X11: Allow drag and drop of text/plain in addition to text/uri-list

Fixes #2441

Author: kovidgoyal

docs/changelog.rst

@@ -77,6 +77,9 @@ To update |kitty|, :doc:`follow the instructions <binary>`.
 - Workaround for bug in less that causes colors to reset at wrapped lines
   (:iss:`2381`)
 
+- X11: Allow drag and drop of text/plain in addition to text/uri-list
+  (:iss:`2441`)
+
 - Dont strip :code:`&` and :code:`-` from the end of URLs (:iss:`2436`)
 
 - Fix ``@selection`` placeholder not working with launch command (:iss:`2417`)

glfw/x11_init.c

@@ -385,6 +385,8 @@ static bool initExtensions(void)
     _glfw.x11.XdndSelection = XInternAtom(_glfw.x11.display, "XdndSelection", False);
     _glfw.x11.XdndTypeList = XInternAtom(_glfw.x11.display, "XdndTypeList", False);
     _glfw.x11.text_uri_list = XInternAtom(_glfw.x11.display, "text/uri-list", False);
+    _glfw.x11.text_plain = XInternAtom(_glfw.x11.display, "text/plain", False);
+    _glfw.x11.text_plain_utf8 = XInternAtom(_glfw.x11.display, "text/plain;charset=utf-8", False);
 
     // ICCCM, EWMH and Motif window property atoms
     // These can be set safely even without WM support

glfw/x11_platform.h

@@ -267,6 +267,8 @@ typedef struct _GLFWlibraryX11
     Atom            XdndSelection;
     Atom            XdndTypeList;
     Atom            text_uri_list;
+    Atom            text_plain;
+    Atom            text_plain_utf8;
 
     // Selection (clipboard) atoms
     Atom            TARGETS;

glfw/x11_window.c

@@ -1478,6 +1478,10 @@ static void processEvent(XEvent *event)
                     {
                         _glfw.x11.xdnd.format = _glfw.x11.text_uri_list;
                         break;
+                    } else if (formats[i] == _glfw.x11.text_plain_utf8 && (_glfw.x11.xdnd.format == None || _glfw.x11.xdnd.format == _glfw.x11.text_plain)) {
+                        _glfw.x11.xdnd.format = _glfw.x11.text_plain_utf8;
+                    } else if (formats[i] == _glfw.x11.text_plain && _glfw.x11.xdnd.format == None) {
+                        _glfw.x11.xdnd.format = _glfw.x11.text_plain;
                     }
                 }