Resize a rectangle (ie.: an image) while keeping the aspect ratio, without float.
You can scale up and down the proportions so the edges will be either at most or at least the given one.
Python, 6 lines
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Copy to clipboard1 2 3 4 5 6 | def scale(w, h, x, y, maximum=True):
nw = y * w / h
nh = x * h / w
if maximum ^ (nw >= x):
return nw or 1, y
return x, nh or 1
|
The code is really short, but it somehow gave me a headache.
Thank's to Maz http://maz.p0d.org for helping to make it work well.
Usage:
# scale so the 800/600 object will have sides of *at least* 128
>>> scale(800,600, 128,128, False)
(170, 128)
# scale so the 800/600 object can fit in a box of 128/128
>>> scale(800,600, 128,128, True)
(128, 96)
# can scale up too
>>> scale(4,3, 900,1600, True)
(900, 675)
>>> scale(4,3, 900,1600, False)
(2133, 1600)
>>> scale(2,8, 1,8, True)
(1, 4)
Sorry, this algorithm isn't guaranteed for a non-square window:
I think line 4 should be corrected from (nw >= nh) to:
Thank you Pavel, i noticed this kind of case but somehow forgot to fix it.