QuestPDF/QuestPDF.Previewer/PreviewerCanvas.cs

using QuestPDF.Drawing;
using QuestPDF.Infrastructure;
using SkiaSharp;

namespace QuestPDF.Previewer
{
    public record RenderedPageInfo(SKPicture Picture, Size Size);
    
    internal sealed class PreviewerCanvas : SkiaCanvasBase, IRenderingCanvas
    {
        private SKPictureRecorder? _currentRecorder;
        
        public ICollection<RenderedPageInfo> Pictures { get; } = new List<RenderedPageInfo>();

        private Size? _currentSize;

        public override void BeginDocument()
        {
            Pictures.Clear();
        }

        public override void BeginPage(Size size)
        {
            _currentSize = size;
            _currentRecorder = new SKPictureRecorder();
            Canvas = _currentRecorder.BeginRecording(new SKRect(0, 0, size.Width, size.Height));

            using var paint = new SKPaint() { Color = SKColors.White };
            Canvas.DrawRect(0, 0, size.Width, size.Height, paint);
        }

        public override void EndPage()
        {
            var picture = _currentRecorder?.EndRecording();
            
            if (picture != null && _currentSize.HasValue)
                Pictures.Add(new RenderedPageInfo(picture, _currentSize.Value));

            _currentRecorder?.Dispose();
            _currentRecorder = null;
        }

        public override void EndDocument() { }
    }
}