A line that can be diagonal

project/src/main/java/de/unistuttgart/informatik/fius/jvk/provided/shapes/FreeLine.java

@@ -0,0 +1,85 @@
+/*
+ * This source file is part of the FIUS JVK 2019 project.
+ * For more information see github.com/FIUS/JVK-2019
+ *
+ * Copyright (c) 2019 the FIUS JVK 2019 project authors.
+ * 
+ * This software is available under the MIT license.
+ * SPDX-License-Identifier:    MIT
+ */
+package de.unistuttgart.informatik.fius.jvk.provided.shapes;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+import de.unistuttgart.informatik.fius.icge.simulation.Position;
+
+
+/**
+ * A finite length line shape that can be parallel to the coordinate axes or diagonal
+ */
+public class FreeLine implements Shape {
+
+    private List<Position> points;
+
+    /**
+     * Create a new line by specifying start and end position of the line.
+     * 
+     * @param start
+     *     the start of the line
+     * @param end
+     *     the end of the line; may differ from the line start in both x and y direction
+     */
+    public FreeLine(Position start, Position end) {
+        List<Position> points = new ArrayList<>();
+        Integer deltaX = end.getX() - start.getX();
+        Integer deltaY = end.getY() - start.getY();
+        Integer xDir = (deltaX == 0) ? 0 : (deltaX > 0) ? 1 : -1;
+        Integer yDir = (deltaY == 0) ? 0 : (deltaY > 0) ? 1 : -1;
+
+        points.add(start);
+        Position currentPos = start;
+
+        if (deltaX == 0) { // vertical line
+            while (deltaY != 0) {
+                currentPos = new Position(currentPos.getX(), currentPos.getY() + yDir);
+                points.add(currentPos);
+                deltaY -= yDir;
+            }
+        } else if (deltaY == 0) { // horizontal line
+            while (deltaX != 0) {
+                currentPos = new Position(currentPos.getX() + xDir, currentPos.getY());
+                points.add(currentPos);
+                deltaX -= xDir;
+            }
+        } else { // diagonal line
+            Float grade = Math.abs(deltaY / deltaX.floatValue());
+            if (grade < 1.f) {
+                grade = Math.signum(deltaY) * grade;
+                Float currentY = (float) start.getY();
+                while (deltaX != 0) {
+                    currentY += grade;
+                    currentPos = new Position(currentPos.getX() + xDir, Math.round(currentY));
+                    points.add(currentPos);
+                    deltaX -= xDir;
+                }
+            } else { // grade >= 1.0f
+                grade = Math.signum(deltaX) * Math.abs(deltaX / deltaY.floatValue());
+                Float currentX = (float) start.getX();
+                while (deltaY != 0) {
+                    currentX += grade;
+                    currentPos = new Position(Math.round(currentX), currentPos.getY() + yDir);
+                    points.add(currentPos);
+                    deltaY -= yDir;
+                }
+            }
+        }
+        this.points = points;
+    }
+
+    @Override
+    public Iterator<Position> iterator() {
+        return this.points.iterator();
+    }
+}