@thi.ng/text-canvas/line.js

Text based canvas, drawing, plotting, tables with arbitrary formatting (incl. ANSI/HTML)

import { peek } from "@thi.ng/arrays/peek";
import { liangBarsky2Raw } from "@thi.ng/geom-clip-line/liang-barsky";
import { Canvas } from "./canvas.js";
import { charCode } from "./utils.js";
const line = (canvas, ax, ay, bx, by, char, format = canvas.format) => {
  const { x1, y1, x2, y2 } = peek(canvas.clipRects);
  const clipped = liangBarsky2Raw(ax, ay, bx, by, x1, y1, x2, y2);
  if (!clipped) return;
  ax = clipped[0] | 0;
  ay = clipped[1] | 0;
  bx = clipped[2] | 0;
  by = clipped[3] | 0;
  const dx = Math.abs(bx - ax);
  const dy = -Math.abs(by - ay);
  const w = canvas.width;
  let sx = ax < bx ? 1 : -1;
  let sy = ay < by ? 1 : -1;
  let err = dx + dy;
  char = charCode(
    char !== void 0 ? char : peek(canvas.styles).dot,
    format
  );
  while (true) {
    canvas.data[ax + ay * w] = char;
    if (ax === bx && ay === by) return;
    let t = err << 1;
    if (t < dx) {
      err += dx;
      ay += sy;
    }
    if (t > dy) {
      err += dy;
      ax += sx;
    }
  }
};
export {
  line
};