`instanceof HTMLCanvasElement/CanvasRenderingContext2D` fails when the item is inside an iframe or when running in a protected environment. We could guess the types from their toString() value but let's keep things flexible and assume it's a sufficient condition if the item has a context2D which has item as `canvas`.
* Adds step-after functionality, true defaults to step-before
* Update stepped line sample to include all variations of steppedLine configurations
* Update documentation on steppedLine values
* Add tests for new steppedLine values 'before' and 'after'
* Fixed different calculation of scale min and max when dataset contains no values
* Removed trailing spaces
* Added test for correct min/max calculation
* Removed trailing spaces
Merge most of the horizontalBar controller into the bar one but also fix stack groups and bar positioning when scales are stacked or when a min and/or max tick values are explicitly defined. Note that this is a breaking change for derived controllers that rely on the following removed methods: `calculateBarBase`, `calculateBarX`, `calculateBarY`, `calculateBarWidth` and `calculateBarHeight`.
* respect new scale option 'order' when ordering scales
* scale service - respect new weight scale option for axes ordering
* added test for scale ordering by weight
* removed trailing spaces from layout weight scale order test
* Make parseTime private
* start on fixing time scale
* Reimplement existing functionality
* Tidy tests
* Fix labels for non-linearly sized units
Months, quarters and years have non-constant numbers of seconds. A scale that's linear WRT milliseconds produces incorrect tick labels due to the label formatting losing precision (eg year labels lose month and day so a label of 2016-12-32 displays as 2016 instead of 2017).
* Re-implement tick generation
As in v2.5
Radar chart position is not center horizontally with v2.5.0.
Right and left of `furthestLimits` would be switched wrongly on
this refactoring commit.
e1606f88ed
* Undo fix for #3585 since it has broken the stacked bar charts when the axis has a user defined minimum value.
* When a value of 0 is requested for a vertical logarithmic axis, return the bottom point
The `fill` option now accepts the index of the target dataset (number) or a string starting by "+" or "-" followed by a number representing the dataset index relative to the current one (e.g. `fill: "-2"` on dataset at index 3 will fill to dataset at index 1). It's also possible to "propagate" the filling to the target of an hidden dataset (`options.plugins.filler.propagate`). Fill boundaries `zero`, `top` and `bottom` have been deprecated and replaced by `origin`, `start` and `end`.
Implementation has been moved out of the line element into a new plugin (`src/plugins/plugin.filler.js`) and does not rely anymore on the deprecated model `scaleTop`, `scaleBottom` and `scaleZero` values. Drawing Bézier splines has been refactored in the canvas helpers (note that `Chart.helpers.canvas` is now an alias of `Chart.canvasHelpers`).
Add 3 new examples and extend utils with a pseudo-random number generator that can be initialized with `srand`. That makes possible to design examples starting always with the same initial data.
Attempt to make easier the creation of unit tests that check the drawing output. Until now, this was done by checking calls on a 'fake' context, which is hard to maintain (need to update pixel values by hands) and also not reliable when optimizing code (i.e. different calls sequence but same result).
As of now, it's possible to define 'auto' tests based on JSON/PNG fixtures: chart is generated from the JSON file and compared to the associated PNG image. The image diff is done using `pixelmatch`. As an example (and in preparation of the `filler` plugin), add auto tests for the line element `fill` options.
`karma.conf.ci.js` has been merged into `karma.conf.js` for local testing consistency: `gulp unittestWatch` has been replaced by `gulp unittest --watch` and thus use exactly the same config file. Upgrade to latest jasmine and karma packages and remove deprecated `gulp-karma` dependency (directly use `karma.Server` in gulp).
Split `test/mockContext.js` into smaller `test/jasmine.*` modules to make easier unit tests maintenance and finally, move all `*.test.js` files under the `test/specs` folder.
