def testFilterScanline(self):
prev = [20, 21, 22, 210, 211, 212]
line = [30, 32, 34, 230, 233, 236]
fo = 3
out = png.filter_scanline(0, line, fo, prev) # none
self.assertEqual(list(out), [0, 30, 32, 34, 230, 233, 236])
out = png.filter_scanline(1, line, fo, prev) # sub
self.assertEqual(list(out), [1, 30, 32, 34, 200, 201, 202])
out = png.filter_scanline(2, line, fo, prev) # up
self.assertEqual(list(out), [2, 10, 11, 12, 20, 22, 24])
out = png.filter_scanline(3, line, fo, prev) # average
self.assertEqual(list(out), [3, 20, 22, 23, 110, 112, 113])
out = png.filter_scanline(4, line, fo, prev) # paeth
self.assertEqual(
list(out),
[
4,
self.paeth(30, 0, 20, 0),
self.paeth(32, 0, 21, 0),
self.paeth(34, 0, 22, 0),
self.paeth(230, 30, 210, 20),
self.paeth(233, 32, 211, 21),
self.paeth(236, 34, 212, 22),
],
)
def testFilterScanlineFirstLine(self):
fo = 3 # bytes per pixel
line = [30, 31, 32, 230, 231, 232]
out = png.filter_scanline(0, line, fo, None) # none
self.assertEqual(list(out), [0, 30, 31, 32, 230, 231, 232])
out = png.filter_scanline(1, line, fo, None) # sub
self.assertEqual(list(out), [1, 30, 31, 32, 200, 200, 200])
out = png.filter_scanline(2, line, fo, None) # up
self.assertEqual(list(out), [2, 30, 31, 32, 230, 231, 232])
out = png.filter_scanline(3, line, fo, None) # average
self.assertEqual(list(out), [3, 30, 31, 32, 215, 216, 216])
out = png.filter_scanline(4, line, fo, None) # paeth
self.assertEqual(list(out), [
4, self.paeth(30, 0, 0, 0), self.paeth(31, 0, 0, 0),
self.paeth(32, 0, 0, 0), self.paeth(230, 30, 0, 0),
self.paeth(231, 31, 0, 0), self.paeth(232, 32, 0, 0)
])
def testFilterScanline(self):
prev = [20, 21, 22, 210, 211, 212]
line = [30, 32, 34, 230, 233, 236]
fo = 3
out = png.filter_scanline(0, line, fo, prev) # none
self.assertEqual(list(out), [0, 30, 32, 34, 230, 233, 236])
out = png.filter_scanline(1, line, fo, prev) # sub
self.assertEqual(list(out), [1, 30, 32, 34, 200, 201, 202])
out = png.filter_scanline(2, line, fo, prev) # up
self.assertEqual(list(out), [2, 10, 11, 12, 20, 22, 24])
out = png.filter_scanline(3, line, fo, prev) # average
self.assertEqual(list(out), [3, 20, 22, 23, 110, 112, 113])
out = png.filter_scanline(4, line, fo, prev) # paeth
self.assertEqual(list(out), [
4, self.paeth(30, 0, 20, 0), self.paeth(32, 0, 21, 0),
self.paeth(34, 0, 22, 0), self.paeth(230, 30, 210, 20),
self.paeth(233, 32, 211, 21), self.paeth(236, 34, 212, 22)
])
def test_filter_first(self):
"""Test that filter_scanline works for the first line
when there is no previous line.
"""
fo = 3 # bytes per pixel
line = [30, 31, 32, 230, 231, 232]
out = png.filter_scanline(0, line, fo, None) # none
self.assertEqual(list(out), [0, 30, 31, 32, 230, 231, 232])
out = png.filter_scanline(1, line, fo, None) # sub
self.assertEqual(list(out), [1, 30, 31, 32, 200, 200, 200])
out = png.filter_scanline(2, line, fo, None) # up
self.assertEqual(list(out), [2, 30, 31, 32, 230, 231, 232])
out = png.filter_scanline(3, line, fo, None) # average
self.assertEqual(list(out), [3, 30, 31, 32, 215, 216, 216])
out = png.filter_scanline(4, line, fo, None) # paeth
self.assertEqual(list(out), [
4, paeth(30, 0, 0, 0), paeth(31, 0, 0, 0),
paeth(32, 0, 0, 0), paeth(230, 30, 0, 0),
paeth(231, 31, 0, 0), paeth(232, 32, 0, 0)
])
def test_filter(self):
"""Test that filter_scanline works for lines subsequent
to the first line.
"""
prev = [20, 21, 22, 210, 211, 212]
line = [30, 32, 34, 230, 233, 236]
fo = 3
out = png.filter_scanline(0, line, fo, prev) # none
self.assertEqual(list(out), [0, 30, 32, 34, 230, 233, 236])
out = png.filter_scanline(1, line, fo, prev) # sub
self.assertEqual(list(out), [1, 30, 32, 34, 200, 201, 202])
out = png.filter_scanline(2, line, fo, prev) # up
self.assertEqual(list(out), [2, 10, 11, 12, 20, 22, 24])
out = png.filter_scanline(3, line, fo, prev) # average
self.assertEqual(list(out), [3, 20, 22, 23, 110, 112, 113])
out = png.filter_scanline(4, line, fo, prev) # paeth
self.assertEqual(list(out), [
4, paeth(30, 0, 20, 0), paeth(32, 0, 21, 0),
paeth(34, 0, 22, 0), paeth(230, 30, 210, 20),
paeth(233, 32, 211, 21), paeth(236, 34, 212, 22)
])
