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  1. JDK
  2. JDK-8304038

Shape with opaque color should not show background transparent pixels

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    • 2d
    • generic
    • generic

      A DESCRIPTION OF THE PROBLEM :
      When using the Graphics2D.draw function, the pixels drawn are getting changed depending on the fact whether the used paint is fully opaque (alpha = 255) or semi-transparent (alpha <255).

      STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
      Run the provided code source code.

      EXPECTED VERSUS ACTUAL BEHAVIOR :
      EXPECTED -
      The resulting image "output.png" should not contain any red pixels.
      ACTUAL -
      The resulting image "output.png" does contain red pixels.

      ---------- BEGIN SOURCE ----------


      package main.app;

      import javax.imageio.ImageIO;
      import java.awt.Color;
      import java.awt.Graphics2D;
      import java.awt.geom.Ellipse2D;
      import java.awt.geom.RoundRectangle2D;
      import java.awt.image.BufferedImage;
      import java.io.File;
      import java.io.IOException;

      public class Example {

          public static void main(String[] args) throws IOException {
              BufferedImage image = new BufferedImage(150, 50, BufferedImage.TYPE_4BYTE_ABGR);
              Graphics2D graphics = image.createGraphics();

              graphics.setPaint(Color.white);
              graphics.fillRect(0, 0, image.getWidth(), image.getHeight());

              Ellipse2D.Double circle = new Ellipse2D.Double(10, 10, 30, 30);
              Ellipse2D.Double ellipse = new Ellipse2D.Double(57, 12, 36, 26);
              RoundRectangle2D.Double roundRectangle = new RoundRectangle2D.Double(110, 10, 30, 30, 20, 20);

              graphics.setPaint(new Color(255, 0, 0 , 254));
              graphics.draw(roundRectangle);
              graphics.draw(circle);
              graphics.draw(ellipse);

              graphics.setPaint(new Color(0, 255, 0, 255));
              graphics.draw(roundRectangle);
              graphics.draw(circle);
              graphics.draw(ellipse);

              ImageIO.write(image, "png", new File("output.png"));
          }

      }
      ---------- END SOURCE ----------

      FREQUENCY : always


            prr Philip Race
            webbuggrp Webbug Group
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              Created:
              Updated: