From davidcapello on November 25, 2013 17:11:09

Rewrite the current Animation Editor as a timeline at the bottom of the screen that can be viewed at the same time we edit the sprite. In this way we can move through frames/layers and see where we are located. With this new Timeline the StatusBar doesn't have to show the layers anymore.

The first version of the Timeline can be just that: the current animation editor visible next to the sprite editor. But a next version of the timeline should include the following features:

• Make onionskin settings configurable from the Timeline (issue Make onionskin settings configurable #110 and issue Overlay/Tint Onion Skin #167).
• Select/delete multiple frames/layers (issue Select multiple frames #182).
• Change its state: visibility, lock status.
• Move multiple frames/layers (issue Ability to select and manipulate multiple items simultaneously #97 , maybe issue Change Order of Frames in Timeline #274).
• Insert multiple N new frames at once (issue Animation -- quickly insert many frames (enter N) #271).
• Loop or ping-pong a section of the animation (issue Loop section #123, issue Set the range of animation frames #159, and issue Select multiple frames #182).
• Possibility to tag/label frames (issue Possibility to tag frames #153, Timeline Markers for Multiple Animations #500).
• Option to return to the start frame of the animation after playback (comment in issue Loop section #123).
• Reverse frames/cels (issue Reverse frame order #503).
• Add support for cels that persist over several frames (issue Persistent and Impersistent layers for animation #99, Animation -- "use previous frame" frame mode (<--) (including sequence of frames) #269, Add support to keep a cel in several frames #389). In previous versions of Aseprite we were able to use "linked cels" (new issue Animation - Keyframes + FPS #439), maybe this could be done with similar concept, but with an easier implementation (the use-previous frame flag).
• Remove cels automatically when they are empty (issue If we clear the whole content of a cel, show it as empty in the timeline #559)
• Draw and paste on all frames at the same time (issue Draw on all frames at the same time #56 , and maybe issue Copy content of selection to a frame range #95). This could be done selecting a frame range and pressing a little "Edit/paste on selected all frames" button in the Timeline. This is related to issue Copy content of selection to a frame range #95 where we should be able to select a frame range, and then paste that range in other location (other frame, other x-y position).
• Possibility to swap frames/cels (issue Swap frames/cels #224).
• Disable a frame (or a set of frames) to preview the animation with those frames (issue ability to disable frames #244).
• Lock frames (issue Lock frames #1230)

Review bugs:

• Issue Missing images in timeline view when copying frames #93 : Missing images in timeline view when copying frames.
• Issue The mini editor blacks out part of the screen when viewing an animation. #98 : The mini editor blacks out part of the screen when viewing an animation
• Issue Animation Editor Bug moving a cel from a transparent layer to background #258 : Animation Editor Bug
• Issue Timeline pane draws over Mini-Editor #290 : Timeline pane draws over Mini-Editor

Review features:

• Issue Overlay/Tint Onion Skin #167 : Overlay/Tint Onion Skin
• Issue Layer from bottom #198 : Layer from bottom
• Issue Layer thumbnail #152, Timeline thumbnails issues #1271: Layer thumbnails (and frames thumbnails too with mouse hover event)

Duplicated issues:

• Issue Layer Window #213 : Layer Window

Original issue: http://code.google.com/p/aseprite/issues/detail?id=293
Mockup & more comments: https://plus.google.com/102156040653649496700/posts/hQ2VbGwUUny