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# Commands for manipulating rects.
Rect =
# Create a rect given the top left and bottom right corners.
create: (x1, y1, x2, y2) ->
bottom: y2
top: y1
left: x1
right: x2
width: x2 - x1
height: y2 - y1
copy: (rect) ->
bottom: rect.bottom
top: rect.top
left: rect.left
right: rect.right
width: rect.width
height: rect.height
# Translate a rect by x horizontally and y vertically.
translate: (rect, x = 0, y = 0) ->
bottom: rect.bottom + y
top: rect.top + y
left: rect.left + x
right: rect.right + x
width: rect.width
height: rect.height
# Subtract rect2 from rect1, returning an array of rects which are in rect1 but not rect2.
subtract: (rect1, rect2) ->
# Bound rect2 by rect1
rect2 = @create(
Math.max(rect1.left, rect2.left),
Math.max(rect1.top, rect2.top),
Math.min(rect1.right, rect2.right),
Math.min(rect1.bottom, rect2.bottom)
)
# If bounding rect2 has made the width or height negative, rect1 does not contain rect2.
return [Rect.copy rect1] if rect2.width < 0 or rect2.height < 0
#
# All the possible rects, in the order
# +-+-+-+
# |1|2|3|
# +-+-+-+
# |4| |5|
# +-+-+-+
# |6|7|8|
# +-+-+-+
# where the outer rectangle is rect1 and the inner rectangle is rect 2. Note that the rects may be of
# width or height 0.
#
rects = [
# Top row.
@create rect1.left, rect1.top, rect2.left, rect2.top
@create rect2.left, rect1.top, rect2.right, rect2.top
@create rect2.right, rect1.top, rect1.right, rect2.top
# Middle row.
@create rect1.left, rect2.top, rect2.left, rect2.bottom
@create rect2.right, rect2.top, rect1.right, rect2.bottom
# Bottom row.
@create rect1.left, rect2.bottom, rect2.left, rect1.bottom
@create rect2.left, rect2.bottom, rect2.right, rect1.bottom
@create rect2.right, rect2.bottom, rect1.right, rect1.bottom
]
rects.filter (rect) -> rect.height > 0 and rect.width > 0
# Determine whether two rects overlap.
intersects: (rect1, rect2) ->
rect1.right > rect2.left and
rect1.left < rect2.right and
rect1.bottom > rect2.top and
rect1.top < rect2.bottom
# Determine whether two rects overlap, including 0-width intersections at borders.
intersectsStrict: (rect1, rect2) ->
rect1.right >= rect2.left and rect1.left <= rect2.right and
rect1.bottom >= rect2.top and rect1.top <= rect2.bottom
equals: (rect1, rect2) ->
for property in ["top", "bottom", "left", "right", "width", "height"]
return false if rect1[property] != rect2[property]
true
intersect: (rect1, rect2) ->
@create (Math.max rect1.left, rect2.left), (Math.max rect1.top, rect2.top),
(Math.min rect1.right, rect2.right), (Math.min rect1.bottom, rect2.bottom)
root = exports ? (window.root ?= {})
root.Rect = Rect
extend window, root unless exports?
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