diff options
Diffstat (limited to 'src/devices/grohtml-old/design.ms')
| -rwxr-xr-x | src/devices/grohtml-old/design.ms | 129 |
1 files changed, 0 insertions, 129 deletions
diff --git a/src/devices/grohtml-old/design.ms b/src/devices/grohtml-old/design.ms deleted file mode 100755 index 6216d4eb..00000000 --- a/src/devices/grohtml-old/design.ms +++ /dev/null @@ -1,129 +0,0 @@ -.nr PS 12 -.nr VS 14 -.LP -.TL -Design of grohtml -.sp 1i -.SH -What is grohtml -.LP -Grohtml is a back end for groff which generates html. -The aim of grohtml is to produce respectible html given -fairly typical groff input. -.SH -Limitations of grohtml -.LP -Although basic text can be translated -in a straightforward fashion there are some areas where grohtml -has to try and guess text relationship. In particular whenever -grohtml encounters text tables and indented paragraphs or -two column mode it will try and utilize the html table construct -to preserve columns. Grohtml also attempts to work out which -lines should be automatically formatted by the browser. -Ultimately in trying to make reasonable guesses most of the time -it will make mistakes occasionally. -.PP -Tbl, pic, eqn's are also generated using images which may be -considered a limitation. -.SH -Overview of html.cc -.LP -This file briefly provides an overview of how html.cc operates. -The html device driver works as follows: -.IP (i) .5i -firstly it creates a linked list of all words on a page. -.IP (ii) .5i -it runs through the page and finds the left most margin. Later -on when generating the page it removes the margin. -.IP (iii) .5i -scans a page and builds two kinds of regions ascii text and graphical. -The graphical regions consist of tbl's, eqn's, pic's -(basically anything that cannot be textually displayed). -It will scan through a page to find lines (such as footer etc) -and places these into tiny graphical regions. Certain fonts -also are treated as a graphical region - as html has no easy -equivalent. For example Greek math symbols. -.LP -Finally all graphical regions are translated into png files and -all text regions into html text. -.PP -To give grohtml a sporting chance of accuratly deciding which -is a graphical region and which is text, the front end programs -tbl, eqn, pic have all been tweeked to encapsulate pictures, tables -and equations with the following lines: -.sp -.nf -\f[CR]\&.if '\\*(.T'html' \\X(graphic-start(\c - -\&.if '\\*(.T'html' \\X(graphic-end(\c -\fP -.fi -.sp -these appear to grohtml as: -.sp -.nf -\f[CR]\&x X graphic-start - -\&... - -\&x X graphic-end\fP -.fi -.sp -.LP -In addition to graphic-start and graphic-end there are two -other "special characters" which are used. -.sp -\f[CR]\&x X index:N\fP -.sp -where N is a number. The purpose of this sequence is to stop -devhtml from automatically producing links to headings which -have a header level >N. -The line: -.sp -\f[CR]\&x X html:STRING\fR -.sp -.LP -allows a STRING to be passed through to the output file with -no processing whatsoever. Ie it allows users to include html -commands, via macro, such as: -.sp -\f[CR]\&.URL "Latest Emacs" "ftp://somewonderful.gnu.software"\fP -.sp -.LP -Where the URL macro bundles the info into STRING above. -For more info consult: \f[CR]tmac/tmac.arkup\fP. -.PP -While scanning through a page the html device copies headings and titles -into a list of links which are later written to the beginning -of the html document. -.SH -Table handling code -.LP -Provided that the -t option is not present when grohtml is run the grohtml -driver will attempt to find textual tables and generate html tables. -This allows .RS and .RE commands to operate with auto formatting. It also -should grohtml to process .2C correctly. However, the table handling code -has to examine the troff output and \fIguess\fR when a table starts and -finishes. It is well to know the limitations of this approach as it -sometimes makes the wrong decision. -.LP -Here are some of the rules that grohtml uses for terminating a html table: -.LP -.IP "(i)" .5i -A table will be terminated when grohtml finds line which is all in bold -font (it believes that this is a header which is outside of a table). -This might be considered incorrect behaviour especially if you use .2C -which generates a heading on the left column when the corresponding -right row is blank. -.IP "(ii)" .5i -A table is terminated when grohtml sees that the complete line is -has been spanned by words. Ie no gaps exist. -.IP "(nb)" .5i -the documentation about these rules is particularly incomplete and needs finishing -when time prevails. -.SH -Dependencies -.LP -Grohtml is dependent upon grops, gs which are invoked to -generate all png files. Png files are generated whenever a table, picture, -equation or line is encountered. |