Scale.cs

using System.Threading.Tasks;
using System.Xml;
using SkiaSharp;
using Waher.Layout.Layout2D.Model.Attributes;
 
namespace Waher.Layout.Layout2D.Model.Transforms
{
    public class Scale : PivotTrasformation
    {
        private FloatAttribute scaleX;
        private FloatAttribute scaleY;
 
        public Scale(Layout2DDocument Document, ILayoutElement Parent)
            : base(Document, Parent)
        {
        }
 
        public override string LocalName => "Scale";
 
        public FloatAttribute ScaleXAttribute
        {
            get => this.scaleX;
            set => this.scaleX = value;
        }
 
        public FloatAttribute ScaleYAttribute
        {
            get => this.scaleY;
            set => this.scaleY = value;
        }
 
        public override Task FromXml(XmlElement Input)
        {
            this.scaleX = new FloatAttribute(Input, "scaleX", this.Document);
            this.scaleY = new FloatAttribute(Input, "scaleY", this.Document);
 
            return base.FromXml(Input);
        }
 
        public override void ExportAttributes(XmlWriter Output)
        {
            base.ExportAttributes(Output);
 
            this.scaleX?.Export(Output);
            this.scaleY?.Export(Output);
        }
 
        public override ILayoutElement Create(Layout2DDocument Document, ILayoutElement Parent)
        {
            return new Scale(Document, Parent);
        }
 
        public override void CopyContents(ILayoutElement Destination)
        {
            base.CopyContents(Destination);
 
            if (Destination is Scale Dest)
            {
                Dest.scaleX = this.scaleX?.CopyIfNotPreset(Destination.Document);
                Dest.scaleY = this.scaleY?.CopyIfNotPreset(Destination.Document);
            }
        }
 
        public override async Task AfterMeasureDimensions(DrawingState State)
        {
            await base.AfterMeasureDimensions(State);
 
            this.sx = await this.scaleX.Evaluate(State.Session, 1);
            this.sy = await this.scaleY.Evaluate(State.Session, 1);
 
            SKMatrix M = SKMatrix.CreateScale(this.sx, this.sy, this.xCoordinate, this.yCoordinate);
            this.TransformBoundingBox(M);
        }
 
        private float sx;
        private float sy;
 
        public override async Task Draw(DrawingState State)
        {
            SKMatrix M = State.Canvas.TotalMatrix;
            State.Canvas.Scale(this.sx, this.sy, this.xCoordinate, this.yCoordinate);
 
            await base.Draw(State);
 
            State.Canvas.SetMatrix(M);
        }
 
        public override void ExportStateAttributes(XmlWriter Output)
        {
            base.ExportStateAttributes(Output);
 
            this.scaleX?.ExportState(Output);
            this.scaleY?.ExportState(Output);
        }
    }
}