SpatialDistribution.cs

using System.Threading.Tasks;
using SkiaSharp;
 
namespace Waher.Layout.Layout2D.Model.Groups
{
    public abstract class SpatialDistribution : LayoutContainer
    {
        protected Padding[] measured;
 
        public SpatialDistribution(Layout2DDocument Document, ILayoutElement Parent)
            : base(Document, Parent)
        {
        }
 
        public abstract Task<ICellLayout> GetCellLayout(DrawingState State);
 
        public override async Task DoMeasureDimensions(DrawingState State)
        {
            await base.DoMeasureDimensions(State);
 
            this.cellLayout = await this.GetCellLayout(State);
 
            if (this.HasChildren)
            {
                foreach (ILayoutElement Child in this.Children)
                {
                    if (!Child.IsVisible)
                        continue;
 
                    if (Child is IDynamicChildren DynamicChildren)
                    {
                        foreach (ILayoutElement Child2 in DynamicChildren.DynamicChildren)
                            await this.cellLayout.Add(Child2);
                    }
                    else
                        await this.cellLayout.Add(Child);
                }
 
                this.cellLayout.Flush();
            }
        }
 
        public override async Task AfterMeasureDimensions(DrawingState State)
        {
            await base.AfterMeasureDimensions(State);
 
            this.cellLayout?.Distribute(false);
 
            this.Left = 0;
            this.Top = 0;
            this.Right = null;
            this.Bottom = null;
            this.Width = this.cellLayout.TotWidth;
            this.Height = this.cellLayout.TotHeight;
        }
 
        private ICellLayout cellLayout = null;
 
        public override void MeasurePositions(DrawingState State)
        {
            base.MeasurePositions(State);
            
            this.cellLayout?.MeasurePositions(State);
            this.cellLayout?.Distribute(true);
            this.measured = this.cellLayout?.Align();
        }
 
        protected override bool MeasureChildrenPositions => false;  // Cell Layout calls MeasurePositions on children.
 
        public override async Task Draw(DrawingState State)
        {
            SKCanvas Canvas = State.Canvas;
            SKMatrix M = Canvas.TotalMatrix;
 
            foreach (Padding P in this.measured)
            {
                Canvas.Translate(P.OffsetX, P.OffsetY);
                await P.Element.Draw(State);
                Canvas.SetMatrix(M);
            }
        }
 
    }
}