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Merge pull request #11601 from Snuffleupagus/rm-nativeImageDecoderSupport

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[api-minor] Decode all JPEG images with the built-in PDF.js decoder in `src/core/jpg.js`
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Tim van der Meij 2020-05-23 15:33:46 +02:00 • committed by GitHub
commit 3b615e4ca3
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23 changed files with 57 additions and 682 deletions
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98
src/core/image_utils.js
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@ -15,103 +15,7 @@
/* eslint no-var: error */
import { assert, info, shadow } from "../shared/util.js";
import { ColorSpace } from "./colorspace.js";
import { JpegStream } from "./jpeg_stream.js";
import { RefSetCache } from "./primitives.js";
import { Stream } from "./stream.js";
class NativeImageDecoder {
constructor({
xref,
resources,
handler,
forceDataSchema = false,
pdfFunctionFactory,
}) {
this.xref = xref;
this.resources = resources;
this.handler = handler;
this.forceDataSchema = forceDataSchema;
this.pdfFunctionFactory = pdfFunctionFactory;
}
canDecode(image) {
return (
image instanceof JpegStream &&
image.maybeValidDimensions &&
NativeImageDecoder.isDecodable(
image,
this.xref,
this.resources,
this.pdfFunctionFactory
)
);
}
decode(image) {
// For natively supported JPEGs send them to the main thread for decoding.
const dict = image.dict;
let colorSpace = dict.get("ColorSpace", "CS");
colorSpace = ColorSpace.parse(
colorSpace,
this.xref,
this.resources,
this.pdfFunctionFactory
);
return this.handler
.sendWithPromise("JpegDecode", [
image.getIR(this.forceDataSchema),
colorSpace.numComps,
])
.then(function ({ data, width, height }) {
return new Stream(data, 0, data.length, dict);
});
}
/**
* Checks if the image can be decoded and displayed by the browser without any
* further processing such as color space conversions.
*/
static isSupported(image, xref, res, pdfFunctionFactory) {
const dict = image.dict;
if (dict.has("DecodeParms") || dict.has("DP")) {
return false;
}
const cs = ColorSpace.parse(
dict.get("ColorSpace", "CS"),
xref,
res,
pdfFunctionFactory
);
// isDefaultDecode() of DeviceGray and DeviceRGB needs no `bpc` argument.
return (
(cs.name === "DeviceGray" || cs.name === "DeviceRGB") &&
cs.isDefaultDecode(dict.getArray("Decode", "D"))
);
}
/**
* Checks if the image can be decoded by the browser.
*/
static isDecodable(image, xref, res, pdfFunctionFactory) {
const dict = image.dict;
if (dict.has("DecodeParms") || dict.has("DP")) {
return false;
}
const cs = ColorSpace.parse(
dict.get("ColorSpace", "CS"),
xref,
res,
pdfFunctionFactory
);
const bpc = dict.get("BitsPerComponent", "BPC") || 1;
return (
(cs.numComps === 1 || cs.numComps === 3) &&
cs.isDefaultDecode(dict.getArray("Decode", "D"), bpc)
);
}
}
class GlobalImageCache {
static get NUM_PAGES_THRESHOLD() {
@ -207,4 +111,4 @@ class GlobalImageCache {
}
}
export { NativeImageDecoder, GlobalImageCache };
export { GlobalImageCache };