commit version 22.12.12447

includes/weathermap/lib/WMLine.class.php

@@ -0,0 +1,61 @@
+<?php
+
+/**
+ * A Line is simply a Vector that passes through a Point
+ */
+class WMLine
+{
+    private $point;
+    private $vector;
+
+    public function __construct($p, $v)
+    {
+        $this->point = $p;
+        $this->vector = $v;
+    }
+
+    public function getSlope()
+    {
+        return $this->vector->getSlope();
+    }
+
+    public function getYIntercept()
+    {
+        $slope = $this->getSlope();
+        $intercept = $this->point->y - $this->point->x * $slope;
+
+        return $intercept;
+    }
+
+    public function __toString()
+    {
+        return sprintf("/%s-%s/", $this->point, $this->vector);
+    }
+
+    /**
+     * Find the point where this line and another one cross
+     *
+     * @param $line2 the other line
+     * @return WMPoint the crossing point
+     * @throws WeathermapInternalFail
+     */
+    public function findCrossingPoint($line2)
+    {
+        $slope1 = $this->vector->getSlope();
+        $slope2 = $line2->vector->getSlope();
+
+        if ($slope1 == $slope2) {
+            // for a general case, this should probably be handled better
+            // but for our use, there should never be parallel lines
+            throw new WeathermapInternalFail("ParallelLinesNeverCross");
+        }
+
+        $intercept1 = $this->getYIntercept();
+        $intercept2 = $line2->getYIntercept();
+
+        $xCrossing = ($intercept2 - $intercept1) / ($slope1 - $slope2);
+        $yCrossing = $intercept1 + $slope1*$xCrossing;
+
+        return new WMPoint($xCrossing, $yCrossing);
+    }
+}