Use objc_util functions to draw on a `ui.View`

[Webmaster4o]

Can I draw on a ui.View with ObjC functions? ui.ImageContext doesn't have an objc counterpart. I'm specifically trying to use a CAShapeLayer.

[AtomBombed]

Couldn't you just use ui.Path and add the points and paths drawings as a subview to the ui.View? Hopefully that made sense.

Check out the sketch.py example in the Examples folder for an example.

[JonB]

ok, simple, stupid example.

import ui,time
from objc_util import *
# create a view
v=ui.View()
v.bg_color='white'
vv=ObjCInstance(v)

# grab view's layer
layer=vv.layer()

# add a shapelayer
CAShapeLayer=ObjCClass('CAShapeLayer')
shlayer=CAShapeLayer.layer()
shlayer.frame=layer.bounds()
layer.addSublayer_(shlayer)

# add some stuff to the shapelayer, using a ui.Path
p=ui.Path.rounded_rect(5,5,80,80,22)
shlayer.path=ObjCInstance(p).CGPath()

#stroke it
shlayer.strokeColor = UIColor.colorWithRed(0.75,green=0.0,blue=0.0,alpha=1.0).CGColor()
shlayer.fillColor=UIColor.colorWithRed(1,green=1.0,blue=1.0,alpha=1.0).CGColor()
shlayer.lineWidth = 9
shlayer.strokeEnd=.0

#sublayer must be added before view is presented... dunno why.
v.present('sheet')

# demo.  seems to have built in default animation
time.sleep(1)
on_main_thread(lambda: shlayer.setStrokeEnd_(1))()
time.sleep(1)
on_main_thread(lambda: shlayer.setStrokeEnd_(0))()
time.sleep(1)
for i in range(30):
	on_main_thread(lambda: shlayer.setStrokeEnd_(i/29.))()
	time.sleep(.1)

[Webmaster4o]

Thanks @JonB I came up with a similar example a few hours before you: https://github.com/controversial/ui2/blob/master/ui2/view_classes/ProgressPathView.py

I should really report back here sooner when I find a solution.

I had found addSublayer_() in a StackOverflow answer and realized it was perfect ;)