direction property

The angle of this offset as radians clockwise from the positive x-axis, in the range -pi to pi, assuming positive values of the x-axis go to the right and positive values of the y-axis go down.

Zero means that dy is zero and dx is zero or positive.

Values from zero to pi/2 indicate positive values of dx and dy, the bottom-right quadrant.

Values from pi/2 to pi indicate negative values of dx and positive values of dy, the bottom-left quadrant.

Values from zero to -pi/2 indicate positive values of dx and negative values of dy, the top-right quadrant.

Values from -pi/2 to -pi indicate negative values of dx and dy, the top-left quadrant.

When dy is zero and dx is negative, the direction is pi.

When dx is zero, direction is pi/2 if dy is positive and -pi/2 if dy is negative.

See also:

• distance, to compute the magnitude of the vector.
• Canvas.rotate, which uses the same convention for its angle.