vis.js is a dynamic, browser-based visualization library
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let LabelAccumulator = require('./LabelAccumulator').default;
/**
* Helper class for Label which explodes the label text into lines and blocks within lines
*
* @private
*/
class LabelSplitter {
/**
* @param {CanvasRenderingContext2D} ctx Canvas rendering context
* @param {Label} parent reference to the Label instance using current instance
* @param {boolean} selected
* @param {boolean} hover
*/
constructor(ctx, parent, selected, hover) {
this.ctx = ctx;
this.parent = parent;
/**
* Callback to determine text width; passed to LabelAccumulator instance
*
* @param {String} text string to determine width of
* @param {String} mod font type to use for this text
* @return {Object} { width, values} width in pixels and font attributes
*/
let textWidth = (text, mod) => {
if (text === undefined) return 0;
// TODO: This can be done more efficiently with caching
let values = this.parent.getFormattingValues(ctx, selected, hover, mod);
let width = 0;
if (text !== '') {
// NOTE: The following may actually be *incorrect* for the mod fonts!
// This returns the size with a regular font, bold etc. may
// have different sizes.
let measure = this.ctx.measureText(text);
width = measure.width;
}
return {width, values: values};
};
this.lines = new LabelAccumulator(textWidth);
}
/**
* Split passed text of a label into lines and blocks.
*
* # NOTE
*
* The handling of spacing is option dependent:
*
* - if `font.multi : false`, all spaces are retained
* - if `font.multi : true`, every sequence of spaces is compressed to a single space
*
* This might not be the best way to do it, but this is as it has been working till now.
* In order not to break existing functionality, for the time being this behaviour will
* be retained in any code changes.
*
* @param {string} text text to split
* @returns {Array<line>}
*/
process(text) {
if (text === undefined || text === "") {
return this.lines.finalize();
}
var font = this.parent.fontOptions;
// Normalize the end-of-line's to a single representation - order important
text = text.replace(/\r\n/g, '\n'); // Dos EOL's
text = text.replace(/\r/g, '\n'); // Mac EOL's
// Note that at this point, there can be no \r's in the text.
// This is used later on splitStringIntoLines() to split multifont texts.
let nlLines = String(text).split('\n');
let lineCount = nlLines.length;
if (font.multi) {
// Multi-font case: styling tags active
for (let i = 0; i < lineCount; i++) {
let blocks = this.splitBlocks(nlLines[i], font.multi);
// Post: Sequences of tabs and spaces are reduced to single space
if (blocks === undefined) continue;
if (blocks.length === 0) {
this.lines.newLine("");
continue;
}
if (font.maxWdt > 0) {
// widthConstraint.maximum defined
//console.log('Running widthConstraint multi, max: ' + this.fontOptions.maxWdt);
for (let j = 0; j < blocks.length; j++) {
let mod = blocks[j].mod;
let text = blocks[j].text;
this.splitStringIntoLines(text, mod, true);
}
} else {
// widthConstraint.maximum NOT defined
for (let j = 0; j < blocks.length; j++) {
let mod = blocks[j].mod;
let text = blocks[j].text;
this.lines.append(text, mod);
}
}
this.lines.newLine();
}
} else {
// Single-font case
if (font.maxWdt > 0) {
// widthConstraint.maximum defined
// console.log('Running widthConstraint normal, max: ' + this.fontOptions.maxWdt);
for (let i = 0; i < lineCount; i++) {
this.splitStringIntoLines(nlLines[i]);
}
} else {
// widthConstraint.maximum NOT defined
for (let i = 0; i < lineCount; i++) {
this.lines.newLine(nlLines[i]);
}
}
}
return this.lines.finalize();
}
/**
* normalize the markup system
*
* @param {boolean|'md'|'markdown'|'html'} markupSystem
* @returns {string}
*/
decodeMarkupSystem(markupSystem) {
let system = 'none';
if (markupSystem === 'markdown' || markupSystem === 'md') {
system = 'markdown';
} else if (markupSystem === true || markupSystem === 'html') {
system = 'html'
}
return system;
}
/**
*
* @param {string} text
* @returns {Array}
*/
splitHtmlBlocks(text) {
let blocks = [];
// TODO: consolidate following + methods/closures with splitMarkdownBlocks()
// NOTE: sequences of tabs and spaces are reduced to single space; scan usage of `this.spacing` within method
let s = {
bold: false,
ital: false,
mono: false,
spacing: false,
position: 0,
buffer: "",
modStack: []
};
s.mod = function() {
return (this.modStack.length === 0) ? 'normal' : this.modStack[0];
};
s.modName = function() {
if (this.modStack.length === 0)
return 'normal';
else if (this.modStack[0] === 'mono')
return 'mono';
else {
if (s.bold && s.ital) {
return 'boldital';
} else if (s.bold) {
return 'bold';
} else if (s.ital) {
return 'ital';
}
}
};
s.emitBlock = function(override=false) { // eslint-disable-line no-unused-vars
if (this.spacing) {
this.add(" ");
this.spacing = false;
}
if (this.buffer.length > 0) {
blocks.push({ text: this.buffer, mod: this.modName() });
this.buffer = "";
}
};
s.add = function(text) {
if (text === " ") {
s.spacing = true;
}
if (s.spacing) {
this.buffer += " ";
this.spacing = false;
}
if (text != " ") {
this.buffer += text;
}
};
while (s.position < text.length) {
let ch = text.charAt(s.position);
if (/[ \t]/.test(ch)) {
if (!s.mono) {
s.spacing = true;
} else {
s.add(ch);
}
} else if (/</.test(ch)) {
if (!s.mono && !s.bold && /<b>/.test(text.substr(s.position,3))) {
s.emitBlock();
s.bold = true;
s.modStack.unshift("bold");
s.position += 2;
} else if (!s.mono && !s.ital && /<i>/.test(text.substr(s.position,3))) {
s.emitBlock();
s.ital = true;
s.modStack.unshift("ital");
s.position += 2;
} else if (!s.mono && /<code>/.test(text.substr(s.position,6))) {
s.emitBlock();
s.mono = true;
s.modStack.unshift("mono");
s.position += 5;
} else if (!s.mono && (s.mod() === 'bold') && /<\/b>/.test(text.substr(s.position,4))) {
s.emitBlock();
s.bold = false;
s.modStack.shift();
s.position += 3;
} else if (!s.mono && (s.mod() === 'ital') && /<\/i>/.test(text.substr(s.position,4))) {
s.emitBlock();
s.ital = false;
s.modStack.shift();
s.position += 3;
} else if ((s.mod() === 'mono') && /<\/code>/.test(text.substr(s.position,7))) {
s.emitBlock();
s.mono = false;
s.modStack.shift();
s.position += 6;
} else {
s.add(ch);
}
} else if (/&/.test(ch)) {
if (/&lt;/.test(text.substr(s.position,4))) {
s.add("<");
s.position += 3;
} else if (/&amp;/.test(text.substr(s.position,5))) {
s.add("&");
s.position += 4;
} else {
s.add("&");
}
} else {
s.add(ch);
}
s.position++
}
s.emitBlock();
return blocks;
}
/**
*
* @param {string} text
* @returns {Array}
*/
splitMarkdownBlocks(text) {
let blocks = [];
// TODO: consolidate following + methods/closures with splitHtmlBlocks()
// NOTE: sequences of tabs and spaces are reduced to single space; scan usage of `this.spacing` within method
let s = {
bold: false,
ital: false,
mono: false,
beginable: true,
spacing: false,
position: 0,
buffer: "",
modStack: []
};
s.mod = function() {
return (this.modStack.length === 0) ? 'normal' : this.modStack[0];
};
s.modName = function() {
if (this.modStack.length === 0)
return 'normal';
else if (this.modStack[0] === 'mono')
return 'mono';
else {
if (s.bold && s.ital) {
return 'boldital';
} else if (s.bold) {
return 'bold';
} else if (s.ital) {
return 'ital';
}
}
};
s.emitBlock = function(override=false) { // eslint-disable-line no-unused-vars
if (this.spacing) {
this.add(" ");
this.spacing = false;
}
if (this.buffer.length > 0) {
blocks.push({ text: this.buffer, mod: this.modName() });
this.buffer = "";
}
};
s.add = function(text) {
if (text === " ") {
s.spacing = true;
}
if (s.spacing) {
this.buffer += " ";
this.spacing = false;
}
if (text != " ") {
this.buffer += text;
}
};
while (s.position < text.length) {
let ch = text.charAt(s.position);
if (/[ \t]/.test(ch)) {
if (!s.mono) {
s.spacing = true;
} else {
s.add(ch);
}
s.beginable = true
} else if (/\\/.test(ch)) {
if (s.position < text.length+1) {
s.position++;
ch = text.charAt(s.position);
if (/ \t/.test(ch)) {
s.spacing = true;
} else {
s.add(ch);
s.beginable = false;
}
}
} else if (!s.mono && !s.bold && (s.beginable || s.spacing) && /\*/.test(ch)) {
s.emitBlock();
s.bold = true;
s.modStack.unshift("bold");
} else if (!s.mono && !s.ital && (s.beginable || s.spacing) && /\_/.test(ch)) {
s.emitBlock();
s.ital = true;
s.modStack.unshift("ital");
} else if (!s.mono && (s.beginable || s.spacing) && /`/.test(ch)) {
s.emitBlock();
s.mono = true;
s.modStack.unshift("mono");
} else if (!s.mono && (s.mod() === "bold") && /\*/.test(ch)) {
if ((s.position === text.length-1) || /[.,_` \t\n]/.test(text.charAt(s.position+1))) {
s.emitBlock();
s.bold = false;
s.modStack.shift();
} else {
s.add(ch);
}
} else if (!s.mono && (s.mod() === "ital") && /\_/.test(ch)) {
if ((s.position === text.length-1) || /[.,*` \t\n]/.test(text.charAt(s.position+1))) {
s.emitBlock();
s.ital = false;
s.modStack.shift();
} else {
s.add(ch);
}
} else if (s.mono && (s.mod() === "mono") && /`/.test(ch)) {
if ((s.position === text.length-1) || (/[.,*_ \t\n]/.test(text.charAt(s.position+1)))) {
s.emitBlock();
s.mono = false;
s.modStack.shift();
} else {
s.add(ch);
}
} else {
s.add(ch);
s.beginable = false;
}
s.position++
}
s.emitBlock();
return blocks;
}
/**
* Explodes a piece of text into single-font blocks using a given markup
*
* @param {string} text
* @param {boolean|'md'|'markdown'|'html'} markupSystem
* @returns {Array.<{text: string, mod: string}>}
* @private
*/
splitBlocks(text, markupSystem) {
let system = this.decodeMarkupSystem(markupSystem);
if (system === 'none') {
return [{
text: text,
mod: 'normal'
}]
} else if (system === 'markdown') {
return this.splitMarkdownBlocks(text);
} else if (system === 'html') {
return this.splitHtmlBlocks(text);
}
}
/**
* @param {string} text
* @returns {boolean} true if text length over the current max with
* @private
*/
overMaxWidth(text) {
let width = this.ctx.measureText(text).width;
return (this.lines.curWidth() + width > this.parent.fontOptions.maxWdt);
}
/**
* Determine the longest part of the sentence which still fits in the
* current max width.
*
* @param {Array} words Array of strings signifying a text lines
* @return {number} index of first item in string making string go over max
* @private
*/
getLongestFit(words) {
let text = '';
let w = 0;
while (w < words.length) {
let pre = (text === '') ? '' : ' ';
let newText = text + pre + words[w];
if (this.overMaxWidth(newText)) break;
text = newText;
w++;
}
return w;
}
/**
* Determine the longest part of the string which still fits in the
* current max width.
*
* @param {Array} words Array of strings signifying a text lines
* @return {number} index of first item in string making string go over max
*/
getLongestFitWord(words) {
let w = 0;
while (w < words.length) {
if (this.overMaxWidth(words.slice(0,w))) break;
w++;
}
return w;
}
/**
* Split the passed text into lines, according to width constraint (if any).
*
* The method assumes that the input string is a single line, i.e. without lines break.
*
* This method retains spaces, if still present (case `font.multi: false`).
* A space which falls on an internal line break, will be replaced by a newline.
* There is no special handling of tabs; these go along with the flow.
*
* @param {string} str
* @param {string} [mod='normal']
* @param {boolean} [appendLast=false]
* @private
*/
splitStringIntoLines(str, mod = 'normal', appendLast = false) {
// Still-present spaces are relevant, retain them
str = str.replace(/^( +)/g, '$1\r');
str = str.replace(/([^\r][^ ]*)( +)/g, '$1\r$2\r');
let words = str.split('\r');
while (words.length > 0) {
let w = this.getLongestFit(words);
if (w === 0) {
// Special case: the first word is already larger than the max width.
let word = words[0];
// Break the word to the largest part that fits the line
let x = this.getLongestFitWord(word);
this.lines.newLine(word.slice(0, x), mod);
// Adjust the word, so that the rest will be done next iteration
words[0] = word.slice(x);
} else {
// skip any space that is replaced by a newline
let newW = w;
if (words[w - 1] === ' ') {
w--;
} else if (words[newW] === ' ') {
newW++;
}
let text = words.slice(0, w).join("");
if (w == words.length && appendLast) {
this.lines.append(text, mod);
} else {
this.lines.newLine(text, mod);
}
// Adjust the word, so that the rest will be done next iteration
words = words.slice(newW);
}
}
}
}
export default LabelSplitter;