sveinn-steinarsson
commented
10 years ago I like the idea and I think you should make it into a stand-alone plugin for Flot.
I would however consider using something else than $.grep since it looks at all elements in the list.
- Given that the list is ordered by a strictly increasing X value, you don't need to look at elements beyond the position of xmax.
- Also the position of xmin can perhaps be found more quickly. One idea is to implement a method similar to binary search.
dsrink
I suggest to add support to only account for data which is actually visible, i.e. after applying min/max range.
My suggestion is to add a pre-filter. Without that, the graphs will look ugly.
An example: You have a graph of 4000 data points. You downsample that to a threshold of 800. After zooming in (using e.g. the selection plugin) to a quarter of the graph, you will see only 200 data points, although the range would contain 1000, out of which downsample should rather display 800 data points. Alternate example: 4000 data points, threshold 800, a 10% range, 80 data points displayed instead of 400.
This way, the point of downsampling is somewhat undermined.
I have prepared a change which fixes that, and skips the added behaviour if min/max are not defined. Note that "out of range" is determined only on x axis, not on y, on purpose - since otherwise threshold plugin might miss some lines to data points outside of the graph. I tested this only for an ordinary graph (with time series x data), hope that it doesn't break anything else.