Differences

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--- cmap [2020/02/23 13:35]
christian [Wrong PostScript]
+++ 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 126: / Line 126: @@
 ===== Monster from the wild =====
+CMaps are not well defined. Therefore, there are some interesting variations of them in the wild. Here is a small selection of some issues.
+==== Codespace problems ====
-==== Mappings outside the codespace ====
+=== Wrong code length ===
 <code postscript>
@@ Line 146: / Line 148: @@
 This can be seen often. These illegal mappings are collected into the ''#unmapped'' variable of a Mappings object.
+=== Mappings outside the codespace ===
+<code postscript>
+%...
+begincodespacerange
+<0001> <1004>
+endcodespacerange
+beginbfchar
+<0003> <00A0>
+<0005> <0022>
+<0008> <0025>
+<000F> <002C>
+<0010> <00AD>
+%...
+</code>
+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 196: / 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".