Use a template to create your custom Label:
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.widget import Widget
from kivy.properties import ObjectProperty, NumericProperty
kv = '''
[MyLabel@Label]:
text: ctx.text if hasattr(ctx, 'text') else ''
font_size: 24
markup: True
<MyWidget>:
id: f_wid
BoxLayout:
size: f_wid.size
orientation: 'vertical'
MyLabel:
text: "Hello world 1"
MyLabel:
text: "Hello world 2"
MyLabel:
text: "Hello world 3"
MyLabel:
text: "Hello world 4"
MyLabel:
text: "Hello world 1"
MyLabel:
text: "Hello world 2"
MyLabel:
text: "Hello world 3"
MyLabel:
text: "Hello world 4"
'''
Builder.load_string(kv)
import kivy
kivy.require('1.7.1') # replace with your current kivy version !
from kivy.app import App
from kivy.uix.widget import Widget
class MyWidget(Widget):
pass
class MyApp(App):
def build(self):
return MyWidget()
if __name__ == '__main__':
MyApp().run()
To have font size depended on screen size, instead of using fixed values calculate it using self.heigh
:
[MyLabel@Label]:
text: ctx.text if hasattr(ctx, 'text') else ''
font_size: self.height/2
markup: True
UPDATE
Alternative approach is setting variable using #:set syntax:
kv = '''
#:set default_font_size "36sp"
<MyWidget>:
id: f_wid
BoxLayout:
size: f_wid.size
orientation: 'vertical'
Label:
text: "Hello world 1"
font_size: default_font_size
Label:
text: "Hello world 2"
font_size: default_font_size
Label:
text: "Hello world 3"
font_size: default_font_size
Label:
text: "Hello world 4"
font_size: default_font_size
Label:
text: "Hello world 1"
font_size: default_font_size
Label:
text: "Hello world 2"
font_size: default_font_size
Label:
text: "Hello world 3"
font_size: default_font_size
Label:
text: "Hello world 4"
font_size: default_font_size
'''
Builder.load_string(kv)