80 lines
2.6 KiB
C#
80 lines
2.6 KiB
C#
using System;
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using System.IO;
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using System.Threading.Tasks;
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using System.Windows;
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using System.Windows.Media.Imaging;
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using Windows.Data.Pdf;
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using Windows.Storage;
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using Windows.Storage.Streams;
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namespace Ink_Canvas.Helpers
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{
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/// <summary>
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/// 使用 Windows.Data.Pdf（WinRT）将 PDF 页渲染为 WPF 可用的位图。
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/// </summary>
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internal static class PdfWinRtHelper
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{
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public static async Task<uint> GetPageCountAsync(string pdfPath)
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{
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if (string.IsNullOrWhiteSpace(pdfPath) || !File.Exists(pdfPath))
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return 0;
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var file = await StorageFile.GetFileFromPathAsync(pdfPath).AsTask();
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var doc = await PdfDocument.LoadFromFileAsync(file).AsTask();
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if (doc.IsPasswordProtected)
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return 0;
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return doc.PageCount;
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}
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public static async Task<BitmapSource> RenderPageToBitmapSourceAsync(string pdfPath, uint pageIndex)
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{
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if (string.IsNullOrWhiteSpace(pdfPath) || !File.Exists(pdfPath))
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return null;
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var file = await StorageFile.GetFileFromPathAsync(pdfPath).AsTask();
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var doc = await PdfDocument.LoadFromFileAsync(file).AsTask();
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if (doc.IsPasswordProtected)
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return null;
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if (pageIndex >= doc.PageCount)
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return null;
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var page = doc.GetPage(pageIndex);
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try
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{
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using (var ras = new InMemoryRandomAccessStream())
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{
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await page.RenderToStreamAsync(ras).AsTask();
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ras.Seek(0);
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var ms = new MemoryStream();
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using (var netStream = ras.AsStreamForRead())
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netStream.CopyTo(ms);
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ms.Position = 0;
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try
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{
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return await Application.Current.Dispatcher.InvokeAsync(() =>
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{
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var bi = new BitmapImage();
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bi.BeginInit();
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bi.StreamSource = ms;
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bi.CacheOption = BitmapCacheOption.OnLoad;
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bi.EndInit();
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bi.Freeze();
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return (BitmapSource)bi;
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});
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}
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finally
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{
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ms.Dispose();
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}
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}
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}
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finally
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{
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(page as IDisposable)?.Dispose();
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}
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}
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}
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}
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