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epubreader/public/pdfjs/controllers/textlayer_controller.js
2023-06-18 01:47:01 +02:00

346 lines
11 KiB
JavaScript

PDFJS.Reader.TextLayerController = function (options, reader) {
var EXPAND_DIVS_TIMEOUT = 300; // ms
this.reader = reader;
this.textLayerDiv = options.textLayerDiv;
this.eventBus = options.eventBus || null;
this.textContent = null;
this.renderingDone = false;
this.pageIdx = options.pageIndex;
this.pageNumber = this.pageIdx + 1;
this.matches = [];
this.viewport = options.viewport;
this.textDivs = [];
this.textLayerRenderTask = null;
this.enhanceTextSelection = options.enhanceTextSelection;
this._bindMouse();
return this;
};
PDFJS.Reader.TextLayerController.prototype._finishRendering = function () {
this.renderingDone = true;
if (!this.enhanceTextSelection) {
var endOfContent = document.createElement('div');
endOfContent.className = 'endOfContent';
this.textLayerDiv.appendChild(endOfContent);
}
if (this.eventBus !== null) {
this.eventBus.dispatch('textlayerrendered', {
source: this,
pageNumber: this.pageNumber,
numTextDivs: this.textDivs.length,
});
}
};
/**
* Renders the text layer.
* @param {number} timeout (optional) if specified, the rendering waits
* for specified amount of ms.
*/
PDFJS.Reader.TextLayerController.prototype.render = function(timeout) {
if (!this.textContent || this.renderingDone) {
return;
}
this.cancel();
this.textDivs = [];
var textLayerFrag = document.createDocumentFragment();
this.textLayerRenderTask = PDFJS.renderTextLayer({
textContent: this.textContent,
container: textLayerFrag,
viewport: this.viewport,
textDivs: this.textDivs,
timeout: timeout,
enhanceTextSelection: this.enhanceTextSelection,
});
this.textLayerRenderTask.promise.then(function () {
this.textLayerDiv.appendChild(textLayerFrag);
this._finishRendering();
this.updateMatches();
}.bind(this), function (reason) {
// cancelled or failed to render text layer -- skipping errors
});
};
/**
* Cancels rendering of the text layer.
*/
PDFJS.Reader.TextLayerController.prototype.cancel = function () {
if (this.textLayerRenderTask) {
this.textLayerRenderTask.cancel();
this.textLayerRenderTask = null;
}
};
PDFJS.Reader.TextLayerController.prototype.setTextContent = function (textContent) {
this.cancel();
this.textContent = textContent;
};
PDFJS.Reader.TextLayerController.prototype.convertMatches = function(matches, matchesLength) {
var reader = this.reader;
var i = 0;
var iIndex = 0;
var bidiTexts = this.textContent.items;
var end = bidiTexts.length - 1;
var queryLen = reader.search_state ?
reader.search_state.query.length : null;
var ret = [];
if (!matches) {
return ret;
}
for (var m = 0, len = matches.length; m < len; m++) {
// Calculate the start position.
var matchIdx = matches[m];
// Loop over the divIdxs.
while (i !== end && matchIdx >= (iIndex + bidiTexts[i].str.length)) {
iIndex += bidiTexts[i].str.length;
i++;
}
if (i === bidiTexts.length) {
console.error('Could not find a matching mapping');
}
var match = {
begin: {
divIdx: i,
offset: matchIdx - iIndex
}
};
// Calculate the end position.
if (matchesLength) { // multiterm search
matchIdx += matchesLength[m];
} else { // phrase search
matchIdx += queryLen;
}
// Somewhat the same array as above, but use > instead of >= to get
// the end position right.
while (i !== end && matchIdx > (iIndex + bidiTexts[i].str.length)) {
iIndex += bidiTexts[i].str.length;
i++;
}
match.end = {
divIdx: i,
offset: matchIdx - iIndex
};
ret.push(match);
}
return ret;
};
PDFJS.Reader.TextLayerController.prototype.renderMatches = function (matches) {
// Early exit if there is nothing to render.
if (matches.length === 0) {
return;
}
var reader = this.reader;
var bidiTexts = this.textContent.items;
var textDivs = this.textDivs;
var prevEnd = null;
var pageIdx = this.pageIdx;
var isSelectedPage = (pageIdx === reader.selected.pageIdx);
var selectedMatchIdx = reader.selected.matchIdx;
var highlightAll = true;
var infinity = {
divIdx: -1,
offset: undefined
};
function beginText(begin, className) {
var divIdx = begin.divIdx;
textDivs[divIdx].textContent = '';
appendTextToDiv(divIdx, 0, begin.offset, className);
}
function appendTextToDiv(divIdx, fromOffset, toOffset, className) {
var div = textDivs[divIdx];
var content = bidiTexts[divIdx].str.substring(fromOffset, toOffset);
var node = document.createTextNode(content);
if (className) {
var span = document.createElement('span');
span.className = className;
span.appendChild(node);
div.appendChild(span);
return;
}
div.appendChild(node);
}
var i0 = selectedMatchIdx, i1 = i0 + 1;
if (highlightAll) {
i0 = 0;
i1 = matches.length;
} else if (!isSelectedPage) {
// Not highlighting all and this isn't the selected page, so do nothing.
return;
}
for (var i = i0; i < i1; i++) {
var match = matches[i];
var begin = match.begin;
var end = match.end;
var isSelected = (isSelectedPage && i === selectedMatchIdx);
var id = "match:" + pageIdx + ":" + i;
var highlightSuffix = (isSelected ? ' selected ' + id : ' ' + id);
// Match inside new div.
if (!prevEnd || begin.divIdx !== prevEnd.divIdx) {
// If there was a previous div, then add the text at the end.
if (prevEnd !== null) {
appendTextToDiv(prevEnd.divIdx, prevEnd.offset, infinity.offset);
}
// Clear the divs and set the content until the starting point.
beginText(begin);
} else {
appendTextToDiv(prevEnd.divIdx, prevEnd.offset, begin.offset);
}
if (begin.divIdx === end.divIdx) {
appendTextToDiv(begin.divIdx, begin.offset, end.offset,
'highlight' + highlightSuffix);
} else {
appendTextToDiv(begin.divIdx, begin.offset, infinity.offset,
'highlight begin' + highlightSuffix);
for (var n0 = begin.divIdx + 1, n1 = end.divIdx; n0 < n1; n0++) {
textDivs[n0].className = 'highlight middle' + highlightSuffix;
}
beginText(end, 'highlight end' + highlightSuffix);
}
prevEnd = end;
}
if (prevEnd) {
appendTextToDiv(prevEnd.divIdx, prevEnd.offset, infinity.offset);
}
};
PDFJS.Reader.TextLayerController.prototype.updateMatches = function () {
// Only show matches when all rendering is done.
if (!this.renderingDone) {
return;
}
var reader = this.reader;
// Only show matches when search is active
if (reader.search_active !== true) {
return;
}
// Clear all matches.
var matches = this.matches;
var textDivs = this.textDivs;
var bidiTexts = this.textContent.items;
var clearedUntilDivIdx = -1;
// Clear all current matches.
for (var i = 0, len = matches.length; i < len; i++) {
var match = matches[i];
var begin = Math.max(clearedUntilDivIdx, match.begin.divIdx);
for (var n = begin, end = match.end.divIdx; n <= end; n++) {
var div = textDivs[n];
div.textContent = bidiTexts[n].str;
div.className = '';
}
clearedUntilDivIdx = match.end.divIdx + 1;
}
// Convert the matches on the page controller into the match format
// used for the textLayer.
var pageMatches = reader.pageMatches[this.pageIdx] || null,
pageMatchesLength = reader.pageMatchesLength ?
reader.pageMatchesLength[this.pageIdx] || null : null;
this.matches = this.convertMatches(pageMatches, pageMatchesLength);
this.renderMatches(this.matches);
};
/**
* Fixes text selection: adds additional div where mouse was clicked.
* This reduces flickering of the content if mouse slowly dragged down/up.
* @private
*/
PDFJS.Reader.TextLayerController.prototype._bindMouse = function () {
var div = this.textLayerDiv;
var self = this;
var expandDivsTimer = null;
div.addEventListener('mousedown', function (e) {
if (self.enhanceTextSelection && self.textLayerRenderTask) {
self.textLayerRenderTask.expandTextDivs(true);
if ((typeof PDFJSDev === 'undefined' ||
!PDFJSDev.test('FIREFOX || MOZCENTRAL')) &&
expandDivsTimer) {
clearTimeout(expandDivsTimer);
expandDivsTimer = null;
}
return;
}
var end = div.querySelector('.endOfContent');
if (!end) {
return;
}
if (typeof PDFJSDev === 'undefined' ||
!PDFJSDev.test('FIREFOX || MOZCENTRAL')) {
// On non-Firefox browsers, the selection will feel better if the height
// of the endOfContent div will be adjusted to start at mouse click
// location -- this will avoid flickering when selections moves up.
// However it does not work when selection started on empty space.
var adjustTop = e.target !== div;
if (typeof PDFJSDev === 'undefined' || PDFJSDev.test('GENERIC')) {
adjustTop = adjustTop && window.getComputedStyle(end).
getPropertyValue('-moz-user-select') !== 'none';
}
if (adjustTop) {
var divBounds = div.getBoundingClientRect();
var r = Math.max(0, (e.pageY - divBounds.top) / divBounds.height);
end.style.top = (r * 100).toFixed(2) + '%';
}
}
end.classList.add('active');
});
div.addEventListener('mouseup', function (e) {
if (self.enhanceTextSelection && self.textLayerRenderTask) {
if (typeof PDFJSDev === 'undefined' ||
!PDFJSDev.test('FIREFOX || MOZCENTRAL')) {
expandDivsTimer = setTimeout(function() {
if (self.textLayerRenderTask) {
self.textLayerRenderTask.expandTextDivs(false);
}
expandDivsTimer = null;
}, 300);
} else {
self.textLayerRenderTask.expandTextDivs(false);
}
return;
}
var end = div.querySelector('.endOfContent');
if (!end) {
return;
}
if (typeof PDFJSDev === 'undefined' ||
!PDFJSDev.test('FIREFOX || MOZCENTRAL')) {
end.style.top = '';
}
end.classList.remove('active');
});
};