stretch between

diylc/diylc-core/src/test/java/org/diylc/components/AbstractCurvedComponentTest.java

@@ -0,0 +1,131 @@
+/*
+
+    DIY Layout Creator (DIYLC).
+    Copyright (c) 2009-2025 held jointly by the individual authors.
+
+    This file is part of DIYLC.
+
+    DIYLC is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    DIYLC is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with DIYLC.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+package org.diylc.components;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.awt.Color;
+import java.awt.Graphics2D;
+import java.awt.geom.Path2D;
+import java.awt.geom.Point2D;
+
+import org.junit.Test;
+
+import org.diylc.components.AbstractCurvedComponent.PointCount;
+import org.diylc.core.ComponentState;
+import org.diylc.core.IDrawingObserver;
+
+public class AbstractCurvedComponentTest {
+
+  private static final double DELTA = 1e-6;
+
+  @Test
+  public void stretchBetween_putsTheEndsExactlyOnTheSuppliedPoints() {
+    CurvedTestComponent c = new CurvedTestComponent();
+    c.stretchBetween(new Point2D.Double(10, 20), new Point2D.Double(110, 20));
+    assertPoint(10, 20, c.getControlPoint(0));
+    assertPoint(110, 20, c.getControlPoint(3));
+  }
+
+  @Test
+  public void stretchBetween_bowsTheIntermediatePointsOffTheChord() {
+    CurvedTestComponent c = new CurvedTestComponent();
+    c.stretchBetween(new Point2D.Double(0, 0), new Point2D.Double(100, 0));
+    assertTrue("first handle should not sit on the chord", c.getControlPoint(1).getY() > 1);
+    assertTrue("second handle should not sit on the chord", c.getControlPoint(2).getY() > 1);
+  }
+
+  @Test
+  public void stretchBetween_bowIsSymmetric() {
+    CurvedTestComponent c = new CurvedTestComponent();
+    c.stretchBetween(new Point2D.Double(0, 0), new Point2D.Double(100, 0));
+    assertEquals(c.getControlPoint(1).getY(), c.getControlPoint(2).getY(), DELTA);
+    assertEquals(100 - c.getControlPoint(2).getX(), c.getControlPoint(1).getX(), DELTA);
+  }
+
+  @Test
+  public void stretchBetween_sagsTheSameWayRegardlessOfDrawingDirection() {
+    CurvedTestComponent forward = new CurvedTestComponent();
+    forward.stretchBetween(new Point2D.Double(0, 0), new Point2D.Double(100, 0));
+    CurvedTestComponent backward = new CurvedTestComponent();
+    backward.stretchBetween(new Point2D.Double(100, 0), new Point2D.Double(0, 0));
+    assertEquals(forward.getControlPoint(1).getY(), backward.getControlPoint(2).getY(), DELTA);
+    assertEquals(forward.getControlPoint(2).getY(), backward.getControlPoint(1).getY(), DELTA);
+  }
+
+  @Test
+  public void stretchBetween_scalesTheBowWithTheDistance() {
+    CurvedTestComponent shortWire = new CurvedTestComponent();
+    shortWire.stretchBetween(new Point2D.Double(0, 0), new Point2D.Double(50, 0));
+    CurvedTestComponent longWire = new CurvedTestComponent();
+    longWire.stretchBetween(new Point2D.Double(0, 0), new Point2D.Double(200, 0));
+    assertEquals(4 * shortWire.getControlPoint(1).getY(), longWire.getControlPoint(1).getY(), DELTA);
+  }
+
+  @Test
+  public void stretchBetween_collapsesOntoASinglePointWithoutDividingByZero() {
+    CurvedTestComponent c = new CurvedTestComponent();
+    c.stretchBetween(new Point2D.Double(40, 40), new Point2D.Double(40, 40));
+    for (int i = 0; i < c.getControlPointCount(); i++) {
+      assertPoint(40, 40, c.getControlPoint(i));
+    }
+  }
+
+  @Test
+  public void stretchBetween_keepsTheEndsForEveryPointCount() {
+    for (PointCount pointCount : PointCount.values()) {
+      CurvedTestComponent c = new CurvedTestComponent();
+      c.setPointCount(pointCount);
+      c.stretchBetween(new Point2D.Double(0, 0), new Point2D.Double(100, 60));
+      assertPoint(0, 0, c.getControlPoint(0));
+      assertPoint(100, 60, c.getControlPoint(c.getControlPointCount() - 1));
+    }
+  }
+
+  private static void assertPoint(double x, double y, Point2D actual) {
+    assertEquals(x, actual.getX(), DELTA);
+    assertEquals(y, actual.getY(), DELTA);
+  }
+
+  private static class CurvedTestComponent extends AbstractCurvedComponent<Void> {
+
+    private static final long serialVersionUID = 1L;
+
+    @Override
+    protected void drawCurve(Path2D curve, Graphics2D g2d, ComponentState componentState,
+        IDrawingObserver drawingObserver) {}
+
+    @Override
+    protected Color getDefaultColor() {
+      return Color.black;
+    }
+
+    @Override
+    public Void getValue() {
+      return null;
+    }
+
+    @Override
+    public void setValue(Void value) {}
+  }
+}

diylc/diylc-core/src/test/java/org/diylc/components/AbstractOrthogonalComponentTest.java

@@ -130,6 +130,32 @@ public class AbstractOrthogonalComponentTest {
     assertPoint(100, 50, c.getControlPoint(2));
   }
 
+  // --- stretching ---
+
+  @Test
+  public void stretchBetween_keepsTheEndsAndStaysAxisAligned() {
+    OrthogonalTestComponent c = component(0, 0, 100, 50, 60, 20);
+    c.stretchBetween(new Point2D.Double(10, 10), new Point2D.Double(210, 110));
+    assertPoint(10, 10, c.getControlPoint(0));
+    assertPoint(210, 110, c.getControlPoint(2));
+    assertAxisAligned(c);
+  }
+
+  @Test
+  public void stretchBetween_placesTheBendsWhereSetPointCountWould() {
+    OrthogonalTestComponent stretched = component(0, 0, 100, 50, 60, 20);
+    stretched.setPointCount(PointCount.FIVE);
+    stretched.stretchBetween(new Point2D.Double(0, 0), new Point2D.Double(100, 50));
+
+    OrthogonalTestComponent expanded = component(0, 0, 100, 50, 60, 20);
+    expanded.setPointCount(PointCount.FIVE);
+
+    for (int i = 0; i < expanded.getControlPointCount(); i++) {
+      assertPoint(expanded.getControlPoint(i).getX(), expanded.getControlPoint(i).getY(),
+          stretched.getControlPoint(i));
+    }
+  }
+
   // --- transformer ---
 
   @Test