Added API route to draw overlay text

openflexure_microscope/api/v1/blueprints/camera/__init__.py

@@ -2,7 +2,7 @@ from openflexure_microscope.api.v1.views import MicroscopeView
 
 from flask import Blueprint
 
-from . import capture, record, preview, config
+from . import capture, record, preview, config, overlay
 
 
 def construct_blueprint(microscope_obj):
@@ -31,4 +31,9 @@ def construct_blueprint(microscope_obj):
         '/preview/<string:operation>', 
         view_func=preview.GPUPreviewAPI.as_view('gpu_preview', microscope=microscope_obj))
 
+    # Overlay routes
+    blueprint.add_url_rule(
+        '/overlay', 
+        view_func=overlay.OverlayAPI.as_view('overlay', microscope=microscope_obj))
+
     return(blueprint)

openflexure_microscope/api/v1/blueprints/camera/overlay.py

@@ -0,0 +1,39 @@
+from openflexure_microscope.api.v1.views import MicroscopeView
+from openflexure_microscope.api.utilities import JsonPayload
+
+from flask import Response, Blueprint, jsonify, request, abort, url_for, redirect, send_file
+
+class OverlayAPI(MicroscopeView):
+
+    def post(self):
+        """
+        Set overlay text
+
+        .. :quickref: Overlay; Set camera overlay text
+
+        **Example requests**:
+
+        .. sourcecode:: http
+
+          POST /camera/overlay HTTP/1.1
+          Accept: application/json
+
+          {
+            "text": "2019/01/15 14:48", 
+            "size": 50 
+          }
+
+        :>header Accept: application/json
+
+        :<header Content-Type: application/json
+        :status 200: preview started/stopped
+        """
+        
+        payload = JsonPayload(request)
+        text = payload.param('text', default="", convert=str)
+        size = payload.param('size', default=50, convert=int)
+
+        self.microscope.camera.camera.annotate_text = text
+        self.microscope.camera.camera.annotate_text_size = size
+
+        return jsonify({'text': text, 'size': size})