Add functionality to give pie & doughnut datasets a weight attribute, which affects the relative thickness of the dataset when there are multiple datasets in pie & doughnut charts. The default weight of each dataset is 1, providing any other numerical value will allow the pie or doughnut dataset to be drawn with a thickness relative to its default size.
For example a weight of 2 will allow the dataset to be drawn double its typical dataset thickness. Note that the weight attribute will only affect a pie or doughnut chart if there is more than one visible dataset. Using weight on a pie or doughnut dataset when there is only one dataset on the chart will have no affect.
Remove the logic that computed an "optimal" tooltip format. Instead, always fallback to the `datetime` adapter format which is more efficient and stable. Additionally, remove the adapter `presets` API, which is not needed anymore.
These methods shouldn't have been public since they are specific to the chart controller internal logic. Note that this scale custom merging will be removed in v3.
Merge `core/core.js` in `core/core.controller.js`, split default options next to their associated code and deprecate `Chart.types` (not sure what it was for).
This changes the behavior of `autoSkip` so that it does not force the
display of the last tick. If the last tick can be displayed with equal
spacing to the rest of the ticks, it will be. Otherwise, it is not.
- Remove `Math.round` in the category scale code
- Add `helpers._alignPixel` to align grid/tick/axis border lines
- Fix grid/tick/axis border line calculation
- Add a check of the width of the axis border
- Refactor core.scale code
`controllers.*.js` and `core.datasetController.js` are now importable (no more function export), that's why there is so many changes mainly due to one indentation level removed. Split code for `bar/horizontalBar` and `doughnut/pie` in separate files, added a global controllers import (`src/controllers/index.js`) and add tests to check that all dataset controllers are correctly registered under `chart.controllers.{type}`.
