UI: Move OpenGL render operators to sub-menu

Move 3D Viewport and Sequencer OpenGL render operators into a
"Render Preview" sub-menu.

The goal is to make the operation more clear, and being able to add
new entries to render the active scene or Sequencer scene (handy when
using the new "Sync Scene").

This also reduces the length of the `View` menu which in some cases
can get quite long.

See PR for details and screenshots.

Resolves #146302

Pull Request: https://projects.blender.org/blender/blender/pulls/146316

scripts/startup/bl_ui/space_sequencer.py

@@ -457,6 +457,17 @@ class SEQUENCER_MT_proxy(Menu):
         layout.prop(st, "proxy_render_size", text="")
 
 
+class SEQUENCER_MT_view_render(Menu):
+    bl_label = "Render Preview"
+
+    def draw(self, _context):
+        layout = self.layout
+        layout.operator("render.opengl", text="Render Sequencer Image", icon='RENDER_STILL').sequencer = True
+        props = layout.operator("render.opengl", text="Render Sequencer Animation", icon='RENDER_ANIMATION')
+        props.animation = True
+        props.sequencer = True
+
+
 class SEQUENCER_MT_view(Menu):
     bl_label = "View"
 
@@ -536,10 +547,7 @@ class SEQUENCER_MT_view(Menu):
             layout.menu("SEQUENCER_MT_range")
             layout.separator()
 
-        layout.operator("render.opengl", text="Sequence Render Image", icon='RENDER_STILL').sequencer = True
-        props = layout.operator("render.opengl", text="Sequence Render Animation", icon='RENDER_ANIMATION')
-        props.animation = True
-        props.sequencer = True
+        layout.menu("SEQUENCER_MT_view_render")
         layout.separator()
 
         layout.operator("sequencer.export_subtitles", text="Export Subtitles", icon='EXPORT')
@@ -3191,6 +3199,7 @@ classes = (
     SEQUENCER_HT_playback_controls,
     SEQUENCER_MT_editor_menus,
     SEQUENCER_MT_range,
+    SEQUENCER_MT_view_render,
     SEQUENCER_MT_view,
     SEQUENCER_MT_preview_zoom,
     SEQUENCER_MT_proxy,

scripts/startup/bl_ui/space_view3d.py

@@ -1481,23 +1481,7 @@ class VIEW3D_MT_view(Menu):
 
         layout.separator()
 
-        layout.operator(
-            "render.opengl",
-            text="Viewport Render Image",
-            icon='RENDER_STILL',
-        )
-        layout.operator(
-            "render.opengl",
-            text="Viewport Render Animation",
-            icon='RENDER_ANIMATION',
-        ).animation = True
-        props = layout.operator(
-            "render.opengl",
-            text="Viewport Render Keyframes",
-        )
-        props.animation = True
-        props.render_keyed_only = True
-
+        layout.menu("VIEW3D_MT_view_render")
         layout.separator()
 
         layout.menu("INFO_MT_area")
@@ -1655,6 +1639,31 @@ class VIEW3D_MT_view_regions(Menu):
         layout.operator("view3d.clear_render_border")
 
 
+class VIEW3D_MT_view_render(Menu):
+    bl_label = "Render Preview"
+
+    def draw(self, _context):
+        layout = self.layout
+        layout.operator(
+            "render.opengl",
+            text="Render Viewport Image",
+            icon='RENDER_STILL',
+        )
+        layout.operator(
+            "render.opengl",
+            text="Render Viewport Animation",
+            icon='RENDER_ANIMATION',
+        ).animation = True
+
+        layout.separator()
+        props = layout.operator(
+            "render.opengl",
+            text="Render Viewport Keyframes",
+        )
+        props.animation = True
+        props.render_keyed_only = True
+
+
 # ********** Select menus, suffix from context.mode **********
 
 class VIEW3D_MT_select_object_more_less(Menu):
@@ -9119,6 +9128,7 @@ classes = (
     VIEW3D_MT_view_align_selected,
     VIEW3D_MT_view_viewpoint,
     VIEW3D_MT_view_regions,
+    VIEW3D_MT_view_render,
     VIEW3D_MT_select_object,
     VIEW3D_MT_select_object_more_less,
     VIEW3D_MT_select_pose,