Initial commit

convertToAscii.js

@@ -0,0 +1,63 @@
+module.exports = convertToAscii = async (file, dotSize = 24, verticalSpacinModifier = 4, output = __dirname + '/tmp.img.png') => {
+    const hobbitImageFile = file;
+    const density = 'Ñ@#W$9876543210?!abc;:+=-,._ ';
+
+    const { createCanvas } = require('canvas')
+    const ImageDataURI = require('image-data-uri');
+    var sizeOf = require('image-size');
+    var dimensions = sizeOf(hobbitImageFile);
+
+    const hobbit = {
+        width: dimensions.width,
+        height: dimensions.height,
+        pixels: [],
+    }
+
+    function clamp(input, min, max) {
+        return input < min ? min : input > max ? max : input;
+    }
+
+    function map(current, in_min, in_max, out_min, out_max) {
+        const mapped = ((current - in_min) * (out_max - out_min)) / (in_max - in_min) + out_min;
+        return clamp(mapped, out_min, out_max);
+    }
+
+    await new Promise((res, rej) => {
+        var PNG = require('png-js');
+        PNG.decode(hobbitImageFile, function(pixels) {
+
+            const canvas = createCanvas(hobbit.width * dotSize, hobbit.height * dotSize);
+            const ctx = canvas.getContext('2d')
+
+            hobbit.pixels = pixels;
+
+            ctx.fillStyle = 'black';
+            ctx.fillRect(0, 0, hobbit.width * dotSize, hobbit.height * dotSize);
+
+            for(let x = 0; x < hobbit.width; x++) {
+                for(let y = 0; y < hobbit.height; y++) {
+                    const pixelPosition = (x + y*hobbit.width)*4;
+                    const r = hobbit.pixels[pixelPosition + 0];
+                    const g = hobbit.pixels[pixelPosition + 1];
+                    const b = hobbit.pixels[pixelPosition + 2];
+                    const a = hobbit.pixels[pixelPosition + 3];
+                    
+                    const avg = Math.floor((r+g+b)/ 3);
+
+                    const gray = map(255 - avg, 0, 255, 0, density.length);
+                    
+                    ctx.font = (dotSize + verticalSpacinModifier) + "px Courier";
+                    ctx.textAlign = 'center';
+                    ctx.textBaseline = 'middle';
+                    ctx.fillStyle = `white`;
+                    ctx.fillText(density.charAt(gray), x*dotSize + dotSize/2, y*dotSize + dotSize/2);
+                }
+            }
+            
+            ImageDataURI.outputFile(canvas.toDataURL(), output);
+            console.log(output, 'converted');
+            res(1);
+        });
+
+    });
+}