private static Bitmap RenderImage(PdfRenderer.Page page)
{
var bitmap = Bitmap.CreateBitmap(page.Width, page.Height, Bitmap.Config.Argb8888);
// Fill with default while color first
var canvas = new Canvas(bitmap);
var paint = new Paint()
{
Color = Color.White
};
canvas.DrawRect(new Rect(0, 0, page.Width, page.Height), paint);
// Render content
page.Render(bitmap, null, null, PdfRenderMode.ForDisplay);
return(bitmap);
}
protected override Android.Graphics.Bitmap RunInBackground(params string[] @params)
{
if (IsCancelled)
{
RecycleBitmap(_pdfPageBitmap);
return(null);
}
string url = (string)@params[0];
int position = int.Parse(@params[1]);
double zoom = double.Parse(@params[2]);
_pdfPageBitmap = null;
if (File.Exists(url))
{
var file = new Java.IO.File(url);
var mFileDescriptor = ParcelFileDescriptor.Open(file, ParcelFileMode.ReadOnly);
// This is the PdfRenderer we use to render the PDF.
if (mFileDescriptor != null)
{
// create a new renderer
using (PdfRenderer renderer = new PdfRenderer(mFileDescriptor))
{
using (PdfRenderer.Page page = renderer.OpenPage(position))
{
try
{
_pdfPageBitmap = Android.Graphics.Bitmap.CreateBitmap((int)(page.Width.Px() * zoom), (int)(page.Height.Px() * zoom), Android.Graphics.Bitmap.Config.Argb4444);
page.Render(_pdfPageBitmap, null, null, PdfRenderMode.ForDisplay);
}
catch (Exception e)
{
_listener.RenderingErrorCaught(string.Format("PdfPageGenerationTask failed for index {0} :{1}", TaskIndex.ToString(), e.Message));
Console.WriteLine(e);
}
page.Close();
}
renderer.Close();
}
}
}
return(_pdfPageBitmap);
}
private void showPage(int index)
{
if (pdfRenderer.PageCount <= index)
{
return;
}
// Make sure to close the current page before opening another one.
if (null != currentPage)
{
currentPage.Close();
}
currentPage = pdfRenderer.OpenPage(index);
Bitmap bitmap = Bitmap.CreateBitmap(currentPage.Width, currentPage.Height,
Bitmap.Config.Argb8888);
currentPage.Render(bitmap, null, null, PdfRenderMode.ForDisplay);
_imageView.SetImageBitmap(bitmap);
updateUi();
}
// Indexer (read only) for accessing a pdf:
public Bitmap this[int i]
{
get
{
page = renderer.OpenPage(i);
// create bitmap of page
var ratio = (float)page.Height / page.Width;
var newHeight = ScreenWidth * ratio;
bitmap = Bitmap.CreateBitmap(ScreenWidth, (int)newHeight, Bitmap.Config.Argb8888);
// render for showing on the screen
page.Render(bitmap, null, null, PdfRenderMode.ForDisplay);
page.Close();
page.Dispose();
return(bitmap);
}
}
public void ConvertPagetoBitMap(int index)
{
if (this.Element.ImageStreams.ContainsKey(index))
{
return;
}
int scaleFactor = 1;
Stream stream = null;
PdfRenderer.Page page = PdfRenderer.OpenPage(index);
Bitmap bitmap = Bitmap.CreateBitmap((int)(page.Width * scaleFactor), (int)(page.Height * scaleFactor), Bitmap.Config.Argb8888);
bitmap.EraseColor(Android.Graphics.Color.White);
page.Render(bitmap, new Rect(0, 0, (int)(page.Width * scaleFactor), (int)(page.Height * scaleFactor)), null, PdfRenderMode.ForDisplay);
page.Close();
stream = new MemoryStream();
bitmap.Compress(Bitmap.CompressFormat.Png, 100, stream);
this.Element.ImageStreams.Add(index, bitmap);
this.Element.PDFViewModel.Items[index].PageData = bitmap;
}
private Bitmap ConvertSinglePageToImages(int PageIndex)
{
using (currentPage = renderer.OpenPage(PageIndex))
{
using (Bitmap bitmap = Bitmap.CreateBitmap(currentPage.Width, currentPage.Height, Bitmap.Config.Argb4444))
{
currentPage.Render(bitmap, null, null, PdfRenderMode.ForDisplay);
Double scale = 1f / 1f;
Bitmap resizedBitmap = Bitmap.CreateScaledBitmap(
bitmap,
(Int32)(bitmap.Width * scale),
(Int32)(bitmap.Height * scale),
false
);
currentPage.Close();
return(resizedBitmap);
}
}
}
void RenderPages(bool next = true)
{
Stream inputStream = Assets.Open(fileName);
using (var outputStream = this.OpenFileOutput("_sample.pdf", Android.Content.FileCreationMode.Private))
{
inputStream.CopyTo(outputStream);
}
var fileStreamPath = this.GetFileStreamPath("_sample.pdf");
MemoryStream m_memoryStream = new MemoryStream();
File.OpenRead(fileStreamPath.AbsolutePath).CopyTo(m_memoryStream);
var renderer = new PdfRenderer(ParcelFileDescriptor.Open(fileStreamPath, ParcelFileMode.ReadOnly));
ClearPages();
pages = new List <Bitmap>();
if (pageCount == 0)
{
pageCount = renderer.PageCount;
}
bool goingBackFromEnd = (pageCount == pageCurrent && pageGroupCount < pageMax && !next);
// set starting page number
int pageGroupStart;
if (next)
{
pageGroupStart = pageCurrent;
}
else if (goingBackFromEnd)
{
// if we're at the end and going back we need to adjust the page group start by the previous group count instead of the maximum
pageGroupStart = pageCurrent - pageGroupCount;
// we also need to update the current page here instead of in the loop so it stays on track
pageCurrent = pageGroupStart;
}
else
{
pageGroupStart = pageCurrent - pageMax;
}
// get next paging group count
int pagesLeft = pageCount - pageCurrent;
if (pagesLeft < pageMax && next)
{
// use pages left if that's below the maximum
pageGroupCount = pagesLeft;
}
else
{
pageGroupCount = pageMax;
}
// render pages
for (int i = 0; i < pageGroupCount; i++)
{
if (next)
{
page = renderer.OpenPage(pageGroupStart + i);
pageCurrent++;
}
else
{
page = renderer.OpenPage(pageGroupStart - (i + 1));
if (!goingBackFromEnd)
{
pageCurrent--;
}
}
// create bitmap of page
var ratio = (float)page.Height / page.Width;
var newHeight = screenWidth * ratio;
bitmap = Bitmap.CreateBitmap(screenWidth, (int)newHeight, Bitmap.Config.Argb8888);
// render for showing on the screen
page.Render(bitmap, null, null, PdfRenderMode.ForDisplay);
// add bitmaps to list for recycler
pages.Add(bitmap);
// close the page
page.Close();
if (pageCurrent >= pageCount)
{
break;
}
}
// close the renderer
renderer.Close();
// if going back to previous pages we need to reverse the page list to keep the correct order
if (!next)
{
pages.Reverse();
}
textPageCurrent.Text = "Viewing pages " + (pageCurrent - (pageGroupCount - 1)) + "-" + pageCurrent + " of " + pageCount;
// set up recycler using bitmap list
mAdapter.Pages = pages;
mAdapter.NotifyDataSetChanged();
}
public async Task <IMediaModel> GenerateThumbImageFromPDF(DirectoryInfo argCurrentDataFolder, MediaModel argExistingMediaModel, IMediaModel argNewMediaModel)
{
IMediaModel returnValue = new MediaModel();
try
{
await Task.Run(() =>
{
string outFilePath = System.IO.Path.Combine(argCurrentDataFolder.FullName, argNewMediaModel.OriginalFilePath);
// Initialize PDFRenderer by passing PDF file from location.
PdfRenderer renderer = new PdfRenderer(GetSeekableFileDescriptor(argCurrentDataFolder, argExistingMediaModel));
int pageCount = renderer.PageCount;
// Use `openPage` to open a specific page in PDF.
PdfRenderer.Page page = renderer.OpenPage(0);
//Creates bitmap
Bitmap bmp = Bitmap.CreateBitmap(page.Width, page.Height, Bitmap.Config.Argb8888);
//renderes page as bitmap, to use portion of the page use second and third parameter
page.Render(bmp, null, null, PdfRenderMode.ForDisplay);
//Save the bitmap
var stream = new FileStream(outFilePath, FileMode.Create);
bmp.Compress(Bitmap.CompressFormat.Png, 100, stream);
stream.Close();
page.Close();
returnValue = argNewMediaModel;
});
}
catch (DirectoryNotFoundException ex)
{
ErrorInfo t = new ErrorInfo("Directory not found when trying to create image from PDF file")
{
{ "Original ID", argExistingMediaModel.Id },
{ "Original File", argExistingMediaModel.MediaStorageFilePath },
{ "Clipped Id", argNewMediaModel.Id },
{ "New path", "pdfimage" }
};
App.Current.Services.GetService <IErrorNotifications>().NotifyException("PDF to Image", ex, t);
return(returnValue);
}
catch (Exception ex)
{
ErrorInfo t = new ErrorInfo("Exception when trying to create image from PDF file")
{
{ "Original ID", argExistingMediaModel.Id },
{ "Original File", argExistingMediaModel.MediaStorageFilePath },
{ "Clipped Id", argNewMediaModel.Id }
};
App.Current.Services.GetService <IErrorNotifications>().NotifyException("PDF to Image", ex, t);
return(returnValue);
}
return(returnValue);
}
void RenderPages()
{
Stream inputStream = Assets.Open(fileName);
using (var outputStream = this.OpenFileOutput("_sample.pdf", Android.Content.FileCreationMode.Private))
{
inputStream.CopyTo(outputStream);
}
var fileStreamPath = this.GetFileStreamPath("_sample.pdf");
MemoryStream m_memoryStream = new MemoryStream();
File.OpenRead(fileStreamPath.AbsolutePath).CopyTo(m_memoryStream);
var renderer = new PdfRenderer(ParcelFileDescriptor.Open(fileStreamPath, ParcelFileMode.ReadOnly));
var screenWidth = Resources.DisplayMetrics.WidthPixels;
// render all pages
pageCount = renderer.PageCount;
for (int i = 0; i < pageCount; i++)
{
page = renderer.OpenPage(i);
// create bitmap at appropriate size
var ratio = (float)page.Height / page.Width;
var newHeight = screenWidth * ratio;
bitmap = Bitmap.CreateBitmap(screenWidth, (int)newHeight, Bitmap.Config.Argb8888);
// render PDF page to bitmap
page.Render(bitmap, null, null, PdfRenderMode.ForDisplay);
// add bitmap to list
pages.Add(bitmap);
// close the page
page.Close();
// if free memory is less than the size of two page bitmaps and we still have pages left to load
// we'll stop loading and then display a message about downloading the full doc
// * this catch doesn't seem to work on Android O but it worked on a Nexus 5 running Android M, apparently Android O changes some memory handling
Debug.WriteLine("\nMemory usage " + i + "\n" + "Bitmap Byte Count: " + bitmap.ByteCount + "\nMemory Available: " + MemoryAvailable());
if (bitmap.ByteCount * 2 > MemoryAvailable() && i < pageCount - 1)
{
lowMemory = true;
break;
}
}
// close the renderer
renderer.Close();
// Create an adapter for the RecyclerView, and pass it the
// data set (the bitmap list) to manage:
mAdapter = new PdfBitmapAdapter(pages);
// Register the item click handler (below) with the adapter:
mAdapter.ItemClick += OnItemClick;
// Plug the adapter into the RecyclerView:
mRecyclerView.SetAdapter(mAdapter);
if (lowMemory)
{
try
{
AlertDialog.Builder alert = new AlertDialog.Builder(this);
alert.SetTitle("Out Of Memory");
alert.SetMessage("You are only viewing " + pages.Count + " out of " + pageCount + " pages.");
alert.SetPositiveButton("OK", (senderAlert, args) => { });
Dialog dialog = alert.Create();
dialog.Show();
}
catch (Exception e)
{
Debug.WriteLine("Exception: " + e.Message);
}
}
}
