angle

I have two lines: Line1 and Line2. Each line is defined by two points (P1L1(x1, y1), P2L1(x2, y2) and P1L1(x1, y1), P2L3(x2, y3)) . I want to know the inner angle defined by these two lines. For do it I calculate the angle of each line with the abscissa: double theta1 = atan(m1) * (180.0 / PI); double theta2 = atan(m2) * (180.0 / PI); After to know the angle I calculate the following: double angle = abs(theta2 - theta1); The problem or doubt that I have is: sometimes I get the correct angle but sometimes I get the complementary angle (for me outer). How can I know when subtract 180º to know

I want to get a simple solution to calculate the angle of a line (like a pointer of a clock). I have 2 points: cX, cY - the center of the line. eX, eY - the end of the line. The result is angle (0 <= a < 360). Which function is able to provide this value? Christian Mann You want the arctangent: dy = ey - cy dx = ex - cx theta = arctan(dy/dx) theta *= 180/pi // rads to degs Erm, note that the above is obviously not compiling Javascript code. You'll have to look through documentation for the arctangent function. Edit: Using Math.atan2(y,x) will handle all of the special cases and extra logic for

Many algorithms (e.g. Graham scan ) require points or vectors to be sorted by their angle (perhaps as seen from some other point, i.e. using difference vectors). This order is inherently cyclic, and where this cycle is broken to compute linear values often doesn't matter that much. But the real angle value doesn't matter much either, as long as cyclic order is maintained. So doing an atan2 call for every point might be wasteful. What faster methods are there to compute a value which is strictly monotonic in the angle, the way atan2 is? Such functions apparently have been called “pseudoangle”

I need to calculate the 2 angles (yaw and pitch) for a 3D object to face an arbitrary 3D point. These rotations are known as "Euler" rotations simply because after the first rotation, (lets say Z, based on the picture below) the Y axis also rotates with the object. This is the code I'm using but its not working fully. When on the ground plane (Y = 0) the object correctly rotates to face the point, but as soon as I move the point upwards in Y, the rotations don't look correct. // x, y, z represent a fractional value between -[1] and [1] // a "unit vector" of the point I need to rotate towards

I am making a virtual speedometer in android. I use the RotateAnimation() to rotate the speedometer needle. Is there any way to get the angular position of the needle during the rotation? That is, if the needle is rotating from 0 to 360 degree, I want to display the needles angle at each point during the period of animation. I use the following code to perform the animation. RotateAnimation rpmNeedleDeflection = new RotateAnimation(-32, 213, (float) 135, needle.getHeight()/2); rpmNeedleDeflection.setDuration(1500); rpmNeedleDeflection.setFillAfter(true); needle.startAnimation

Given two circle segments of the same circle: A=[a1, a2] and B=[b1, b2], with: a1, a2, b1, b2 values in degree between -inf and +inf a1 <= a2 ; b1 <= b2 a2-a1<=360; b2-b1<=360 How can I find out if these two circle segments overlap? (i.E. if they intersect or touch in at least one point) Examples: A=[ -45°, 45°]; B=[ 10°, 20°] ==> overlap A=[ -45°, 45°]; B=[ 90°, 180°] ==> no overlap A=[ -45°, 45°]; B=[ 180°, 360°] ==> overlap A=[ -405°, -315°]; B=[ 180°, 360°] ==> overlap A=[-3600°, -3601°]; B=[ 3601°, 3602°] ==> overlap (touching counts as overlap) A=[ 3600°, 3601°]; B=[-3601°,-3602°] ==>