Creating ASCII art with C ＃

You've seen those cool “ Letter ” Art ？ Using some English letters and symbols to form some kind of text or image ？ Some people try to create this art letter by letter , But today we will do it ourselves ！

What is? ASCII art ？

Basically ,ASCII Art is a text-based art form . Artistic text or text used in programs or documents , From ASCII The characters and symbols of characters .

What is? ASCII：https://en.wikipedia.org/wiki/ASCII

How it works ？

Good question ！

To explain this , We must understand what the image is made of .

Images , More specifically , A digital image consists of pixels , Based on the resolution of the image .

therefore , A resolution of 400 * 600（ high \ wide ） The image of 240000 Pixels . Pixels are the smallest part of a digital image . Each pixel can contain data about the color of that pixel , Pixels have different numbers of bits to represent them , Each bit represents a color option

• 1 bpp,2^1 = 2 Color （ monochrome ）

• 2 bpp,2^2 = 4 Color

• 3 bpp,2^3 = 8 Color

• 4 bpp, 2^4 = 16 color

• 8 bpp,2^8 = 256 color

• 16 bpp, 2^16 = 65,536 color （“ High color ”）

• 24 bpp, 2^24 = 16,777,216 color （“ True color ”）

High color ：https://en.wikipedia.org/wiki/Highcolor

True color ：https://en.wikipedia.org/wiki/24-bit_color

So how do we construct colors ？

There are several ways to define colors using color space , One of the most popular is sRGB.

sRGB Represents standard red, green and blue , It's a color space , Or a specific set of colors , By HP and Microsoft on 1996 Created in , The goal is to standardize the colors depicted by electronic products .

let me put it another way , Red 、 The combination of green and blue will produce different colors . The range of each value can be in 0 To 255 Between , So take the color representation as an example ：

(R:255,G:0,B:0) = Red

(R:0,G:255,B:0) = green

(R: 0,G:0,B:255) = Blue

(R:255,G:255,B:255) = white

(R:0,G:0,B:0) = black

(R:100,G:100 ,B:100) = gray

Let's move on to code implementation .

Print the image as ASCII art

hypothesis , We want to convert this image to ASCII art ：

Lovely little dog

Please note that , We have some parts of the picture that are darker , Some parts are brighter . This is exactly what we are creating ASCII What you want to simulate in Art , Some characters can represent a dark pixel , Such as spaces “” Or point “.”. Some can represent a bright pixel , for example “@” or “W”, But why should I choose these ？ It's easy to understand , The denser the letters , The brighter it will look on a dark background, right ？

So let's define our “ palette ”：

string asciiChars = "  .,:[email protected]@";

These letters must be sorted according to their density , To work properly .

Suppose we have a pixel , And we know it is RGB value , How do we translate it into ASCII character , If we look at its grayscale color , It will be easier to understand the brightness or darkness of pixels . The grayscale hue can be determined by RGB The average of the values generates .

for example , Red (255,0,0) Gray scale is expressed as (85,85,85).

Start with this part , All that's left is to take the average and get its position in the character array we created earlier .

therefore , If the color average has [0,255] Maybe , and ASCII Characters only [0,10] Maybe , We want to be in the ASCII Take the relative part of the color value in the character array ,

The more letters we put in the character array , We will have more possibilities to represent our brightness value .

I don't want to show every pixel , Because there are too many pixels . So I resized the image to match 130 The width of the pixel .

final result ：

This is great. ！

But I still need to change the font , Make the space between letters even , And fine tune the row height , So that the picture is displayed in the correct size , Instead of looking crushed .

Does it also apply to video ？

And then I thought , Video is basically a collection of digital images ！ If I change my code , From a short mp4 How about extracting frames from video files ？

It's possible , I just need to find a way to extract frames , And reuse my code . So I found one named NuGet Gallery | Emgu.CV Cross platform of image processing library .NET Wrappers .

NuGet Gallery | Emgu.CV ：https://www.nuget.org/packages/Emgu.CV/

To reduce console write flicker , I collected every character that needs to be inserted into the string builder object , And when processing the pixels of each frame is completed , I will have to StringBuilder Values are pushed to the console . And position the console cursor at the beginning of the text

Look at this. ：

Isn't it cool ！

The last step

The last step , Can we parse the video in real time ？

Use the same library , You can easily set video capture as a webcam , And see yourself as a bunch “W” and “@” and “.”

Happy learning ！

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