let LabelAccumulator = require('./LabelAccumulator').default;
let ComponentUtil = require('./ComponentUtil').default;
// Hash of prepared regexp's for tags
var tagPattern = {
// HTML
'<b>': /<b>/,
'<i>': /<i>/,
'<code>': /<code>/,
'</b>': /<\/b>/,
'</i>': /<\/i>/,
'</code>': /<\/code>/,
// Markdown
'*': /\*/, // bold
'_': /\_/, // ital
'`': /`/, // mono
'afterBold': /[^\*]/,
'afterItal': /[^_]/,
'afterMono': /[^`]/,
};
/**
* Internal helper class for parsing the markup tags for HTML and Markdown.
*
* NOTE: Sequences of tabs and spaces are reduced to single space.
* Scan usage of `this.spacing` within method
*/
class MarkupAccumulator {
/**
* Create an instance
*
* @param {string} text text to parse for markup
*/
constructor(text) {
this.text = text;
this.bold = false;
this.ital = false;
this.mono = false;
this.spacing = false;
this.position = 0;
this.buffer = "";
this.modStack = [];
this.blocks = [];
}
/**
* Return the mod label currently on the top of the stack
*
* @returns {string} label of topmost mod
* @private
*/
mod() {
return (this.modStack.length === 0) ? 'normal' : this.modStack[0];
}
/**
* Return the mod label currently active
*
* @returns {string} label of active mod
* @private
*/
modName() {
if (this.modStack.length === 0)
return 'normal';
else if (this.modStack[0] === 'mono')
return 'mono';
else {
if (this.bold && this.ital) {
return 'boldital';
} else if (this.bold) {
return 'bold';
} else if (this.ital) {
return 'ital';
}
}
}
/**
* @private
*/
emitBlock() {
if (this.spacing) {
this.add(" ");
this.spacing = false;
}
if (this.buffer.length > 0) {
this.blocks.push({ text: this.buffer, mod: this.modName() });
this.buffer = "";
}
}
/**
* Output text to buffer
*
* @param {string} text text to add
* @private
*/
add(text) {
if (text === " ") {
this.spacing = true;
}
if (this.spacing) {
this.buffer += " ";
this.spacing = false;
}
if (text != " ") {
this.buffer += text;
}
}
/**
* Handle parsing of whitespace
*
* @param {string} ch the character to check
* @returns {boolean} true if the character was processed as whitespace, false otherwise
*/
parseWS(ch) {
if (/[ \t]/.test(ch)) {
if (!this.mono) {
this.spacing = true;
} else {
this.add(ch);
}
return true;
}
return false;
}
/**
* @param {string} tagName label for block type to set
* @private
*/
setTag(tagName) {
this.emitBlock();
this[tagName] = true;
this.modStack.unshift(tagName);
}
/**
* @param {string} tagName label for block type to unset
* @private
*/
unsetTag(tagName) {
this.emitBlock();
this[tagName] = false;
this.modStack.shift();
}
/**
* @param {string} tagName label for block type we are currently processing
* @param {string|RegExp} tag string to match in text
* @returns {boolean} true if the tag was processed, false otherwise
*/
parseStartTag(tagName, tag) {
// Note: if 'mono' passed as tagName, there is a double check here. This is OK
if (!this.mono && !this[tagName] && this.match(tag)) {
this.setTag(tagName);
return true;
}
return false;
}
/**
* @param {string|RegExp} tag
* @param {number} [advance=true] if set, advance current position in text
* @returns {boolean} true if match at given position, false otherwise
* @private
*/
match(tag, advance = true) {
let [regExp, length] = this.prepareRegExp(tag);
let matched = regExp.test(this.text.substr(this.position, length));
if (matched && advance) {
this.position += length - 1;
}
return matched;
}
/**
* @param {string} tagName label for block type we are currently processing
* @param {string|RegExp} tag string to match in text
* @param {RegExp} [nextTag] regular expression to match for characters *following* the current tag
* @returns {boolean} true if the tag was processed, false otherwise
*/
parseEndTag(tagName, tag, nextTag) {
let checkTag = (this.mod() === tagName);
if (tagName === 'mono') { // special handling for 'mono'
checkTag = checkTag && this.mono;
} else {
checkTag = checkTag && !this.mono;
}
if (checkTag && this.match(tag)) {
if (nextTag !== undefined) {
// Purpose of the following match is to prevent a direct unset/set of a given tag
// E.g. '*bold **still bold*' => '*bold still bold*'
if ((this.position === this.text.length-1) || this.match(nextTag, false)) {
this.unsetTag(tagName);
}
} else {
this.unsetTag(tagName);
}
return true;
}
return false;
}
/**
* @param {string|RegExp} tag string to match in text
* @param {value} value string to replace tag with, if found at current position
* @returns {boolean} true if the tag was processed, false otherwise
*/
replace(tag, value) {
if (this.match(tag)) {
this.add(value);
this.position += length - 1;
return true;
}
return false;
}
/**
* Create a regular expression for the tag if it isn't already one.
*
* The return value is an array `[RegExp, number]`, with exactly two value, where:
* - RegExp is the regular expression to use
* - number is the lenth of the input string to match
*
* @param {string|RegExp} tag string to match in text
* @returns {Array} regular expression to use and length of input string to match
* @private
*/
prepareRegExp(tag) {
let length;
let regExp;
if (tag instanceof RegExp) {
regExp = tag;
length = 1; // ASSUMPTION: regexp only tests one character
} else {
// use prepared regexp if present
var prepared = tagPattern[tag];
if (prepared !== undefined) {
regExp = prepared;
} else {
regExp = new RegExp(tag);
}
length = tag.length;
}
return [regExp, length];
}
}
/**
* 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 (!ComponentUtil.isValidLabel(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 s = new MarkupAccumulator(text);
let parseEntities = (ch) => {
if (/&/.test(ch)) {
let parsed = s.replace(s.text, '<', '<')
|| s.replace(s.text, '&', '&');
if (!parsed) {
s.add("&");
}
return true;
}
return false;
};
while (s.position < s.text.length) {
let ch = s.text.charAt(s.position);
let parsed = s.parseWS(ch)
|| (/</.test(ch) && (
s.parseStartTag('bold', '<b>')
|| s.parseStartTag('ital', '<i>')
|| s.parseStartTag('mono', '<code>')
|| s.parseEndTag('bold', '</b>')
|| s.parseEndTag('ital', '</i>')
|| s.parseEndTag('mono', '</code>')))
|| parseEntities(ch);
if (!parsed) {
s.add(ch);
}
s.position++
}
s.emitBlock();
return s.blocks;
}
/**
*
* @param {string} text
* @returns {Array}
*/
splitMarkdownBlocks(text) {
let s = new MarkupAccumulator(text);
let beginable = true;
let parseOverride = (ch) => {
if (/\\/.test(ch)) {
if (s.position < this.text.length + 1) {
s.position++;
ch = this.text.charAt(s.position);
if (/ \t/.test(ch)) {
s.spacing = true;
} else {
s.add(ch);
beginable = false;
}
}
return true
}
return false;
}
while (s.position < s.text.length) {
let ch = s.text.charAt(s.position);
let parsed = s.parseWS(ch)
|| parseOverride(ch)
|| ((beginable || s.spacing) && (
s.parseStartTag('bold', '*')
|| s.parseStartTag('ital', '_')
|| s.parseStartTag('mono', '`')))
|| s.parseEndTag('bold', '*', 'afterBold')
|| s.parseEndTag('ital', '_', 'afterItal')
|| s.parseEndTag('mono', '`', 'afterMono');
if (!parsed) {
s.add(ch);
beginable = false;
}
s.position++
}
s.emitBlock();
return s.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;