Choropleth keep d3.geoAlbers the default projection but deprecate it

[kum-deepak]

Reference #1379

[kum-deepak]

@gordonwoodhull The code seems to keep a flag to apply the projection again if it changes. I have a hunch that _projectionFlag can be removed.

If consider the general convention of dc, in case of any change other than data, render must be called. I think that it can be cleaned up.

I will create an independent commit so that you can reject that part without affecting the core work.

[kum-deepak]

I am updating the VC example where in 6 seconds the projection is changed and the chart re-rendered. I am pushing that as a separate commit, the last commit should not be merged, it is only for testing.

[kum-deepak]

I have disabled cross browser tests, those were always failing for me :)

Maybe we switch back to old scheme of invoking cross browser testing.

[gordonwoodhull]

Yeah, I tried to find earlier discussion, but certainly disabling saucelabs for pull requests was intentional (16e6863). So I'm reverting eff5bf9.

I wouldn't say that there is a convention that redraw is only for data changes. Rather I would say that redraw works for whatever people have debugged it for. So I think I'll keep _projectionFlag. No one ever said simplicity was one of dc.js's virtues. 😉

[gordonwoodhull]

I took the first commit and tested using your VC example test, only with redraw not render, and with a more dramatic projection change (Mercator). Works great!

[gordonwoodhull]

Thanks @kum-deepak!

[kum-deepak]

Thanks @gordonwoodhull!

I am intending to devote time on this project for reasonable time. We are relying on this library heavily and will like it to do even more. To that effect, I will participate in cleaning up as much as possible.

I have realized that the code has been written over many years and has varying code quality across files.

Should we open a separate task for discussion - to cover what someone can expect out of redraw vs render. This will simplify the library and make life easier for users.

[gordonwoodhull]

Sure, it's worth discussing.

In general the functional difference is that redraw will transition from the old state to the new state, but render starts from a blank SVG, so there is usually a blink.

Zooming is one example of something besides the data changing, and although the choropleth doesn't have transitions, perhaps it could morph from one projection to another.

[kum-deepak]

It makes sense. :) There is so much I do not know about this library.