Solve weird animation issues with the tooltip. The optimization in Chart.Element.transition when the animation finishes to set `_view = _model` caused problems during update because we were using `helpers.extend` all over the place.
I changed to code so that we regenerate the model variable rather than continuously extending the old version. I also removed unnecessary tooltip reinitializations from the controller which should improve overall performance during interaction.
In order to simulate real-time chart updates (i.e. horizontal animation), it's necessary to distinguish a removed or added value from a simple update. The dataset controller now hooks array methods that alter the data array length to synchronize metadata accordingly. Also remove the duplicate calls of updateBezierControlPoints() for line and radar charts.
Responsiveness is currently based on the use of an iframe, however this method causes performance issues and could be troublesome when used with ad blockers. So make sure that the user is still able to create a chart without iframe when responsive is false.
CanvasRenderingContext2D.fillText() accepts a fourth parameter called maxWidth that sets the maximum width of the drawn text, enforced by scaling the entire line.
This commit uses the title element's layout dimensions to set maxWidth and avoid overflow outside of the canvas.
Now that the aspect ratio is correctly handled, fix samples for charts with aspect ratio of 1 which was vertically too large. Also fix the default aspect ratio for radar charts which wasn't applied when creating a chart directly using new Chart(ctx, { type: 'radar' }).
When responsive is false and no canvas height explicitly set, the aspectRatio option wasn't applied because of the canvas default height. Prevent the retinaScale method to change the canvas display size since this method is called for none responsive charts, but instead make the resize() responsible of these changes. Also, as discussed some time ago, moved most of the core.js logic into core.controller.js. Clean up the destroy process and make sure that initial canvas values are properly saved and restored.
Ensure that the hidden iframe is stretched vertically in order to detect height changes. Remove the classlist check/call since it was incorrectly spelled (should be classList), but also useless since the iframe has just been generated. Also remove the callback check: addResizeListener should never be called w/o a valid callback.
Fixes a rendering issue when there are multiple datasets on a pie chart and they do not all contain the same number of data in their datasets
Fixes#3309
Add "onHover" to the legend options that will hold a user defined function (default is null) and called when a "mousemove" event is registered on top of a label item, with same parameters as the "onClick" option.
Also introduced logic that determines if the type of event passed to the legend "handleEvent" function is one we can handle. Currently allowing "click" and "mousemove" events. If the event is not one of those we stop the function execution (this is for the sake of reusing the legend hitbox calculations).
When dealing with time-delineated datasets, often we have data for known
intervals of time. For example, we may have a dataset which represents number
of purchases per day:
```json
{
labels: ['2016-01-01', '2016-01-02', '2016-01-03']
datasets: [
{
data: [12, 87, 42]
}
],
'...': '...'
}
```
In this case, Chart.js will attempt to figure out the best interval to display
the data, and could pick `hours` as the unit. However, in this case, we would
prefer to just use the `days` interval since our data's granularity can not be
represented well with `hours`.
To remedy this, this commit adds the `minUnit` option which allows
users to (optionally) specify what the minimum unit they would like
to use.
Previously buildLabelDiffs() was called at the end of buildTicks() and
hence labelDiffs cache was calculated twice (in getMinimumBoxSize() and
then in fitBox()).
Change the linter in gulp tasks to be consistent with Code Climate results which are based on ESLint using .eslintrc options. However, defaults Code Climate rules are too strict, so turn as warnings the 'complexity' and 'max-statements' rules (other errors has been fixed). Note that the Gulp task name has been changed for `gulp lint`.
Zooming in can cause the params `datasetIndex` and `index` to be null in method `getLabelMoment`. This happens when no ticks are visible on scale. It also throws an error and the chart becomes broken.
