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260 lines
7.6 KiB
260 lines
7.6 KiB
let util = require('../../../../util');
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/**
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* Created by Alex on 3/17/2015.
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*/
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class Label {
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constructor(body,options) {
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this.body = body;
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this.fontOptions = {};
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this.defaultOptions = {
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color: '#343434',
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size: 14, // px
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face: 'arial',
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background: 'none',
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stroke: 0, // px
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strokeColor: 'white',
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align:'horizontal'
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}
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util.extend(this.fontOptions, this.defaultOptions);
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this.setOptions(options);
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this.size = {top: 0, left: 0, width: 0, height: 0, yLine: 0}; // could be cached
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}
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setOptions(options) {
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this.options = options;
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if (options.label !== undefined) {
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this.labelDirty = true;
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}
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if (options.font) {
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if (typeof options.font === 'string') {
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let optionsArray = options.font.split(" ");
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this.fontOptions.size = optionsArray[0].replace("px",'');
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this.fontOptions.face = optionsArray[1];
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this.fontOptions.color = optionsArray[2];
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}
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else if (typeof options.font === 'object') {
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this.fontOptions = util.bridgeObject(options.font);
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}
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this.fontOptions.size = Number(this.fontOptions.size);
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}
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}
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/**
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* Main function. This is called from anything that wants to draw a label.
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* @param ctx
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* @param x
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* @param y
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* @param selected
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* @param baseline
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*/
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draw(ctx, x, y, selected, baseline = 'middle') {
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// if no label, return
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if (this.options.label === undefined)
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return;
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// check if we have to render the label
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let viewFontSize = this.fontOptions.size * this.body.view.scale;
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if (this.options.label && viewFontSize < this.options.scaling.label.drawThreshold - 1)
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return;
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// update the size cache if required
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this.calculateLabelSize(ctx, selected, x, y, baseline);
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// create the fontfill background
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this._drawBackground(ctx);
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// draw text
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this._drawText(ctx, selected, x, y, baseline);
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}
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/**
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* Draws the label background
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* @param {CanvasRenderingContext2D} ctx
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* @private
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*/
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_drawBackground(ctx) {
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if (this.fontOptions.background !== undefined && this.fontOptions.background !== "none") {
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ctx.fillStyle = this.fontOptions.background;
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let lineMargin = 2;
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switch (this.fontOptions.align) {
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case 'middle':
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ctx.fillRect(-this.size.width * 0.5, -this.size.height * 0.5, this.size.width, this.size.height);
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break;
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case 'top':
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ctx.fillRect(-this.size.width * 0.5, -(this.size.height + lineMargin), this.size.width, this.size.height);
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break;
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case 'bottom':
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ctx.fillRect(-this.size.width * 0.5, lineMargin, this.size.width, this.size.height);
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break
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default:
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ctx.fillRect(this.size.left, this.size.top, this.size.width, this.size.height);
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break;
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}
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}
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}
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/**
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*
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* @param ctx
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* @param x
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* @param baseline
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* @private
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*/
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_drawText(ctx, selected, x, y, baseline = 'middle') {
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let fontSize = this.fontOptions.size;
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let viewFontSize = fontSize * this.body.view.scale;
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// this ensures that there will not be HUGE letters on screen by setting an upper limit on the visible text size (regardless of zoomLevel)
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if (viewFontSize >= this.options.scaling.label.maxVisible) {
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fontSize = Number(this.options.scaling.label.maxVisible) / this.body.view.scale;
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}
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let yLine = this.size.yLine;
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let [fontColor, strokeColor] = this._getColor(viewFontSize);
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[x, yLine] = this._setAlignment(ctx, x, yLine, baseline);
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// configure context for drawing the text
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ctx.font = (selected ? 'bold ' : '') + fontSize + "px " + this.fontOptions.face;
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ctx.fillStyle = fontColor;
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ctx.textAlign = 'center';
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// set the strokeWidth
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if (this.fontOptions.stroke > 0) {
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ctx.lineWidth = this.fontOptions.stroke;
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ctx.strokeStyle = strokeColor;
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ctx.lineJoin = 'round';
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}
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// draw the text
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for (let i = 0; i < this.lineCount; i++) {
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if (this.fontOptions.stroke > 0) {
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ctx.strokeText(this.lines[i], x, yLine);
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}
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ctx.fillText(this.lines[i], x, yLine);
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yLine += fontSize;
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}
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}
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_setAlignment(ctx, x, yLine, baseline) {
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// check for label alignment (for edges)
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// TODO: make alignment for nodes
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if (this.fontOptions.align !== 'horizontal') {
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x = 0;
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yLine = 0;
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let lineMargin = 2;
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if (this.fontOptions.align === 'top') {
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ctx.textBaseline = 'alphabetic';
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yLine -= 2 * lineMargin; // distance from edge, required because we use alphabetic. Alphabetic has less difference between browsers
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}
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else if (this.fontOptions.align === 'bottom') {
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ctx.textBaseline = 'hanging';
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yLine += 2 * lineMargin;// distance from edge, required because we use hanging. Hanging has less difference between browsers
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}
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else {
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ctx.textBaseline = 'middle';
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}
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}
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else {
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ctx.textBaseline = baseline;
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}
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return [x,yLine];
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}
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/**
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* fade in when relative scale is between threshold and threshold - 1.
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* If the relative scale would be smaller than threshold -1 the draw function would have returned before coming here.
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*
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* @param viewFontSize
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* @returns {*[]}
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* @private
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*/
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_getColor(viewFontSize) {
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let fontColor = this.fontOptions.color || '#000000';
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let strokeColor = this.fontOptions.strokeColor || '#ffffff';
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if (viewFontSize <= this.options.scaling.label.drawThreshold) {
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let opacity = Math.max(0, Math.min(1, 1 - (this.options.scaling.label.drawThreshold - viewFontSize)));
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fontColor = util.overrideOpacity(fontColor, opacity);
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strokeColor = util.overrideOpacity(strokeColor, opacity);
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}
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return [fontColor, strokeColor];
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}
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/**
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*
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* @param ctx
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* @param selected
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* @returns {{width: number, height: number}}
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*/
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getTextSize(ctx, selected = false) {
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let size = {
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width: this._processLabel(ctx,selected),
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height: this.fontOptions.size * this.lineCount
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};
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return size;
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}
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/**
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*
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* @param ctx
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* @param selected
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* @param x
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* @param y
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* @param baseline
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*/
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calculateLabelSize(ctx, selected, x = 0, y = 0, baseline = 'middle') {
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if (this.labelDirty === true) {
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this.size.width = this._processLabel(ctx,selected);
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}
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this.size.height = this.fontOptions.size * this.lineCount;
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this.size.left = x - this.size.width * 0.5;
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this.size.top = y - this.size.height * 0.5;
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this.size.yLine = y + (1 - this.lineCount) * 0.5 * this.fontOptions.size;
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if (baseline === "hanging") {
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this.size.top += 0.5 * this.fontOptions.size;
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this.size.top += 4; // distance from node, required because we use hanging. Hanging has less difference between browsers
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this.size.yLine += 4; // distance from node
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}
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this.labelDirty = false;
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}
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/**
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* This calculates the width as well as explodes the label string and calculates the amount of lines.
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* @param ctx
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* @param selected
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* @returns {number}
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* @private
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*/
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_processLabel(ctx,selected) {
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let width = 0;
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let lines = [''];
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let lineCount = 0;
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if (this.options.label !== undefined) {
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lines = String(this.options.label).split('\n');
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lineCount = lines.length;
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ctx.font = (selected ? 'bold ' : '') + this.fontOptions.size + "px " + this.fontOptions.face;
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width = ctx.measureText(lines[0]).width;
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for (let i = 1; i < lineCount; i++) {
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let lineWidth = ctx.measureText(lines[i]).width;
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width = lineWidth > width ? lineWidth : width;
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}
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}
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this.lines = lines;
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this.lineCount = lineCount;
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return width;
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}
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}
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export default Label;
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