calc-line-slope ( point1 point2 -- slope )

Vocabulary

ui.gadgets.charts.lines.private

Word description

Given the two points belonging to a straight line, calculate the slope of the line, assuming the line equation is y(x) = slope * x + b.

Inputs and outputs

point1	an object
point2	an object
slope	an object

The formula for the calculation is slope = (y1-y2) / (x1-x2), therefore it'll throw a division by zero error if both points have the same x coordinate.

Examples

USING: ui.gadgets.charts.lines.private prettyprint ; { 1 1 } { 10 10 } calc-line-slope .
1

USING: ui.gadgets.charts.lines.private prettyprint ; { 0 0 } { 10 20 } calc-line-slope .
2

See also

y-at, calc-x, calc-y

Definition

USING: kernel math math.vectors sequences ;

IN: ui.gadgets.charts.lines.private

: calc-line-slope ( point1 point2 -- slope ) v- first2 swap / ;