved many questions for us. Let's take Huawei Honor 7 as an example. We know that its size is 5.2 inches and the resolution is 1920px*1080px (1920px is the portrait in the formula, and 1080px is the landscape in the formula). If you don’t believe it, just use the formula to calculate the PPI, is it 424ppi? I calculated it and the result was 423.6359942465958. Those who know how to round will know that 424 is an approximate value.
Is the pixel size fixed?
Let me say this first, pixels have no actual physical size. Why, as usual, give an example.
In the above two pictures, the first is the screen parameters of the Apple 6 mobile phone, and the second is the screen parameters of the Huawei Honor 7 with the highest appearance rate. Everyone pay attention, the resolution of these two phones is 1920px*1080px. However, the screen size of Apple's mobile phone is 0.2 inches smaller than that of Huawei Honor 7. Another, however, the screen pixel density (PPI) of the Apple mobile phone is 45 PPI higher than that of the Huawei Honor 7, which is 45 more pixels per inch. What does this show? Explaining the same length of one inch, the Apple mobile phone uses 469 ppi to display, and Huawei only uses 424 ppi to display. Can you tell me which phone has a more refined display effect? The same one inch, the same pixels, why the Apple mobile phone has 469 pixels per inch, and Huawei has only 424 pixels? We know that inch is a unit of length, and it has a fixed physical size. Then the problem can only lie in the pixels. This shows that the pixel has become smaller on Apple mobile phones. Therefore, the pixel, like a golden hoop, can become bigger and smaller.
The resolution of the computer screen can be adjusted. Could it be achieved by adjusting its pixel size?
You are wrong, if it is so simple, would I have an egg to write this article? In fact, the number of pixels is fixed on the same device, which is set by the manufacturer at the factory. Only between different devices, there is a difference in pixel size. Since the number of pixels is already set on the same device, how can the resolution be adjusted on the computer? No matter how I adjust it, there are still so many pixels.
The resolution recommended by the system is 1366px*768px. Do you know what it means? That's right, Microsoft has set 768 pixels vertically and 1366 pixels horizontally on this screen. No matter how much you pull, this number will not change. So, why can I still adjust the resolution? If I adjust it to 800px*600px, by definition, the horizontal direction is 600 pixels, and the vertical direction is 800 pixels. Actually, if you adjust the resolution to 800*600, the system will assign you 800*600 effective pixels, which is the real color block. As for the other numbers, the system makes its own claim. Through a series of calculations, it gives you an analog color block, which is filled into exactly 1366*768 color blocks. These pixel blocks used to replenish the number are put together with the real pixel blocks. It's like a regular army, with a lot of miscellaneous troops in it, but the team can't bring it.
Is the display effect of a mobile phone with a larger PPI more refined?
To answer this question, we must first understand, what exactly does a pixel contain? A pixel is actually a color block. If you don't believe it, just go ahead and look at the wind, rain and thunder and lightning map. The same one inch, Apple mobile phone can display 469 colors, Huawei can only display 424 colors, of course, the display effect of Apple mobile phones is better. That is, when the Apple 6 leaves the factory, the same number of smaller pixel blocks has been set on the screen, which means that more colors can be displayed.
The clarity of the screen is actually determined by the resolution and size. It is more accurate to measure the clarity of the screen with the ppi index.
Author: Product Manager Ma Zhongxin
link: https: //www.jianshu.com/p/c3387bcc4f6e#
Source: Jane book
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