/// <summary>
/// Helper method that applies any pixel changes between the image version and the latest version
/// </summary>
/// <param name="canvas">Which canvas to apply changes to</param>
private void ApplyChangedPixelsToImage(CanvasImage canvasImage)
{
Canvas canvas = canvasImage.canvas;
// Get changed pixels
IEnumerable <PixelChange> pixelChanges = databaseContext.PixelChanges
.Where(p => p.CanvasVersion > canvas.ImageVersion && p.Canvas.Name == canvas.Name)
.OrderBy(p => p.CanvasVersion);
if (!pixelChanges.Any())
{
return;
}
// Update bitmap with changes
Bitmap bitmap = canvasImage.GetBitmap();
foreach (PixelChange pixelChange in pixelChanges)
{
bitmap.SetPixel(pixelChange.X, pixelChange.Y, ColorTranslator.FromHtml(pixelChange.Color));
//placeContext.PixelChanges.Remove(pixelChange);
}
canvasImage.SetBitmap(bitmap);
canvas.ImageVersion = pixelChanges.Last().CanvasVersion;
databaseContext.SaveChanges();
}
/// GET: CanvasImage?name=""&version=#
/// Returns a .png image representing the canvas.
///
public ActionResult Index(String name, String version)
{
// Check for cached image first
System.IO.MemoryStream cachedMemoryStream = (System.IO.MemoryStream)System.Web.HttpContext.Current.Cache.Get(name + "&" + version);
if (cachedMemoryStream != null)
{
return(File(cachedMemoryStream.ToArray(), "image/png"));
}
// Get canvas from database
CanvasImage canvasImage = databaseContext.CanvasImages.Find(name);
if (canvasImage == null)
{
return(HttpNotFound());
}
// Apply all changed pixels, save, and generate png
ApplyChangedPixelsToImage(canvasImage);
System.IO.MemoryStream ms = new System.IO.MemoryStream();
canvasImage.GetBitmap().Save(ms, System.Drawing.Imaging.ImageFormat.Png);
// Save to cache
System.Web.HttpContext.Current.Cache.Insert(name + "&" + version, (object)ms);
return(File(ms.ToArray(), "image/png"));
}