python - 如何按比例（尊重纵横比）缩放矩形？

Question

我试图通过设置和查找来简单地获取一个给定的xby框y并将其放大，反之亦然。这个公式将如何用 Python 表示（为了便于阅读）。我试图把这个盒子装在一个更大的盒子里，这样内盒总是能装在更大的盒子里。xy

Answer 1

new_y = (float(new_x) / x) * y

或者

new_x = (float(new_y) / y) * x

Answer 2

注意：我并不真正使用 Python，所以这是伪代码。

您需要的是两个框的相对纵横比，因为这决定了哪些新轴必须与新框的大小相同：

r_old = old_w / old_h
r_new = new_w / new_h

if (r_old > r_new) then
   w = new_w              // width of mapped rect
   h = w / r_old          // height of mapped rect
   x = 0                  // x-coord of mapped rect
   y = (new_h - h) / 2    // y-coord of centered mapped rect
else
   h = new_h
   w = h * r_old
   y = 0
   x = (new_w - w) / 2
endif

Answer 3

>>> import fractions
>>> x, y = 10, 10
>>> fix_rat = fractions.Fraction(x, y)
>>> fix_rat
Fraction(1, 1)
>>> x = 8
>>> if fractions.Fraction(x, y) != fix_rat:
    y = x / fix_rat #well instead of y you should put the last one that has been changed
                    #but this is just an example


>>> y
Fraction(8, 1)
>>>