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  1. JDK
  2. JDK-8051421

Graphics.drawLine() draws an extra pixel at the beginning of the line

    Details

    • Subcomponent:
    • CPU:
      x86_64
    • OS:
      linux

      Description

      FULL PRODUCT VERSION :
      java version "1.7.0_55"
      OpenJDK Runtime Environment (mageia-2.4.7.1.mga4-x86_64 u55-b13)
      OpenJDK 64-Bit Server VM (build 24.51-b03, mixed mode)


      ADDITIONAL OS VERSION INFORMATION :
      Linux localhost 3.12.21-desktop-2.mga4 #1 SMP Thu Jun 5 21:33:44 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

      A DESCRIPTION OF THE PROBLEM :
      Graphics.drawLine() draws an extra pixel at the beginning of the line, close to the first point (x1, y1). Please note that this bug isn't reproducible under Microsoft Windows 7 64 bits with Oracle Java 1.7 update 60. Disabling the anti-aliasing has no effect. The Java2D pipeline based on XRender is used under GNU Linux and trying to disable it with -Dsun.java2d.xrender=false doesn't help.

      ADDITIONAL REGRESSION INFORMATION:
      java version "1.7.0_55"
      OpenJDK Runtime Environment (mageia-2.4.7.1.mga4-x86_64 u55-b13)
      OpenJDK 64-Bit Server VM (build 24.51-b03, mixed mode)

      STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
      Run the short self-contained concise example I provided below. It draws a diagonal cross composed of 2 lines.

      EXPECTED VERSUS ACTUAL BEHAVIOR :
      EXPECTED -
      drawLine(int x1, int y1, int x2, int y2) should draw a line between the points (x1, y1) and (x2, y2).
      ACTUAL -
      drawLine(int x1, int y1, int x2, int y2) draws a line between the points (x1, y1) and (x2, y2) but it extends the line near (x1, y1).

      REPRODUCIBILITY :
      This bug can be reproduced always.

      ---------- BEGIN SOURCE ----------
      import java.awt.BasicStroke;
      import java.awt.Canvas;
      import java.awt.Color;
      import java.awt.Frame;
      import java.awt.Graphics;
      import java.awt.Graphics2D;
      import java.awt.event.WindowAdapter;
      import java.awt.event.WindowEvent;

      import javax.swing.SwingUtilities;


      public class Test {

      public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {

      @Override
      public void run() {
      Frame frame=new Frame();
      frame.add(new Canvas(){
      private static final long serialVersionUID = 1L;

      @Override
      public void paint(Graphics g){
      final Graphics2D g2=(Graphics2D)g.create();
      g2.setStroke(new BasicStroke(1.0f,BasicStroke.CAP_BUTT,BasicStroke.JOIN_MITER));
      g2.setColor(Color.BLACK);
      final int delta=3;
      final int width=20;
      final int height=20;
      g2.drawLine(delta,delta,width-delta-1,height-delta-1);
      g2.drawLine(width-delta-1,delta,delta,height-delta-1);
      g2.dispose();
      }
      });
      frame.setSize(600,600);
      frame.addWindowListener(new WindowAdapter() {
      @Override
      public void windowClosing(WindowEvent we) {
      System.exit(0);
      }
      });
      frame.setVisible(true);
      }
      });
      }
      }

      ---------- END SOURCE ----------

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            • Assignee:
              Unassigned
              Reporter:
              webbuggrp Webbug Group
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              Dates

              • Created:
                Updated: