[Bug]: Invalid rendering because of no colorspace

[calixteman]

Attach (recommended) or Link to PDF file

image2.pdf

Web browser and its version

Firefox nightly

Operating system and its version

Windows 11

PDF.js version

last one

Is the bug present in the latest PDF.js version?

Yes

Is a browser extension

No

Steps to reproduce the problem

Open the pdf

What is the expected behavior?

What went wrong?

Link to a viewer

No response

Additional context

The bug has been reported:
https://issues.apache.org/jira/browse/PDFBOX-5851

As mentioned in the bug report, scn and SCN are used without a previous call to cs so we fallback on DeviceGray:

pdf.js/src/core/evaluator.js

Lines 4876 to 4877 in ed83d7c

	this.fillColorSpace = ColorSpace.singletons.gray;
	this.strokeColorSpace = ColorSpace.singletons.gray;

We should probably have a null rgb color or something like that to indicate to use a fully transparent one.

The rendering is correct in either Acrobat or Chrome.

[Snuffleupagus]

As mentioned in the bug report, scn and SCN are used without a previous call to cs so we fallback on DeviceGray:

Yes, because as far as I understand that's what the PDF specification says should be the default value in https://opensource.adobe.com/dc-acrobat-sdk-docs/pdfstandards/PDF32000_2008.pdf#G7.3881830

Parameter	Type	Value
color space	name or array	The current colour space in which colour values shall be interpreted (see 8.6, "Colour Spaces"). There are two separate colour space parameters: one for stroking and one for all other painting operations. Initial value: DeviceGray.

We should probably have a null rgb color or something like that to indicate to use a fully transparent one.

We might need to somehow limit that to the /Pattern handling, since given the above I'd worry about regressions elsewhere if we do that unconditionally (especially since the PDF document in question is corrupt).