ImageFile.cs

using SkiaSharp;
using System.IO;
using System.Threading.Tasks;
using System.Xml;
using Waher.Layout.Layout2D.Model.Attributes;
using Waher.Runtime.IO;
 
namespace Waher.Layout.Layout2D.Model.Images
{
    public class ImageFile : Image
    {
        private StringAttribute fileName;
 
        public ImageFile(Layout2DDocument Document, ILayoutElement Parent)
            : base(Document, Parent)
        {
        }
 
        public override string LocalName => "ImageFile";
 
        public StringAttribute FileNameAttribute
        {
            get => this.fileName;
            set => this.fileName = value;
        }
 
        public override Task FromXml(XmlElement Input)
        {
            this.fileName = new StringAttribute(Input, "fileName", this.Document);
 
            return base.FromXml(Input);
        }
 
        public override void ExportAttributes(XmlWriter Output)
        {
            base.ExportAttributes(Output);
 
            this.fileName?.Export(Output);
        }
 
        public override ILayoutElement Create(Layout2DDocument Document, ILayoutElement Parent)
        {
            return new ImageFile(Document, Parent);
        }
 
        public override void CopyContents(ILayoutElement Destination)
        {
            base.CopyContents(Destination);
 
            if (Destination is ImageFile Dest)
                Dest.fileName = this.fileName?.CopyIfNotPreset(Destination.Document);
        }
 
        protected override async Task<SKImage> LoadImage(DrawingState State)
        {
            string FileName = await this.fileName.Evaluate(State.Session, string.Empty);
            if (!string.IsNullOrEmpty(FileName) && File.Exists(FileName))
            {
                byte[] Bin = await Files.ReadAllBytesAsync(FileName);
                SKBitmap Bitmap = SKBitmap.Decode(Bin);
                return SKImage.FromBitmap(Bitmap);
            }
            else
                return null;
        }
 
        public override void ExportStateAttributes(XmlWriter Output)
        {
            base.ExportStateAttributes(Output);
 
            this.fileName?.ExportState(Output);
        }
    }
}