Differences

This shows you the differences between two versions of the page.

--- cmap [2020/02/23 13:43]
christian [Mappings outside the codespace]
+++ cmap [2020/02/23 14:33] (current)
christian [CMap]
@@ Line 1: / Line 1: @@
 ====== CMap ======
-CMaps(([[https://www-cdf.fnal.gov/offline/PostScript/5014.CIDFont_Spec.pdf|5014.CIDFont_Spec.pdf]] Adobe CMap and CIDFont Files Specification)) (Character Maps) define unidirectional mapping from a code to another.
+CMaps(([[https://www-cdf.fnal.gov/offline/PostScript/5014.CIDFont_Spec.pdf|5014.CIDFont_Spec.pdf]] Adobe CMap and CIDFont Files Specification)) (Character Maps) define unidirectional mapping from a code to another. (This should not be confused with the cmap table(([[https://docs.microsoft.com/en-us/typography/opentype/spec/cmap|cmap — Character to Glyph Index Mapping Table]])) of an OpenType font.)
 CMaps provide a very general mechanism which can describe any mappings, including unicode which was developed later. Input codes of variable length (1, 2, 3 or more bytes) can be mapped to characters.
@@ Line 165: / Line 165: @@
 </code>
-Here, only the first mapping matches the code space. All others fall outside of it.
+Here, only the first mapping matches the code space. All others fall outside of it, because the second byte has to be between <00> and <04>.
 ==== Wrong PostScript ====
@@ Line 216: / Line 216: @@
 </code>
-It looks as if two codes (<24> and <50>) are mapped to a string of 2-byte characters. I have not found anything about this in the documenation. Seen in a PDF with the ''Producer'' "Mac OS X 10.7.1 Quartz PDFContext".
+Two codes (<24> and <50>) are mapped to a string of 2-byte characters. This is defined by the PDF spec(({{pdf:pdf32000_2008.pdf|PDF specification (ISO standard PDF 32000-1:2008)}})) in section 9.10.3 "ToUnicode CMaps". This has not been implemented yet.
+Seen in a PDF with the ''Producer'' "Mac OS X 10.7.1 Quartz PDFContext".