Mercurial > hg > xemacs-beta
comparison src/redisplay.c @ 2367:ecf1ebac70d8
[xemacs-hg @ 2004-11-04 23:05:23 by ben]
commit mega-patch
configure.in: Turn off -Winline and -Wchar-subscripts.
Use the right set of cflags when compiling modules.
Rewrite ldap configuration to separate the inclusion of lber
(needed in recent Cygwin) from the basic checks for the
needed libraries.
add a function for MAKE_JUNK_C; initially code was added to
generate xemacs.def using this, but it will need to be rewritten.
add an rm -f for junk.c to avoid weird Cygwin bug with cp -f onto
an existing file.
Sort list of auto-detected functions and eliminate unused checks for
stpcpy, setlocale and getwd.
Add autodetection of Cygwin scanf problems
BETA: Rewrite section on configure to indicate what flags are important
and what not.
digest-doc.c, make-dump-id.c, profile.c, sorted-doc.c: Add proper decls for main().
make-msgfile.c: Document that this is old junk.
Move proposal to text.c.
make-msgfile.lex: Move proposal to text.c.
make-mswin-unicode.pl: Convert error-generating code so that the entire message will
be seen as a single unrecognized token.
mule/mule-ccl.el: Update docs.
lispref/mule.texi: Update CCL docs.
ldap/eldap.c: Mule-ize.
Use EXTERNAL_LIST_LOOP_2 instead of deleted EXTERNAL_LIST_LOOP.
* XEmacs 21.5.18 "chestnut" is released.
---------------------------------------------------------------
MULE-RELATED WORK:
---------------------------------------------------------------
---------------------------
byte-char conversion
---------------------------
buffer.c, buffer.h, insdel.c, text.c: Port FSF algorithm for byte-char conversion, replacing broken
previous version. Track the char position of the gap. Add
functions to do char-byte conversion downwards as well as upwards.
Move comments about algorithm workings to internals manual.
---------------------------
work on types
---------------------------
alloc.c, console-x-impl.h, dump-data.c, dump-data.h, dumper.c, dialog-msw.c, dired-msw.c, doc.c, editfns.c, esd.c, event-gtk.h, event-msw.c, events.c, file-coding.c, file-coding.h, fns.c, glyphs-eimage.c, glyphs-gtk.c, glyphs-msw.c, glyphs-shared.c, glyphs-x.c, glyphs.c, glyphs.h, gui.c, hpplay.c, imgproc.c, intl-win32.c, lrecord.h, lstream.c, keymap.c, lisp.h, libsst.c, linuxplay.c, miscplay.c, miscplay.h, mule-coding.c, nas.c, nt.c, ntheap.c, ntplay.c, objects-msw.c, objects-tty.c, objects-x.c, print.c, process-nt.c, process.c, redisplay.h, select-common.h, select-gtk.c, select-x.c, sgiplay.c, sound.c, sound.h, sunplay.c, sysfile.h, sysdep.c, syswindows.h, text.c, unexnt.c, win32.c, xgccache.c: Further work on types. This creates a full set of types for all
the basic semantics of `char' that I have so far identified, so that
its semantics can always be identified for the purposes of proper
Mule-safe code, and the raw use of `char' always avoided.
(1) More type renaming, for consistency of naming.
Char_ASCII -> Ascbyte
UChar_ASCII -> UAscbyte
Char_Binary -> CBinbyte
UChar_Binary -> Binbyte
SChar_Binary -> SBinbyte
(2) Introduce Rawbyte, CRawbyte, Boolbyte, Chbyte, UChbyte, and
Bitbyte and use them.
(3) New types Itext, Wexttext and Textcount for separating out
the concepts of bytes and textual units (different under UTF-16
and UTF-32, which are potential internal encodings).
(4) qxestr*_c -> qxestr*_ascii.
lisp.h: New; goes with other qxe() functions. #### Maybe goes in a
different section.
lisp.h: Group generic int-type defs together with EMACS_INT defs.
lisp.h: * lisp.h (WEXTTEXT_IS_WIDE)
New defns.
lisp.h: New type to replace places where int occurs as a boolean.
It's signed because occasionally people may want to use -1 as
an error value, and because unsigned ints are viral -- see comments
in the internals manual against using them.
dynarr.c: int -> Bytecount.
---------------------------
Mule-izing
---------------------------
device-x.c: Partially Mule-ize.
dumper.c, dumper.h: Mule-ize. Use Rawbyte. Use stderr_out not printf. Use wext_*().
sysdep.c, syswindows.h, text.c: New Wexttext API for manipulation of external text that may be
Unicode (e.g. startup code under Windows).
emacs.c: Mule-ize. Properly deal with argv in external encoding.
Use wext_*() and Wexttext. Use Rawbyte.
#if 0 some old junk on SCO that is unlikely to be correct.
Rewrite allocation code in run-temacs.
emacs.c, symsinit.h, win32.c: Rename win32 init function and call it even earlier, to
initialize mswindows_9x_p even earlier, for use in startup code
(XEUNICODE_P).
process.c: Use _wenviron not environ under Windows, to get Unicode environment
variables.
event-Xt.c: Mule-ize drag-n-drop related stuff.
dragdrop.c, dragdrop.h, frame-x.c: Mule-ize.
text.h: Add some more stand-in defines for particular kinds of conversion;
use in Mule-ization work in frame-x.c etc.
---------------------------
Freshening
---------------------------
intl-auto-encap-win32.c, intl-auto-encap-win32.h: Regenerate.
---------------------------
Unicode-work
---------------------------
intl-win32.c, syswindows.h: Factor out common options to MultiByteToWideChar and
WideCharToMultiByte. Add convert_unicode_to_multibyte_malloc()
and convert_unicode_to_multibyte_dynarr() and use. Add stuff for
alloca() conversion of multibyte/unicode.
alloc.c: Use dfc_external_data_len() in case of unicode coding system.
alloc.c, mule-charset.c: Don't zero out and reinit charset Unicode tables. This fucks up
dump-time loading. Anyway, either we load them at dump time or
run time, never both.
unicode.c: Dump the blank tables as well.
---------------------------------------------------------------
DOCUMENTATION, MOSTLY MULE-RELATED:
---------------------------------------------------------------
EmacsFrame.c, emodules.c, event-Xt.c, fileio.c, input-method-xlib.c, mule-wnnfns.c, redisplay-gtk.c, redisplay-tty.c, redisplay-x.c, regex.c, sysdep.c: Add comment about Mule work needed.
text.h: Add more documentation describing why DFC routines were not written
to return their value. Add some other DFC documentation.
console-msw.c, console-msw.h: Add pointer to docs in win32.c.
emacs.c: Add comments on sources of doc info.
text.c, charset.h, unicode.c, intl-win32.c, intl-encap-win32.c, text.h, file-coding.c, mule-coding.c: Collect background comments and related to text matters and
internationalization, and proposals for work to be done, in text.c
or Internals manual, stuff related to specific textual API's in
text.h, and stuff related to internal implementation of Unicode
conversion in unicode.c. Put lots of pointers to the comments to
make them easier to find.
s/mingw32.h, s/win32-common.h, s/win32-native.h, s/windowsnt.h, win32.c: Add bunches of new documentation on the different kinds of
builds and environments under Windows and how they work.
Collect this info in win32.c. Add pointers to these docs in
the relevant s/* files.
emacs.c: Document places with long comments.
Remove comment about exiting, move to internals manual, put
in pointer.
event-stream.c: Move docs about event queues and focus to internals manual, put
in pointer.
events.h: Move docs about event stream callbacks to internals manual, put
in pointer.
profile.c, redisplay.c, signal.c: Move documentation to the Internals manual.
process-nt.c: Add pointer to comment in win32-native.el.
lisp.h: Add comments about some comment conventions.
lisp.h: Add comment about the second argument.
device-msw.c, redisplay-msw.c: @@#### comments are out-of-date.
---------------------------------------------------------------
PDUMP WORK (MOTIVATED BY UNICODE CHANGES)
---------------------------------------------------------------
alloc.c, buffer.c, bytecode.c, console-impl.h, console.c, device.c, dumper.c, lrecord.h, elhash.c, emodules.h, events.c, extents.c, frame.c, glyphs.c, glyphs.h, mule-charset.c, mule-coding.c, objects.c, profile.c, rangetab.c, redisplay.c, specifier.c, specifier.h, window.c, lstream.c, file-coding.h, file-coding.c: PDUMP:
Properly implement dump_add_root_block(), which never worked before,
and is necessary for dumping Unicode tables.
Pdump name changes for accuracy:
XD_STRUCT_PTR -> XD_BLOCK_PTR.
XD_STRUCT_ARRAY -> XD_BLOCK_ARRAY.
XD_C_STRING -> XD_ASCII_STRING.
*_structure_* -> *_block_*.
lrecord.h: some comments added about
dump_add_root_block() vs dump_add_root_block_ptr().
extents.c: remove incorrect comment about pdump problems with gap array.
---------------------------------------------------------------
ALLOCATION
---------------------------------------------------------------
abbrev.c, alloc.c, bytecode.c, casefiddle.c, device-msw.c, device-x.c, dired-msw.c, doc.c, doprnt.c, dragdrop.c, editfns.c, emodules.c, file-coding.c, fileio.c, filelock.c, fns.c, glyphs-eimage.c, glyphs-gtk.c, glyphs-msw.c, glyphs-x.c, gui-msw.c, gui-x.c, imgproc.c, intl-win32.c, lread.c, menubar-gtk.c, menubar.c, nt.c, objects-msw.c, objects-x.c, print.c, process-nt.c, process-unix.c, process.c, realpath.c, redisplay.c, search.c, select-common.c, symbols.c, sysdep.c, syswindows.h, text.c, text.h, ui-byhand.c: New macros {alloca,xnew}_{itext,{i,ext,raw,bin,asc}bytes} for
more convenient allocation of these commonly requested items.
Modify functions to use alloca_ibytes, alloca_array, alloca_extbytes,
xnew_ibytes, etc. also XREALLOC_ARRAY, xnew.
alloc.c: Rewrite the allocation functions to factor out repeated code.
Add assertions for freeing dumped data.
lisp.h: Moved down and consolidated with other allocation stuff.
lisp.h, dynarr.c: New functions for allocation that's very efficient when mostly in
LIFO order.
lisp.h, text.c, text.h: Factor out some stuff for general use by alloca()-conversion funs.
text.h, lisp.h: Fill out convenience routines for allocating various kinds of
bytes and put them in lisp.h. Use them in place of xmalloc(),
ALLOCA().
text.h: Fill out the convenience functions so the _MALLOC() kinds match
the alloca() kinds.
---------------------------------------------------------------
ERROR-CHECKING
---------------------------------------------------------------
text.h: Create ASSERT_ASCTEXT_ASCII() and ASSERT_ASCTEXT_ASCII_LEN()
from similar Eistring checkers and change the Eistring checkers to
use them instead.
---------------------------------------------------------------
MACROS IN LISP.H
---------------------------------------------------------------
lisp.h: Redo GCPRO declarations. Create a "base" set of functions that can
be used to generate any kind of gcpro sets -- regular, ngcpro,
nngcpro, private ones used in GC_EXTERNAL_LIST_LOOP_2.
buffer.c, callint.c, chartab.c, console-msw.c, device-x.c, dialog-msw.c, dired.c, extents.c, ui-gtk.c, rangetab.c, nt.c, mule-coding.c, minibuf.c, menubar-msw.c, menubar.c, menubar-gtk.c, lread.c, lisp.h, gutter.c, glyphs.c, glyphs-widget.c, fns.c, fileio.c, file-coding.c, specifier.c: Eliminate EXTERNAL_LIST_LOOP, which does not check for circularities.
Use EXTERNAL_LIST_LOOP_2 instead or EXTERNAL_LIST_LOOP_3
or EXTERNAL_PROPERTY_LIST_LOOP_3 or GC_EXTERNAL_LIST_LOOP_2
(new macro). Removed/redid comments on EXTERNAL_LIST_LOOP.
---------------------------------------------------------------
SPACING FIXES
---------------------------------------------------------------
callint.c, hftctl.c, number-gmp.c, process-unix.c: Spacing fixes.
---------------------------------------------------------------
FIX FOR GEOMETRY PROBLEM IN FIRST FRAME
---------------------------------------------------------------
unicode.c: Add workaround for newlib bug in sscanf() [should be fixed by
release 1.5.12 of Cygwin].
toolbar.c: bug fix for problem of initial frame being 77 chars wide on Windows.
will be overridden by my other ws.
---------------------------------------------------------------
FIX FOR LEAKING PROCESS HANDLES:
---------------------------------------------------------------
process-nt.c: Fixes for leaking handles. Inspired by work done by Adrian Aichner
<adrian@xemacs.org>.
---------------------------------------------------------------
FIX FOR CYGWIN BUG (Unicode-related):
---------------------------------------------------------------
unicode.c: Add workaround for newlib bug in sscanf() [should be fixed by
release 1.5.12 of Cygwin].
---------------------------------------------------------------
WARNING FIXES:
---------------------------------------------------------------
console-stream.c: `reinit' is unused.
compiler.h, event-msw.c, frame-msw.c, intl-encap-win32.c, text.h: Add stuff to deal with ANSI-aliasing warnings I got.
regex.c: Gather includes together to avoid warning.
---------------------------------------------------------------
CHANGES TO INITIALIZATION ROUTINES:
---------------------------------------------------------------
buffer.c, emacs.c, console.c, debug.c, device-x.c, device.c, dragdrop.c, emodules.c, eval.c, event-Xt.c, event-gtk.c, event-msw.c, event-stream.c, event-tty.c, events.c, extents.c, faces.c, file-coding.c, fileio.c, font-lock.c, frame-msw.c, glyphs-widget.c, glyphs.c, gui-x.c, insdel.c, lread.c, lstream.c, menubar-gtk.c, menubar-x.c, minibuf.c, mule-wnnfns.c, objects-msw.c, objects.c, print.c, scrollbar-x.c, search.c, select-x.c, text.c, undo.c, unicode.c, window.c, symsinit.h: Call reinit_*() functions directly from emacs.c, for clarity.
Factor out some redundant init code. Move disallowed stuff
that had crept into vars_of_glyphs() into complex_vars_of_glyphs().
Call init_eval_semi_early() from eval.c not in the middle of
vars_of_() in emacs.c since there should be no order dependency
in the latter calls.
---------------------------------------------------------------
ARMAGEDDON:
---------------------------------------------------------------
alloc.c, emacs.c, lisp.h, print.c: Rename inhibit_non_essential_printing_operations to
inhibit_non_essential_conversion_operations.
text.c: Assert on !inhibit_non_essential_conversion_operations.
console-msw.c, print.c: Don't do conversion in SetConsoleTitle or FindWindow to avoid
problems during armageddon. Put #errors for NON_ASCII_INTERNAL_FORMAT
in places where problems would arise.
---------------------------------------------------------------
CHANGES TO THE BUILD PROCEDURE:
---------------------------------------------------------------
config.h.in, s/cxux.h, s/usg5-4-2.h, m/powerpc.h: Add comment about correct ordering of this file.
Rearrange everything to follow this -- put all #undefs together
and before the s&m files. Add undefs for HAVE_ALLOCA, C_ALLOCA,
BROKEN_ALLOCA_IN_FUNCTION_CALLS, STACK_DIRECTION. Remove unused
HAVE_STPCPY, HAVE_GETWD, HAVE_SETLOCALE.
m/gec63.h: Deleted; totally broken, not used at all, not in FSF.
m/7300.h, m/acorn.h, m/alliant-2800.h, m/alliant.h, m/altos.h, m/amdahl.h, m/apollo.h, m/att3b.h, m/aviion.h, m/celerity.h, m/clipper.h, m/cnvrgnt.h, m/convex.h, m/cydra5.h, m/delta.h, m/delta88k.h, m/dpx2.h, m/elxsi.h, m/ews4800r.h, m/gould.h, m/hp300bsd.h, m/hp800.h, m/hp9000s300.h, m/i860.h, m/ibmps2-aix.h, m/ibmrs6000.h, m/ibmrt-aix.h, m/ibmrt.h, m/intel386.h, m/iris4d.h, m/iris5d.h, m/iris6d.h, m/irist.h, m/isi-ov.h, m/luna88k.h, m/m68k.h, m/masscomp.h, m/mg1.h, m/mips-nec.h, m/mips-siemens.h, m/mips.h, m/news.h, m/nh3000.h, m/nh4000.h, m/ns32000.h, m/orion105.h, m/pfa50.h, m/plexus.h, m/pmax.h, m/powerpc.h, m/pyrmips.h, m/sequent-ptx.h, m/sequent.h, m/sgi-challenge.h, m/symmetry.h, m/tad68k.h, m/tahoe.h, m/targon31.h, m/tekxd88.h, m/template.h, m/tower32.h, m/tower32v3.h, m/ustation.h, m/vax.h, m/wicat.h, m/xps100.h: Delete C_ALLOCA, HAVE_ALLOCA, STACK_DIRECTION,
BROKEN_ALLOCA_IN_FUNCTION_CALLS. All of this is auto-detected.
When in doubt, I followed recent FSF sources, which also have
these things deleted.
author | ben |
---|---|
date | Thu, 04 Nov 2004 23:08:28 +0000 |
parents | 04bc9d2f42c7 |
children | 3d8143fc88e1 |
comparison
equal
deleted
inserted
replaced
2366:2a392e0c390a | 2367:ecf1ebac70d8 |
---|---|
520 static const struct sized_memory_description rune_dglyph_description = { | 520 static const struct sized_memory_description rune_dglyph_description = { |
521 sizeof (struct rune_dglyph), rune_dglyph_description_1 | 521 sizeof (struct rune_dglyph), rune_dglyph_description_1 |
522 }; | 522 }; |
523 | 523 |
524 static const struct memory_description rune_object_description_1[] = { | 524 static const struct memory_description rune_object_description_1[] = { |
525 { XD_STRUCT_ARRAY, RUNE_DGLYPH, 1, &rune_dglyph_description }, | 525 { XD_BLOCK_ARRAY, RUNE_DGLYPH, 1, &rune_dglyph_description }, |
526 { XD_END } | 526 { XD_END } |
527 }; | 527 }; |
528 | 528 |
529 static const struct sized_memory_description rune_object_description = { | 529 static const struct sized_memory_description rune_object_description = { |
530 0, rune_object_description_1 | 530 0, rune_object_description_1 |
551 sizeof (rune_dynarr), | 551 sizeof (rune_dynarr), |
552 rune_dynarr_description_1 | 552 rune_dynarr_description_1 |
553 }; | 553 }; |
554 | 554 |
555 static const struct memory_description display_block_description_1[] = { | 555 static const struct memory_description display_block_description_1[] = { |
556 { XD_STRUCT_PTR, offsetof (display_block, runes), | 556 { XD_BLOCK_PTR, offsetof (display_block, runes), |
557 1, &rune_dynarr_description }, | 557 1, &rune_dynarr_description }, |
558 { XD_END } | 558 { XD_END } |
559 }; | 559 }; |
560 | 560 |
561 static const struct sized_memory_description display_block_description = { | 561 static const struct sized_memory_description display_block_description = { |
593 sizeof (glyph_block_dynarr), | 593 sizeof (glyph_block_dynarr), |
594 glyph_block_dynarr_description_1 | 594 glyph_block_dynarr_description_1 |
595 }; | 595 }; |
596 | 596 |
597 static const struct memory_description display_line_description_1[] = { | 597 static const struct memory_description display_line_description_1[] = { |
598 { XD_STRUCT_PTR, offsetof (display_line, display_blocks), | 598 { XD_BLOCK_PTR, offsetof (display_line, display_blocks), |
599 1, &display_block_dynarr_description }, | 599 1, &display_block_dynarr_description }, |
600 { XD_STRUCT_PTR, offsetof (display_line, left_glyphs), | 600 { XD_BLOCK_PTR, offsetof (display_line, left_glyphs), |
601 1, &glyph_block_dynarr_description }, | 601 1, &glyph_block_dynarr_description }, |
602 { XD_STRUCT_PTR, offsetof (display_line, right_glyphs), | 602 { XD_BLOCK_PTR, offsetof (display_line, right_glyphs), |
603 1, &glyph_block_dynarr_description }, | 603 1, &glyph_block_dynarr_description }, |
604 { XD_END } | 604 { XD_END } |
605 }; | 605 }; |
606 | 606 |
607 static const struct sized_memory_description display_line_description = { | 607 static const struct sized_memory_description display_line_description = { |
1567 && STRINGP (XCAR (XCDR (entry)))) | 1567 && STRINGP (XCAR (XCDR (entry)))) |
1568 { | 1568 { |
1569 Lisp_Object format = XCAR (XCDR (entry)); | 1569 Lisp_Object format = XCAR (XCDR (entry)); |
1570 Bytebpos len = XSTRING_LENGTH (format); | 1570 Bytebpos len = XSTRING_LENGTH (format); |
1571 Ibyte *src = XSTRING_DATA (format), *end = src + len; | 1571 Ibyte *src = XSTRING_DATA (format), *end = src + len; |
1572 Ibyte *result = alloca_array (Ibyte, len); | 1572 Ibyte *result = alloca_ibytes (len); |
1573 Ibyte *dst = result; | 1573 Ibyte *dst = result; |
1574 | 1574 |
1575 while (src < end) | 1575 while (src < end) |
1576 { | 1576 { |
1577 Ichar c = itext_ichar (src); | 1577 Ichar c = itext_ichar (src); |
2142 /* The variable ctl-arrow allows the user to specify what characters | 2142 /* The variable ctl-arrow allows the user to specify what characters |
2143 can actually be displayed and which octal should be used for. | 2143 can actually be displayed and which octal should be used for. |
2144 #### This variable should probably have some rethought done to | 2144 #### This variable should probably have some rethought done to |
2145 it. | 2145 it. |
2146 | 2146 |
2147 #### It would also be really nice if you could specify that | 2147 See also |
2148 the characters come out in hex instead of in octal. Mule | 2148 |
2149 does that by adding a ctl-hexa variable similar to ctl-arrow, | 2149 (Info-goto-node "(internals)Future Work -- Display Tables") |
2150 but that's bogus -- we need a more general solution. I | 2150 |
2151 think you need to extend the concept of display tables | 2151 */ |
2152 into a more general conversion mechanism. Ideally you | |
2153 could specify a Lisp function that converts characters, | |
2154 but this violates the Second Golden Rule and besides would | |
2155 make things way way way way slow. | |
2156 | |
2157 So instead, we extend the display-table concept, which was | |
2158 historically limited to 256-byte vectors, to one of the | |
2159 following: | |
2160 | |
2161 a) A 256-entry vector, for backward compatibility; | |
2162 b) char-table, mapping characters to values; | |
2163 c) range-table, mapping ranges of characters to values; | |
2164 d) a list of the above. | |
2165 | |
2166 The (d) option allows you to specify multiple display tables | |
2167 instead of just one. Each display table can specify conversions | |
2168 for some characters and leave others unchanged. The way the | |
2169 character gets displayed is determined by the first display table | |
2170 with a binding for that character. This way, you could call a | |
2171 function `enable-hex-display' that adds a hex display-table to | |
2172 the list of display tables for the current buffer. | |
2173 | |
2174 #### ...not yet implemented... Also, we extend the concept of | |
2175 "mapping" to include a printf-like spec. Thus you can make all | |
2176 extended characters show up as hex with a display table like | |
2177 this: | |
2178 | |
2179 #s(range-table data ((256 524288) (format "%x"))) | |
2180 | |
2181 Since more than one display table is possible, you have | |
2182 great flexibility in mapping ranges of characters. */ | |
2183 Ichar printable_min = (CHAR_OR_CHAR_INTP (b->ctl_arrow) | 2152 Ichar printable_min = (CHAR_OR_CHAR_INTP (b->ctl_arrow) |
2184 ? XCHAR_OR_CHAR_INT (b->ctl_arrow) | 2153 ? XCHAR_OR_CHAR_INT (b->ctl_arrow) |
2185 : ((EQ (b->ctl_arrow, Qt) || EQ (b->ctl_arrow, Qnil)) | 2154 : ((EQ (b->ctl_arrow, Qt) || EQ (b->ctl_arrow, Qnil)) |
2186 ? 255 : 160)); | 2155 ? 255 : 160)); |
2187 | 2156 |
7732 mark_glyph_block_dynarr (dl->right_glyphs); | 7701 mark_glyph_block_dynarr (dl->right_glyphs); |
7733 } | 7702 } |
7734 } | 7703 } |
7735 | 7704 |
7736 | 7705 |
7737 /***************************************************************************** | 7706 |
7738 Line Start Cache Description and Rationale | 7707 /* |
7739 | 7708 |
7740 The traditional scrolling code in Emacs breaks in a variable height world. | 7709 Info on line-start cache: |
7741 It depends on the key assumption that the number of lines that can be | 7710 |
7742 displayed at any given time is fixed. This led to a complete separation | 7711 (Info-goto-node "(internals)Line Start Cache") |
7743 of the scrolling code from the redisplay code. In order to fully support | 7712 */ |
7744 variable height lines, the scrolling code must actually be tightly | |
7745 integrated with redisplay. Only redisplay can determine how many lines | |
7746 will be displayed on a screen for any given starting point. | |
7747 | |
7748 What is ideally wanted is a complete list of the starting buffer position | |
7749 for every possible display line of a buffer along with the height of that | |
7750 display line. Maintaining such a full list would be very expensive. We | |
7751 settle for having it include information for all areas which we happen to | |
7752 generate anyhow (i.e. the region currently being displayed) and for those | |
7753 areas we need to work with. | |
7754 | |
7755 In order to ensure that the cache accurately represents what redisplay | |
7756 would actually show, it is necessary to invalidate it in many situations. | |
7757 If the buffer changes, the starting positions may no longer be correct. | |
7758 If a face or an extent has changed then the line heights may have altered. | |
7759 These events happen frequently enough that the cache can end up being | |
7760 constantly disabled. With this potentially constant invalidation when is | |
7761 the cache ever useful? | |
7762 | |
7763 Even if the cache is invalidated before every single usage, it is | |
7764 necessary. Scrolling often requires knowledge about display lines which | |
7765 are actually above or below the visible region. The cache provides a | |
7766 convenient light-weight method of storing this information for multiple | |
7767 display regions. This knowledge is necessary for the scrolling code to | |
7768 always obey the First Golden Rule of Redisplay. | |
7769 | |
7770 If the cache already contains all of the information that the scrolling | |
7771 routines happen to need so that it doesn't have to go generate it, then we | |
7772 are able to obey the Third Golden Rule of Redisplay. The first thing we | |
7773 do to help out the cache is to always add the displayed region. This | |
7774 region had to be generated anyway, so the cache ends up getting the | |
7775 information basically for free. In those cases where a user is simply | |
7776 scrolling around viewing a buffer there is a high probability that this is | |
7777 sufficient to always provide the needed information. The second thing we | |
7778 can do is be smart about invalidating the cache. | |
7779 | |
7780 TODO -- Be smart about invalidating the cache. Potential places: | |
7781 | |
7782 + Insertions at end-of-line which don't cause line-wraps do not alter the | |
7783 starting positions of any display lines. These types of buffer | |
7784 modifications should not invalidate the cache. This is actually a large | |
7785 optimization for redisplay speed as well. | |
7786 | |
7787 + Buffer modifications frequently only affect the display of lines at and | |
7788 below where they occur. In these situations we should only invalidate | |
7789 the part of the cache starting at where the modification occurs. | |
7790 | |
7791 In case you're wondering, the Second Golden Rule of Redisplay is not | |
7792 applicable. | |
7793 ****************************************************************************/ | |
7794 | 7713 |
7795 /* This will get used quite a bit so we don't want to be constantly | 7714 /* This will get used quite a bit so we don't want to be constantly |
7796 allocating and freeing it. */ | 7715 allocating and freeing it. */ |
7797 static line_start_cache_dynarr *internal_cache; | 7716 static line_start_cache_dynarr *internal_cache; |
7798 | 7717 |