0eb1433c78
Currently the `fontName`-property contains an actual /Name-instance, which is a problem given that its fallback value is an empty string; seeca7f546828/src/core/default_appearance.js (L35)The reason that this is a problem can be seen inca7f546828/src/core/primitives.js (L30-L34), since an empty string short-circuits the cache. Essentially, in PDF documents, a /Name-instance cannot be empty and the way that the `DefaultAppearanceEvaluator` does things is unfortunately not entirely correct. Hence the `fontName`-property is changed to instead contain a string, rather than a /Name-instance, which simplifies the code overall. *Please note:* I'm tagging this patch with "[api-minor]", since PR 12831 is included in the current pre-release (although we're not using the `fontName`-property in the display-layer).
100 lines
3.0 KiB
JavaScript
100 lines
3.0 KiB
JavaScript
/* Copyright 2020 Mozilla Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import { OPS, warn } from "../shared/util.js";
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import { ColorSpace } from "./colorspace.js";
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import { escapePDFName } from "./core_utils.js";
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import { EvaluatorPreprocessor } from "./evaluator.js";
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import { Name } from "./primitives.js";
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import { StringStream } from "./stream.js";
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class DefaultAppearanceEvaluator extends EvaluatorPreprocessor {
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constructor(str) {
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super(new StringStream(str));
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}
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parse() {
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const operation = {
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fn: 0,
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args: [],
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};
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const result = {
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fontSize: 0,
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fontName: "",
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fontColor: /* black = */ new Uint8ClampedArray(3),
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};
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try {
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while (true) {
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operation.args.length = 0; // Ensure that `args` it's always reset.
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if (!this.read(operation)) {
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break;
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}
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if (this.savedStatesDepth !== 0) {
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continue; // Don't get info in save/restore sections.
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}
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const { fn, args } = operation;
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switch (fn | 0) {
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case OPS.setFont:
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const [fontName, fontSize] = args;
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if (fontName instanceof Name) {
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result.fontName = fontName.name;
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}
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if (typeof fontSize === "number" && fontSize > 0) {
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result.fontSize = fontSize;
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}
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break;
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case OPS.setFillRGBColor:
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ColorSpace.singletons.rgb.getRgbItem(args, 0, result.fontColor, 0);
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break;
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case OPS.setFillGray:
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ColorSpace.singletons.gray.getRgbItem(args, 0, result.fontColor, 0);
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break;
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case OPS.setFillColorSpace:
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ColorSpace.singletons.cmyk.getRgbItem(args, 0, result.fontColor, 0);
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break;
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}
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}
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} catch (reason) {
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warn(`parseDefaultAppearance - ignoring errors: "${reason}".`);
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}
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return result;
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}
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}
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// Parse DA to extract font and color information.
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function parseDefaultAppearance(str) {
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return new DefaultAppearanceEvaluator(str).parse();
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}
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// Create default appearance string from some information.
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function createDefaultAppearance({ fontSize, fontName, fontColor }) {
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let colorCmd;
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if (fontColor.every(c => c === 0)) {
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colorCmd = "0 g";
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} else {
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colorCmd =
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Array.from(fontColor)
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.map(c => (c / 255).toFixed(2))
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.join(" ") + " rg";
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}
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return `/${escapePDFName(fontName)} ${fontSize} Tf ${colorCmd}`;
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}
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export { createDefaultAppearance, parseDefaultAppearance };
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