[gsoc] add support for cheese-like video effects
Submitted by Raluca-Elena Podiuc
Link to original bug (#654448)
Description
As part of my GSOC application, I want to add Cheese's video effects to Empathy.
Proposed changes to the UI:
- add a "Video effects" button: -- either an always visible button -- or a button in the menu that appears when pressing the "i" button on the user's video preview
- add a "Video effects" menu entry in the window's main-menu
Selecting that button would swap the main display with one that would enable the user to select an effect from an NxN grid similar to Cheese. Clutter-based buttons can be displayed over the effect preview grid to select the next/previous page of effects. Clicking on an effect enables it and adds it to the gst-bin.
The first page of effects will display a "No effect" entry enabling the user to disable effects at any time.
While the effect preview grid is displayed, the video from the camera should still be sent over the network as normal. When an effect is chosen the effect is applied early in the gst bin before splitting it for the window and network. This way the effect is on for both the local window and the other participants in the conversation.