[Pkg-javascript-commits] [pdf.js] 142/207: Refactoring text layer builder
David Prévot
taffit at moszumanska.debian.org
Mon Jul 28 15:36:41 UTC 2014
This is an automated email from the git hooks/post-receive script.
taffit pushed a commit to branch master
in repository pdf.js.
commit 2a052c4aadb2b694728d5afc3ef52b473cc05b66
Author: Tim van der Meij <timvandermeij at gmail.com>
Date: Sat Jun 21 22:53:26 2014 +0200
Refactoring text layer builder
---
web/text_layer_builder.js | 150 +++++++++++++++++++---------------------------
1 file changed, 62 insertions(+), 88 deletions(-)
diff --git a/web/text_layer_builder.js b/web/text_layer_builder.js
index 5bc618e..cc9aabd 100644
--- a/web/text_layer_builder.js
+++ b/web/text_layer_builder.js
@@ -19,25 +19,22 @@
var FIND_SCROLL_OFFSET_TOP = -50;
var FIND_SCROLL_OFFSET_LEFT = -400;
+var MAX_TEXT_DIVS_TO_RENDER = 100000;
+var RENDER_DELAY = 200; // ms
/**
- * TextLayerBuilder provides text-selection
- * functionality for the PDF. It does this
- * by creating overlay divs over the PDF
- * text. This divs contain text that matches
- * the PDF text they are overlaying. This
- * object also provides for a way to highlight
- * text that is being searched for.
+ * TextLayerBuilder provides text-selection functionality for the PDF.
+ * It does this by creating overlay divs over the PDF text. These divs
+ * contain text that matches the PDF text they are overlaying. This object
+ * also provides a way to highlight text that is being searched for.
*/
var TextLayerBuilder = function textLayerBuilder(options) {
- var textLayerFrag = document.createDocumentFragment();
-
this.textLayerDiv = options.textLayerDiv;
this.layoutDone = false;
this.divContentDone = false;
this.pageIdx = options.pageIndex;
this.matches = [];
- this.lastScrollSource = options.lastScrollSource;
+ this.lastScrollSource = options.lastScrollSource || null;
this.viewport = options.viewport;
this.isViewerInPresentationMode = options.isViewerInPresentationMode;
this.textDivs = [];
@@ -46,31 +43,27 @@ var TextLayerBuilder = function textLayerBuilder(options) {
window.PDFFindController = null;
}
- if (typeof this.lastScrollSource === 'undefined') {
- this.lastScrollSource = null;
- }
-
- this.renderLayer = function textLayerBuilderRenderLayer() {
+ this.renderLayer = function textLayerBuilder_renderLayer() {
+ var textLayerFrag = document.createDocumentFragment();
var textDivs = this.textDivs;
+ var textDivsLength = textDivs.length;
var canvas = document.createElement('canvas');
var ctx = canvas.getContext('2d');
- // No point in rendering so many divs as it'd make the browser unusable
- // even after the divs are rendered
- var MAX_TEXT_DIVS_TO_RENDER = 100000;
- if (textDivs.length > MAX_TEXT_DIVS_TO_RENDER) {
+ // No point in rendering many divs as it would make the browser
+ // unusable even after the divs are rendered.
+ if (textDivsLength > MAX_TEXT_DIVS_TO_RENDER) {
return;
}
- for (var i = 0, ii = textDivs.length; i < ii; i++) {
+ for (var i = 0; i < textDivsLength; i++) {
var textDiv = textDivs[i];
- if ('isWhitespace' in textDiv.dataset) {
+ if (textDiv.dataset.isWhitespace !== undefined) {
continue;
}
ctx.font = textDiv.style.fontSize + ' ' + textDiv.style.fontFamily;
var width = ctx.measureText(textDiv.textContent).width;
-
if (width > 0) {
textLayerFrag.appendChild(textDiv);
var textScale = textDiv.dataset.canvasWidth / width;
@@ -87,19 +80,17 @@ var TextLayerBuilder = function textLayerBuilder(options) {
this.updateMatches();
};
- this.setupRenderLayoutTimer = function textLayerSetupRenderLayoutTimer() {
- // Schedule renderLayout() if user has been scrolling, otherwise
- // run it right away
- var RENDER_DELAY = 200; // in ms
+ this.setupRenderLayoutTimer =
+ function textLayerBuilder_setupRenderLayoutTimer() {
+ // Schedule renderLayout() if the user has been scrolling,
+ // otherwise run it right away.
var self = this;
var lastScroll = (this.lastScrollSource === null ?
0 : this.lastScrollSource.lastScroll);
- if (Date.now() - lastScroll > RENDER_DELAY) {
- // Render right away
+ if (Date.now() - lastScroll > RENDER_DELAY) { // Render right away
this.renderLayer();
- } else {
- // Schedule
+ } else { // Schedule
if (this.renderTimer) {
clearTimeout(this.renderTimer);
}
@@ -109,7 +100,7 @@ var TextLayerBuilder = function textLayerBuilder(options) {
}
};
- this.appendText = function textLayerBuilderAppendText(geom, styles) {
+ this.appendText = function textLayerBuilder_appendText(geom, styles) {
var style = styles[geom.fontName];
var textDiv = document.createElement('div');
this.textDivs.push(textDiv);
@@ -140,35 +131,31 @@ var TextLayerBuilder = function textLayerBuilder(options) {
} else {
textDiv.dataset.canvasWidth = geom.width * this.viewport.scale;
}
-
};
- this.setTextContent = function textLayerBuilderSetTextContent(textContent) {
+ this.setTextContent = function textLayerBuilder_setTextContent(textContent) {
this.textContent = textContent;
var textItems = textContent.items;
- for (var i = 0; i < textItems.length; i++) {
+ for (var i = 0, len = textItems.length; i < len; i++) {
this.appendText(textItems[i], textContent.styles);
}
this.divContentDone = true;
-
this.setupRenderLayoutTimer();
};
- this.convertMatches = function textLayerBuilderConvertMatches(matches) {
+ this.convertMatches = function textLayerBuilder_convertMatches(matches) {
var i = 0;
var iIndex = 0;
var bidiTexts = this.textContent.items;
var end = bidiTexts.length - 1;
var queryLen = (PDFFindController === null ?
0 : PDFFindController.state.query.length);
-
var ret = [];
- // Loop over all the matches.
- for (var m = 0; m < matches.length; m++) {
+ for (var m = 0, len = matches.length; m < len; m++) {
+ // Calculate the start position.
var matchIdx = matches[m];
- // # Calculate the begin position.
// Loop over the divIdxs.
while (i !== end && matchIdx >= (iIndex + bidiTexts[i].str.length)) {
@@ -176,9 +163,8 @@ var TextLayerBuilder = function textLayerBuilder(options) {
i++;
}
- // TODO: Do proper handling here if something goes wrong.
- if (i == bidiTexts.length) {
- console.error('Could not find matching mapping');
+ if (i === bidiTexts.length) {
+ console.error('Could not find a matching mapping');
}
var match = {
@@ -188,11 +174,11 @@ var TextLayerBuilder = function textLayerBuilder(options) {
}
};
- // # Calculate the end position.
+ // Calculate the end position.
matchIdx += queryLen;
- // Somewhat same array as above, but use a > instead of >= to get the end
- // position right.
+ // 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++;
@@ -219,32 +205,23 @@ var TextLayerBuilder = function textLayerBuilder(options) {
var prevEnd = null;
var isSelectedPage = (PDFFindController === null ?
false : (this.pageIdx === PDFFindController.selected.pageIdx));
-
var selectedMatchIdx = (PDFFindController === null ?
-1 : PDFFindController.selected.matchIdx);
-
var highlightAll = (PDFFindController === null ?
false : PDFFindController.state.highlightAll);
-
- var infty = {
+ var infinity = {
divIdx: -1,
offset: undefined
};
function beginText(begin, className) {
var divIdx = begin.divIdx;
- var div = textDivs[divIdx];
- div.textContent = '';
+ textDivs[divIdx].textContent = '';
appendTextToDiv(divIdx, 0, begin.offset, className);
}
- function appendText(from, to, className) {
- appendTextToDiv(from.divIdx, from.offset, to.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) {
@@ -257,12 +234,7 @@ var TextLayerBuilder = function textLayerBuilder(options) {
div.appendChild(node);
}
- function highlightDiv(divIdx, className) {
- textDivs[divIdx].className = className;
- }
-
- var i0 = selectedMatchIdx, i1 = i0 + 1, i;
-
+ var i0 = selectedMatchIdx, i1 = i0 + 1;
if (highlightAll) {
i0 = 0;
i1 = matches.length;
@@ -271,36 +243,39 @@ var TextLayerBuilder = function textLayerBuilder(options) {
return;
}
- for (i = i0; i < i1; i++) {
+ 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 isSelected = (isSelectedPage && i === selectedMatchIdx);
var highlightSuffix = (isSelected ? ' selected' : '');
+
if (isSelected && !this.isViewerInPresentationMode) {
- scrollIntoView(textDivs[begin.divIdx], { top: FIND_SCROLL_OFFSET_TOP,
- left: FIND_SCROLL_OFFSET_LEFT });
+ scrollIntoView(textDivs[begin.divIdx],
+ { top: FIND_SCROLL_OFFSET_TOP,
+ left: FIND_SCROLL_OFFSET_LEFT });
}
// Match inside new div.
if (!prevEnd || begin.divIdx !== prevEnd.divIdx) {
- // If there was a previous div, then add the text at the end
+ // If there was a previous div, then add the text at the end.
if (prevEnd !== null) {
- appendText(prevEnd, infty);
+ appendTextToDiv(prevEnd.divIdx, prevEnd.offset, infinity.offset);
}
- // clears the divs and set the content until the begin point.
+ // Clear the divs and set the content until the starting point.
beginText(begin);
} else {
- appendText(prevEnd, begin);
+ appendTextToDiv(prevEnd.divIdx, prevEnd.offset, begin.offset);
}
if (begin.divIdx === end.divIdx) {
- appendText(begin, end, 'highlight' + highlightSuffix);
+ appendTextToDiv(begin.divIdx, begin.offset, end.offset,
+ 'highlight' + highlightSuffix);
} else {
- appendText(begin, infty, 'highlight begin' + highlightSuffix);
- for (var n = begin.divIdx + 1; n < end.divIdx; n++) {
- highlightDiv(n, 'highlight middle' + highlightSuffix);
+ 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);
}
@@ -308,27 +283,27 @@ var TextLayerBuilder = function textLayerBuilder(options) {
}
if (prevEnd) {
- appendText(prevEnd, infty);
+ appendTextToDiv(prevEnd.divIdx, prevEnd.offset, infinity.offset);
}
};
- this.updateMatches = function textLayerUpdateMatches() {
- // Only show matches, once all rendering is done.
+ this.updateMatches = function textLayerBuilder_updateMatches() {
+ // Only show matches when all rendering is done.
if (!this.renderingDone) {
return;
}
- // Clear out all matches.
+ // Clear all matches.
var matches = this.matches;
var textDivs = this.textDivs;
var bidiTexts = this.textContent.items;
var clearedUntilDivIdx = -1;
- // Clear out all current matches.
- for (var i = 0; i < matches.length; i++) {
+ // 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; n <= match.end.divIdx; n++) {
+ for (var n = begin, end = match.end.divIdx; n <= end; n++) {
var div = textDivs[n];
div.textContent = bidiTexts[n].str;
div.className = '';
@@ -340,11 +315,10 @@ var TextLayerBuilder = function textLayerBuilder(options) {
return;
}
- // Convert the matches on the page controller into the match format used
- // for the textLayer.
- this.matches = matches = (this.convertMatches(PDFFindController === null ?
- [] : (PDFFindController.pageMatches[this.pageIdx] || [])));
-
+ // Convert the matches on the page controller into the match format
+ // used for the textLayer.
+ this.matches = this.convertMatches(PDFFindController === null ?
+ [] : (PDFFindController.pageMatches[this.pageIdx] || []));
this.renderMatches(this.matches);
};
};
--
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