Why pixels per inch instead of pixels per square inch?

I understand what you mean, a pixel has length and width, but its length and width are equal, so knowing the number of pixels per inch, as well as the length and width of **, you can calculate the number of pixels, and the pixel per square pixel you say is equivalent to calculating it to tell you. Every inch of the suit is not yet counted to tell you, but you can do it yourself. To use an analogy:

If you ask the PE teacher how many students are doing exercises on the playground, the PE teacher says 5 horizontally and 11 vertically, and you know that it is 55 when you do the math. So why didn't the teacher just say 55, and I'm not sure if the standard of pixel inches was scientifically determined, or whether it was decided by the earliest experts in this area. There are many unreasonable standards in history, such as keyboards, and the inch standards of the display screen are completely unreasonable, because the actual area of a 17-inch widescreen is smaller than that of a 15-inch ordinary screen.

I guess this should also be the first person to set the standard, but I didn't expect the screen to change to widescreen in the future. caused this ridiculous problem.

What you are talking about is the unit of resolution Resolution, called resolution (RTHK is called resolution) is the precision of the screen image, which refers to the number of pixels that the display can display. Since the dots, lines, and surfaces on the screen are made up of pixels, the more pixels a display can display, the finer the picture will be, and the more information can be displayed in the same screen area, so resolution is one of the most important performance indicators. Think of the image as a large chessboard, and the resolution is expressed as the number of intersections of all the meridian and latitude lines.

Resolution, which refers to the number of pixels contained in a unit length, is usually measured in pixels inches (ppi). For a screen with a resolution of 1024 768, that is, each horizontal line contains 1024 pixels, with a total of 768 lines, that is, the number of scanned columns is 1024 columns, and the number of rows is 768. Resolution is not only related to the display size, but also affected by factors such as CRT point spacing, bandwidth, etc.

Among them, it is closely related to the refresh rate, strictly speaking, only when the refresh rate is "flicker-free refresh rate", the highest resolution that the display can achieve, that is, the highest resolution of the display. There are many types of resolution and their meanings vary, so it is important to understand exactly what resolution means in each context and to understand the interrelationship between the different representations. Don't fall into your own circle of thinking.

You're talking about the concept of resolution, which is defined as the value of a pixel per unit length, both directions, and the pixel is the product of the value of the pixels in both directions, which is an area concept.

Pixels per square inch Simplifying.

**There are differences in the concept and principle of the pixel pure scum and size, and the specific differences are as follows:

1. The concept is different.

Pixel: Refers to the smallest unit in an image represented by a sequence of numbers.

Size: refers to the size of **, that is, length and width.

2. The principle is different.

Pixel: Think of a pixel as an indivisible unit or element in an entire image. Indivisibility means that it can no longer be cut into smaller units or elements, but exists in a single color cell. Every bitmap image.

Contains a certain amount of pixels that determine the size of the image on the screen.

Size: It simply refers to the length and size of something.

This is the resolution, not the size, which means that there are 400x533 = 213200 pixels per square inch. Display resolution (screen resolution) is the precision of the screen image and refers to how many pixels the display can display.

Since the dots, lines, and surfaces on the screen are made up of pixels, the more pixels a display can display, the finer the picture will be, and the more information can be displayed in the same screen area, so resolution is a very important performance indicator. Think of the image as a large chessboard, and the resolution is expressed as the number of intersections of all the meridian and latitude lines.

1. The two refer to different things.

PPI refers to the smallest point that the screen can parse, therefore, the PPI value is the density of pixels on the screen, the higher the PPI, the clearer the image; In general, DPI can be understood as a sampling point, which is the smallest unit that can be parsed by a physical device.

2. The two are different for equipment.

PPI is the unit of image resolution, the higher the image PPI value, the richer the details of the picture, because the number of pixels per unit area is more, the ** taken by digital cameras may vary depending on the brand or production time, the common ones are 72ppi, 180ppi and 300ppi.

dpi refers to output resolution, for the output equipment, the output resolution of the general laser printer is 300dpi-600dpi, the printing phototypesetting machine reaches 1200dpi-2400dpi, and the common printing is generally between 150dpi and 300dpi.

3. The two have different meanings.

PPI means pixels per inch and is roughly equivalent to centimeters. The pixel is a concept dedicated to the screen; dpi stands for dots per inch, and when printing, it can be used as a print dot on electronic devices such as mice, which can be understood as the minimum operating threshold (i.e., how far away the device will treat two dots as a single dot).

First, the reference is different.

1. Points: also known as DPI, is a unit of measurement, used for dot matrix digital images, referring to the number of sampled, displayed or output points in each inch of length.

2. Pixel: Also known as ppi, it is the number of pixels (pixels) per inch diagonal.

Second, the calculation method is different.

2. Pixel: Calculate the number of pixels in the diagonal direction (right-angled triangle) with the number of pixels in the long heel height, and then divide the number of pixels diagonally by the screen size is ppi, and the formula is expressed as ppi= (x 2+y 2) z.

Third, the scope of use is different.

1. Points: mostly used to describe the printing quality of the printer.

2. Pixel: mostly used to describe the resolution of the display.

Difference Between DPI and PPI.

Concept ppi (pixels per inch): image resolution (the number of pixels per inch in an image) dpi (dots per inch): print resolution (the number of dots that can be printed per inch, i.e., print accuracy).

The relationship between print size, image size, and resolution can be expressed using the following formula: Image size = Image resolution Print size, Image size Image resolution = Print size. The size of the image is fixed for a particular image, so the resolution and print size are inversely proportional.

PPI (pixels per inch) is the unit of image resolution, the higher the image PPI value, the richer the details of the picture, because the number of pixels per unit area is more, the ** taken by digital cameras may vary depending on the brand or production time, the common ones are 72ppi, 180ppi and 300ppi, the default is so much (A710 shoots out 180ppi, I personally feel that this parameter seems to have little impact, generally no one mentions this). dpi (dots per inch) refers to output resolution, for the output equipment, the output resolution of the general laser printer is 300dpi-600dpi, the printing phototypesetting machine reaches 1200dpi-2400dpi, and the common printing is generally between 150dpi and 300dpi.

71 pixels. The size of the pixel is inseparable from the resolution, how many pixels are included in an inch or a centimeter print length, the more pixels are included, the higher the resolution, the clearer the image, the fewer pixels are included, the lower the resolution, the worse the image quality.

Most web pages are commonly used in the production of ** resolution of 72, that is, each inch of pixels is 72, 1 inch is equal to centimeters, and Douhu can be converted to 28 pixels per centimeter; Another example is the length of 15x15 cm, which is equal to the length of 420*420 pixels.

For example, if the resolution is 72dpi, that is, there are 72 pixels in each inch, and each pixel is 1 72 inches. If the accuracy is 300 dpi, then it is 1 300 inches per pixel.

The value of the pixel is absolute, its size is constant, and the resolution is relative. In other words, the resolution is the pixel value at a certain size; The pixel value of ** is an expression of the total pixel, which represents the true size (independent of resolution, it is an absolute value).

For example, 1024*768, if it is a 17-inch screen, it has a pixel value of 1024*768, but if you want to replace it with a 21-inch display, you can still use this resolution, but its resolution will decrease (because the total area increases, and the pixel value per unit area decreases) is stupid, but if it is 12 million pixels, it represents the total pixel value of a **or**, that is, its length and width product is this value, and the size it represents is certain—— It doesn't matter if you're on a 17-inch screen or a 47-inch screen, it doesn't change – it's just the resolution.

For example, a 5 million pixel **, its absolute size is inches (width), that is, the real size of the pixel 2560 1920 when it is not distorted - of course, we need to reduce the use of ** when we wash**, and it may be used with such a large size if you don't open your eyes.

The meaning is actually about the same, the resolution is not the same, the size is different, and the higher the resolution, the bigger it can be.

Generally, 640*480 is called pixels, simply speaking, DPI is the number of points per inch, 640*480 is this**640 points on the long side, 480 points on the short side. The general display resolution is 72dpi. Printing resolution 100-150dpi, printing generally indicates the resolution, refers to the number of points per inch of length, and dpi can be subdivided into horizontal resolution and vertical resolution.

Summary. px (pixel): Pixel, which is a unit of length relative to the resolution of the display, 1px = 1 pixel.

pt (point): point, is a standard unit of length, 1pt is equal to 1 72 inches, that is to say, 1 inch is equal to: relative length unit.

The font size relative to the text within the current object. If the current font size for inline text is not artificially set, it will be relative to the browser's default font size. rem：

It is also a relative length unit, relative to the root element() font size. %: The percentage unit, relative to the font size of the parent element.

Each inch contains 72 pixels, is an inch wide or high?

Hello, it is a pleasure to serve you. Inches refer to the width.

How can you describe the width in inches if it is not in the same straight line?

Each inch is the distance between each inch, or it can be called the width of the spacing.

What does the unit length in PS mean?

px (pixel): Pixel, which is a unit of length relative to the resolution of the display, 1px = 1 pixel. pt（point）：

A point is a standard unit of length and age, 1pt is equal to 1 72 inches, that is, 1 inch is equal to: relative length units. The font size relative to the text within the current object.

If the font size of the current inline text is not artificially set, the font size will be recognized relative to the browser's silent grip. rem: is also a relative unit of length, relative to the root element() font size.

Percentage units, relative to the font size of the parent element.

What does it mean to have 72 pixels per inch?

Are you there? For example, the resolution of the screen is 720 x 720, which means that there are 72 pixels per inch.