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Also cache "sub" ColorSpaces globally (PR 19583 follow-up)

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Some ColorSpaces can reference other ColorSpaces, and since it's fairly common for many pages to use the same ColorSpaces (see e.g. `issue17061.pdf`) this can help reduce a lot of unnecessary re-parsing especially for e.g. `ICCBased` ColorSpaces.
This commit is contained in:
Jonas Jenwald 2025-03-01 15:28:11 +01:00
parent 0c1ac54f48
commit 33dfc4dd5f
1 changed files with 87 additions and 10 deletions
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97
src/core/colorspace.js
View file

@ -389,7 +389,13 @@ class ColorSpace {
"before calling `ColorSpace.parseAsync`."
);
}
const parsedCS = this.#parse(cs, xref, resources, pdfFunctionFactory);
const parsedCS = this.#parse(
cs,
xref,
resources,
pdfFunctionFactory,
globalColorSpaceCache
);
// Attempt to cache the parsed ColorSpace, by name and/or reference.
this.#cache(
@ -420,7 +426,13 @@ class ColorSpace {
if (cachedCS) {
return cachedCS;
}
const parsedCS = this.#parse(cs, xref, resources, pdfFunctionFactory);
const parsedCS = this.#parse(
cs,
xref,
resources,
pdfFunctionFactory,
globalColorSpaceCache
);
// Attempt to cache the parsed ColorSpace, by name and/or reference.
this.#cache(
@ -434,7 +446,47 @@ class ColorSpace {
return parsedCS;
}
static #parse(cs, xref, resources = null, pdfFunctionFactory) {
/**
* NOTE: This method should *only* be invoked from `this.#parse`,
* when parsing "sub" ColorSpaces.
*/
static #subParse(
cs,
xref,
resources,
pdfFunctionFactory,
globalColorSpaceCache
) {
let csRef;
if (cs instanceof Ref) {
const cachedCS = globalColorSpaceCache.getByRef(cs);
if (cachedCS) {
return cachedCS;
}
csRef = cs;
}
const parsedCS = this.#parse(
cs,
xref,
resources,
pdfFunctionFactory,
globalColorSpaceCache
);
// Only cache the parsed ColorSpace globally, by reference.
if (csRef) {
globalColorSpaceCache.set(/* name = */ null, csRef, parsedCS);
}
return parsedCS;
}
static #parse(
cs,
xref,
resources = null,
pdfFunctionFactory,
globalColorSpaceCache
) {
cs = xref.fetchIfRef(cs);
if (cs instanceof Name) {
switch (cs.name) {
@ -462,7 +514,8 @@ class ColorSpace {
resourcesCS,
xref,
resources,
pdfFunctionFactory
pdfFunctionFactory,
globalColorSpaceCache
);
}
cs = resourcesCS;
@ -506,9 +559,15 @@ class ColorSpace {
const stream = xref.fetchIfRef(cs[1]);
const dict = stream.dict;
numComps = dict.get("N");
const alt = dict.get("Alternate");
if (alt) {
const altCS = this.#parse(alt, xref, resources, pdfFunctionFactory);
const altRaw = dict.getRaw("Alternate");
if (altRaw) {
const altCS = this.#subParse(
altRaw,
xref,
resources,
pdfFunctionFactory,
globalColorSpaceCache
);
// Ensure that the number of components are correct,
// and also (indirectly) that it is not a PatternCS.
if (altCS.numComps === numComps) {
@ -527,12 +586,24 @@ class ColorSpace {
case "Pattern":
baseCS = cs[1] || null;
if (baseCS) {
baseCS = this.#parse(baseCS, xref, resources, pdfFunctionFactory);
baseCS = this.#subParse(
baseCS,
xref,
resources,
pdfFunctionFactory,
globalColorSpaceCache
);
}
return new PatternCS(baseCS);
case "I":
case "Indexed":
baseCS = this.#parse(cs[1], xref, resources, pdfFunctionFactory);
baseCS = this.#subParse(
cs[1],
xref,
resources,
pdfFunctionFactory,
globalColorSpaceCache
);
const hiVal = Math.max(0, Math.min(xref.fetchIfRef(cs[2]), 255));
const lookup = xref.fetchIfRef(cs[3]);
return new IndexedCS(baseCS, hiVal, lookup);
@ -540,7 +611,13 @@ class ColorSpace {
case "DeviceN":
const name = xref.fetchIfRef(cs[1]);
numComps = Array.isArray(name) ? name.length : 1;
baseCS = this.#parse(cs[2], xref, resources, pdfFunctionFactory);
baseCS = this.#subParse(
cs[2],
xref,
resources,
pdfFunctionFactory,
globalColorSpaceCache
);
const tintFn = pdfFunctionFactory.create(cs[3]);
return new AlternateCS(numComps, baseCS, tintFn);
case "Lab":