PageRange[] ComputeWrittenPageRanges(SparseIntArray writtenPages)
{
var pageRanges = new List <PageRange> ();
int start = -1;
int end = -1;
int writtenPageCount = writtenPages.Size();
for (int i = 0; i < writtenPageCount; i++)
{
if (start < 0)
{
start = writtenPages.ValueAt(i);
}
int oldEnd = end = start;
while (i < writtenPageCount && (end - oldEnd) <= 1)
{
oldEnd = end;
end = writtenPages.ValueAt(i);
i++;
}
var pageRange = new PageRange(start, end);
pageRanges.Add(pageRange);
start = end = -1;
}
return(pageRanges.ToArray());
}
protected override Java.Lang.Object DoInBackground(params Java.Lang.Object[] native_parms)
{
// Go over all the pages and write only the requested ones.
// Create an adapter with the stats and an inflater
// to load resources for the printer density.
var adapter = new MotoGpStatAdapter(items,
(LayoutInflater)self.mPrintContext.GetSystemService(
Context.LayoutInflaterService));
int currentPage = -1;
int pageContentHeight = 0;
int viewType = -1;
View view = null;
Android.Graphics.Pdf.PdfDocument.Page page = null;
var dummyParent = new LinearLayout(self.mPrintContext);
dummyParent.Orientation = Android.Widget.Orientation.Vertical;
// The content is laid out and rendered in screen pixels with
// the width and height of the paper size times the print
// density but the PDF canvas size is in points which are 1/72",
// so we will scale down the content.
float scale = System.Math.Min(
(float)mPdfDocument.PageContentRect.Width() / self.mRenderPageWidth,
(float)mPdfDocument.PageContentRect.Height() / self.mRenderPageHeight);
int itemCount = adapter.Count;
for (int i = 0; i < itemCount; i++)
{
// Be nice and respond to cancellation.
if (IsCancelled)
{
return(null);
}
// Get the next view.
int nextViewType = adapter.GetItemViewType(i);
if (viewType == nextViewType)
{
view = adapter.GetView(i, view, dummyParent);
}
else
{
view = adapter.GetView(i, null, dummyParent);
}
viewType = nextViewType;
// Measure the next view
self.MeasureView(view);
// Add the height but if the view crosses the page
// boundary we will put it to the next one.
pageContentHeight += view.MeasuredHeight;
if (currentPage < 0 || pageContentHeight > self.mRenderPageHeight)
{
pageContentHeight = view.MeasuredHeight;
currentPage++;
// Done with the current page - finish it.
if (page != null)
{
mPdfDocument.FinishPage(page);
}
// If the page is requested, render it.
if (self.ContainsPage(pages, currentPage))
{
page = mPdfDocument.StartPage(currentPage);
page.Canvas.Scale(scale, scale);
// Keep track which pages are written.
mWrittenPages.Append(mWrittenPages.Size(), currentPage);
}
else
{
page = null;
}
}
// If the current view is on a requested page, render it.
if (page != null)
{
// Layout an render the content.
view.Layout(0, 0, view.MeasuredWidth, view.MeasuredHeight);
view.Draw(page.Canvas);
// Move the canvas for the next view.
page.Canvas.Translate(0, view.Height);
}
}
// Done with the last page.
if (page != null)
{
mPdfDocument.FinishPage(page);
}
// Write the data and return success or failure.
try {
var fos = new Java.IO.FileOutputStream(destination.FileDescriptor);
mPdfDocument.WriteTo(new OutputStreamInvoker(fos));
// Compute which page ranges were written based on
// the bookkeeping we maintained.
var pageRanges = self.ComputeWrittenPageRanges(mWrittenPages);
callback.OnWriteFinished(pageRanges);
} catch (IOException) {
callback.OnWriteFailed((string)null);
} finally {
mPdfDocument.Close();
}
return(null);
}
