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https://issues.apache.org/jira/browse/PDFBOX-2149?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14037734#comment-14037734
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John Hewson commented on PDFBOX-2149:
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Sorry, I reversed your change in [r1604018|http://svn.apache.org/r1604018]
because it shouldn't be possible for getFontDescriptor() to return null, either
the font is embedded in which case it must have a FontDescriptor, as this is
where the embedded file is stored, or it is a Type 1 system font in which case
it will have an AFM file, or it is a TTF system font in which case its
FontDescriptor is populated in PDTrueTypeFont's constructor.
It looks like getFontDescriptor() and getAFM() could do with some refactoring
to make this clearer, as it stands these methods have several code paths which
return null - they just shouldn't get called in practice. Anyway, if for some
reason we do get an NPE here then I'd prefer to have the NPE and get a bug
report so that we can understand what's going on with the font in question -
because I have no way to guess, and I suspect that PDFBox will break elsewhere
with such a font.
> Font Refactoring
> ----------------
>
> Key: PDFBOX-2149
> URL: https://issues.apache.org/jira/browse/PDFBOX-2149
> Project: PDFBox
> Issue Type: Improvement
> Components: FontBox, PDModel
> Affects Versions: 2.0.0
> Reporter: John Hewson
>
> To fix bugs such as PDFBOX-2140 and to enable Unicode TTF embedding we need
> to sort out long-standing font/text encoding issues. The main issue is that
> encoding is done in an ad-hoc manner, sometimes in the PDFont subclasses,
> sometimes elsewhere. For example TTFGlyph2D does its own decoding, and this
> code is copy & pasted into PDTrueTypeFont. Likewise, PDFont handles CMaps and
> Encodings despite the fact that these two encoding methods are mutually
> exclusive. The end result is that the process of reading Encodings/CMaps is
> often following rules which are completely invalid for that font type but
> mostly work by luck.
> Phase 1
> - Refactor PDFont subclasses to remove setXXX methods which allow the object
> to be corrupted. Proper use of inheritance can remove all cases where public
> setXXX methods are used during font loading.
> - Clean up TTF loading and the loadTTF in anticipation of Unicode TTF
> embedding, FontBox's TrueTypeFont class is externally mutable via setXXX
> methods used only by TTFParser: these can be made package-private.
> - the Encoding class and EncodingManager could do with some cleaning up prior
> to further refactoring.
> - PDSimpleFont does not do anything, its functionality should be moved into
> its superclass, PDFont.
> - PDFont#determineEncoding() loads CMaps when only Encodings are applicable,
> and vice versa. Loading needs to be pushed down into the appropriate
> subclasses, as a starting point the relevant code should at least be copied
> into the relevant subclasses ready for further refactoring.
> - TTFGlyph2D does its own decoding of char codes, rather than using the
> font's #encode method (fair enough because #encode is broken) and there's a
> copy and pasted version of the same code in PDTrueTypeFont - we need to
> consolidate this code into PDTrueTypeFont where it belongs.
> Phase 2
> - Refactor loading of CMaps and Encodings from font dictionaries, this will
> involve changes to PDFont and its subclasses to delegate loading to
> subclasses where it can be properly encapsulated
> - May need to alter the class hierarchy w.r.t CIDFont to facilitate this, as
> CIDFont isn't really a PDFont - it's parent Type0 font is responsible for its
> CMap. We'll see.
> Phase 3
> - Refactor the decoding of character codes by PDFont and its subclasses, this
> will involve replacing the #getCodeFromArray, #encode and #encodeToCID
> methods.
> - Fix decoding of content stream character codes in PDFStreamEngine, using
> the newly refactored PDFont and using the current font's CMap to determine
> the code width.
> Phase 4
> - Add support for generating embedded TTFs with Unicode
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