Heatmap error checking and documentation for data larger than Bitmap supports

Found this on rendering big datasets in to a heat map. From my point of view it looks like that the internal plotting runs into an variable limit (i guess singed short (2^15)) and than stretches the last row of data al the way to the end as seen in pictures,

OK Render less than 2^15 rows in y dimension

Faild renders at more than 2^15 rows

[Test]
[TestCase(3768,"outOK1.png")]
[TestCase(32768,"outOK2.png")]
[TestCase(34000,"outFail1.png")]
[TestCase(60000,"outFail2.png")]
        public void ScottplotBoundary( int traceCount ,string path) {
            Random r           = new Random();
            int    sampleCount = 500;
            
            var zData = new double[traceCount, sampleCount];
            for (var i = 0; i < traceCount; i++) {
                for (var i1 = 0; i1 < sampleCount; i1++) {
                    zData[i, i1] = r.NextDouble() ; 
                }
            }
            
            var                plt = new Plot();
            CoordinatedHeatmap hmc = plt.AddHeatMapCoordinated(zData);
            plt.AxisAuto(0, 0);
            plt.SaveFig(path);
        }

found on nuget 4-1.6-beta – running on core 3.1

[StendProg]

Hi @swharden, I think this exceptions must be part of optional validation. I use 2k*2k = 4M bitmaps a lot, and it’s very close to provided limits…

[swharden]

I came to a compromise and like @StendProg suggested moved the size-checking code into the deep validation method. I also extended the XML documentation for the AddHeatmap() methods to indicate rendering may become unpredictable for large arrays with ~10M or more values.

Thanks again for both of your input!