symisc / ascii_art

Real-Time ASCII Art Rendering Library

ASCII Art

Real-Time ASCII Art Rendering Library - Live demo: https://art.pixlab.io

Integration Reference Guide: https://pixlab.io/art

ASCII Art is a single file C/C++ library that let you transform an input image or video frame into printable ASCII characters at real-time using a single decision tree. Real-time performance is achieved by using pixel intensity comparison inside internal nodes of the tree.

ASCII Camera Now Availabe On Unity Asset Store: https://assetstore.unity.com/packages/slug/165558

For a general overview on how the algorithm works, check the bottom of the demo page.

ASCII art is a related (and older) graphic design technique for producing images from printable characters. This implementation is based on the paper:

N. Markus, M. Fratarcangeli, I. S. Pandzic and J. Ahlberg, "Fast Rendering of Image Mosaics and ASCII Art", Computer Graphics Forum, 2015, http://dx.doi.org/10.1111/cgf.12597

Getting started

Embedding the library in your application is straightforward. All you have to do is drop the ascii_art.c and its header file in your source tree plus the hex model that can be downloaded here and perform the following API calls successively:

1. Call AsciiArtInit first to initialize the ascii_render structure defined in the ascii_art.h header file.
2. Prepare the image to be processed by converting it to the grayscale colorspace. You can rely on some external library like OpenCV cvtColor or the built-in AsciiArtLoadImage interface.
3. Allocate a buffer big enough to hold the entire ASCII text output. The amount of bytes needed is returned via the AsciiArtTextBufSize interface. This step is optional if you do not want a text output but instead a binary ASCII glyphs image.
4. Finally, transform the input image into ASCII glyphs/text via AsciiArtRender.

Below is a simple C program that demonstrates a typical usage of the ASCII Art C/C++ interfaces.

#include "ascii_art.h"

ascii_render sRender; /* Stack allocated */
	
/* Initialize the render structure */
AsciiArtInit(&sRender);
	
/* Load an image from disk */
int width, height;
unsigned char *zBlob = AsciiArtLoadImage(argv[1],&width,&height);
if( zBlob == 0 ){
	puts("Cannot load image");
	return;
}
	
/* Allocate a buffer big enough to hold the entire text output */
size_t nBytes = AsciiArtTextBufSize(&sRender, width, height);
unsigned char *zText = malloc(nBytes);
	
/* Finally, process */ 
AsciiArtRender(&sRender, zBlob, &width, &height, zText,1);
/* zBlob[] hold the binary ASCII glyphs now */
	
/* Output the result */
fwrite(zText, sizeof(char), nBytes, stdout);
	
/* Release memory */
free(zText);
free(zBlob);

sample.c source code

Resources

• The C/C++ API reference (Only three interfaces are exported plus another optional), the hex model are all available on the official PixLab page at: https://pixlab.io/art
• The live demo: https://art.pixlab.io
• Please report any issue or feature request here on Github.
• Unity Asset Store Package: https://assetstore.unity.com/packages/slug/165558

ascii_art's Issues

How to create a png output file as shown in the demo image

The image at URL has middle image in png format
https://camo.githubusercontent.com/65164475128f734e471dd21552dbc9b2e65f14f7/68747470733a2f2f692e696d6775722e636f6d2f63644a427a58492e706e67

I am able to save the generated ascii characters in '.txt' file. How to create a png file for the same ? Is there any existing code for the same ?

How to compile this project? undefined reference to `AsciiArtLoadImage'

I am getting below error when compiling with cmake
CMakeFiles/test.dir/sample.c.o: In function main': sample.c:(.text+0x7b): undefined reference to AsciiArtLoadImage'

Below command is also giving same error
gcc -W -Wall -O6 -o ascii_test sample.c ascii_art.c stb_image.h

`#ifdev` is causing undefined reference to `main' (I want to use AsciiArtLoadImage)

ascii_art/ascii_art.c

Line 343 in 0a12822

#endif /* STB_IMAGE_IMPLEMENTATION */

^this statement is causing

/usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/9/../../../x86_64-linux-gnu/Scrt1.o: in function `_start':
(.text+0x24): undefined reference to `main'
collect2: error: ld returned 1 exit status

while I have defined main where I'm trying to use AsciiArtLoadImage, such that

int main() {
     const char* path = "me.bmp";
     int* h; int* w ;
     char* img = AsciiArtLoadImage(path, h, w);
     return 0;
 
 }

can work. Can anyone tell me how this scenario can work?

Source for live image to ascii

Where can I find the source for https://art.pixlab.io/#render_cam ?: the code that that produces ascii output with video input.

Is it done client side ?