1 files changed, 103 insertions, 0 deletions
diff --git a/gr-qtgui/python/qtgui/graphicoverlay.py b/gr-qtgui/python/qtgui/graphicoverlay.py
new file mode 100644
index 0000000000..defef31d17
--- /dev/null
+++ b/gr-qtgui/python/qtgui/graphicoverlay.py
@@ -0,0 +1,103 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+#
+# Copyright 2020 Free Software Foundation, Inc.
+#
+# This file is part of GNU Radio
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+#
+
+import sys
+import threading
+import time
+
+from gnuradio import gr
+import pmt
+
+# This thread just gets us out of the sync_block's init function so the messaging
+# system and scheduler are active.
+class offloadThread(threading.Thread):
+  def __init__(self, callback, overlayList, listDelay, repeat):
+    threading.Thread.__init__(self)
+    self.callback = callback
+    self.overlayList = overlayList
+    self.listDelay = listDelay
+    self.threadRunning = False
+    self.stopThread = False
+    self.repeat = repeat
+
+  def run(self):
+    self.stopThread = False
+    self.threadRunning = True
+
+    # Wait for main __init__ to finish
+    time.sleep(0.5)
+
+    if (type(self.overlayList) == list and self.listDelay > 0.0):
+        while self.repeat and not self.stopThread:
+            for curItem in self.overlayList:
+                self.callback(curItem)
+
+                if self.stopThread:
+                    break
+
+                time.sleep(self.listDelay)
+
+                if self.stopThread:
+                    break
+    else:
+        self.callback(self.overlayList)
+
+    self.threadRunning = False
+
+class GrGraphicOverlay(gr.sync_block):
+    """
+    This block is an example of how to feed an overlay to a graphic item.
+    The graphic item overlay is expecting a dictionary with the following
+    keys: 'filename','x','y', and optionally a 'scalefactor'.  A list of
+    dictionaries can also be supplied to support multiple items.
+
+    Any file can be added to the graphic item as an overlay and the
+    particular item indexed by its filename can be updated by passing
+    in new x/y coordinates.  To remove an overlay, use coordinates -1,-1
+    for the x,y coordinates.
+
+    This sample block sends either a dictionary or list of dictionaries
+    to the graphicitem block.  To test updating a single overlay item,
+    you can use a list with the same file but different coordinates and
+    use the update delay > 0.0 to animate it.
+    """
+    def __init__(self, overlayList, listDelay, repeat):
+        gr.sync_block.__init__(self, name="GrGraphicsOverlay", in_sig=None,
+                               out_sig=None)
+
+        self.overlayList = overlayList
+        self.listDelay = listDelay
+        if type(self.overlayList) is not dict and type(self.overlayList) is not list:
+            gr.log.error("The specified input is not valid.  "
+                  "Please specify either a dictionary item with the following keys: "
+                  "'filename','x','y'[,'scalefactor'] or a list of dictionary items.")
+            sys.exit(1)
+
+        self.message_port_register_out(pmt.intern("overlay"))
+
+        self.thread = offloadThread(self.overlayCallback, self.overlayList, listDelay,
+                                    repeat)
+        self.thread.start()
+
+    def overlayCallback(self, msgData):
+        # Need to let init finish before this can be called so need to thread it out.
+        meta = pmt.to_pmt(msgData)
+        pdu = pmt.cons(meta, pmt.PMT_NIL)
+        self.message_port_pub(pmt.intern('overlay'), pdu)
+
+    def stop(self):
+        self.thread.stopThread = True
+
+        while self.thread.threadRunning:
+            time.sleep(0.1)
+
+        return True
+