def test_paper_example(self):
solver = SimplexSolver()
left = Variable('left')
middle = Variable('middle')
right = Variable('right')
solver.add_constraint(middle == (left + right) / 2)
solver.add_constraint(right == left + 10)
solver.add_constraint(right <= 100)
solver.add_constraint(left >= 0)
# Check that all the required constraints are true:
self.assertAlmostEqual((left.value + right.value) / 2, middle.value)
self.assertAlmostEqual(right.value, left.value + 10)
self.assertGreaterEqual(left.value, 0)
self.assertLessEqual(right.value, 100)
# Set the middle value to a stay
middle.value = 45.0
solver.add_stay(middle)
# Check that all the required constraints are true:
self.assertAlmostEqual((left.value + right.value) / 2, middle.value)
self.assertAlmostEqual(right.value, left.value + 10)
self.assertGreaterEqual(left.value, 0)
self.assertLessEqual(right.value, 100)
# But more than that - since we gave a position for middle, we know
# where all the points should be.
self.assertAlmostEqual(left.value, 40)
self.assertAlmostEqual(middle.value, 45)
self.assertAlmostEqual(right.value, 50)
def test_paper_example(self):
solver = SimplexSolver()
left = Variable('left')
middle = Variable('middle')
right = Variable('right')
solver.add_constraint(middle == (left + right) / 2)
solver.add_constraint(right == left + 10)
solver.add_constraint(right <= 100)
solver.add_constraint(left >= 0)
# Check that all the required constraints are true:
self.assertAlmostEqual((left.value + right.value) / 2, middle.value)
self.assertAlmostEqual(right.value, left.value + 10)
self.assertGreaterEqual(left.value, 0)
self.assertLessEqual(right.value, 100)
# Set the middle value to a stay
middle.value = 45.0
solver.add_stay(middle)
# Check that all the required constraints are true:
self.assertAlmostEqual((left.value + right.value) / 2, middle.value)
self.assertAlmostEqual(right.value, left.value + 10)
self.assertGreaterEqual(left.value, 0)
self.assertLessEqual(right.value, 100)
# But more than that - since we gave a position for middle, we know
# where all the points should be.
self.assertAlmostEqual(left.value, 40)
self.assertAlmostEqual(middle.value, 45)
self.assertAlmostEqual(right.value, 50)
def test_buttons(self):
"A test of a horizontal layout of two buttons on a screen."
class Button(object):
def __init__(self, identifier):
self.left = Variable('left' + identifier, 0)
self.width = Variable('width' + identifier, 0)
def __repr__(self):
return u'(%s:%s)' % (self.left.value, self.width.value)
solver = SimplexSolver()
b1 = Button('b1')
b2 = Button('b2')
left_limit = Variable('left', 0)
right_limit = Variable('width', 0)
left_limit.value = 0
solver.add_stay(left_limit, REQUIRED)
stay = solver.add_stay(right_limit, WEAK)
# The two buttons are the same width
solver.add_constraint(b1.width == b2.width)
# b1 starts 50 from the left margin.
solver.add_constraint(b1.left == left_limit + 50)
# b2 ends 50 from the right margin
solver.add_constraint(left_limit + right_limit == b2.left + b2.width +
50)
# b2 starts at least 100 from the end of b1
solver.add_constraint(b2.left >= (b1.left + b1.width + 100))
# b1 has a minimum width of 87
solver.add_constraint(b1.width >= 87)
# b1's preferred width is 87
solver.add_constraint(b1.width == 87, STRONG)
# b2's minimum width is 113
solver.add_constraint(b2.width >= 113)
# b2's preferred width is 113
solver.add_constraint(b2.width == 113, STRONG)
# Without imposign a stay on the right, right_limit will be the minimum width for the layout
self.assertAlmostEqual(b1.left.value, 50.0)
self.assertAlmostEqual(b1.width.value, 113.0)
self.assertAlmostEqual(b2.left.value, 263.0)
self.assertAlmostEqual(b2.width.value, 113.0)
self.assertAlmostEqual(right_limit.value, 426.0)
# The window is 500 pixels wide.
right_limit.value = 500
stay = solver.add_stay(right_limit, REQUIRED)
self.assertAlmostEqual(b1.left.value, 50.0)
self.assertAlmostEqual(b1.width.value, 113.0)
self.assertAlmostEqual(b2.left.value, 337.0)
self.assertAlmostEqual(b2.width.value, 113.0)
self.assertAlmostEqual(right_limit.value, 500.0)
solver.remove_constraint(stay)
# Expand to 700 pixels
right_limit.value = 700
stay = solver.add_stay(right_limit, REQUIRED)
self.assertAlmostEqual(b1.left.value, 50.0)
self.assertAlmostEqual(b1.width.value, 113.0)
self.assertAlmostEqual(b2.left.value, 537.0)
self.assertAlmostEqual(b2.width.value, 113.0)
self.assertAlmostEqual(right_limit.value, 700.0)
solver.remove_constraint(stay)
# Contract to 600
right_limit.value = 600
stay = solver.add_stay(right_limit, REQUIRED)
self.assertAlmostEqual(b1.left.value, 50.0)
self.assertAlmostEqual(b1.width.value, 113.0)
self.assertAlmostEqual(b2.left.value, 437.0)
self.assertAlmostEqual(b2.width.value, 113.0)
self.assertAlmostEqual(right_limit.value, 600.0)
solver.remove_constraint(stay)
def test_buttons(self):
"A test of a horizontal layout of two buttons on a screen."
class Button(object):
def __init__(self, identifier):
self.left = Variable('left' + identifier, 0)
self.width = Variable('width' + identifier, 0)
def __repr__(self):
return u'(%s:%s)' % (self.left.value, self.width.value)
solver = SimplexSolver()
b1 = Button('b1')
b2 = Button('b2')
left_limit = Variable('left', 0)
right_limit = Variable('width', 0)
left_limit.value = 0
solver.add_stay(left_limit, REQUIRED)
stay = solver.add_stay(right_limit, WEAK)
# The two buttons are the same width
solver.add_constraint(b1.width == b2.width)
# b1 starts 50 from the left margin.
solver.add_constraint(b1.left == left_limit + 50)
# b2 ends 50 from the right margin
solver.add_constraint(left_limit + right_limit == b2.left + b2.width + 50)
# b2 starts at least 100 from the end of b1
solver.add_constraint(b2.left >= (b1.left + b1.width + 100))
# b1 has a minimum width of 87
solver.add_constraint(b1.width >= 87)
# b1's preferred width is 87
solver.add_constraint(b1.width == 87, STRONG)
# b2's minimum width is 113
solver.add_constraint(b2.width >= 113)
# b2's preferred width is 113
solver.add_constraint(b2.width == 113, STRONG)
# Without imposign a stay on the right, right_limit will be the minimum width for the layout
self.assertAlmostEqual(b1.left.value, 50.0)
self.assertAlmostEqual(b1.width.value, 113.0)
self.assertAlmostEqual(b2.left.value, 263.0)
self.assertAlmostEqual(b2.width.value, 113.0)
self.assertAlmostEqual(right_limit.value, 426.0)
# The window is 500 pixels wide.
right_limit.value = 500
stay = solver.add_stay(right_limit, REQUIRED)
self.assertAlmostEqual(b1.left.value, 50.0)
self.assertAlmostEqual(b1.width.value, 113.0)
self.assertAlmostEqual(b2.left.value, 337.0)
self.assertAlmostEqual(b2.width.value, 113.0)
self.assertAlmostEqual(right_limit.value, 500.0)
solver.remove_constraint(stay)
# Expand to 700 pixels
right_limit.value = 700
stay = solver.add_stay(right_limit, REQUIRED)
self.assertAlmostEqual(b1.left.value, 50.0)
self.assertAlmostEqual(b1.width.value, 113.0)
self.assertAlmostEqual(b2.left.value, 537.0)
self.assertAlmostEqual(b2.width.value, 113.0)
self.assertAlmostEqual(right_limit.value, 700.0)
solver.remove_constraint(stay)
# Contract to 600
right_limit.value = 600
stay = solver.add_stay(right_limit, REQUIRED)
self.assertAlmostEqual(b1.left.value, 50.0)
self.assertAlmostEqual(b1.width.value, 113.0)
self.assertAlmostEqual(b2.left.value, 437.0)
self.assertAlmostEqual(b2.width.value, 113.0)
self.assertAlmostEqual(right_limit.value, 600.0)
solver.remove_constraint(stay)
