Image creating dynamically using writablebitmap perfomance lag and UI freezing when increasing image size in WASM.

[tomchoondal]

We are using WriteableBitmap for creating images dynamically. Its working in wasm but as size of the image increasing (in our case height) the performance lags and the UI freezes.

We used the following pattern.

var height = widget.ImageVM.LineItems.Count; //height varies from 0 to any value (for us 200px after this UI freezes)
var width = widget.ImageVM.LineItems[0].DataPointItems.Count; //width is fixed to 256px
var bm = new WriteableBitmap(width, height);

byte[] imageArray = new byte[height * width * 4];
for (int x = 0; x < height; x++)
{
for (int y = 0; y < imageArray.Length; y += 4)
{
imageArray[y] = 0;
imageArray[y + 1] = 0;
imageArray[y + 2] = 255;
imageArray[y + 3] = 255;
}

}
using (Stream stream = bm.PixelBuffer.AsStream())
{
//write to bitmap
await stream.WriteAsync(imageArray, 0, imageArray.Length);
}

_image.Source = bm;
_image.Height = height;
any suggestions/alternatives for better image creation.

[jeromelaban]

Thanks for the question. If your app uses the .NET interpreter (the default), it is likely that this piece of code will be slow.

Make sure to use AOT to improve your app's performance.

[tomchoondal]

@jeromelaban Thanks for the quick reply. I tried your recommendation and definitely improved the performance, but still we are lagging on UI when we are trying to render high sized images using above code.

[jeromelaban]

Thanks. If you can create a repro, it will be easier to troubleshoot. You can also use the browser profiler to troubleshoot performance issues.

[tomchoondal]

@jeromelaban , We (Baker Hughes) have started creating our application in your latest uno 5.2.46.54. We are getting a build error always after adding a small change "System.ApplicationException: Unable to move PACKAGE DIST C:\Workspaces\RigLink\RigLink\RigLink\obj\Debug\net8.0-browserwasm\dist_work to C:\Workspaces\RigLink\RigLink\RigLink\bin\Debug\net8.0-browserwasm\dist\package_a99f46ff3fa3a174f2e19f6bdf36ebf1caaa1bff: System.IO.IOException: Access to the path 'C:\Workspaces\RigLink\RigLink\RigLink\obj\Debug\net8.0-browserwasm\dist_work' is denied."
I am getting this error always, I am running VS2022 in admin mode and still getting. Some times it will disappears when change the run from wasm to windows. We are mainly concentrating on WASM and WinUI. A help from your side highly appreciated

[jeromelaban]

Thank you for the report. Can you provide a binlog: https://platform.uno/docs/articles/uno-builds-troubleshooting.html. Also how are you building the app? Using the command line or using visual studio? If in visual studio, which command are you using?

[tomchoondal]

In visual studio 2022 we are selecting WASM project and Building.

[jeromelaban]

Thanks. Make sure to provide a binlog to help troubleshooting further. Thanks!

[tomchoondal]

@jeromelaban, I am unable to install Uno.CommunityToolkit.WinUI.UI.Controls nuget package. When I am trying to install
I am getting following error.

I am using Uno Platform Extension of version 5.2.48.56