UIGraphicsImageRenderer in background thread #22597
Description
Apple platform
iOS
Framework version
net8.0-*
Affected platform version
ios workload 18.0.8319/8.0.100
Description
UIGraphicsRenderer API is thread safe to use on background thread despite having "UI" prefix, it is just convenient wrapper around Core Graphics.
https://developer.apple.com/forums/thread/774527?answerId=825346022#825346022
Corresponding dotnet apis are forced to be main thread only
[Register("UIGraphicsRenderer", true)]
[SupportedOSPlatform("maccatalyst")]
[SupportedOSPlatform("ios")]
[SupportedOSPlatform("tvos")]
public class UIGraphicsRenderer : NSObject
{
[BindingImpl((BindingImplOptions)3)]
private static readonly NativeHandle class_ptr = ObjCRuntime.Class.GetHandle("UIGraphicsRenderer");
public override NativeHandle ClassHandle => class_ptr;
[BindingImpl((BindingImplOptions)3)]
public virtual bool AllowsImageOutput
{
[Export("allowsImageOutput")]
get
{
UIApplication.EnsureUIThread();
byte ret = ((!base.IsDirectBinding) ? Messaging.bool_objc_msgSendSuper(base.SuperHandle, Selector.GetHandle("allowsImageOutput")) : Messaging.bool_objc_msgSend(base.Handle, Selector.GetHandle("allowsImageOutput")));
return ret != 0;
}
}
So I can not use it to generate images in background.
For instance you can not implement custom SDImageTransformer due to the fact that transformations are being executed on background thread
https://github.com/SDWebImage/SDWebImage/wiki/Advanced-Usage#transformer-50
Steps to Reproduce
no specific steps
Did you find any workaround?
There is a workaround with UIGraphics.BeginImageContext but it is deprecated already in favour to UIGraphicsImageRenderer
https://developer.apple.com/documentation/uikit/uigraphicsbeginimagecontextwithoptions(_:_:_:)?language=objc
Relevant log output
No response