Question

I’m using rectangles defined in terms of their x y coordinates and their width and height. I figured out how to rotate them in terms of coordinates (x = cos(deg) * x - sin(deg) * y y = sin(deg) * x + cos(deg) * y) but I’m stuck on the height and width. I’m sure there’s an obvious solution that I’m missing. If it matters, I’m using Python.

edit Sorry for the confusing description. My intention is to get the width and height either reversed or negated due to whatever the angle is. For example, in a 90 degree rotation the values would switch. In a 180 degree rotation the width would be negative. Also, I only intend to use multiples of 90 in my script. I could just use if statements, but I assumed there would be a more “elegant” method.

Answer 1

From the way you describe only rotating by 90 degrees, and the way you seem to be defining width and height, perhaps you are looking for something like

direction = 1     // counter-clockwise degrees
// or
direction = -1    // clockwise 90 degrees

new_height = width * direction
new_width = -height * direction
width = new_width
height = new_height

Not sure why you want to have negative values for width and height, though .. because otherwise each 90 degree rotation effectively just swaps width and height, regardless which way you rotate.