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Diffstat (limited to 'doc/emacs/msdos.texi')
| -rw-r--r-- | doc/emacs/msdos.texi | 55 |
1 files changed, 42 insertions, 13 deletions
diff --git a/doc/emacs/msdos.texi b/doc/emacs/msdos.texi index fb876340b41..6933130d5bd 100644 --- a/doc/emacs/msdos.texi +++ b/doc/emacs/msdos.texi @@ -808,6 +808,13 @@ communications with subprocesses to programs that exhibit unusual behavior with respect to buffering pipe I/O. @ifnottex +@vindex w32-pipe-read-delay + If you need to invoke MS-DOS programs as Emacs subprocesses, you may +see low rate of reading data from such programs. Setting the variable +@code{w32-pipe-read-delay} to a non-zero value may improve throughput +in these cases; we suggest the value of 50 for such situations. The +default is zero. + @findex w32-shell-execute The function @code{w32-shell-execute} can be useful for writing customized commands that run MS-Windows applications registered to @@ -978,21 +985,43 @@ fontconfig library used in modern Free desktops: The old XLFD based format is also supported for backwards compatibility. @cindex font backend selection (MS-Windows) - Emacs 23 and later supports a number of font backends. Currently, -the @code{gdi} and @code{uniscribe} backends are supported on Windows. -The @code{gdi} font backend is available on all versions of Windows, -and supports all fonts that are natively supported by Windows. The -@code{uniscribe} font backend is available on Windows 2000 and later, -and supports TrueType and OpenType fonts. Some languages requiring -complex layout can only be properly supported by the Uniscribe -backend. By default, both backends are enabled if supported, with -@code{uniscribe} taking priority over @code{gdi}. To override that -and use the GDI backend even if Uniscribe is available, invoke Emacs -with the @kbd{-xrm Emacs.fontBackend:gdi} command-line argument, or -add a @code{Emacs.fontBackend} resource with the value @code{gdi} in -the Registry under either the + Emacs on MS-Windows supports a number of font backends. Currently, +the @code{gdi}, @code{uniscribe}, and @code{harfbuzz} backends are +available. The @code{gdi} font backend is available on all versions +of Windows, and supports all fonts that are natively supported by +Windows. The @code{uniscribe} font backend is available on Windows +2000 and later, and supports TrueType and OpenType fonts. The +@code{harfbuzz} font backend is available if Emacs was built with +HarfBuzz support, and if the HarfBuzz DLL is installed on your system; +like @code{uniscribe}, this backend supports only TrueType and +OpenType fonts. Some languages requiring complex layout can only be +properly supported by the Uniscribe or HarfBuzz backends. By default, +two backends are enabled for each frame: @code{gdi} and either +@code{harfbuzz} or @code{uniscribe}, depending on which one is +available (if both are available, only @code{harfbuzz} is enabled by +default). The @code{harfbuzz} and @code{uniscribe} backends take +priority over @code{gdi} when Emacs looks for a suitable font. To +override that and use the GDI backend even if Uniscribe is available, +invoke Emacs with the @kbd{-xrm Emacs.fontBackend:gdi} command-line +argument, or add a @code{Emacs.fontBackend} resource with the value +@code{gdi} in the Registry under either the @samp{HKEY_CURRENT_USER\SOFTWARE\GNU\Emacs} or the @samp{HKEY_LOCAL_MACHINE\SOFTWARE\GNU\Emacs} key (@pxref{Resources}). +Similarly, to use the Uniscribe backend even if HarfBuzz is available, +use @kbd{-xrm Emacs.fontBackend:uniscribe} on the command line that +invokes Emacs. You can also request all the 3 backends via the +@code{font-backend} frame parameter, but be warned that in that case +font searches for characters for which no fonts are available on the +system will take longer. + +Alternatively, you could specify a font backend for a frame via the +@code{font-backend} frame parameter, using +@code{modify-frame-parameters} (@pxref{Parameter Access,,, elisp, The +Emacs Lisp Reference Manual}). You can also request specific font +backend(s) for all your frames via @code{default-frame-alist} and +@code{initial-frame-alist} (@pxref{Frame Parameters}). Note that the +value of the @code{font-backend} parameter should be a list of +symbols, as in @code{(uniscribe)} or @w{@code{(harfbuzz uniscribe gdi)}}. @cindex font properties (MS Windows) @noindent |