I'm a newbie to KineticJS and have been going through the tutorials. I want to take an image that has a 'front' and rotate it a random number of degrees and then have it move forward a number of pixels/inches in that new direction.
I was able to use this rotation tutorial to rotate my image.
I see how to use transitionTo to send an image to an x/y coordinate.
I'm having trouble tying the two together. I feel like I need randomly generate e a new x/y coordinate and then determine the degree difference between where my image is pointing and a line drawn from the center of the image to the new x/y point.
Does anyone have any tips for doing something like this? How would one draw two lines from one point and determine the angle between them?
Thanks in advance.
You have to calculate the new coordinates thanks to the law of cosines. http://en.wikipedia.org/wiki/Law_of_cosines Once you have calculated the angle, you have to be careful because you will get an absolute angle.
Don't hesitate if you need more help. I also have to do this calculation using KineticJS.
Good luck !
The JS Math Object will be useful I guess : http://www.w3schools.com/jsref/jsref_obj_math.asp
来源：https://stackoverflow.com/questions/16365552/how-to-rotate-an-image-x-degrees-then-move-in-that-direction