Gtk UI: full color scheme support

 * implemented by exporting the most important Scintilla STYLEs
   as CSS variables and defining named widgets for the main UI
   components.
 * ~/.teco_css will then apply the Scintilla styles to the
   Gtk UI.
   This file is also for additional tweaks, e.g. enabling
   translucency.
 * A fallback.css is provided which does just that and is able
   to apply the terminal.tes and solarized.tes color schemes.
 * Other important aspects of theming like font sizes and names
   have not yet been dealt with.
   (We may want to apply the corresponding Scintilla settings
   to some widgets...)

2 files changed, 61 insertions, 0 deletions

diff --git a/doc/sciteco.1.in b/doc/sciteco.1.in
index 1d21ecf..0a96cab 100644
--- a/doc/sciteco.1.in
+++ b/doc/sciteco.1.in
@@ -314,6 +314,19 @@ standard library \fBsession.tes\fP macros.
 When the \(lqsession.vcs\(rq macro is used, these files
 will also be created in the roots of Git, Mercurial and
 Subversion repositories or working copies.
+.TP
+.B $SCITECOCONFIG/.teco_css
+When using the Gtk UI, this will be the location of a
+CSS file that can be used to apply \*(ST color schemes
+to the entire UI and to do other style customizations.
+.TP
+.B @pkgdatadir@/fallback.css
+When using the Gtk UI, this is a fallback stylesheet
+in case
+.B $SCITECOCONFIG/.teco_css
+does not exist.
+It may also be used as a template for
+.BR $SCITECOCONFIG/.teco_css .
 .
 .
 .SH SEE ALSO
diff --git a/doc/sciteco.7.template b/doc/sciteco.7.template
index bdb25bc..9f3ba8f 100644
--- a/doc/sciteco.7.template
+++ b/doc/sciteco.7.template
@@ -688,6 +688,48 @@ macro or \fBED\fP hook (for syntax highlighting).
 \*(ST ships with a standard library with color schemes
 and lexer configurations for a wide range of languages.
 .
+.SS Gtk CSS Styling
+.
+While the tools mentioned above are sufficient for
+Curses UIs, the Gtk+ 3 UI has many more styling possibilities.
+The basic color scheme will be automatically effective for
+the buffer view since this is handled by Scintilla.
+In order to apply the color scheme to the other UI components,
+a CSS file must be provided that overrides certain styling
+settings of the Gtk theme.
+.LP
+Therefore \*(ST automatically exports the following Gtk
+CSS variables that can be referred to by user-provided
+CSS files:
+.TP
+.B @sciteco_default_fg_color
+The foreground color of Scintilla's \fBSTYLE_DEFAULT\fP.
+.TP
+.B @sciteco_default_bg_color
+The background color of Scintilla's \fBSTYLE_DEFAULT\fP.
+.TP
+.B @sciteco_calltip_fg_color
+The foreground color of Scintilla's \fBSTYLE_CALLTIP\fP.
+.TP
+.B @sciteco_calltip_bg_color
+The background color of Scintilla's \fBSTYLE_CALLTIP\fP.
+.LP
+Furthermore, \*(ST defines the following named widgets for its
+main UI components: \fB#sciteco-info-bar\fP, \fB#sciteco-message-bar\fP,
+\fB#sciteco-cmdline\fP and \fB#sciteco-info-popup\fP.
+.LP
+The CSS file is loaded from
+.B $SCITECOCONFIG/.teco_css
+if it is existing.
+Else, \*(ST loads the fallback CSS at
+.BR @pkgdatadir@/fallback.css ,
+which can also be used as a template when writing \fB.teco_css\fP.
+The CSS file can be written such that it works for any
+\*(ST color scheme and may also be used to tweak other
+aspects of \*(ST's user interface.
+Please refer to the Gtk documentation for more details on
+CSS theming.
+.
 .
 .SH ARITHMETICS AND EXPRESSIONS
 .
@@ -1792,6 +1834,12 @@ Scinterm manual, documenting the mapping of
 .UR http://foicica.com/scinterm/manual.html
 Scinterm manual
 .UE
+.TP
+Gtk+ 3 documentation, containg details about
+its CSS support and syntax:
+.UR https://developer.gnome.org/gtk3/stable/GtkCssProvider.html
+GtkCssProvider
+.UE
 .
 .
 .SH AUTHOR