PDFOffice_Windows_exe/PDF Office/ViewModels/EditTools/Background/BackgroundDocumentContentViewModel.cs

using ComPDFKit.PDFDocument;
using ComPDFKit.PDFPage;
using ComPDFKitViewer;
using ComPDFKitViewer.PdfViewer;
using PDF_Office.EventAggregators;
using PDF_Office.Helper;
using PDF_Office.Model;
using PDF_Office.Model.EditTools.Background;
using Prism.Commands;
using Prism.Events;
using Prism.Mvvm;
using Prism.Regions;
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Media;
using System.Windows.Media.Imaging;

namespace PDF_Office.ViewModels.EditTools.Background
{
    public class BackgroundDocumentContentViewModel : BindableBase, INavigationAware
    {
        public IEventAggregator eventAggregator;
        public IRegionManager regionManager;
        public CPDFViewer PDFViewer;
        public CPDFDocument Document;
        public CPDFBackground background;
        private BackgroundInfo BackgroundInfo;

        public string ViewerRegionName { get; set; }


        private ImageSource _imageSource = null;
        public ImageSource ImageSource
        {
            get { return _imageSource; }
            set
            {
                SetProperty(ref _imageSource, value);
            }
        }


        public BackgroundDocumentContentViewModel(IEventAggregator eventAggregator, IRegionManager regionManager)
        {
            this.eventAggregator = eventAggregator;
            this.regionManager = regionManager;
            eventAggregator.GetEvent<SetBackgroundEvent>().Subscribe(SetBackground);
            ViewerRegionName = RegionNames.BackgroundViewRegionName;
        }

        public async void AwaitRenderBitmap(CPDFDocument doc)
        {
            await RenderBitmap(doc);
        }

        private void UndoManager_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
        {
        }

        private WriteableBitmap GetBackground(CPDFDocument oldDoc, double zoom, int pageIndex)
        {
            System.Windows.Size pageSize = oldDoc.GetPageSize(pageIndex);

            CPDFDocument newDoc = CPDFDocument.CreateDocument();
            newDoc.InsertPage(0, pageSize.Width, pageSize.Height, null);

           CreateBackground(newDoc);
            CPDFPage newPage = newDoc.PageAtIndex(0);
            double scale = 96.0 / 72.0;
            zoom = zoom * scale;
            Rect renderRect = new Rect(0, 0, (int)(pageSize.Width * scale), (int)(pageSize.Height * scale));
            byte[] imageArray = new byte[(int)(renderRect.Width * renderRect.Height * 4)];

            newPage.RenderPageBitmapWithMatrix((float)zoom, renderRect, 0x00FFFFFF, imageArray, 1, true);
            WriteableBitmap WirteBitmap = new WriteableBitmap((int)renderRect.Width, (int)renderRect.Height, 96, 96, PixelFormats.Bgra32, null);
            WirteBitmap.WritePixels(new Int32Rect(0, 0, (int)renderRect.Width, (int)renderRect.Height), imageArray, WirteBitmap.BackBufferStride, 0);
            return WirteBitmap;
        }

        private void CurrentViewer_CustomDrawHandler(object sender, CustomDrawData e)
        {
            if (e.DrawPages.Count > 0 && e.DrawContext != null)
            {
                foreach (DrawPageData drawPageData in e.DrawPages)
                {
                    WriteableBitmap backgroundBitmap = GetBackground(PDFViewer.Document, e.Zoom, drawPageData.PageIndex);
                    e.DrawContext.DrawImage(backgroundBitmap, drawPageData.PageBound);
                }
            }
        }

        public void SetBackground(BackgroundInfo backgroundInfo)
        {
            this.BackgroundInfo = backgroundInfo;
            PDFViewer.InvalidChildVisual(false);
        }

        public void CreateBackground(CPDFDocument document)
        {
            if(BackgroundInfo != null)
            {
            background = Document.GetBackground();

            if (BackgroundInfo.BackgroundType == C_Background_Type.BG_TYPE_COLOR)
            {
                background.SetBackgroundType(C_Background_Type.BG_TYPE_COLOR);
                background.SetColor(BackgroundInfo.Color);
                background.SetScale(100);
            }
            else
            {
                background.SetBackgroundType(C_Background_Type.BG_TYPE_IMAGE);
                background.SetImage(BackgroundInfo.ImageArray, BackgroundInfo.ImageWidth, BackgroundInfo.ImageHeight, ComPDFKit.Import.C_Scale_Type.fitCenter);
                background.SetScale(0.1f);
            }
            background.SetHorizalign(BackgroundInfo.Horizalign);
            background.SetVertalign(BackgroundInfo.Vertalign);
            background.SetOpacity(BackgroundInfo.Opacity);
            background.SetPages(BackgroundInfo.PageRange);
            background.SetRotation(BackgroundInfo.Rotation);
            background.SetXOffset(BackgroundInfo.HorizOffset);
            background.SetYOffset(BackgroundInfo.VertOffset);
            background.SetAllowsView(true);
            background.Update();
            // background.Release();
            }
        }

        public static BitmapSource ToBitmapSource(System.Drawing.Bitmap image)
        {
            IntPtr ptr = image.GetHbitmap();//obtain the Hbitmap
            BitmapSource bs = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap
            (
                ptr,
                IntPtr.Zero,
                Int32Rect.Empty,
                System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions()
            );
            return bs;
        }


        public async Task RenderBitmap(CPDFDocument doc)
        {

            CPDFPage page = doc.PageAtIndex(0, true);

            byte[] bmp_data = new byte[(int)page.PageSize.Width * (int)page.PageSize.Height * 4];
            Bitmap bitmap = await ToolMethod.RenderPageBitmap(Document, (int)(page.PageSize.Width * 1.4), (int)(page.PageSize.Height * 1.4), 0, true, true);
            //await Task.Run(delegate
            //{
            //    page.RenderPageBitmap(0, 0, (int)page.PageSize.Width, (int)page.PageSize.Height, 0xffffffff, bmp_data, 1);
            //});
            //PixelFormat fmt = PixelFormats.Bgra32;
            //BitmapSource bps = BitmapSource.Create((int)page.PageSize.Width, (int)page.PageSize.Height, 96.0, 96.0, fmt, null, bmp_data, ((int)page.PageSize.Width * fmt.BitsPerPixel + 7) / 8);
            ImageSource = ToBitmapSource(bitmap);
            doc.ReleasePages();
        }

        public bool IsNavigationTarget(NavigationContext navigationContext)
        {
            return true;
        }

        public void OnNavigatedFrom(NavigationContext navigationContext)
        {
        }

        public void OnNavigatedTo(NavigationContext navigationContext)
        {
            CPDFViewer pdfViewer;

            navigationContext.Parameters.TryGetValue<CPDFViewer>(ParameterNames.PDFViewer, out pdfViewer);
            if (pdfViewer != null)
            {
                if (!regionManager.Regions[ViewerRegionName].Views.Contains(PDFViewer))
                {
                    PDFViewer = new CPDFViewer();
                    PDFViewer.InitDocument(pdfViewer.Document.FilePath);
                    Document = PDFViewer.Document;
                    PDFViewer.CustomDrawHandler += CurrentViewer_CustomDrawHandler;
                    PDFViewer.UndoManager.PropertyChanged += UndoManager_PropertyChanged;
                    regionManager.AddToRegion(ViewerRegionName, PDFViewer);
                    PDFViewer.SetAnnotInteraction(!PDFViewer.GetAnnotInteraction());
                    PDFViewer.Load();
                    PDFViewer.ChangeViewMode(ViewMode.Single);
                    PDFViewer.SetMouseMode(MouseModes.Default);
                }
            }
        }
    }
}