RC file

Using an rc file, you should invoke a method defined in the Gtk::RC module:

Gtk::RC.parse 'filename'

This method parses the file assigned by filename, and use the style defined there.

Gtk::RC.parse_string string

This method parses a given string and use the style described in it.
This way is usually used with here document. for example:

Gtk::RC.parse_string <<EOS
style "default"
{
  fontset = "-*-helvetica-medium-r-normal--14-*,-*-fixed-medium-r-normal--14-*"
}
widget_class "*" style "default"
EOS

Generally speaking, in the GTK's rc file, style statement defines a style, and widget or widget_class statement assigns its style to a widget.

Following sample shows a pink button: sample script rc-hello.rb:

require 'gtk'

Gtk::RC.parse_string <<EOS
style "button"
{
  bg[NORMAL] = {1.0, 0.8, 0.8}
}
widget_class "*GtkButton" style "button"
EOS

window = Gtk::Window.new(Gtk::WINDOW_TOPLEVEL)
button = Gtk::Button.new('Hello World')
window.add button
button.show
window.show
Gtk.main

result screen shot:

The "Gtk::RC.parse_string" loads GTK's rc strings and sets the style. The following documents to the line of EOS is passed to Gtk::RC.parse_string as an argument and parsed by GTK.

Here is a description of the string:

• style "button"
  It creates the new style named as a "button" defined by following strings between { and }.
• bg[NORMAL] = {1.0, 0.8, 0.8}
  It sets the background color in the "NORMAL" state. The following 3 decimals means the three primary colors, Red, Green, Blue in the order of appearance, are values in the range from 0.0 to 1.0. They must be in floating-point style, or they will register as 0. So note that simple "1" will not work, it must be "1.0".
• widget_class "*GtkButton" style "button"
  This sets a style of a widget of "GtkButton" class to the "button" style defined above. The directive of "widget_class" uses a class name to determine widgets. Note that the word of ``class name'' in this context is NOT Ruby's class name but GTK's class name, which is equals to Ruby's class name except "::". (ex: The GTK's classname of Gtk::Button is "GtkButton".)

style "style name"

style "style name" = "existing style name"

It defines a style. The content closed by {} is the definition itself. You can copy a existing style then describe differences with second syntax.

• To specify a color:
  You can specify a color with following format:
  • fg[state] = {red, green, blue} # set a foreground color of a widget.
    
  • bg[state] = {red, green, blue} # set a background color of a widget.
    
  The 3 decimals means the three primary colors, Red, Green, Blue in the order of appearance, are values in the range from 0.0 to 1.0. They must be in floating-point format. A black is expressed by {0.0, 0.0, 0.0}, and a white is by {1.0, 1.0, 1.0}.
  ex:
  fg[NORMAL] = {0.0, 0.0, 0.0}
bg[NORMAL] = {0.8, 0.8, 0.8}
• state:
  
  • NORMAL -- a normal state of the widget.
    
  • PRELIGHT -- a mouse cursor is over the widget(but not pressed).
    
  • ACTIVE -- the widget is pressed or clicked.
    
  • INSENSITIVE -- non-active state of the widget.
    
  • SELECTED -- the widget is selected.
    
• To specify a background pixmap:
  you can specify a background pixmap with following format.
  • bg_pixmap[state] = "filename"
    
  a pixmap file is searched in the pixmap_path(mentioned later).
• font:
  
  • font = "font name"
    
  • fontset = "font name"
    
  This specifies a font or fontset in the XLFD format.

pixmap_path "path:path:..."

This is used for searching a pixmap file specified by the bg_pixmap. Searching path is separated by a colon(:).

widget_class "widget class set" style "style name"

widget "widget set" style "style name"

This assignes the style specified by a "style name" to the widget given by a "widget class set" or "widget set".

The directive of widget_class uses a class name to determine widgets. Note that the word of ``class name'' in this context is not Ruby's class name but GTK's class name, which is equals to Ruby's class name except "::". (ex: The GTK's classname of Gtk::Button is "GtkButton".) The directive of widget is specified by name. widget name is set by a method of Gtk::Widget#set_name. On my experience, if you don't set it, it becomes same to class name.

A widget class set or a widget set is specified widget has-a tree. For example, if a Gtk::Button is added to Gtk::Window, the button is specified by "GtkWindow.GtkButton" in a class name form. A wildcard `*' is also available in this syntax, so "*GtkButton" expresses all widget of GtkButton class.

Gtk::RC.parse_string <<EOS
pixmap_path "."
style "default"
{
  fg[NORMAL] = {0.0, 0.0, 1.0}
  bg_pixmap[NORMAL] = "stone.xpm"
  font = "-adobe-courier-bold-r-normal--18-*"
}
widget_class "*" style "default"
EOS

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