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I came across a weird difference of colors by passing in an un-normalized RGB tuple to the ui.set_color function. I was wanting just regular green (#00ff00) but instead I got a neon green.

It happens anytime the green value is greater than 1 in the tuple. It stays the same after 2, so it’s almost as if it’s brightness is mapped from 1-> 2.

What color space is this? I want to take full advantage of this in the color picker!

import ui


class Colors (ui.View):
    def __init__(self, *args, **kwargs):
        return super().__init__(self, *args, **kwargs)

    def draw(self):
        neon = ui.Path.rect(5, 5, 100, 100)
        ui.set_color((0, 2, 0))
        neon.fill()

        normal = ui.Path.rect(110, 5, 100, 100)
        ui.set_color(("#00ff00"))
        normal.fill()


example = Colors(bg_color="white")
example.present() 

Try, this script, then
- tap on the button, then on the syringe
- you will receive a viewfinder (no way to get it in the print screen ) that you move on one of your squares,
- tap ok, the real rgb will appear, surprise, no one is #00FF00

# coding: utf-8
from objc_util import *
import ui

def colorPickerViewControllerDidFinish_(_self, _cmd, _controller):
    #print('colorPickerViewControllerDidFinish')
    UIColorPickerViewController = ObjCInstance(_controller)

def colorPickerViewControllerDidSelectColor_(_self, _cmd, _controller):
    #print('colorPickerViewControllerDidSelectColor')
    UIColorPickerViewController = ObjCInstance(_controller)
    cl = UIColorPickerViewController.selectedColor()
    rgb = (cl.red(),cl.green(),cl.blue())
    coloredButtonItem(UIColorPickerViewController.buttonItem, rgb)

methods = [colorPickerViewControllerDidFinish_, colorPickerViewControllerDidSelectColor_]
protocols = ['UIColorPickerViewControllerDelegate']
try:
        MyUIColorPickerViewControllerDelegate = ObjCClass('MyUIColorPickerViewControllerDelegate')
except Exception as e:
    MyUIColorPickerViewControllerDelegate = create_objc_class('MyUIColorPickerViewControllerDelegate', methods=methods, protocols=protocols)

def coloredButtonItem(btn,rgb):
    import ui
    if rgb:
        with ui.ImageContext(32,32) as ctx: 
            path = ui.Path.rect(0,0,32,32)
            ui.set_color(rgb)
            path.fill()     
            btn.image = ctx.get_image().with_rendering_mode(ui.RENDERING_MODE_ORIGINAL)

def UIColorPickerViewController(w, h, alpha_slider=True, title='', rgb=None, popover=None):
    v = ui.View()
    v.name = title
    v.rgb = rgb
    vc = ObjCInstance(v)
    colorpicker = ObjCClass('UIColorPickerViewController').new().autorelease()
    #print(dir(colorpicker))
    delegate = MyUIColorPickerViewControllerDelegate.alloc().init()
    colorpicker.delegate = delegate 

    colorpicker.setSupportsAlpha_(alpha_slider) 
    if rgb:
        color = ObjCClass('UIColor').colorWithRed_green_blue_alpha_(rgb[0], rgb[1], rgb[2], 1.0)
        colorpicker.setSelectedColor_(color)

    clview = colorpicker.view()
    v.frame = (0,0,w,h)
    vc.addSubview_(clview)
    done_button = ui.ButtonItem(title='ok')
    def tapped(sender):
        cl = colorpicker.selectedColor()
        v.rgb = (cl.red(),cl.green(),cl.blue())
        v.close()
    done_button.action = tapped
    color_button = ui.ButtonItem()
    coloredButtonItem(color_button,rgb)
    v.right_button_items = [done_button,color_button]

    colorpicker.buttonItem = color_button

    if popover:
        x,y = popover
        v.present('popover', popover_location=(x,y))
    else:
        v.present('sheet')

    v.wait_modal()
    return v.rgb    

def rgb_to_hex(rgb):
    r,g,b = rgb
    r = int(255*r)
    g = int(255*g)
    b = int(255*b)
    return f'#{r:02x}{g:02x}{b:02x}'

class Colors (ui.View):
    def __init__(self, *args, **kwargs):
        return super().__init__(self, *args, **kwargs)

    def draw(self):
        neon = ui.Path.rect(5, 5, 100, 100)
        ui.set_color((0, 2, 0))
        neon.fill()

        normal = ui.Path.rect(110, 5, 100, 100)
        ui.set_color(("#00ff00"))
        normal.fill()


# Protect against import    
if __name__ == '__main__':
    example = Colors(bg_color="white")
    lbl = ui.Label(frame=(5,120,200,32))
    lbl.alignment = ui.ALIGN_CENTER
    example.add_subview(lbl)
    b1 = ui.ButtonItem()
    b1.title = '💉'
    def b1_action(sender):
        # compute x,y of an ui.ButtonItem
        vi = ObjCInstance(sender).view()
        r = vi.convertRect_toView_(vi.bounds(),ObjCInstance(example))
        # x,y in screen coordinates, not in view
        x,y,w,h = r.origin.x,r.origin.y,r.size.width,r.size.height
        x,y = x+w/2, y+h
        w,h = 200,50
        rgb = UIColorPickerViewController(w,h, alpha_slider=False, popover=(x,y))
        if rgb:
            lbl.text = rgb_to_hex(rgb)
    b1.action = b1_action
    example.right_button_items =(b1,)
    example.present('fullscreen')