# The sub-rect fraction is measured against the stretch size, not the primitive
# rect. Gecko trims the rect of a repeating background to the fill area while
# leaving its origin on the first tile, so the rect can be much narrower than
# one repetition and dividing by it reads the fraction at the wrong scale.
#
# One repetition here is 3600 and the rect is 400, so the rect reads the
# fraction 9x too large. The visible part is 360..400 of the repetition, i.e.
# texels 2..3 of the 20x20 sheet, which is grey. Measured against the rect it
# saturates to texels 18..20 -- the sheet's blue border -- painting the whole
# visible area one flat wrong colour. That is how bug 2069245 appeared as a
# black square over the content, and it is the same defect as bug 2068996.
root:
  items:
    - image: checkerboard(2, 1, 1, 16, 16)
      bounds: 0 0 400 400
      stretch-size: 3600 3600
      clip-rect: [360, 360, 40, 40]