add option to disable automatic command transmission

README.md

@@ -199,17 +199,19 @@ import ueberzug.lib.v0 as ueberzug
    
    Methods:  
    
-   | Name             | Returns      | Description                          |
-   |------------------|--------------|--------------------------------------|
-   | create_placement | Placement    | prevents the use of the same identifier multiple times,<br>takes the same arguments as the Placement constructor (excluding canvas parameter) |
-   | \_\_call\_\_     | Function     | Decorator which returns a function which calls the decorated function with the keyword parameter canvas=this_canvas_object.<br>Of course other arguments are also passed through. |
+   | Name                 | Returns      | Description                          |
+   |----------------------|--------------|--------------------------------------|
+   | create_placement     | Placement    | prevents the use of the same identifier multiple times,<br>takes the same arguments as the Placement constructor (excluding canvas parameter) |
+   | \_\_call\_\_         | Function     | Decorator which returns a function which calls the decorated function with the keyword parameter canvas=this_canvas_object.<br>Of course other arguments are also passed through. |
+   | request_transmission | -            | Transmits queued commands if automatic\_transmission is enabled or force=True is passed as keyword argument. |
    
-   Properties:  
+   Properties / Attributes:  
    
    | Name          | Type                    | Setter | Description                          |
    |---------------|-------------------------|--------|--------------------------------------|
    | lazy_drawing  | context manager factory | No     | prevents the transmission of commands till the with-statement was left<br>`with canvas.lazy_drawing: pass`|
    | synchronous_lazy_drawing  | context manager factory | No     | Does the same as lazy_drawing. Additionally forces the redrawing of the windows to happen immediately. |
+   | automatic\_transmission  | bool | Yes    | Transmit commands instantly on changing a placement. If it's disabled commands won't be transmitted till a lazy_drawing or synchronous_lazy_drawing with-statement was left or request_transmission(force=True) was called. Default: True |
 
 
 

ueberzug/lib/v0/__init__.py

@@ -309,6 +309,7 @@ class Canvas:
         self.__process = None
         self.__transmitter = None
         self.__used_identifiers = set()
+        self.automatic_transmission = True
 
     def create_placement(self, identifier, *args, **kwargs):
         """Creates a placement associated with this canvas.
@@ -390,9 +391,10 @@ class Canvas:
 
         self.__transmitter.enqueue(command)
 
-    def request_transmission(self):
+    def request_transmission(self, *, force=False):
         """Requests the transmission of every command in the queue."""
         if not self.__process.responsive:
             self.__process.start()
 
-        self.__transmitter.transmit()
+        if self.automatic_transmission or force:
+            self.__transmitter.transmit()