/// <summary>Read an update rectangle from the server.</summary>
/// <returns>A CCR task enumerator</returns>
private async Task ReadRectangle()
{
var packet = new byte[12];
using (var cancellation = new CancellationTokenSource())
{
cancellation.CancelAfter(DefaultTimeout);
await this.ReadPacketAsync(packet, cancellation.Token);
}
var left = (packet[0] << 8) | packet[1];
var top = (packet[2] << 8) | packet[3];
var width = (packet[4] << 8) | packet[5];
var height = (packet[6] << 8) | packet[7];
var encoding = ConvertBigEndianU32(packet, 8);
if (encoding != 0)
{
throw new InvalidDataException("Unexpected encoding");
}
byte[] pixels;
var size = width * height;
switch (this.pixelFormat.BitsPerPixel)
{
case 8:
pixels = new byte[size];
break;
case 16:
pixels = new byte[size * 2];
break;
case 32:
pixels = new byte[size * 4];
break;
default:
throw new InvalidDataException();
}
var rectangle = new Rectangle(left, top, width, height, pixels);
using (var cancellation = new CancellationTokenSource())
{
cancellation.CancelAfter(DefaultTimeout);
await this.ReadPacketAsync(pixels, cancellation.Token);
}
this.onRectangle(rectangle);
}
/// <summary>Draws an update rectangle into the current frame buffer.</summary>
/// <param name="rectangle">The rectangle to update.</param>
private void OnRectangle(Rectangle rectangle)
{
if (!this.hasRectangle)
{
this.hasRectangle = true;
this.FinishConnecting();
}
var dest = this.frameBufferBitmap.PixelBuffer;
var width = this.frameBufferBitmap.PixelWidth;
var height = this.frameBufferBitmap.PixelHeight;
var leftOffset = rectangle.Left * 4;
var scan = rectangle.Width * 4;
var src = WindowsRuntimeBufferExtensions.AsBuffer(rectangle.Pixels);
for (int y = 0; y < rectangle.Height; y++)
{
var destOffset = ((y + rectangle.Top) * width * 4) + leftOffset;
var srcOffset = y * scan;
src.CopyTo((uint)srcOffset, dest, (uint)destOffset, (uint)scan);
}
this.frameBufferBitmap.Invalidate();
}
/// <summary>Handles an update to a rectangle in the frame buffer</summary>
/// <remarks>This assumes that the rectangle is completely within the
/// frame buffer dimensions and that the pixel format is BGR32</remarks>
/// <param name="update">The update information</param>
private void HandleRectangle(Rectangle update)
{
var rect = new Int32Rect(
update.Left,
update.Top,
update.Width,
update.Height);
var array = update.Pixels;
this.DoInvoke(() => this.Framebuffer.WritePixels(
rect,
array,
rect.Width * 4,
0));
}
