In many cases, the canvas render size is changed by the lib, causing the state stack to be discarded, meaning that we can't use save() and restore() to release the context with its initial state (i.e. before creating the chart). Since we don't need (want) to manually save / restore the context initial state, simply make sure to reset it to the default state to give a fresh context back to the user. That also means we don't need to revert the scale when the pixel device ratio is not 1.
When legend is disabled (i.e. {options: {legend: false}}), me.legend is null. Add the same test on me.tooltip even if the tooltip object is always created in case of {options: {tooltips: false}}.
When the iframe is attached to the DOM, its content is reloaded (invaliding the resize listener) so make sure to install the handler after the iframe is loaded. Optimize resize events by throttling resize process until the next animation frame. Rewrite the unit test "waitForResize" method, the previous one (timeout) was too weak and most tests was failing on FF.
I added new samples to explain behaviour and modified all samples to have consistent styling. In updating the samples,
I removed the use of jQuery and instead use standard methods.
For the custom tooltip samples, I updated the styling to show color boxes like the regular tooltips.
Add support for creating a chart from the canvas id and prevent exceptions, at construction time, when the given item doesn't provide a valid CanvasRenderingContext2D or when the getContext API is not accessible (e.g. undefined by add-ons to prevent fingerprinting). New jasmine matcher to verify chart validity.
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.
