PDFBOX-6032: add configurable default image factory

[kimilg]

• This PR addresses PDFBOX-6032 by introducing a new overload of PDImageXObject#createFromByteArray that accepts a user-supplied defaultFactory parameter for customizable image conversion behavior.
• The goal is to allow users to provide a defaultFactory for custom image conversion. This factory is used directly for formats like BMP and GIF, and acts as a fallback for PNG and TIFF when the optimized conversion path fails and would otherwise fall back to LosslessFactory.

[rototor]

Here I'm a bit confused, also by the naming stuff.

I would rather extend the existing method with a parameter. I think "DefaultFactory" is a bad name. I.e., the way I would implement this would be

// Method with signature of the existing method is just forwarding to the other  new overload
public static PDImageXObject createFromByteArray(PDDocument document, byte[] byteArray, String name)
{
return createFromByteArray(document,byteArray,name, null);
}

// Extend the existing method with the one parameter
public static PDImageXObject createFromByteArray(PDDocument document, byte[] byteArray, String name, DefaultFactory defaultFactory) throws {
  // .. logic like it is now BUT instead of just encoding this lossless we first check if we have a *fallback*

if( defaultFactory != null ) 
  return defaultFactory.create...(...)
// otherwise just do the PNGEncoder Lossless stuff like it is now.
}

And therefor I think defaultFactory is bad name. It should be a fallback.

[lehmi]

I've proposed DefaultFactory and I'm not really happy with that name.

Fallback won't be correct as it isn't a fallback in all cases. It is for png and tiff which can't be processed but it isn't for bmp and gif.

How about CustomFactory?

[kimilg]

Thanks for the feedback.
I’ve removed the duplicate logic, and the code feels more compact and cleaner now.
Naming the functional interface is tricky - a precise name gets too long, but a short one feels too vague.
I renamed it to CustomFactory because it more clearly reflects its intended usage than DefaultFactory.

[rototor]

Some JavaDoc to describe what this interface is about would be nice.

But other than that, the changes look fine for me.

[kimilg]

Right, I forgot to add it earlier. I've now added a JavaDoc comment to this class.

[THausherr]

Thanks for the PR; I forgot the magic words in the commit message, please close the PR yourself.