/// <summary>
/// Only call within the dispatcher since dll calls are made.
/// </summary>
/// <param name="pdfBitmap"></param>
/// <param name="image"></param>
/// <param name="dispatcher"></param>
/// <param name="scale"></param>
/// <param name="viewport"></param>
internal PdfBitmap(
FpdfBitmapT pdfBitmap,
Image<Bgra32> image,
ThreadDispatcher dispatcher,
float scale,
RectangleF viewport)
{
_pdfBitmap = pdfBitmap;
_dispatcher = dispatcher;
Scale = scale;
Viewport = viewport;
Image = image;
}
protected override unsafe PdfBitmap OnExecute(CancellationToken cancellationToken)
{
try
{
cancellationToken.ThrowIfCancellationRequested();
_bitmap = fpdfview.FPDFBitmapCreateEx(
(int)_viewport.Size.Width,
(int)_viewport.Size.Height,
(int)FPDFBitmapFormat.BGRA,
IntPtr.Zero,
0);
if (_bitmap == null)
{
throw new Exception("failed to create a bitmap object");
}
cancellationToken.ThrowIfCancellationRequested();
if (_backgroundColor.HasValue)
{
fpdfview.FPDFBitmapFillRect(
_bitmap,
0,
0,
(int)_viewport.Size.Width,
(int)_viewport.Size.Height,
_backgroundColor.Value.ToPixel <Argb32>().Argb);
cancellationToken.ThrowIfCancellationRequested();
}
using var clipping = new FS_RECTF_
{
Left = 0,
Right = _viewport.Size.Width,
Bottom = 0,
Top = _viewport.Size.Height
};
// | | a b 0 |
// | matrix = | c d 0 |
// | | e f 1 |
using var matrix = new FS_MATRIX_
{
A = _scale,
B = 0,
C = 0,
D = _scale,
E = -_viewport.X,
F = -_viewport.Y
};
fpdfview.FPDF_RenderPageBitmapWithMatrix(_bitmap, _pageInstance, matrix, clipping, (int)_flags);
cancellationToken.ThrowIfCancellationRequested();
var scan0 = fpdfview.FPDFBitmapGetBuffer(_bitmap);
var image = Image.WrapMemory <Bgra32>(
scan0.ToPointer(),
(int)_viewport.Size.Width,
(int)_viewport.Size.Height);
return(new PdfBitmap(_bitmap, image, _dispatcher, _scale, _viewport));
}
catch (OperationCanceledException)
{
if (_bitmap != null)
{
fpdfview.FPDFBitmapDestroy(_bitmap);
}
throw;
}
catch (Exception ex)
{
if (_bitmap != null)
{
fpdfview.FPDFBitmapDestroy(_bitmap);
}
throw new Exception("Error rendering page. Check inner exception.", ex);
}
}
