Cmake install

[zdenop]

This is aim to sync with autotools make install to satisfied requests like #3674
Question is if to install also pdf.tff - autotools install it, but it is not needed as there is pdf_ttf.h.

Relevant code is here:

tesseract/src/api/pdfrenderer.cpp

Lines 619 to 633 in 60fd2b4

	stream.str("");
	stream << datadir_.c_str() << "/pdf.ttf";
	const uint8_t *font;
	std::ifstream input(stream.str().c_str(), std::ios::in | std::ios::binary);
	std::vector<unsigned char> buffer(std::istreambuf_iterator<char>(input), {});
	auto size = buffer.size();
	if (size) {
	font = buffer.data();
	} else {
	#if !defined(NDEBUG)
	tprintf("Cannot open file \"%s\"!\nUsing internal glyphless font.\n", stream.str().c_str());
	#endif
	font = pdf_ttf;
	size = sizeof(pdf_ttf);
	}

[egorpugin]

There is some x file in PR.

[amitdo]

Question is if to install also pdf.tff - autotools install it, but it is not needed as there is pdf_ttf.h.

@stweil, should we do the same for autotools, not install pdf.tff?

[stweil]

That might be an incompatible change and require a new major version, even if the file was unused.

[egorpugin]

@stweil
Please consider making 5.0 branch, so we can push modern c++ or big (and possibly breaking) changes into main.

[amitdo]

Egor, your request conflicts with mine from #3673 - to focus on 5.x in 2022.

[zdenop]

That might be an incompatible change and require a new major version, even if the file was unused.

Any guidelines for this? I had a look at https://semver.org/ and IMO such change has no effect on API and the new version would be backward compatible.

[stweil]

I think that the C / C++ API is only one aspect of compatibility.

Removing a file would break distributions which still have that file in their list of installed files. Users might have used that file for special applications.

Note that it is not necessary to add pdf.tff to the cmake install rules. They never installed it, so nothing breaks if they now install additional files, but not that one.