First determine the radius of the circle: R = sqrt((117/2)^2+(18/2)^2) = 59.2 pixels. The point you are interested in is initially the upper left hand corner of the box, which after rotation 280 degrees clockwise ends up at the botton left. The starting point of that corner is at angle pi-arctan(18/117) relative to the center of the circle, or 171.2 degrees (note - angle measurements are measured counter-clockwise from the positive x-axis). You rotate it 280 degrees clockwise (that's -280 degrees) and it ends up at 171.3 - 280 = -108.7 degrees. The (x,y) coordinates of the point relative to the center of the cicrle is (R cos(108.7), R sin(108.7)), which is (-19.0, -56.0). The dimension 't' in your figure is R+x, or 59.2-19 = 40.2 pixels, and the dimension 'u' is equal to y, or -56.0 pixels.