image manipulation

first, let’s do some math

Sin = Opposite / Hypotenuse Cosine = Adjacent / Hypotenuse Tangent = Opposite / Adjacent

when rotate a trangle, we need to calculate it’s bounding box

the bounding box height = (sin(angle) * (width of original box)) + (cos(angle) * (height of original box))

the bounding box weight = (cos(angle) * (width of original box)) + (sin(angle) * (height of original box))