Initial

java/ANIMATE/GrayModel.java

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+import java.awt.image.*;
+
+// This class implements a gray color model
+// scheme based on another color model. It acts
+// like a gray filter. To compute the amount of
+// gray for a pixel, it takes the max of the red,
+// green, and blue components and uses that value
+// for all three color components.
+
+public class GrayModel extends ColorModel
+{
+   ColorModel originalModel;
+
+   public GrayModel(ColorModel originalModel)
+   {
+      super(originalModel.getPixelSize());
+      this.originalModel = originalModel;
+   }
+
+// The amount of gray is the max of the red, green, and blue
+   protected int getGrayLevel(int pixel)
+   {
+      return Math.max(originalModel.getRed(pixel),
+         Math.max(originalModel.getGreen(pixel),
+            originalModel.getBlue(pixel)));
+   }
+
+// Leave the alpha values untouched
+   public int getAlpha(int pixel)
+   {
+      return originalModel.getAlpha(pixel);
+   }
+
+// Since gray requires red, green and blue to be the same,
+// use the same gray level value for red, green, and blue
+
+   public int getRed(int pixel)
+   {
+      return getGrayLevel(pixel);
+   }
+
+   public int getGreen(int pixel)
+   {
+      return getGrayLevel(pixel);
+   }
+
+   public int getBlue(int pixel)
+   {
+      return getGrayLevel(pixel);
+   }
+
+// Normally, this method queries the red, green, blue and
+// alpha values and returns them in the form 0xaarrggbb. To
+// keep from computing the gray level 3 times, we just override
+// this method, get the gray level once, and return it as the
+// red, green, and blue, and add in the original alpha value.
+
+   public int getRGB(int pixel)
+   {
+      int gray = getGrayLevel(pixel);
+      return (getAlpha(pixel) << 24) + (gray << 16) +
+         (gray << 8) + gray;
+   }
+}