public async Task <List <Annotation> > GetAnnotationsAsync(int pageNumber)
{
string annotationJSON = await chromePage.EvaluateFunctionAsync <string>("getAnnotations", new[] { (pageNumber + 1).ToString() });
PageViewport viewport = await GetPageViewport(pageNumber, 1);
List <Annotation> annotations = Newtonsoft.Json.JsonConvert.DeserializeObject <List <Annotation> >(annotationJSON);
foreach (Annotation a in annotations)
{
// reverse the Y-coordinate to convert from PDF coordinates
if (a.rect != null)
{
if (a.rect.Count == 4)
{
a.rect[1] = viewport.height - a.rect[1];
a.rect[3] = viewport.height - a.rect[3];
float newY = a.rect[3];
a.rect[3] = a.rect[1];
a.rect[1] = newY;
}
}
}
return(annotations);
}
/// <summary>
/// Renders a page to a System.Drawing.Bitmap object, and sets a maximum width and height for the resultant image.
/// Note that using the maximum width and height will not force the page to use those sizes. First, aspect-ratio is
/// always maintained, so this method is designed to ensure the rendered page will fit inside the box defined by
/// maxWidth and maxHeight. Secondly, this method will not scale the document up to fill the requested space.
/// </summary>
/// <param name="pageNumber">The zero-based page number.</param>
/// <param name="maxWidth">The maximum width in pixels that the rendered page is allowed to be.</param>
/// <param name="maxHeight">The maximum height in pixels that the rendered page is allowed to be.</param>
/// <returns>The Bitmap object containing the rendered page.</returns>
public async Task <Bitmap> RenderPageAsync(int pageNumber, int maxWidth, int maxHeight)
{
// This function is slightly annoying in that it's going to end up calling GetPageViewport twice,
// when one call would really suffice. Should really restructure to remove the unnecessary call.
double pageScale = 1.0;
PageViewport viewport = await GetPageViewport(pageNumber, 1.0f);
if (viewport.width > maxWidth || viewport.height > maxHeight)
{
// the viewport width or height is bigger than the maximum we want to allow, so we need to alter the page scale
pageScale = Math.Min(maxWidth / viewport.width, maxHeight / viewport.height);
}
return(await RenderPageAsync(pageNumber, pageScale));
}
/// <summary>
/// Renders a page to a System.Drawing.Bitmap object.
/// </summary>
/// <param name="pageNumber">The zero-based page number.</param>
/// <param name="pageScale">The page scale to use - a larger scale equates to a bigger final image. If you unsure of what scale to use, start at 1.0.</param>
/// <returns>The Bitmap object containing the rendered page.</returns>
public async Task <Bitmap> RenderPageAsync(int pageNumber, double pageScale)
{
PageViewport viewport = await GetPageViewport(pageNumber, (float)pageScale);
int newWidth = (int)Math.Round(viewport.width);
int newHeight = (int)Math.Round(viewport.height);
if (chromePage.Viewport.Width != newWidth || chromePage.Viewport.Height != newHeight)
{
await chromePage.SetViewportAsync(new ViewPortOptions()
{
Width = (int)Math.Round(viewport.width),
Height = (int)Math.Round(viewport.height)
});
}
bool rendered = await chromePage.EvaluateFunctionAsync <bool>("renderPage", new[] { (pageNumber + 1).ToString(), pageScale.ToString() });
//if (!renderEvent.WaitOne(5000))
//{
// Console.WriteLine("RenderPage renderEvent timed out.");
//}
return(await GetPage(pageScale));
}
public async Task <Size> GetPageSizeAsync(int pageNumber, float scale)
{
PageViewport viewport = await GetPageViewport(pageNumber, scale);
return(new Size((int)Math.Round(viewport.width), (int)Math.Round(viewport.height)));
}
