Advanced GUI link

This section has some odds and ends about advanced usage of the GUI.

Python Functions link

There are some Python functions that support the GUI.

More on gui.rebuild link

The gui.rebuild function is a rather slow function that updates the GUI to reflect the current state of Ren'Py. What it does is:

  • Re-runs all of the define statements that define variables in the gui namespace.
  • Re-runs all of the translate python blocks for the current language.
  • Re-runs all of the style statements.
  • Rebuilds all of the styles in the system.

Note that init python blocks are not re-run on gui.rebuild. In this way,

define gui.text_size = persistent.text_size

and:

init python:
    gui.text_size = persistent.text_size

are different.

The default statement, the gui namespace, and gui.rebuild link

The default statement has changed semantics when applied to the gui namespace. When applied to a variable in the gui namespace, the default statement runs interleaved with the define statement, and the default statements are not re-run when gui.rebuild() is called.

What this means is that if we have:

default gui.accent_color = "#c04040"
define gui.hover_color = gui.accent_color

The first time the game is run, the accent color will be set, and then the hover color will be set to the accent color. (Both are then used to set various style colors.)

However, if as part of the game script, we have:

$ gui.accent_color = "#4040c0"
$ gui.rebuild()

Ren'Py will only re-run the define, so it will set the hover color to the accent color, and then update the styles. This makes it possible to have parts of the GUI that change as the game progresses.

GUI Preferences link

Ren'Py also supports a GUI preference system, consisting of a single function and a pair of actions.

Example link

The GUI preference system is used by calling gui.preference() when defining variables, with the name of the preference and the default value. For example, one can use GUI preferences to define the text font and size.

define gui.text_font = gui.preference("font", "DejaVuSans.ttf")
define gui.text_size = gui.preference("size", 22)

It's then possible to use the gui.SetPreference and gui.TogglePreference actions to add change the values of the preferences. Here's some examples that can be added to the preferences screen.

vbox:
    style_prefix "check"
    label _("Options")
    textbutton _("OpenDyslexic") action gui.TogglePreference("font", "OpenDyslexic-Regular.otf", "DejaVuSans.ttf")

vbox:
    style_prefix "radio"
    label _("Text Size")
    textbutton _("Small") action gui.SetPreference("size", 20)
    textbutton _("Medium") action gui.SetPreference("size", 22)
    textbutton _("Big") action gui.SetPreference("size", 24)