On Dec 30, 2004, at 2:20 PM, Paul Bailey wrote:
You're right - just one slider. I intend for the user to define both a
"timebase" and a "duration" for their project elsewhere in the
application
So you have a fixed time scale at the top of the control, and then your
slider with the knobs adjust your keypoints. I think that there are
only a few things that you would need to decide:
1. Should the user be able to zoom in on the control (more precision)?
2. Will you have an editfield to get/set a precise numeric value?
3. Will you have snap-to values such as on the 1/30 boundry?
4. Would the default be to snap unless a control key is down?
5. When you move one slider, how will it affect the other sliders? Do
they move as well, or are they fixed (and one side is compressed)?
6. Will you allow the user to select more than one slider?
7. How does a user define a key point?
8. How does a user remove a key point?
The use of this is loosely based on a 30 frames-per-second (FPS)
model. The user's "timebase" will define the fractions of a 30th of a
second - or "subframes", if you will, that the project is based on.
Each "subframe" will then represent an underlying 16 or 32[haven't
decided yet] value in a lookup table. The MCU will click thru this
lookup table (stored on an EEPROM), and present the value to it's
registers at the defined timebase... i.e. one update every 1/300 of a
second for a timebase of 10.
A control is just a user interface to a structure. The info above
doesn't mean much to me since I don't know much about video editing.
I would guess you will need to make your own control, and I would start
by working in other apps which emulate the type of timeline control you
are looking for. Take lots of notes and then start planning out your
control before you even start coding. The more you plan out before you
get involved in the details, the easier it will be for you to apply
those requirements to code.
I'm using this to create an embedded animation system for use at work
(DIsney) - that's about all I can say about it...
Lucky you. =)
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