voluptasquisquam/src/image/operator/__tests__/paintPolyline.js

Image processing and manipulation in JavaScript

import {Image} from 'test/common';
import 'should';

describe('we check paintPolyline', function () {
    it('should yield the painted image with a line', function () {
        let size = 5;
        let data = new Array(size * size * 3);
        for (let i = 0; i < data.length; i++) {
            data[i] = i;
        }
        let image = new Image(size, size, data, {kind: 'RGB'});

        let points = [[1, 1], [3, 3]];
        image.paintPolyline(points);

        let painted = [
            0, 0, 0, 0, 0,
            0, 1, 0, 0, 0,
            0, 0, 1, 0, 0,
            0, 0, 0, 1, 0,
            0, 0, 0, 0, 0
        ];

        let exptected = getExpected(painted, [255, 0, 0]);

        Array.from(image.data).should.eql(exptected);
    });

    it('should yield the painted image with a rectangle', function () {
        let size = 5;
        let data = new Array(size * size * 3);
        for (let i = 0; i < data.length; i++) {
            data[i] = i;
        }
        let image = new Image(size, size, data, {kind: 'RGB'});

        let points = [[1, 1], [4, 1], [4, 3], [1, 3]];
        image.paintPolyline(points);

        let painted = [
            0, 0, 0, 0, 0,
            0, 1, 1, 1, 1,
            0, 0, 0, 0, 1,
            0, 1, 1, 1, 1,
            0, 0, 0, 0, 0
        ];

        let exptected = getExpected(painted, [255, 0, 0]);

        Array.from(image.data).should.eql(exptected);
    });

    it('should yield the painted image B/W image with a triangle', function () {
        let size = 5;
        let data = new Array(size * size);
        for (let i = 0; i < data.length; i++) {
            data[i] = i;
        }
        let image = new Image(size, size, data, {kind: 'GREY'});

        let points = [[2, 0], [4, 2], [0, 2]];
        image.paintPolyline(points);

        let painted = [
            0, 0, 1, 0, 0,
            0, 0, 0, 1, 0,
            1, 1, 1, 1, 1,
            0, 0, 0, 0, 0,
            0, 0, 0, 0, 0
        ];

        let exptected = getExpectedGrey(painted, [255, 0, 0]);
        Array.from(image.data).should.eql(exptected);
    });
});


function getExpected(painted, color) {
    let result = new Array(painted.length * 3);
    for (let i = 0; i < result.length; i++) {
        result[i] = i;
    }
    for (let i = 0; i < result.length / 3; i++) {
        if (painted[i] === 1) {
            result[i * 3] = color[0];
            result[i * 3 + 1] = color[1];
            result[i * 3 + 2] = color[2];
        }
    }
    return result;
}

function getExpectedGrey(painted, color) {
    let result = new Array(painted.length);
    for (let i = 0; i < result.length; i++) {
        result[i] = i;
    }
    for (let i = 0; i < result.length; i++) {
        if (painted[i] === 1) {
            result[i] = color[0];
        }
    }
    return result;
}