JavaScript Journal - Updating an image without flickering
This is how I'm approaching the problem of trying to simulate live video from a series of preview images.
- After initial page setup, we start the polling service
- After each polling response we look for new preview images ('pre')
- For each preview response, we ask each camera to update its image
- As an optimization we only update the cameras that are currently on screen
- When the new image has loaded, we swap it with the one being displayed (this eliminates flickering)
- If the image has taken longer than two seconds to load than display a 'Loading…' message
- Update the time display in the corner with the timestamp of the image
I am made an updateImage method on my Cameras model. When the new image is loaded into a dummy space, I copy it to the actual model's image and the view re-renders.
To eliminate the flickering, bind to the load event on the new image and wait unti it is fired before changing the src on the image.
I also added some convenience methods to the Collection. I filter down the models based and return it based on status. As long as I return an array of models everything else works.