Drawing on new image - mutate method is not available on Image<T> class

[pcgeek86]

I'm loading ImageSharp into PowerShell so I can write some drawing automation. I want to create images completely from scratch, with a gradient background, and some text overlaid.

According to the documentation, you can create a fresh image with this (translated from C#):

$Image = [SixLabors.ImageSharp.Image[SixLabors.ImageSharp.PixelFormats.Rgba32]]::new(1024, 1024)

Then, in the documentation for Drawing, it says:

Image image = ...; // create any way you like.
Star star = new(x: 100.0f, y: 100.0f, prongs: 5, innerRadii: 20.0f, outerRadii:30.0f);
image.Mutate( x=> x.Fill(Color.Red, star)); // fill the star with red

But there is no mutate() method on the Image<T> class.
How am I supposed to draw on an Image<T>?

PS /> $Image | Get-Member

   TypeName: SixLabors.ImageSharp.Image`1[[SixLabors.ImageSharp.PixelFormats.Rgba32, SixLabors.ImageSharp, Version=3.0.0.0, Culture=neutral, PublicKeyToken=d998eea7b14cab13]]

Name                             MemberType            Definition
----                             ----------            ----------
Clone                            Method                SixLabors.ImageSharp.Image[SixLabors.ImageSharp.PixelFormats.Rgba32] Clone(), SixLabors.ImageSharp.Image[SixLabors.ImageSharp.PixelFormats.Rgba32] Clone(SixLabors.ImageSharp.Configuration configuration)
CloneAs                          Method                SixLabors.ImageSharp.Image[TPixel2] CloneAs[TPixel2](SixLabors.ImageSharp.Configuration configuration), SixLabors.ImageSharp.Image[TPixel2] CloneAs[TPixel2]()
CopyPixelDataTo                  Method                void CopyPixelDataTo(System.Span[SixLabors.ImageSharp.PixelFormats.Rgba32] destination), void CopyPixelDataTo(System.Span[byte] destination)
DangerousTryGetSinglePixelMemory Method                bool DangerousTryGetSinglePixelMemory([ref] System.Memory[SixLabors.ImageSharp.PixelFormats.Rgba32] memory)
Dispose                          Method                void Dispose(), void IDisposable.Dispose()
Equals                           Method                bool Equals(System.Object obj)
GetHashCode                      Method                int GetHashCode()
GetType                          Method                type GetType()
ProcessPixelRows                 Method                void ProcessPixelRows(SixLabors.ImageSharp.PixelAccessorAction[SixLabors.ImageSharp.PixelFormats.Rgba32] processPixels), void ProcessPixelRows[TPixel2](SixLabors.ImageSharp.Image[TPixel2] image2, SixLabors.ImageSharp.PixelAccessorAction[SixLabors.ImageSharp.PixelFormats.Rgba32,TPixel2]…
Save                             Method                void Save(System.IO.Stream stream, SixLabors.ImageSharp.Formats.IImageEncoder encoder)
SaveAsync                        Method                System.Threading.Tasks.Task SaveAsync(System.IO.Stream stream, SixLabors.ImageSharp.Formats.IImageEncoder encoder, System.Threading.CancellationToken cancellationToken = default)
ToString                         Method                string ToString()
Item                             ParameterizedProperty SixLabors.ImageSharp.PixelFormats.Rgba32 Item(int x, int y) {get;set;}
Bounds                           Property              SixLabors.ImageSharp.Rectangle Bounds {get;}
Configuration                    Property              SixLabors.ImageSharp.Configuration Configuration {get;}
Frames                           Property              SixLabors.ImageSharp.ImageFrameCollection[SixLabors.ImageSharp.PixelFormats.Rgba32] Frames {get;}
Height                           Property              int Height {get;}
Metadata                         Property              SixLabors.ImageSharp.Metadata.ImageMetadata Metadata {get;}
PixelType                        Property              SixLabors.ImageSharp.Formats.PixelTypeInfo PixelType {get;}
Size                             Property              SixLabors.ImageSharp.Size Size {get;}
Width                            Property              int Width {get;}

If you try to call mutate(), you get this error:

PS /> $Image.mutate()
InvalidOperation: Method invocation failed because [SixLabors.ImageSharp.Image`1[[SixLabors.ImageSharp.PixelFormats.Rgba32, SixLabors.ImageSharp, Version=3.0.0.0, Culture=neutral, PublicKeyToken=d998eea7b14cab13]]] does not contain a method named 'mutate'.

[tocsoft]

The ImageSharp APIs are primarily built as as extension methods on top of Image

The Mutate and Clone APIs are actaully in SixLabors.ImageSharp.Processing.ProcessingExtensions then a lot of the high level operations (Resize, Rotate etc) that are applied to the IImageProcessingContext are also extension methods in the same namespace.

I'm afraid to say our API is optimised for C# and extensibility (hence all the extension methods) so using them directly in powershell is likely to be a bit of a mess so good luck and I hope you manage to wire something together that doesn't end up too ugly.

[pcgeek86]

Thanks for the info. That should most likely unblock me. Looks like extension methods in PowerShell should be pretty easy to call. It's not something I do often, but I am familiar with the concept.

https://stackoverflow.com/questions/25915450/how-to-use-extension-methods-in-powershell