Feature/290-max-value-perf-fixes

[brett-estabrook]

I have modified the AxisBasedCharts to rework the main render loop. The main changes are to move the Min,Max, and Range values to the top and store them in local variables. This caches the values of these functions so they are not recalculated each bar/line/point render. I made a few other changes that were related to my changes

Notable Changes:

• Above mentioned performance changes

• • Microcharts/Sources/Microcharts/Charts/AxisBasedChart.cs

    Line 177 in e0f1c37

    float maxValue = MaxValue;

• Modified Y Axis drawing so if the developer sets the Min/Max values it does not override them with "nice" values

• • Microcharts/Sources/Microcharts/Charts/AxisBasedChart.cs

    Line 173 in e0f1c37

    bool fixedRange = InternalMaxValue.HasValue || InternalMinValue.HasValue;

• • Microcharts/Sources/Microcharts/Helpers/MeasureHelper.cs

    Line 73 in e0f1c37

    yAxisXShift = 0.0f;

• Fixed Y axis calculations for negative numbers on a line chart
• Added the yAxisShift in the bar/line drawing. For Left Y Axis labels it wasn't taken into account so there wasn't any room
• • Before yAxis Shift:
• • 
• • After yAxis Shift
• • 
• Make sure the NiceMin and NiceMax values are carried into later functions
• Added a Render Completed Event
• • The purpose is to be able to have a loading wheel while its painting; then hide on finish.

• • Microcharts/Sources/Microcharts.Forms/ChartView.cs

    Line 81 in e0f1c37

    ChartPainted?.Invoke(sender, e);

• Fixed an invalid comparison with Property Changed equality testing
• • This was pretty nefarious. I started a review

• • Microcharts/Sources/Microcharts/Charts/Chart.cs

    Line 618 in e0f1c37

    if ((field == null && value != null) || !field.Equals(value))

• Don't double set animation progress when updating a series
• Removed reference to PlanifyInvalidate, this delay was really slow
• Made Dynamic Line chart have way more data

Charts tested:

• Bar
• Point
• Line
• Donut
• Radar

Platform tested :

• Android
• iOS
• MacOS
• Windows

Fix:

• [Bug] Performance hit with MaxValue and MinValue of Axis based charts #290

[brett-estabrook]

Once the pull request for my missing null value changes is finalized I'll mark this as ready for review.

[Seuleuzeuh]

Great work !
I'll try to test it on Android an Windows this week !

[brett-estabrook]

I touched a lot of the drawing code, I've reviewed a number of charts. However, I would recommend another pair of eyes making sure the labels, points, and lines all line up.

[Seuleuzeuh]

Realy great work, thanks for the couple of PR you made.
The null handling it's preaty great !

Only the multiple label drawing must be fixed before merged.
Thanks again @brett-estabrook

[Seuleuzeuh]

@eman1986 it's ready to merge !

[eman1986]

sorry didn't see that this was good to go, merging it in.