View controls

[gwhitney]

At the meeting today, it was resolved that we would like to move all view controls into a coherent piece of the user interface from wherever they may currently be, and expand the collection of such controls. The view controls under potential consideration include the following, which have some internal dependencies/redundancies -- this list is not meant to be definitive/final:

• Play/pause
• Frame number/"media progress bar"/frame scrubber
• Replay (restart)
• Forward/back one frame
• Frame rate
• Pan
• Zoom
• Roll
• Orbit (for potential future 3D visualizations)
• Aspect Ratio
• Axis limits
• Portion of the plotting coordinate plane/space "guaranteed" to be visible upon rendering the visualization on a display with different physical dimensions

Individual visualizers should be able to disable controls, e.g. Histogram wishes to disable Roll. Disabled controls should disappear or possibly just grey out.

None of these view controls should automatically be reflected in the URL/saved state of the visualization, but as many as reasonably can should have the capability to be saved/recorded in the URL. The view controls should have a "snapshot" button that saves/URL encodes all of the current controls that can be saved. There should also be a "reset" button that returns all of the view controls to the state they would have in a fresh visualization with no view controls in the URL (and updates the URL to be such). We will rely on browser back and forward to move to previous snapshot(s) if we have left them via "snapshot" or "reset".

An initial thought as to where these controls should go: another "tab" analogous to the Sequence and Visualization tabs, perhaps called the "View" tab. In its minimized state, it should look very much like standard media controls (play/pause, replay, etc). It should start minimized and (say) in the top left or top right tab position. When it is unminimized, the full suite of view controls should become visible, including the snapshot button (which should be hidden by default). Another possibility would be to have the "media controls" part be in the top bar, say below the Numberscope logo, and then allow the other controls to drop down from there (say via a "rotating triangle" open/close button), perhaps semitransparent for the portion that goes over the canvas. For final resolution/implementation of this issue, we will need to settle on a design for this aspect of the UI; perhaps we can solicit UI advice on what would be best.