Graphics protocol: Add a control to allow clients to specify that the cursor should not move when displaying an image

Fixes #3411

docs/changelog.rst

@@ -102,6 +102,9 @@ To update |kitty|, :doc:`follow the instructions <binary>`.
 - Improve rendering of rounded corners by using a rectircle equation rather
   than a cubic bezier (:iss:`3409`)
 
+- Graphics protocol: Add a control to allow clients to specify that the cursor
+  should not move when displaying an image (:iss:`3411`)
+
 
 0.19.3 [2020-12-19]
 -------------------

docs/graphics-protocol.rst

@@ -401,6 +401,12 @@ colors.
    number of rows in the image placement rectangle. If either of these cause
    the cursor to leave either the screen or the scroll area, the exact
    positioning of the cursor is undefined, and up to implementations.
+   The client can ask the terminal emulator to not move the cursor at all
+   by specifying ``C=1`` in the command, which sets the cursor movement policy
+   to no movement for placing the current image.
+
+.. versionadded:: 0.20.0
+   Support for the C=1 cursor movement policy
 
 
 Deleting images
@@ -680,6 +686,8 @@ Key      Value                 Default    Description
 ``Y``    Positive integer      ``0``      The y-offset within the first cell at which to start displaying the image
 ``c``    Positive integer      ``0``      The number of columns to display the image over
 ``r``    Positive integer      ``0``      The number of rows to display the image over
+``C``    Positive integer      ``0``      Cursor movement policy. ``0`` is the default, to move the cursor after the image.
+                                          ``1`` is to not move the cursor at all when placing images.
 ``z``    32-bit integer        ``0``      The *z-index* vertical stacking order of the image
 
 **Keys for animation frame loading**