OutOfMemoryException

[paultobey]

Hi,

I've been chasing an out-of-memory exception in my LightningChartUltimate-based WPF application for some time. I think I've identified the root cause: AnnotationXY and images:

// Don't fill the annotation. Just show the graphic.
annotation.Fill.Style = RectFillStyle.Bitmap;
annotation.Fill.Bitmap.Image = customImage;

annotation.Fill.Bitmap.ImageAlpha = 0xff; // Not transparent.
annotation.Fill.Bitmap.Layout = BitmapFillLayout.Center;

I use such annotations to display "program start times" on a sensor data graph. Sensor data might span several years with several hundred points per day but no more than 1 such annotation per day per sensor. Maximum sensors per chart is 14. 3 charts active at a time.

customImage is a BitmapFrame, of course, 16x16x32-bit. I think that you are creating an Image instance for each such annotation and that the 14 (sensors) * 720 (days, for example) * 1 (bitmap/day) * 3 (active charts in the application at a time) is responsible for the memory issue. Any chance you'd add a version of the AnnotationXY to take an actual Image instance, rather than a BitmapFrame? Since my annotations use the same Image this change would reduce my Image count to...1 from 30240.

Please?
Paul T.

[ArctionPasi]

That's a lot of bitmaps there...

Same BitmapFrame you can assign for all of them and that part is shared. LightningChart creates a DirectX texture for every annotation, and eats the memory apparently. Making a duplicate checking dictionary/cache inside LightningChart should remove the problem, but programming it and handling the texture disposing is not unfortunately a thing that we can program quickly.

[paultobey]

Yes, the same BitmapFrame is passed for creation of all annotations but it does appear to be during your processing that the OutOfMemoryException is fired.

You don't have an Image cache that you can just drop in?

I'll try to convince my QA guys to defer the defect but they could hold product release.

Paul T.

[ArctionPasi]

Hi Paul,

unfortunately we can't take this in LightningChart agenda right now.

Please try an approach where you set
Annotions.Fill.Bitmap = Annotations[0].Fill.Bitmap.

as a general design guideline, we have to say don't do it like this (don't share the objects) but here it might work.

[paultobey]

This work-around is acceptable for now.

Unfortunately with every fixed issue there's another question. On such a dense chart, I'm seeing black areas as though the chart pixels under the bitmap are being blacked out. Here's a section of a chart with many overlapping bitmaps:

DenseAnnotations.png (13.13 KiB) Viewed 10440 times

The image comes from a PNG file 16x16 with transparent pixels around the outside. I don't see any image changes on my end that would affect this. I've attached the image in case it helps.

Paul T.

[paultobey]

Never mind. I thought that borders and shadows were off, but they were not. All is well.
Paul T.