Features/Font configuration: Difference between revisions

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* In general, font sizes should never be specified. Use the default Sugar font (e.g. which is what you get if you create a gtk.Label), as this is what the user has chosen as their preferred font size.

** also use variations using pango markup e.g. <nowiki><big> </nowiki>

** ~~FIXME: document how~~ the ~~point sizes of<nowiki> <big> and </nowiki> can be read by an activity~~ (~~I think it's just based on scale factor 1.2~~) ~~and maybe propose helper functions to make these values dead-easy to retrieve.~~

** If the user cannot or does not want to use pango markup in a particular scenario, Sugar could provide a helper function to scale the font size from the default for a given widget (see suggested code below)

* There may be exceptional cases where applications want to scale a font to fit nicely in a given space. In this situation, they should use the standard Pango rendering pipelines to render text offscreen (using a sensible seed size value), measure the resultant pixel size, and then retry the rendering based on a new font size if the result was too big or too small.

** The Memorize activity is one example of this - it dynamically chooses a font size which causes the text to fit nicely within the tiles of the game.

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Not (unnecessarily) messing with font sizes will just become another step in "effective Sugarization" of an activity.

Here is sample code for scaling fonts as described above:

def scale_font(widget, scale_steps):

if scale_steps == 0:

return

font = widget.get_pango_context().get_font_description()

font.set_size(int(font.get_size() * pango.SCALE_LARGE * scale_steps))

widget.modify_font(font)

The above function will work for any GtkWidget, allowing the font to be scaled. A scape_steps value of 0 will cause no scaling, -1 is equivalent to <nowiki>, 2 is equivalent to <big><big> or , </nowiki> etc. It works based on the fact that pango.SCALE_LARGE is the scaling factor for a single step up, which has value 1.2 as used in all pango font scaling (and the CSS world).

=== Additional fonts ===

@@ Line 48: / Line 48: @@
 * In general, font sizes should never be specified. Use the default Sugar font (e.g. which is what you get if you create a gtk.Label), as this is what the user has chosen as their preferred font size.
 ** also use variations using pango markup e.g. <nowiki><big> <small> <b></nowiki>
-** FIXME: document how the point sizes of<nowiki> <big> and <small></nowiki> can be read by an activity (I think it's just based on scale factor 1.2) and maybe propose helper functions to make these values dead-easy to retrieve.
+** If the user cannot or does not want to use pango markup in a particular scenario, Sugar could provide a helper function to scale the font size from the default for a given widget (see suggested code below)
 * There may be exceptional cases where applications want to scale a font to fit nicely in a given space. In this situation, they should use the standard Pango rendering pipelines to render text offscreen (using a sensible seed size value), measure the resultant pixel size, and then retry the rendering based on a new font size if the result was too big or too small.
 ** The Memorize activity is one example of this - it dynamically chooses a font size which causes the text to fit nicely within the tiles of the game.
@@ Line 56: / Line 56: @@
 Not (unnecessarily) messing with font sizes will just become another step in "effective Sugarization" of an activity.
+Here is sample code for scaling fonts as described above:
+ def scale_font(widget, scale_steps):
+     if scale_steps == 0:
+         return
+     font = widget.get_pango_context().get_font_description()
+     font.set_size(int(font.get_size() * pango.SCALE_LARGE * scale_steps))
+     widget.modify_font(font)
+The above function will work for any GtkWidget, allowing the font to be scaled. A scape_steps value of 0 will cause no scaling, -1 is equivalent to <nowiki><small>,  2 is equivalent to <big><big> or <span font_size="x-large">, </nowiki> etc. It works based on the fact that pango.SCALE_LARGE is the scaling factor for a single step up, which has value 1.2 as used in all pango font scaling (and the CSS world).
 === Additional fonts ===