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Improve the TextLayerRenderTask implementation
- Change all possible semi-private methods into properly private ones. Note that this code is old enough to predate standard classes. - Move the `appendText` helper function into `TextLayerRenderTask`, as a private method, to avoid having to manually pass in the scope. - Simplify `#layoutText` by directly passing in all necessary data. This is possible after the changes PR 18052.
This commit is contained in:
Jonas Jenwald
parent
bb9bb34721
commit
036fd11ad7
1 changed files with 97 additions and 103 deletions
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@ -162,97 +162,6 @@ function getAscent(fontFamily, lang) {
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return DEFAULT_FONT_ASCENT;
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}
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function appendText(task, geom, lang) {
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// Initialize all used properties to keep the caches monomorphic.
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const textDiv = document.createElement("span");
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const textDivProperties = {
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angle: 0,
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canvasWidth: 0,
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hasText: geom.str !== "",
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hasEOL: geom.hasEOL,
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fontSize: 0,
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};
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task._textDivs.push(textDiv);
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const tx = Util.transform(task._transform, geom.transform);
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let angle = Math.atan2(tx[1], tx[0]);
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const style = task._styleCache[geom.fontName];
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if (style.vertical) {
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angle += Math.PI / 2;
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}
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const fontFamily =
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(task._fontInspectorEnabled && style.fontSubstitution) || style.fontFamily;
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const fontHeight = Math.hypot(tx[2], tx[3]);
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const fontAscent = fontHeight * getAscent(fontFamily, lang);
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let left, top;
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if (angle === 0) {
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left = tx[4];
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top = tx[5] - fontAscent;
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} else {
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left = tx[4] + fontAscent * Math.sin(angle);
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top = tx[5] - fontAscent * Math.cos(angle);
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}
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const scaleFactorStr = "calc(var(--scale-factor)*";
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const divStyle = textDiv.style;
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// Setting the style properties individually, rather than all at once,
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// should be OK since the `textDiv` isn't appended to the document yet.
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if (task._container === task._rootContainer) {
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divStyle.left = `${((100 * left) / task._pageWidth).toFixed(2)}%`;
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divStyle.top = `${((100 * top) / task._pageHeight).toFixed(2)}%`;
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} else {
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// We're in a marked content span, hence we can't use percents.
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divStyle.left = `${scaleFactorStr}${left.toFixed(2)}px)`;
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divStyle.top = `${scaleFactorStr}${top.toFixed(2)}px)`;
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}
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divStyle.fontSize = `${scaleFactorStr}${fontHeight.toFixed(2)}px)`;
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divStyle.fontFamily = fontFamily;
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textDivProperties.fontSize = fontHeight;
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// Keeps screen readers from pausing on every new text span.
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textDiv.setAttribute("role", "presentation");
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textDiv.textContent = geom.str;
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// geom.dir may be 'ttb' for vertical texts.
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textDiv.dir = geom.dir;
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// `fontName` is only used by the FontInspector, and we only use `dataset`
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// here to make the font name available in the debugger.
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if (task._fontInspectorEnabled) {
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textDiv.dataset.fontName =
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style.fontSubstitutionLoadedName || geom.fontName;
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}
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if (angle !== 0) {
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textDivProperties.angle = angle * (180 / Math.PI);
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}
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// We don't bother scaling single-char text divs, because it has very
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// little effect on text highlighting. This makes scrolling on docs with
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// lots of such divs a lot faster.
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let shouldScaleText = false;
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if (geom.str.length > 1) {
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shouldScaleText = true;
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} else if (geom.str !== " " && geom.transform[0] !== geom.transform[3]) {
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const absScaleX = Math.abs(geom.transform[0]),
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absScaleY = Math.abs(geom.transform[3]);
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// When the horizontal/vertical scaling differs significantly, also scale
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// even single-char text to improve highlighting (fixes issue11713.pdf).
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if (
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absScaleX !== absScaleY &&
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Math.max(absScaleX, absScaleY) / Math.min(absScaleX, absScaleY) > 1.5
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) {
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shouldScaleText = true;
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}
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}
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if (shouldScaleText) {
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textDivProperties.canvasWidth = style.vertical ? geom.height : geom.width;
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}
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task._textDivProperties.set(textDiv, textDivProperties);
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task._layoutText(textDiv);
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}
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function layout(params) {
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const { div, scale, properties, ctx, prevFontSize, prevFontFamily } = params;
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const { style } = div;
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@ -368,10 +277,7 @@ class TextLayerRenderTask {
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this._capability.reject(abortEx);
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}
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/**
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* @private
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*/
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_processItems(items, lang) {
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#processItems(items, lang) {
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if (!this._layoutTextParams.ctx) {
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this._textDivProperties.set(this._rootContainer, { lang });
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this._layoutTextParams.ctx = getCtx(lang);
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@ -407,17 +313,105 @@ class TextLayerRenderTask {
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continue;
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}
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textContentItemsStr.push(item.str);
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appendText(this, item, lang);
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this.#appendText(item, lang);
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}
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}
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/**
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* @private
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*/
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_layoutText(textDiv) {
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const textDivProperties = (this._layoutTextParams.properties =
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this._textDivProperties.get(textDiv));
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#appendText(geom, lang) {
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// Initialize all used properties to keep the caches monomorphic.
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const textDiv = document.createElement("span");
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const textDivProperties = {
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angle: 0,
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canvasWidth: 0,
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hasText: geom.str !== "",
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hasEOL: geom.hasEOL,
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fontSize: 0,
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};
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this._textDivs.push(textDiv);
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const tx = Util.transform(this._transform, geom.transform);
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let angle = Math.atan2(tx[1], tx[0]);
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const style = this._styleCache[geom.fontName];
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if (style.vertical) {
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angle += Math.PI / 2;
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}
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const fontFamily =
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(this._fontInspectorEnabled && style.fontSubstitution) ||
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style.fontFamily;
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const fontHeight = Math.hypot(tx[2], tx[3]);
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const fontAscent = fontHeight * getAscent(fontFamily, lang);
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let left, top;
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if (angle === 0) {
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left = tx[4];
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top = tx[5] - fontAscent;
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} else {
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left = tx[4] + fontAscent * Math.sin(angle);
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top = tx[5] - fontAscent * Math.cos(angle);
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}
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const scaleFactorStr = "calc(var(--scale-factor)*";
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const divStyle = textDiv.style;
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// Setting the style properties individually, rather than all at once,
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// should be OK since the `textDiv` isn't appended to the document yet.
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if (this._container === this._rootContainer) {
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divStyle.left = `${((100 * left) / this._pageWidth).toFixed(2)}%`;
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divStyle.top = `${((100 * top) / this._pageHeight).toFixed(2)}%`;
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} else {
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// We're in a marked content span, hence we can't use percents.
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divStyle.left = `${scaleFactorStr}${left.toFixed(2)}px)`;
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divStyle.top = `${scaleFactorStr}${top.toFixed(2)}px)`;
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}
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divStyle.fontSize = `${scaleFactorStr}${fontHeight.toFixed(2)}px)`;
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divStyle.fontFamily = fontFamily;
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textDivProperties.fontSize = fontHeight;
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// Keeps screen readers from pausing on every new text span.
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textDiv.setAttribute("role", "presentation");
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textDiv.textContent = geom.str;
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// geom.dir may be 'ttb' for vertical texts.
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textDiv.dir = geom.dir;
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// `fontName` is only used by the FontInspector, and we only use `dataset`
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// here to make the font name available in the debugger.
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if (this._fontInspectorEnabled) {
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textDiv.dataset.fontName =
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style.fontSubstitutionLoadedName || geom.fontName;
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}
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if (angle !== 0) {
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textDivProperties.angle = angle * (180 / Math.PI);
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}
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// We don't bother scaling single-char text divs, because it has very
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// little effect on text highlighting. This makes scrolling on docs with
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// lots of such divs a lot faster.
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let shouldScaleText = false;
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if (geom.str.length > 1) {
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shouldScaleText = true;
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} else if (geom.str !== " " && geom.transform[0] !== geom.transform[3]) {
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const absScaleX = Math.abs(geom.transform[0]),
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absScaleY = Math.abs(geom.transform[3]);
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// When the horizontal/vertical scaling differs significantly, also scale
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// even single-char text to improve highlighting (fixes issue11713.pdf).
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if (
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absScaleX !== absScaleY &&
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Math.max(absScaleX, absScaleY) / Math.min(absScaleX, absScaleY) > 1.5
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) {
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shouldScaleText = true;
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}
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}
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if (shouldScaleText) {
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textDivProperties.canvasWidth = style.vertical ? geom.height : geom.width;
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}
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this._textDivProperties.set(textDiv, textDivProperties);
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this.#layoutText(textDiv, textDivProperties);
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}
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#layoutText(textDiv, textDivProperties) {
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this._layoutTextParams.div = textDiv;
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this._layoutTextParams.properties = textDivProperties;
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layout(this._layoutTextParams);
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if (textDivProperties.hasText) {
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@ -444,7 +438,7 @@ class TextLayerRenderTask {
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}
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Object.assign(styleCache, value.styles);
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this._processItems(value.items, value.lang);
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this.#processItems(value.items, value.lang);
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pump();
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}, this._capability.reject);
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};
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