{"id":269,"date":"2010-09-02T18:00:06","date_gmt":"2010-09-02T12:30:06","guid":{"rendered":"http:\/\/www.cvr.cc\/?p=269"},"modified":"2010-09-02T18:00:06","modified_gmt":"2010-09-02T12:30:06","slug":"mathml-3-and-tex4ht","status":"publish","type":"post","link":"https:\/\/cvr.cc\/?p=269","title":{"rendered":"MathML 3 and TeX4ht"},"content":{"rendered":"

M<\/small>athML<\/small> 3<\/a> is about to be formalized and going to be released as the new standard for encoding mathematics in web. It differs from the previous standard 2. The main changes that have a bearing on the functionality of Te<\/span>X4ht<\/a> are discussed here.<\/p>\n

Linking<\/h4>\n

M<\/small>athML<\/small> 1 and 2 didn’t have any built in provisions to specify links for various elements in a math formula. The recommendation was to use XL<\/small>ink<\/a> since it was part of the original grand plan for XML<\/small><\/a> in its formative years. However, XL<\/small>ink didn’t gain much popularity nor was it supported widely. Therefore, M<\/small>athML<\/small> 3 now specifies that any M<\/small>athML<\/small> element can accept an href<\/code> attribute that takes an URI<\/small> specifying a hyperlink same as in the HTML<\/small><\/a> element, namely, <a><\/code>. So this has an implication in the current scheme of Te<\/span>X4ht. If readers provide a few examples of how they want to include links in a math fragment in La<\/small><\/span>Te<\/span>X, it will help largely to make a stable and suitable conversion scheme for Te<\/span>X4ht.<\/p>\n

Line breaking<\/h4>\n

Previous standards of M<\/small>athML<\/small> had the same limitations as Te<\/span>X in the matter of breaking long equations. In Te<\/span>X, it is easy for an author to break equations while authoring content taking into consideration of the margin constrains and paper sizes. However, for web content, margin and line-length are irrelevant when the window sizes are unknown or potentially liable to dynamic changes. Therefore, new M<\/small>athML<\/small> 3 specifies a line breaking model and introduces several new attributes to control properties of line breaks and alignments.<\/p>\n

This has deeper implications on the rendering software than on the engine that creates M<\/small>athML<\/small>. However, since the specification allows newer properties for line breaks and alignments, we need to take care of those part in Te<\/span>X4ht which at the moment obeys what the author has input in her La<\/small><\/span>Te<\/span>X document. Since Te<\/span>X is incapable of determining the semantic meaning of equations and hence break points, we have to provide hooks to make Te<\/span>X4ht aware of the real line breaks and obligatory line breaks to adjust with page sizes. A better option will be to make use of breqn<\/code> package while authoring and Te<\/span>X4ht to provide necessary extra functionality to take care of breqn<\/code><\/a> features in combination with M<\/small>athML<\/small>’s newer goodies.<\/p>\n

Image inclusion<\/h4>\n

The usage of <glyph><\/code> element in the previous M<\/small>athML<\/small> specification has been deprecated now. <glyph><\/code> element was used to specify characters from non-standard fonts that do not correspond to Unicode code points. Since the usage becomes difficult in a web context, as one needs to make sure that the font is available, <mglyph><\/code> has been extended with an src<\/code> attribute to facilitate inclusion of a glyph in image format. <mglyph><\/code> now acts as a general image reference element in M<\/small>athML<\/small> much like HTML<\/small>’s <img><\/code> element.<\/p>\n

Elementary math layout<\/h4>\n

Elementary school math layout is difficult to typeset even with Te<\/span>X. Usually people adopt a tabular layout with a lot of complex macros to control space and rules around various number segments. Previous M<\/small>athML<\/small> standards provide elementary school math layout, much like in Te<\/span>X, with a lot of tabular structure which obstructs rendering of math other than visual, particularly audio, because of the interference of tabular elements. M<\/small>athML<\/small> 3 provides better layout elements and scheme which help to specify even borrows and carries and many different kind of layout.<\/p>\n

\n   435.3\n   ______\n  3)1306\n    12\n    __\n     10\n      9\n     __\n      16\n      15\n      __\n       1.0\n         9\n         _\n         1\n<\/pre>\n
MathML version of long division<\/h4>\n
Given below is the M<\/small>athML<\/small> 3 coding of the above long division.<\/p>\n
\n<mlongdiv longdivstyle=\"lefttop\">\n  <mn> 3 <\/mn>\n  <mn> 435.3<\/mn>\n  <mn> 1306<\/mn>\n  <msgroup position=\"2\" shift=\"-1\">\n    <msgroup>\n      <mn> 12<\/mn>\n      <msline length=\"2\"\/>\n    <\/msgroup>\n    <msgroup>\n      <mn> 10<\/mn>\n      <mn> 9<\/mn>\n      <msline length=\"2\"\/>\n    <\/msgroup>\n    <msgroup>\n      <mn> 16<\/mn>\n      <mn> 15<\/mn>\n      <msline length=\"2\"\/>\n      <mn> 1.0<\/mn>\n    <\/msgroup>\n    <msgroup position=\"-1\";>\n       <mn> 9<\/mn>\n      <msline length=\"3\"\/>\n      <mn> 1<\/mn>\n    <\/msgroup>\n  <\/msgroup>\n<\/mlongdiv>\n<\/pre>\n
Directionality<\/h4>\n
M<\/small>athML<\/small> 3 provides support for right to left writing\/reading direction whereas previous versions didn’t have this functionality. The new specifications provide the user to control both writing directions of the identifiers within a formula and layout direction of the formula itself separately. I am not sure, if this has any influence on the behavior of current version of Te<\/span>X4ht which is based on dvi<\/code> files generated by Te<\/span>X while support for xdv<\/code>, extended dvi generated by XeTe<\/span>X, is still very basic which supports multi-directional scripts.<\/p>\n","protected":false},"excerpt":{"rendered":"
MathML 3 is about to be formalized and going to be released as the new standard for encoding mathematics in web. It differs from the previous standard 2. The main changes that have a bearing on the functionality of TeX4ht are discussed here.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[27,15,16],"tags":[],"class_list":["post-269","post","type-post","status-publish","format-standard","hentry","category-mathml","category-tex","category-tex4ht"],"_links":{"self":[{"href":"https:\/\/cvr.cc\/index.php?rest_route=\/wp\/v2\/posts\/269","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cvr.cc\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cvr.cc\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cvr.cc\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/cvr.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=269"}],"version-history":[{"count":0,"href":"https:\/\/cvr.cc\/index.php?rest_route=\/wp\/v2\/posts\/269\/revisions"}],"wp:attachment":[{"href":"https:\/\/cvr.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=269"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cvr.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=269"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cvr.cc\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=269"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}