Port visible bell to Android

* java/org/gnu/emacs/EmacsDrawRectangle.java (perform): Ignore
GC_INVERT.

* java/org/gnu/emacs/EmacsFillRectangle.java
(EmacsFillRectangle) <invertFilter>: New variable.
(perform): If the transfer mode is invert, copy the source
to itself with invertFilter as the color filter.

* java/org/gnu/emacs/EmacsGC.java (EmacsGC) <xorAlu, srcInAlu>:
Delete now-redundant ALUs.
(markDirty): Cease updating the paint's transfermode.

* java/org/gnu/emacs/EmacsSafThread.java (openDocument1): Fix
typo in documentation.

* src/android.c (android_blit_xor): Delete unused function.
(android_copy_area): Remove calls to unused blit functions.

* src/androidgui.h (enum android_gc_function): Rename XOR to
INVERT.

* src/androidterm.c (android_flash): Replace with GXinvert.

1 files changed, 15 insertions, 3 deletions

diff --git a/java/org/gnu/emacs/EmacsDrawRectangle.java b/java/org/gnu/emacs/EmacsDrawRectangle.java
index e40a7c16068..ea0f1c28106 100644
--- a/java/org/gnu/emacs/EmacsDrawRectangle.java
+++ b/java/org/gnu/emacs/EmacsDrawRectangle.java
@@ -22,13 +22,23 @@ package org.gnu.emacs;
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
 import android.graphics.Paint;
+import android.graphics.PorterDuff.Mode;
+import android.graphics.PorterDuffXfermode;
 import android.graphics.Rect;
 import android.graphics.RectF;
+import android.graphics.Xfermode;
 
 import android.util.Log;
 
 public final class EmacsDrawRectangle
 {
+  private static final Xfermode srcInAlu;
+
+  static
+  {
+    srcInAlu = new PorterDuffXfermode (Mode.SRC_IN);
+  };
+
   public static void
   perform (EmacsDrawable drawable, EmacsGC gc,
 	   int x, int y, int width, int height)
@@ -40,8 +50,10 @@ public final class EmacsDrawRectangle
     Canvas canvas;
     Bitmap clipBitmap;
 
-    /* TODO implement stippling.  */
-    if (gc.fill_style == EmacsGC.GC_FILL_OPAQUE_STIPPLED)
+    /* TODO implement stippling for this request.  */
+    if (gc.fill_style == EmacsGC.GC_FILL_OPAQUE_STIPPLED
+	/* And GC_INVERT also.  */
+	|| gc.fill_style == EmacsGC.GC_INVERT)
       return;
 
     canvas = drawable.lockCanvas (gc);
@@ -103,7 +115,7 @@ public final class EmacsDrawRectangle
 	/* Set the transfer mode to SRC_IN to preserve only the parts
 	   of the source that overlap with the mask.  */
 	maskPaint = new Paint ();
-	maskPaint.setXfermode (EmacsGC.srcInAlu);
+	maskPaint.setXfermode (srcInAlu);
 	maskPaint.setStyle (Paint.Style.STROKE);
 
 	/* Draw the source.  */