Fix text alignment in history plot renderer

When more than one lane is drawn, some commits are vertically misaligned
(off by two pixels). This change fixes the alignment.

Bug: 426047
Change-Id: Icbe7ce9f5a6b281b2aaab66e4d76dfc1010b2fb5
Signed-off-by: Konrad Kügler <swamblumat-eclipsebugs@yahoo.de>
Signed-off-by: Rüdiger Herrmann <ruediger.herrmann@gmx.de>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/revplot/AbstractPlotRendererTest.java

@@ -0,0 +1,153 @@
+/*
+ * Copyright (C) 2014 Rüdiger Herrmann <ruediger.herrmann@gmx.de>
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package org.eclipse.jgit.revplot;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.IOException;
+import java.util.LinkedList;
+import java.util.List;
+
+import org.eclipse.jgit.api.Git;
+import org.eclipse.jgit.api.MergeCommand.FastForwardMode;
+import org.eclipse.jgit.api.MergeResult;
+import org.eclipse.jgit.api.errors.GitAPIException;
+import org.eclipse.jgit.junit.RepositoryTestCase;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.Ref;
+import org.eclipse.jgit.lib.Repository;
+import org.junit.Before;
+import org.junit.Test;
+
+public class AbstractPlotRendererTest extends RepositoryTestCase {
+
+	private Git git;
+	private TestPlotRenderer plotRenderer;
+
+	@Override
+	@Before
+	public void setUp() throws Exception {
+		super.setUp();
+		git = new Git(db);
+		plotRenderer = new TestPlotRenderer();
+	}
+
+	@Test
+	public void testDrawTextAlignment() throws Exception {
+		git.commit().setMessage("initial commit").call();
+		git.branchCreate().setName("topic").call();
+		git.checkout().setName("topic").call();
+		git.commit().setMessage("commit 1 on topic").call();
+		git.commit().setMessage("commit 2 on topic").call();
+		git.checkout().setName("master").call();
+		git.commit().setMessage("commit on master").call();
+		MergeResult mergeCall = merge(db.resolve("topic"));
+		ObjectId start = mergeCall.getNewHead();
+		PlotCommitList<PlotLane> commitList = createCommitList(start);
+
+		for (int i = 0; i < commitList.size(); i++)
+			plotRenderer.paintCommit(commitList.get(i), 30);
+
+		List<Integer> indentations = plotRenderer.indentations;
+		assertEquals(indentations.get(2), indentations.get(3));
+	}
+
+	private PlotCommitList<PlotLane> createCommitList(ObjectId start)
+			throws IOException {
+		TestPlotWalk walk = new TestPlotWalk(db);
+		walk.markStart(walk.parseCommit(start));
+		PlotCommitList<PlotLane> commitList = new PlotCommitList<PlotLane>();
+		commitList.source(walk);
+		commitList.fillTo(1000);
+		return commitList;
+	}
+
+	private MergeResult merge(ObjectId includeId) throws GitAPIException {
+		return git.merge().setFastForward(FastForwardMode.NO_FF)
+				.include(includeId).call();
+	}
+
+	private static class TestPlotWalk extends PlotWalk {
+		public TestPlotWalk(Repository repo) {
+			super(repo);
+		}
+	}
+
+	private static class TestPlotRenderer extends
+			AbstractPlotRenderer<PlotLane, Object> {
+
+		List<Integer> indentations = new LinkedList<Integer>();
+
+		@Override
+		protected int drawLabel(int x, int y, Ref ref) {
+			return 0;
+		}
+
+		@Override
+		protected Object laneColor(PlotLane myLane) {
+			return null;
+		}
+
+		@Override
+		protected void drawLine(Object color, int x1, int y1, int x2, int y2,
+				int width) {
+			// do nothing
+		}
+
+		@Override
+		protected void drawCommitDot(int x, int y, int w, int h) {
+			// do nothing
+		}
+
+		@Override
+		protected void drawBoundaryDot(int x, int y, int w, int h) {
+			// do nothing
+		}
+
+		@Override
+		protected void drawText(String msg, int x, int y) {
+			indentations.add(Integer.valueOf(x));
+		}
+	}
+
+}

org.eclipse.jgit/src/org/eclipse/jgit/revplot/AbstractPlotRenderer.java

@@ -97,7 +97,7 @@ public abstract class AbstractPlotRenderer<TLane extends PlotLane, TColor> {
 		final int myLaneX = laneC(myLane);
 		final TColor myColor = laneColor(myLane);
 
-		int maxCenter = 0;
+		int maxCenter = myLaneX;
 		for (final TLane passingLane : (TLane[]) commit.passingLanes) {
 			final int cx = laneC(passingLane);
 			final TColor c = laneColor(passingLane);
@@ -154,7 +154,7 @@ public abstract class AbstractPlotRenderer<TLane extends PlotLane, TColor> {
 		}
 
 		final String msg = commit.getShortMessage();
-		drawText(msg, textx + dotSize + n*2, h / 2);
+		drawText(msg, textx + dotSize, h / 2);
 	}
 
 	/**