w8r / bresenham-zingl

Set of efficient Bresenham rasterisers ported from Alois Zingl' code

Bresenham rasterisation functions by Alois Zingl

Port of C code by Alois Zingl from this paper

ALOIS ZINGL: "A Rasterizing Algorithm for Drawing Curves", 8 November 2012 (2012-11-08), pages 1 - 81

Install

npm i -S bresenham-zingl

import { line, circle, quadBezier } from 'bresenham-zingl';

quadBezier(0,0, 10, 10, 0, 10, (x, y) => console.log(x, y)); // 0,0, ...

Demo

API

User-defined callbacks

setPixel(x, y)

Use that callback to fill the pixel on canvas.

Parameters

parameter	type	description
x	number
y	number

setPixelAlpha(x, y, alpha)

Callback that would also receive the alpha value for the pixel

Parameters

parameter	type	description
x	number
y	number
alpha	number

line(x0, y0, x1, y1, setPixel)

Line segment rasterisation

Parameters

parameter	type	description
x0	number
y0	number
x1	number
y1	number
setPixel	setPixel

lineAA(x0, y0, x1, y1, setPixelAA)

Draw a black (0) anti-aliased line on white (255) background

Parameters

parameter	type	description
x0	number
y0	number
x1	number
y1	number
setPixelAA	setPixelAlpha

Returns number,

lineWidth(x0, y0, x1, y1, wd, setPixel)

Plot an anti-aliased line of width wd

Parameters

parameter	type	description
x0	number
y0	number
x1	number
y1	number
wd	number
setPixel	setPixel

quadRationalBezierSegment(x0, y0, x1, y1, x2, y2, w, setPixel)

plot a limited rational Bezier segment, squared weight

Parameters

parameter	type	description
x0	number
y0	number
x1	number
y1	number
x2	number
y2	number
w	number
setPixel	setPixel

quadRationalBezierSegmentAA(x0, y0, x1, y1, x2, y2, w, setPixelAA)

draw an anti-aliased rational quadratic Bezier segment, squared weight

Parameters

parameter	type	description
x0	number
y0	number
x1	number
y1	number
x2	number
y2	number
w	number
setPixelAA	setPixelAlpha

rotatedEllipse(x, y, a, b, angle, setPixel)

Plot ellipse rotated by angle (radian)

Parameters

parameter	type	description
x	number
y	number
a	number
b	number
angle	number
setPixel	setPixel

rotatedEllipseRect(x0, y0, x1, y1, zd, setPixel)

Rectangle encloMath.sing the ellipse, integer rotation angle

Parameters

parameter	type	description
x0	number
y0	number
x1	number
y1	number
zd	number
setPixel	setPixel

ellipseRect(x0, y0, x1, y1, setPixel)

Rectangular parameter encloMath.sing the ellipse

Parameters

parameter	type	description
x0	number
y0	number
x1	number
y1	number
setPixel	setPixel

circle(xm, ym, r, setPixel)

Circle rasterisation

Parameters

parameter	type	description
xm	number
ym	number
r	number
setPixel	setPixel

circleAA(xm, ym, r, setPixelAA)

Draw a black anti-aliased circle on white background

Parameters

parameter	type	description
xm	number
ym	number
r	number
setPixelAA	setPixelAlpha

quadBezierSegment(x0, y0, x1, y1, x2, y2, setPixel)

plot a limited quadratic Bezier segment

Parameters

parameter	type	description
x0	number
y0	number
x1	number
y1	number
x2	number
y2	number
setPixel	setPixel

quadBezierAA(x0, y0, x1, y1, x2, y2, setPixelAA)

Plot any quadratic Bezier curve with anti-alias

Parameters

parameter	type	description
x0	number
y0	number
x1	number
y1	number
x2	number
y2	number
setPixelAA	setPixelAlpha

quadBezierSegmentAA(x0, y0, x1, y1, x2, y2, setPixelAA)

Draw an limited anti-aliased quadratic Bezier segment

Parameters

parameter	type	description
x0	number
y0	number
x1	number
y1	number
x2	number
y2	number
setPixelAA	setPixelAlpha

cubicBezier(x0, y0, x1, y1, x2, y2, x3, y3, setPixel)

plot any cubic Bezier curve

Parameters

parameter	type	description
x0	number
y0	number
x1	number
y1	number
x2	number
y2	number
x3	number
y3	number
setPixel	setPixel

cubicBezierAA(x0, y0, x1, y1, x2, y2, x3, y3, setPixelAA)

plot any cubic Bezier curve

Parameters

parameter	type	description
x0	number
y0	number
x1	number
y1	number
x2	number
y2	number
x3	number
y3	number
setPixel	setPixelAlpha

License

(The MIT License)

Copyright (c) 2012 Alois Zingl

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

bresenham-zingl's Issues

Cubic bezier infinite loop.

I encountered a bug when placing the handles of a cubic bezier very close together.

bresenham.cubicBezier(0,0, 10, 0, 0, 5, 10, 5, (x, y) => console.log(x, y));

This will result in an infitie loop with the output:

0 0
1 0
2 0
3 0
4 1
5 2
5 3
5 4
6 4
6 4
6 4
6 4
6 4
6 4
…

When moving the handles apart as in

bresenham.cubicBezier(0,0, 10, 0, 0, 6, 10, 6, (x, y) => console.log(x, y));

the algorithm succeeds.

Images

Licensing.

While your library says MIT, I've searched all of zingl's pages and can't find any consistent licensing guidance anywhere. Do you have something to suggest this is an acceptable licensing?

Freature Request: Filled Circle

I went ahead and did a very raw version here (using jimp). Thanks for the port, it was a good starting point!

/* Extended from https://github.com/w8r/bresenham-zingl/blob/master/src/line.js */

module.exports.circle = (image, xm, ym, radius, outerColor, innerColor) => {
  const blendColor = (baseColor, addColor, x, y, alpha) => {
    /* eslint-disable no-bitwise */
    const baseB = (baseColor >> 24) & 0xff;
    const baseG = (baseColor >> 16) & 0xff;
    const baseR = (baseColor >> 8) & 0xff;
    const baseA = (baseColor & 0xff) / 255.0;

    const addB = (addColor >> 24) & 0xff;
    const addG = (addColor >> 16) & 0xff;
    const addR = (addColor >> 8) & 0xff;
    const addA = ((addColor & 0xff) / 255.0) * (1 - (alpha / 255.0));

    const a = 1 - ((1 - baseA) * (1 - addA));
    const r = Math.round(((addR * addA) / a) + ((baseR * baseA * (1 - addA)) / a));
    const g = Math.round(((addG * addA) / a) + ((baseG * baseA * (1 - addA)) / a));
    const b = Math.round(((addB * addA) / a) + ((baseB * baseA * (1 - addA)) / a));

    const color = Math.round(a * 255.0) | (r << 8) | (g << 16) | (b << 24);
    /* eslint-enable no-bitwise */
    image.setPixelColor(color, x, y);
  };
  let x = -radius;
  let y = 0;
  let i;
  let x2;
  let e2;
  let err = 2 - (2 * radius);
  const r = 1 - err;

  do {
    for (let j = xm + x; j <= xm - x; j += 1) {
      if (image.getPixelColor(j, ym - y) === 0) {
        image.setPixelColor(innerColor, j, ym - y);
      }
    }
    for (let j = xm - y; j <= xm + y; j += 1) {
      if (image.getPixelColor(j, ym - x) === 0) {
        image.setPixelColor(innerColor, j, ym - x);
      }
    }

    i = (255 * (err - (2 * (x + y)) - 2)) / r;
    blendColor(i > 0 ? 0x0 : innerColor, outerColor, xm - x, ym + y, Math.abs(i));
    blendColor(i > 0 ? 0x0 : innerColor, outerColor, xm - y, ym - x, Math.abs(i));
    blendColor(i > 0 ? 0x0 : innerColor, outerColor, xm + x, ym - y, Math.abs(i));
    blendColor(i > 0 ? 0x0 : innerColor, outerColor, xm + y, ym + x, Math.abs(i));

    e2 = err;
    x2 = x;
    if (err + y > 0) {
      i = (255 * (err - (2 * x) - 1)) / r;
      if (i < 256) {
        blendColor(0x0, outerColor, xm - x, ym + y + 1, i);
        blendColor(0x0, outerColor, xm - y - 1, ym - x, i);
        blendColor(0x0, outerColor, xm + x, ym - y - 1, i);
        blendColor(0x0, outerColor, xm + y + 1, ym + x, i);
      }
      x += 1;
      err += (x * 2) + 1;
    }
    if (e2 + x2 <= 0) {
      i = (255 * (((2 * y) + 3) - e2)) / r;
      if (i < 256) {
        blendColor(innerColor, outerColor, xm - x2 - 1, ym + y, i);
        blendColor(innerColor, outerColor, xm - y, ym - x2 - 1, i);
        blendColor(innerColor, outerColor, xm + x2 + 1, ym - y, i);
        blendColor(innerColor, outerColor, xm + y, ym + x2 + 1, i);
      }
      y += 1;
      err += (y * 2) + 1;
    }
  } while (x < 0);
};