@thi.ng/rasterize/rect.js

Headless 2D shape drawing, filling & rasterization for arbitrary targets/purposes (no canvas required)

import { isPrimitive } from "@thi.ng/checks";
import { hlineClipped, vlineClipped } from "@thi.ng/grid-iterators/hvline";
import { rows2d } from "@thi.ng/grid-iterators/rows";
import { concat } from "@thi.ng/transducers/concat";
import { ensureShader2D } from "./checks.js";
import { __draw2D } from "./draw.js";
const drawRect = (grid, x, y, w, h, val, fill = false) => {
  x |= 0;
  y |= 0;
  w |= 0;
  h |= 0;
  const {
    data,
    offset,
    size: [width, height],
    stride: [sx, sy]
  } = grid;
  if (fill) {
    if (x < 0) {
      w += x;
      x = 0;
    }
    if (y < 0) {
      h += y;
      y = 0;
    }
    const pts = rows2d({
      cols: Math.min(w, width - x),
      rows: Math.min(h, height - y)
    });
    const shader = ensureShader2D(val);
    if (isPrimitive(val)) {
      for (let { 0: xx, 1: yy } of pts) {
        xx += x;
        yy += y;
        data[offset + xx * sx + yy * sy] = shader(grid, xx, yy);
      }
    } else {
      for (let { 0: xx, 1: yy } of pts) {
        xx += x;
        yy += y;
        grid.setAtUnsafe(xx, yy, shader(grid, xx, yy));
      }
    }
    return grid;
  }
  return __draw2D(
    concat(
      hlineClipped(x, y, w, 0, 0, width, height),
      vlineClipped(x, y + 1, h - 2, 0, 0, width, height),
      hlineClipped(x, y + h - 1, w, 0, 0, width, height),
      vlineClipped(x + w - 1, y + 1, h - 2, 0, 0, width, height)
    ),
    grid,
    val
  );
};
export {
  drawRect
};