chronodiagram/app/www/play.js

class Player {
    constructor(wrapperEl, fileurl) {
        this.wrapperEl = wrapperEl;
        this.svgEl = document.createElementNS('http://www.w3.org/2000/svg', 'svg');
        this.wrapperEl.appendChild(this.svgEl);

        this.scrubberElOld = document.createElement('input');
        this.scrubberElOld.type = "range";
        this.scrubberElOld.min = 0;
        this.scrubberElOld.step = 0.01;
        this.wrapperEl.appendChild(this.scrubberElOld);

        this.scrubberEl = document.createElement('div');
        this.scrubberEl.classList.add('scrubber')
        this.wrapperEl.appendChild(this.scrubberEl);

        this.scrubberElOld.addEventListener("input", (ev) => {
            this.scrubTo(ev.target.value);
        })

        this.inPointPosition = null;
        this.outPointPosition = null;
        this.currentTime = 0;
        this.isPlaying = false;

        this.play(fileurl);
    }

    play(file) {
        const request = new Request(file, {
            method: 'GET',
        });


        fetch(request)
            .then(response => response.json())
            .then(data => {
                this.playStrokes(data)
                // do something with the data sent in the request
            });

    }

    playStrokes(drawing) {
        this.strokes = drawing.shape;
        this.currentPathI = null;
        this.currentPointI = null;
        this.dimensions = drawing.dimensions;
        this.svgEl.setAttribute('viewBox', `0 0 ${this.dimensions[0]} ${this.dimensions[1]}`)
        this.startTime = window.performance.now() - this.strokes[0].points[0][3];
        this.playStrokePosition(0, 1);
        this.duration = this.getDuration();
        this.scrubberElOld.max = this.duration;
        this.playTimout = null;

        const slider = noUiSlider.create(this.scrubberEl, {
            start: [this.currentTime, this.duration],
            connect: true,
            range: {
                'min': 0,
                'max': this.duration
            }
        });

        slider.on("slide", (values, handle) => {
            this.isPlaying = false;
            // console.log(values, handle);
            // both in and out need to have a value
            this.inPointPosition = this.findPositionForTime(values[0]);
            this.outPointPosition = this.findPositionForTime(values[1]);
            if (handle === 0) {
                // in point
                if (
                    this.currentPathI < this.inPointPosition[0] ||
                    this.currentPointI < this.inPointPosition[1]) {
                    this.drawStrokePosition(
                        // this.inPointPosition[0],
                        // this.inPointPosition[1],
                        // always draw at out position, as to see the whole shape of the range
                        this.outPointPosition[0],
                        this.outPointPosition[1],
                    );
                }
            }
            if (handle === 1) {
                // out point
                // this.outPointPosition = this.findPositionForTime(values[1]);
                this.drawStrokePosition(
                    this.outPointPosition[0],
                    this.outPointPosition[1],
                );
            }
            // this.inPointPosition = values;
            // this.outPointPosition = vaalues[0];
            // this.scrubTo()
            // this.scrubTo(ev.target.value);
        });

    }

    getDuration() {
        const points = this.strokes[this.strokes.length - 1].points;
        return points[points.length - 1][3];
    }

    getStrokesForPathRange(in_point, out_point) {
        // get paths for given range. Also, split path at in & out if necessary.
        strokes = {};
        for (let i = in_point[0]; i <= out_point[0]; i++) {
            const path = this.strokes[i];
            const in_i = (in_point[0] === i) ? in_point[1] : 0;
            const out_i = (out_point[0] === i) ? out_point[1] : Math.inf;
            const points = path.points.slice(in_i, out_i);
            strokes[i] = points; // preserve indexes
        }
        return strokes;
    }

    // TODO: when drawing, have a group active & inactive.
    // active is getPathRange(currentIn, currentOut)
    // inactive is what comes before and after.
    // then, playing the video is just running pathRanghe(0, playhead)
    drawStrokePosition(path_i, point_i, show_all) {
        if (typeof show_all === 'undefined')
            show_all = false;

        // check if anything is placed that is in the future from the current playhead
        if (this.currentPathI !== null && this.currentPoint !== null) {
            if (this.currentPathI > path_i) {
                console.log('remove', path_i, ' -> ', this.currentPathI)
                // remove everything that comes later
                for (let i = path_i + 1; i <= this.currentPathI; i++) {
                    // console.log('remove', i);
                    const pathEl = this.svgEl.querySelector(`.path${i}`);
                    if (pathEl) {
                        pathEl.parentNode.removeChild(pathEl);
                    }
                }
            }
        }
        // an inpoint is set, so we're annotating
        // make everything coming before translucent
        if (this.inPointPosition !== null) {
            const [inPath_i, inPoint_i] = this.inPointPosition;
            // returns a static NodeList
            const currentBeforeEls = this.svgEl.querySelectorAll(`.before_in`);
            for (let currentBeforeEl of currentBeforeEls) {
                currentBeforeEl.classList.remove('before_in');
            }

            for (let index = 0; index < inPath_i; index++) {
                const pathEl = this.svgEl.querySelector(`.path${index}`);
                if (pathEl) {
                    pathEl.classList.add('before_in');
                }
            }
        }

        this.currentPathI = path_i;
        this.currentPointI = point_i;

        const path = this.strokes[path_i];
        // console.log(path);
        let pathEl = this.svgEl.querySelector(`.path${path_i}`);
        if (!pathEl) {
            pathEl = document.createElementNS('http://www.w3.org/2000/svg', 'path');
            pathEl.style.stroke = path.color;
            pathEl.classList.add('path' + path_i)
            this.svgEl.appendChild(pathEl)
        }

        const stroke = path.points.slice(0, point_i);
        const d = this.strokes2D(stroke);
        pathEl.setAttribute('d', d);

        this.scrubberElOld.value = path.points[point_i][3];
        this.currentTime = path.points[point_i][3];
    }

    getNextPosition(path_i, point_i) {
        const path = this.strokes[path_i];
        let next_path, next_point;
        if (path.points.length > point_i + 1) {
            next_path = path_i;
            next_point = point_i + 1;
            // setTimeout(() => this.playStroke(next_path, next_point), dt);
        } else if (this.strokes.length > path_i + 1) {
            next_path = path_i + 1;
            next_point = 1;
            // use starttime instead of diff, to prevent floating
        } else {
            return [null, null];
        }

        // when an outpoint is set, stop playing there
        if (this.outPointPosition && (next_path > this.outPointPosition[0] || next_point > this.outPointPosition[1])) {
            return [null, null];
        }

        return [next_path, next_point];
    }

    playStrokePosition(path_i, point_i, allow_interrupt) {
        if (allow_interrupt) {
            if (!this.isPlaying) {
                console.log('not playing because of interrupt');
                return;
            }
        } else {
            this.isPlaying = true;
        }
        this.drawStrokePosition(path_i, point_i);

        const [next_path, next_point] = this.getNextPosition(path_i, point_i);
        if (next_path === null) {
            console.log('done playing');
            return;
        }

        const t = this.strokes[next_path].points[next_point][3];// - path.points[point_i][3];

        const dt = t - (window.performance.now() - this.startTime);
        this.playTimout = setTimeout(() => this.playStrokePosition(next_path, next_point, true), dt);
    }

    playUntil(path_i) {
        // for scrubber
    }

    scrubTo(ms) {
        const [path_i, point_i] = this.findPositionForTime(ms);
        // console.log(path_i, point_i);
        clearTimeout(this.playTimout);
        this.playStrokePosition(path_i, point_i);
        // this.playHead = ms;
    }



    findPositionForTime(ms) {
        ms = Math.min(Math.max(ms, 0), this.duration);
        console.log('scrub to', ms)
        let path_i = 0;
        let point_i = 0;
        this.strokes.every((stroke, index) => {
            const startAt = stroke.points[0][3];
            const endAt = stroke.points[stroke.points.length - 1][3];

            if (startAt > ms) {
                return false; // too far
            }
            if (endAt > ms) {
                // we're getting close. Find the right point_i
                path_i = index;
                stroke.points.every((point, pi) => {
                    if (point[3] > ms) {
                        // too far
                        return false;
                    }
                    point_i = pi;
                    return true;
                });
                return false;
            } else {
                // in case nothings comes after, we store the last best option thus far
                path_i = index;
                point_i = stroke.points.length - 1;
                return true;
            }

        });
        return [path_i, point_i];
    }


    strokes2D(strokes) {
        // strokes to a d attribute for a path
        let d = "";
        let last_stroke = undefined;
        let cmd = "";
        for (let stroke of strokes) {
            if (!last_stroke) {
                d += `M${stroke[0]},${stroke[1]} `;
                cmd = 'M';
            } else {
                if (last_stroke[2] == 1) {
                    d += " m";
                    cmd = 'm';
                } else if (cmd != 'l') {
                    d += ' l ';
                    cmd = 'l';
                }
                let rel_stroke = [stroke[0] - last_stroke[0], stroke[1] - last_stroke[1]];
                d += `${rel_stroke[0]},${rel_stroke[1]} `;
            }
            last_stroke = stroke;

        }
        return d;
    }
}