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cocoscii.js
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cocoscii.js
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/*
rep: A "\n"-seperated ascii representation of the image.
styles: A function to mutate the style dictionary. (shapeIndex: Number, dictionary: Object) => {}
scale: Factor to scale the final image by.
*/
function cocoscii (rep, styles = (idx, dict) => {}, scale = 4) {
const order = "123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnpqrstuvwxyz";
const rows = rep
.split("\n")
.filter(r => !r.match(/^\s*$/))
.map(r => r.split("").filter(ch => ch != " "));
const width = rows.reduce((max, row) => Math.max(max, row.length), 0);
const height = rows.length;
// Get the control points
const points = rows
.map((r, y) => r.map((ch, x) => { return {
idx: order.indexOf(ch),
ch, x, y
}}))
.reduce((flt, r) => [...flt, ...r], []) // Flatten
.filter(p => p.idx != -1)
.sort((p1, p2) => p1.idx - p2.idx);
// Turn them into shapes
const shapes = makeShapes(points);
// ...and draw them
const canvas = drawShapes(shapes, styles, width, height, scale);
// Save to image
const img = new Image();
img.src = canvas.toDataURL("image/png");
return img;
}
function makeShapes ([head, ...tail]) {
function newShape (p) {
return {
type: "dot",
points: [p]
};
}
const shapes = tail.reduce(({cur, shapes}, p) => {
const prev = cur.points.slice(-1)[0];
// Another point in the path
if (p.idx === prev.idx + 1 && ["dot", "path"].indexOf(cur.type) != -1) {
cur.points.push(p);
cur.type = "path";
}
// Line or circle
else if (p.idx === prev.idx) {
cur.points.push(p);
cur.type = cur.points.length < 3 ? "line" : "circle";
}
// New shape
else {
shapes.push(cur);
cur = newShape(p);
}
return {cur, shapes};
}, {cur: newShape(head), shapes:[]});
// Don't forget final shape!
return [...shapes.shapes, shapes.cur];
}
function drawShapes (shapes, styles, width, height, scale) {
let styleDict = {
fill: "#000",
stroke: "",
lineWidth: "1"
};
const canvas = document.createElement("canvas");
const ctx = canvas.getContext("2d");
canvas.width = width * scale;
canvas.height = height * scale;
function getBBox ([{x, y}, ...tail]) {
return tail.reduce(({min, max}, {x, y}) => {
if (x < min.x) min.x = x;
if (x > max.x) max.x = x;
if (y < min.y) min.y = y;
if (y > max.y) max.y = y;
return {min, max};
}, {min: {x, y}, max: {x, y}});
}
ctx.save();
ctx.scale(scale, scale);
shapes.forEach(({type, points}, i) => {
styles(i, styleDict); // Apply function to mutate the shape's styles
const [{x, y}, ...tail] = points;
const {fill, stroke, lineWidth} = styleDict;
ctx.fillStyle = fill;
ctx.strokeStyle = stroke;
ctx.lineWidth = lineWidth;
switch (type) {
case "dot":
// TODO: positioning is not correct. See "gridImg" test case
const args = [x, y, 1 / width, 1 / height];
if (fill) ctx.fillRect(...args);
if (stroke) ctx.strokeRect(...args);
break;
case "line":
case "path":
ctx.beginPath();
ctx.moveTo(x, y);
tail.forEach(({x, y}) => ctx.lineTo(x, y));
if (fill) ctx.fill();
if (stroke) ctx.stroke();
break;
case "circle":
// Get "bounding box" of the circle
const {min, max} = getBBox(points);
const [w, h] = [max.x - min.x, max.y - min.y];
const circ = Math.max(w, h);
// Draw an elipse to fit
ctx.save();
ctx.translate(min.x + w / 2, min.y + h / 2);
ctx.scale(w / circ, h / circ);
ctx.beginPath();
ctx.arc(0, 0, circ / 2, 0, Math.PI * 2, false);
ctx.restore();
if (fill) ctx.fill();
if (stroke) ctx.stroke();
break;
}
});
ctx.restore();
return canvas;
}
export default cocoscii;