transferFunctionEditor.js

const widgets = require('@jupyter-widgets/base');
const _ = require('./lodash');
const semverRange = require('./version').version;
const colorMapHelper = require('./core/lib/helpers/colorMap');
const serialize = require('./core/lib/helpers/serialize');

function K3DTransferFunctionEditor(targetDOMNode, parameters, onChange) {
    const svg = document.createElementNS('http://www.w3.org/2000/svg', 'svg');
    let opacityFunction = parameters.opacityFunction;
    const svgNS = svg.namespaceURI;
    let colorPicker;
    let colorMap = parameters.colorMap;
    let polygon;
    let draggableElement;
    let rect;
    const topMargin = 10;
    const bottomSection = 40;
    const bottomSpacing = 10;
    let opacityCircles = [];
    let colormapCircles = [];

    require('./k3d.css');

    function removeOpacityCircle(evt) {
        const el = evt.target.parentNode;
        const index = opacityCircles.indexOf(el);

        if (index === 0 || index === opacityCircles.length - 1) {
            return;
        }

        svg.removeChild(el);
        opacityCircles.splice(index, 1);
        opacityFunction.splice(index * 2, 2);
        refreshChart(svg, true);

        onChange({ key: 'opacity_function', value: opacityFunction });
        evt.preventDefault();
    }

    function removeColormapCircle(evt) {
        const el = evt.target.parentNode;
        const index = colormapCircles.indexOf(el);

        if (index === 0 || index === colormapCircles.length - 1) {
            return;
        }

        svg.removeChild(el);
        colormapCircles.splice(index, 1);
        colorMap.splice(index * 4, 4);
        refreshChart(svg, true);
        refreshRect(svg, true);

        onChange({ key: 'color_map', value: colorMap });
        evt.preventDefault();
    }

    function makeCircle(cx, cy, r) {
        const circle = document.createElementNS(svg.namespaceURI, 'g');

        [{ offset: 1, color: 'white' }, { offset: 0, color: 'black' }].forEach((conf) => {
            const c = document.createElementNS(svg.namespaceURI, 'circle');

            c.setAttribute('cx', cx + conf.offset);
            c.setAttribute('cy', cy + conf.offset);
            c.setAttribute('r', r);
            c.setAttribute('stroke-width', 1);
            c.setAttribute('stroke', conf.color);
            c.setAttribute('fill', 'transparent');

            circle.appendChild(c);
        });

        return circle;
    }

    function makeDraggable(dom) {
        dom.addEventListener('mousedown', startDragOrAddNew);
        dom.addEventListener('mousemove', drag);
        dom.addEventListener('mouseup', endDrag);
        dom.addEventListener('mouseleave', endDrag);
        dom.addEventListener('touchstart', startDragOrAddNew);
        dom.addEventListener('touchmove', drag);
        dom.addEventListener('touchend', endDrag);
        dom.addEventListener('touchleave', endDrag);
        dom.addEventListener('touchcancel', endDrag);

        function getMousePosition(evt) {
            const CTM = dom.getScreenCTM();
            if (evt.touches) {
                evt = evt.touches[0];
            }
            return {
                x: (evt.clientX - CTM.e) / CTM.a,
                y: (evt.clientY - CTM.f) / CTM.d,
            };
        }

        function startDragOrAddNew(evt) {
            if (evt.target.parentNode.classList.contains('draggable')) {
                draggableElement = evt.target.parentNode;
            } else {
                const coord = getMousePosition(evt);

                if (coord.y > topMargin && coord.y < dom.clientHeight - bottomSection) {
                    opacityFunction.push(colorMap[0] + (coord.x / dom.clientWidth)
                        * (colorMap[colorMap.length - 4] - colorMap[0]));
                    opacityFunction.push(1.0 - (coord.y - topMargin) / (dom.clientHeight - topMargin - bottomSection));

                    opacityFunction = ensureArraySorted(opacityFunction, 1);

                    refreshChart(dom, false);
                    onChange({ key: 'opacity_function', value: opacityFunction });
                }

                if (coord.y > dom.clientHeight - bottomSection + bottomSpacing) {
                    const newX = colorMap[0] + (coord.x / dom.clientWidth)
                        * (colorMap[colorMap.length - 4] - colorMap[0]);
                    let
                        i;
                    // new point injected
                    const data = colorMapHelper.mergeColorMapWithOpacity(colorMap,
                        [
                            colorMap[0], 0.0,
                            newX, 0.5,
                            colorMap[colorMap.length - 4], 1.0,
                        ]);

                    for (i = 0; i < data.length; i += 5) {
                        if (data[i] === newX) {
                            colorMap = colorMap.concat(data.slice(i, i + 4));
                        }
                    }

                    colorMap = ensureArraySorted(colorMap, 3);

                    refreshRect(dom, false);
                    onChange({ key: 'color_map', value: colorMap });
                }
            }
        }

        function drag(evt) {
            let index;

            if (draggableElement) {
                evt.preventDefault();

                const coord = getMousePosition(evt);

                if (draggableElement.classList.contains('polygon')) {
                    index = opacityCircles.indexOf(draggableElement);

                    coord.y = Math.max(coord.y, topMargin);
                    coord.y = Math.min(coord.y, dom.clientHeight - bottomSection);

                    if (index === 0 || index === opacityCircles.length - 1) {
                        coord.x = parseFloat(draggableElement.childNodes[1].getAttribute('cx'));
                    } else {
                        coord.x = Math.min(coord.x,
                            parseFloat(opacityCircles[index + 1].childNodes[1].getAttribute('cx')) - 1);
                        coord.x = Math.max(coord.x,
                            parseFloat(opacityCircles[index - 1].childNodes[1].getAttribute('cx')) + 1);
                    }

                    opacityFunction[index * 2] = colorMap[0] + (coord.x / dom.clientWidth)
                        * (colorMap[colorMap.length - 4] - colorMap[0]);
                    opacityFunction[index * 2 + 1] = 1.0 - (coord.y - topMargin)
                        / (dom.clientHeight - topMargin - bottomSection);

                    onChange({ key: 'opacity_function', value: opacityFunction });
                }

                if (draggableElement.classList.contains('colormap')) {
                    index = colormapCircles.indexOf(draggableElement);

                    coord.y = parseFloat(draggableElement.childNodes[1].getAttribute('cy'));

                    if (index === 0 || index === colormapCircles.length - 1) {
                        coord.x = parseFloat(draggableElement.childNodes[1].getAttribute('cx'));
                    } else {
                        coord.x = Math.min(coord.x,
                            parseFloat(colormapCircles[index + 1].childNodes[1].getAttribute('cx')) - 1);
                        coord.x = Math.max(coord.x,
                            parseFloat(colormapCircles[index - 1].childNodes[1].getAttribute('cx')) + 1);
                    }

                    colorMap[index * 4] = colorMap[0] + (coord.x / dom.clientWidth)
                        * (colorMap[colorMap.length - 4] - colorMap[0]);

                    onChange({ key: 'color_map', value: colorMap });
                }

                draggableElement.childNodes.forEach((el, idx) => {
                    el.setAttribute('cx', coord.x + 1 - idx);
                    el.setAttribute('cy', coord.y + 1 - idx);
                });

                refreshRect(dom, true);
                refreshChart(dom, true);
            }
        }

        function endDrag() {
            draggableElement = false;
        }
    }

    function ensureArraySorted(data, propertiesCount) {
        return data.reduce((prev, value, index) => {
            if (index % (1 + propertiesCount) === 0) {
                prev.push({ v: value, p: data.slice(index + 1, index + 1 + propertiesCount) });
            }

            return prev;
        }, []).sort((a, b) => a.v - b.v).reduce((prev, value) => {
            prev.push(value.v);
            value.p.forEach((v) => {
                prev.push(v);
            });

            return prev;
        }, []);
    }

    function refreshRect(dom, skipCircles) {
        let i;

        colorMapHelper.createSVGGradient(dom, 'colorMap', colorMap, null, true);

        rect.setAttribute('x', 0);
        rect.setAttribute('y', dom.clientHeight - bottomSection + bottomSpacing);
        rect.setAttribute('width', dom.clientWidth);
        rect.setAttribute('height', bottomSection - bottomSpacing);

        if (!skipCircles) {
            colormapCircles.forEach((el) => {
                dom.removeChild(el);
            });

            colormapCircles = [];

            for (i = 0; i < colorMap.length; i += 4) {
                const circle = makeCircle(
                    ((colorMap[i] - colorMap[0]) / (colorMap[colorMap.length - 4] - colorMap[0])) * dom.clientWidth,
                    dom.clientHeight - (bottomSection - bottomSpacing) / 2,
                    5,
                );
                circle.classList.add('draggable');
                circle.classList.add('colormap');

                circle.addEventListener('contextmenu', removeColormapCircle);
                circle.addEventListener('dblclick', (evt) => {
                    const index = colormapCircles.indexOf(evt.target.parentElement);

                    function getColor(colorEvent) {
                        const hex = colorEvent.target.value.substr(1);

                        colorMap[colorPicker.k3dIndex * 4 + 1] = parseInt(hex.substring(0, 2), 16) / 255;
                        colorMap[colorPicker.k3dIndex * 4 + 2] = parseInt(hex.substring(2, 4), 16) / 255;
                        colorMap[colorPicker.k3dIndex * 4 + 3] = parseInt(hex.substring(4, 6), 16) / 255;

                        refreshRect(dom, true);
                        refreshChart(dom, true);
                        onChange({ key: 'color_map', value: colorMap });
                        colorPicker.removeEventListener('change', getColor);
                    }

                    const r = `0${Math.round(colorMap[index * 4 + 1] * 255).toString(16)}`;
                    const g = `0${Math.round(colorMap[index * 4 + 2] * 255).toString(16)}`;
                    const b = `0${Math.round(colorMap[index * 4 + 3] * 255).toString(16)}`;

                    colorPicker.k3dIndex = index;
                    colorPicker.value = `#${r.substr(-2)}${g.substr(-2)}${b.substr(-2)}`;
                    colorPicker.click();

                    colorPicker.addEventListener('change', getColor);
                });

                dom.appendChild(circle);
                colormapCircles.push(circle);
            }
        }
    }

    function refreshChart(dom, skipCircles) {
        let i;

        const path = opacityFunction.concat([colorMap[colorMap.length - 4], 0, colorMap[0], 0]);
        colorMapHelper.createSVGGradient(dom, 'transferFunction', colorMap, opacityFunction, true);

        polygon.points.clear();

        for (i = 0; i < path.length; i += 2) {
            const point = dom.createSVGPoint();
            point.x = ((path[i] - colorMap[0]) / (colorMap[colorMap.length - 4] - colorMap[0])) * dom.clientWidth;
            point.y = (1.0 - path[i + 1]) * (dom.clientHeight - topMargin - bottomSection) + topMargin;
            polygon.points.appendItem(point);
        }

        polygon.setAttribute('fill', 'url(#transferFunction)');
        polygon.setAttribute('stroke-width', 1);
        polygon.setAttribute('stroke', 'black');

        if (!skipCircles) {
            opacityCircles.forEach((el) => {
                dom.removeChild(el);
            });

            opacityCircles = [];

            for (i = 0; i < opacityFunction.length; i += 2) {
                const circle = makeCircle(
                    ((opacityFunction[i] - colorMap[0]) / (colorMap[colorMap.length - 4] - colorMap[0]))
                    * dom.clientWidth,
                    (1.0 - opacityFunction[i + 1])
                    * (dom.clientHeight - topMargin - bottomSection) + topMargin,
                    5,
                );

                circle.classList.add('draggable');
                circle.classList.add('polygon');

                circle.addEventListener('contextmenu', removeOpacityCircle);

                dom.appendChild(circle);
                opacityCircles.push(circle);
            }
        }
    }

    // set width and height
    svg.setAttribute('width', '100%');
    svg.setAttribute('height', '100%');
    svg.classList.add('k3d-transfer-function');

    polygon = document.createElementNS(svgNS, 'polygon');
    rect = document.createElementNS(svgNS, 'rect');
    rect.setAttribute('fill', 'url(#colorMap)');

    svg.appendChild(polygon);
    svg.appendChild(rect);

    colorPicker = document.createElement('input');
    colorPicker.setAttribute('type', 'color');
    colorPicker.classList.add('k3d-color-picker');

    targetDOMNode.appendChild(svg);
    targetDOMNode.appendChild(colorPicker);

    function refresh() {
        refreshChart(svg);
        refreshRect(svg);
    }

    window.addEventListener('resize', refresh, false);

    makeDraggable(svg);

    colorMap = ensureArraySorted(colorMap, 3);
    opacityFunction = ensureArraySorted(opacityFunction, 1);
    refresh();

    this.refresh = refresh;

    this.setColorMap = function (cm) {
        colorMap = cm;
        refresh();
    };

    this.setOpacityFunction = function (of) {
        opacityFunction = of;
        refresh();
    };

    this.getColorMap = function () {
        return colorMap;
    };

    this.getOpacityFunction = function () {
        return opacityFunction;
    };

    this.isDragging = function () {
        return draggableElement !== false;
    };
}

const transferFunctionModel = widgets.DOMWidgetModel.extend({
    defaults: _.extend(_.result({}, 'widgets.DOMWidgetModel.prototype.defaults'), {
        _model_name: 'TransferFunctionModel',
        _view_name: 'TransferFunctionView',
        _model_module: 'k3d',
        _view_module: 'k3d',
        _model_module_version: semverRange,
        _view_module_version: semverRange,
    }),
}, {
    serializers: _.extend({
        color_map: serialize,
        opacity_function: serialize,
    }, widgets.DOMWidgetModel.serializers),
});

const transferFunctionView = widgets.DOMWidgetView.extend({
    render() {
        const containerEnvelope = window.document.createElement('div');
        const container = window.document.createElement('div');

        containerEnvelope.style.cssText = [
            `height:${this.model.get('height')}px`,
            'position: relative',
        ].join(';');

        container.style.cssText = [
            'width: 100%',
            'height: 100%',
            'position: relative',
        ].join(';');

        containerEnvelope.appendChild(container);
        this.el.appendChild(containerEnvelope);

        this.container = container;
        this.on('displayed', this._init, this);
    },

    remove() {

    },

    _init() {
        const self = this;

        this.model.on('change:color_map', this._setColorMap, this);
        this.model.on('change:opacity_function', this._setOpacityFunction, this);

        try {
            this.K3DTransferFunctionEditorInstance = new K3DTransferFunctionEditor(this.container, {
                height: this.model.get('height'),
                colorMap: Array.from(this.model.get('color_map').data),
                opacityFunction: Array.from(this.model.get('opacity_function').data),
            }, ((change) => {
                self.model.set(change.key, {
                    data: new Float32Array(change.value),
                    shape: [change.value.length],
                }, { updated_view: self });
                self.model.save_changes();
            }));
        } catch (e) {
            console.log(e);
        }
    },

    _setColorMap(widget, change, options) {
        if (options.updated_view === this || this.K3DTransferFunctionEditorInstance.isDragging()) {
            return;
        }

        const data = Array.from(this.model.get('color_map').data);
        this.K3DTransferFunctionEditorInstance.setColorMap(Array.from(data));
    },

    _setOpacityFunction(widget, change, options) {
        if (options.updated_view === this || this.K3DTransferFunctionEditorInstance.isDragging()) {
            return;
        }

        const data = this.model.get('opacity_function').data;
        this.K3DTransferFunctionEditorInstance.setOpacityFunction(Array.from(data));
    },

    processPhosphorMessage(msg) {
        widgets.DOMWidgetView.prototype.processPhosphorMessage.call(this, msg);
        switch (msg.type) {
            case 'after-attach':
                this.el.addEventListener('contextmenu', this, true);
                break;
            case 'before-detach':
                this.el.removeEventListener('contextmenu', this, true);
                break;
            case 'resize':
                this.handleResize(msg);
                break;
            default:
                break;
        }
    },

    handleEvent(event) {
        switch (event.type) {
            case 'contextmenu':
                this.handleContextMenu(event);
                break;
            default:
                widgets.DOMWidgetView.prototype.handleEvent.call(this, event);
                break;
        }
    },

    handleContextMenu() {
        // // Cancel context menu if on renderer:
        // if (this.container.contains(event.target)) {
        //     event.preventDefault();
        //     event.stopPropagation();
        // }
    },

    handleResize() {
        if (this.K3DTransferFunctionEditorInstance) {
            this.K3DTransferFunctionEditorInstance.refresh();
        }
    },
});

module.exports = {
    transferFunctionModel,
    transferFunctionView,
    transferFunctionEditor: K3DTransferFunctionEditor,
};