1 files changed, 138 insertions, 0 deletions
diff --git a/java/org/gnu/emacs/EmacsPaintQueue.java b/java/org/gnu/emacs/EmacsPaintQueue.java
new file mode 100644
index 00000000000..5af5868d3b9
--- /dev/null
+++ b/java/org/gnu/emacs/EmacsPaintQueue.java
@@ -0,0 +1,138 @@
+/* Communication module for Android terminals.  -*- c-file-style: "GNU" -*-
+
+Copyright (C) 2023 Free Software Foundation, Inc.
+
+This file is part of GNU Emacs.
+
+GNU Emacs is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or (at
+your option) any later version.
+
+GNU Emacs is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
+
+package org.gnu.emacs;
+
+import java.util.LinkedList;
+import java.util.List;
+
+import android.graphics.Canvas;
+import android.graphics.Paint;
+import android.graphics.Rect;
+
+public class EmacsPaintQueue
+{
+  /* Queue of paint operations.  This is modified from the Emacs
+     thread, and entire paint queues are periodically flushed to the
+     application thread where it is executed.  */
+  private List<EmacsPaintReq> paintOperations;
+
+  /* Number of operations in this queue.  */
+  public int numRequests;
+
+  public
+  EmacsPaintQueue ()
+  {
+    paintOperations = new LinkedList<EmacsPaintReq> ();
+  }
+
+  public void
+  run ()
+  {
+    EmacsDrawable drawable, last;
+    Canvas canvas;
+    EmacsGC gc, lastGC;
+    int i;
+    Paint paint;
+    Rect rect, offsetRect, copyRect;
+
+    canvas = null;
+    last = null;
+    gc = null;
+    paint = new Paint ();
+
+    for (EmacsPaintReq req : paintOperations)
+      {
+	drawable = req.getDrawable ();
+
+	synchronized (req)
+	  {
+	    /* Ignore graphics requests for drawables that have been
+	       destroyed.  */
+	    if (drawable.isDestroyed ())
+	      continue;
+	  }
+
+	canvas = drawable.lockCanvas ();
+
+	if (canvas == null)
+	  /* No canvas is currently available.  */
+	  continue;
+
+	lastGC = gc;
+	gc = req.getGC ();
+	rect = req.getRect ();
+
+	if (gc.clip_rects == null)
+	  {
+	    /* No clipping is applied.  Just draw and continue.  */
+	    canvas.save ();
+	    req.paintTo (canvas, paint, gc);
+	    canvas.restore ();
+	    drawable.damageRect (rect);
+	    continue;
+	  }
+
+	if (gc.clip_rects != null && gc.clip_rects.length > 0)
+	  {
+	    canvas.save ();
+
+	    if (gc.clip_rects.length == 1)
+	      {
+		/* There is only a single clip rect, which is simple
+		   enough.  */
+		canvas.clipRect (gc.clip_rects[0]);
+		req.paintTo (canvas, paint, gc);
+	      }
+	    else
+	      {
+		/* There are multiple clip rects.  Android doesn't let
+		   programs use RegionOp.UNION on the clip rectangle,
+		   so Emacs must iterate over each intersection and
+		   paint it manually.  This seems inefficient but
+		   thankfully Emacs never seems to use more than one
+		   clip rect.  */
+
+		for (i = 0; i < gc.clip_rects.length; ++i)
+		  {
+		    copyRect = new Rect (gc.clip_rects[i]);
+
+		    if (copyRect.intersect (rect))
+		      {
+			canvas.save ();
+			canvas.clipRect (copyRect);
+			req.paintTo (canvas, paint, gc);
+			canvas.restore ();
+		      }
+		  }
+	      }
+
+	    drawable.damageRect (rect);
+	    canvas.restore ();
+	  }
+      }
+  }
+
+  public void
+  appendPaintOperation (EmacsPaintReq req)
+  {
+    paintOperations.add (req);
+    numRequests++;
+  }
+};