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Refactors fake space heuristics for speed.

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This commit is contained in:
Yury Delendik 2015-11-06 08:40:44 -06:00
parent 376f8bde14
commit fa423cfab0
1 changed files with 64 additions and 31 deletions
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95
src/core/evaluator.js
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@ -929,11 +929,17 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
lastAdvanceWidth: 0,
lastAdvanceHeight: 0,
textAdvanceScale: 0,
spaceWidth: 0,
fakeSpaceMin: Infinity,
fakeMultiSpaceMin: Infinity,
fakeMultiSpaceMax: -0,
textRunBreakAllowed: false,
transform: null,
fontName: null
};
var SPACE_FACTOR = 0.3;
var MULTI_SPACE_FACTOR = 1.5;
var MULTI_SPACE_FACTOR_MAX = 4;
var self = this;
var xref = this.xref;
@ -1001,6 +1007,24 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
textContentItem.lastAdvanceWidth = 0;
textContentItem.lastAdvanceHeight = 0;
var spaceWidth = font.spaceWidth / 1000 * textState.fontSize;
if (spaceWidth) {
textContentItem.spaceWidth = spaceWidth;
textContentItem.fakeSpaceMin = spaceWidth * SPACE_FACTOR;
textContentItem.fakeMultiSpaceMin = spaceWidth * MULTI_SPACE_FACTOR;
textContentItem.fakeMultiSpaceMax =
spaceWidth * MULTI_SPACE_FACTOR_MAX;
// It's okay for monospace fonts to fake as much space as needed.
textContentItem.textRunBreakAllowed = !font.isMonospace;
} else {
textContentItem.spaceWidth = 0;
textContentItem.fakeSpaceMin = Infinity;
textContentItem.fakeMultiSpaceMin = Infinity;
textContentItem.fakeMultiSpaceMax = 0;
textContentItem.textRunBreakAllowed = false;
}
textContentItem.initialized = true;
return textContentItem;
}
@ -1076,8 +1100,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
var wordSpacing = textState.wordSpacing;
charSpacing += wordSpacing;
if (wordSpacing > 0) {
addFakeSpaces(wordSpacing * 1000 / textState.fontSize,
textChunk.str);
addFakeSpaces(wordSpacing, textChunk.str);
}
}
@ -1105,21 +1128,20 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
textChunk.lastAdvanceHeight = height;
textChunk.height += Math.abs(height * textChunk.textAdvanceScale);
}
return textChunk;
}
function addFakeSpaces(width, strBuf) {
var spaceWidth = textState.font.spaceWidth;
if (spaceWidth <= 0) {
if (width < textContentItem.fakeSpaceMin) {
return;
}
var fakeSpaces = width / spaceWidth;
if (fakeSpaces > MULTI_SPACE_FACTOR) {
fakeSpaces = Math.round(fakeSpaces);
while (fakeSpaces--) {
strBuf.push(' ');
}
} else if (fakeSpaces > SPACE_FACTOR) {
if (width < textContentItem.fakeMultiSpaceMin) {
strBuf.push(' ');
return;
}
var fakeSpaces = Math.round(width / textContentItem.spaceWidth);
while (fakeSpaces-- > 0) {
strBuf.push(' ');
}
}
@ -1177,16 +1199,18 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
// Optimization to treat same line movement as advance
var isSameTextLine = !textState.font ? false :
((textState.font.vertical ? args[0] : args[1]) === 0);
if (isSameTextLine && textContentItem.initialized) {
advance = args[0] - args[1];
if (isSameTextLine && textContentItem.initialized &&
advance > 0 &&
advance <= textContentItem.fakeMultiSpaceMax) {
textState.translateTextLineMatrix(args[0], args[1]);
textContentItem.width +=
(args[0] - textContentItem.lastAdvanceWidth);
textContentItem.height +=
(args[1] - textContentItem.lastAdvanceHeight);
advance = (args[0] - args[1]) * 1000 / textState.fontSize;
if (advance > 0) {
addFakeSpaces(advance, textContentItem.str);
}
var diff = (args[0] - textContentItem.lastAdvanceWidth) -
(args[1] - textContentItem.lastAdvanceHeight);
addFakeSpaces(diff, textContentItem.str);
break;
}
@ -1229,9 +1253,8 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
if (typeof items[j] === 'string') {
buildTextContentItem(items[j]);
} else {
if (j === 0) {
ensureTextContentItem();
}
ensureTextContentItem();
// PDF Specification 5.3.2 states:
// The number is expressed in thousandths of a unit of text
// space.
@ -1240,25 +1263,35 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
// In the default coordinate system, a positive adjustment
// has the effect of moving the next glyph painted either to
// the left or down by the given amount.
advance = items[j];
var val = advance * textState.fontSize / 1000;
advance = items[j] * textState.fontSize / 1000;
var breakTextRun = false;
if (textState.font.vertical) {
offset = val *
offset = advance *
(textState.textHScale * textState.textMatrix[2] +
textState.textMatrix[3]);
textState.translateTextMatrix(0, val);
// Value needs to be added to height to paint down.
textContentItem.height += offset;
textState.translateTextMatrix(0, advance);
breakTextRun = textContentItem.textRunBreakAllowed &&
advance > textContentItem.fakeMultiSpaceMax;
if (!breakTextRun) {
// Value needs to be added to height to paint down.
textContentItem.height += offset;
}
} else {
offset = val * (
advance = -advance;
offset = advance * (
textState.textHScale * textState.textMatrix[0] +
textState.textMatrix[1]);
textState.translateTextMatrix(-val, 0);
// Value needs to be subtracted from width to paint left.
textContentItem.width -= offset;
advance = -advance;
textState.translateTextMatrix(advance, 0);
breakTextRun = textContentItem.textRunBreakAllowed &&
advance > textContentItem.fakeMultiSpaceMax;
if (!breakTextRun) {
// Value needs to be subtracted from width to paint left.
textContentItem.width += offset;
}
}
if (advance > 0) {
if (breakTextRun) {
flushTextContentItem();
} else if (advance > 0) {
addFakeSpaces(advance, textContentItem.str);
}
}