This blender addon gives you a pie menu with easy access to camera switching and rendering to slots directly from the 3d view and MORE.

Notes:

some features require a workaround to achieve with blender python API.

ex: this addon gets render pixels by saving the render to disk and loading it into Blender then removing it from disk. (so you have to save blend file first).

-Render will be saved to an RT_Slot if the render is completed (or if you close the render window before the render finishes).

Contact me if you have any questions/bugs.

PieMenu HotKey: Shift + Ctrl + Alt + Q . (You can change it)

Features:

• Retain previous render image if using render border.
• Display render border on ImageEditor.
  
• Switch to any camera in the scene.
  
• Set a local camera to a 3d view area.
• Render to any Slot.
• The Pie menu shows which camera is active and if an RT_Slot has an image.