button.nim - Clip the radiobox/checkbox text to match the button bounds

[jlp765]

( Only tested on win platform)

Currently the text of a radiobox or checkbox can overflow the bounds of the button. This means that clicking the text to the right of the button bound does not click the button.

This PR clips the text to match the width of the button bounds (which should be picked up by the developer and trigger them to adjust the sizing of the control).

Test code (there should be a gap of 10 between the two checkboxes where the user clicks neither checkboxes):

import nimx / [ view, button, window ]

runApplication:
    let w = newWindow(newRect(50, 50, 500, 150))
    let checkbox1 = newCheckbox(newRect(10, 20, 75, 16))
    #echo "Frame: " & $checkbox1.frame() & " bounds: " & $checkbox1.bounds()
    checkbox1.title = "Checkbox1"
    checkbox1.name = checkbox1.title
    w.addSubview(checkbox1)
    let checkbox2 = newCheckbox(newRect(95, 20, 75, 16))
    checkbox2.title = "Checkbox2"
    checkbox2.name = checkbox2.title
    w.addSubview(checkbox2)

[yglukhov]

I might be wrong but you'll have to account for xOffset before trimming. Otherwise trimming done above might not be sufficient and the text will still escape the bounds by up to xOffset.