Image Rendering Script (C#)

In this article:

• Rendering Script
• Samples
• Namespaces
• Context
• See Also

Rendering Script

There is only one script in each image rendering script, and it will be invoked one time every time when the image needs to be rendered. The script reads raw pixel data from Context.InputStream and writes BGRA pixels into Context.OutputStream. The type of returned value is ImageRenderingResult. Return ImageRenderingResult.Default after rendering the image. The following is sample script to render an image with single plane of 8-bit luminance to Bgra32 output color format:

var planeOptions = Context.PlaneOptions[0];
var sourceRow = new byte[planeOptions.RowStride];
var outputRow = new byte[Context.OutputRowBytes];
for (var y = 0; y < Context.OutputHeight; ++y) {
    Context.InputStream.ReadExactly(sourceRow, 0, sourceRow.Length);
    for (var x = 0; x < Context.OutputWidth; ++x) {
        var luminance = sourceRow[x * planeOptions.PixelStride];
        outputRow[x * 4] = luminance;
        outputRow[x * 4 + 1] = luminance;
        outputRow[x * 4 + 2] = luminance;
        outputRow[x * 4 + 3] = 255;
    }
    Context.OutputStream.Write(outputRow, 0, outputRow.Length);
}
return ImageRenderingResult.Default;

Samples

The following is sample script to render an image of NV21 (YUV 4:2:0, semi-planar, V before U) format into Bgra32 output color format:

• NV21 Renderer

You can import the downloaded file through the dialog of managing image rendering scripts.

Namespaces

The following namespaces are included by default:

• System.IO

Context

The following are members of Context other than basic members:

• CreateByteArray(count: int): byte[]
  Create an array of bytes for bulk reading from InputStream or writing to OutputStream. A C# script has no need for it: create the array with new directly, for example new byte[count]. It is provided for JavaScript and Python, which cannot construct an array of the CLR themselves.
• InputStream: System.IO.Stream
  Stream to read source image data. The offset to the image data has already been applied.
• OutputFormat: BitmapFormat
  Format of the output bitmap buffer. The following are values defined in BitmapFormat:

  • Bgra32
  • Bgra64
• OutputHeight: int
  Height of the output bitmap buffer in pixels.
• OutputRowBytes: int
  Number of bytes of each row of the output bitmap buffer.
• OutputStream: System.IO.Stream
  Stream to write rendered image into the output bitmap buffer. The stream is valid only during the rendering call.
• OutputWidth: int
  Width of the output bitmap buffer in pixels.
• PlaneOptions: IList<ImagePlaneOptions>
  Options of each plane of the image. The following are members of ImagePlaneOptions:

  • BlackLevel: System.Nullable<uint>
    Black level of the plane, or Null if black level is not defined.
  • EffectiveBits: int
    Effective bits of each pixel of the plane.
  • PixelStride: int
    Number of bytes of each pixel of the plane.
  • RowStride: int
    Number of bytes of each row of the plane.
  • WhiteLevel: System.Nullable<uint>
    White level of the plane, or Null if white level is not defined.
• RenderingOptions: ImageRenderingOptions
  Options of rendering the image. The following are members of ImageRenderingOptions:

  • BlueGain: double
  • ByteOrdering: ByteOrdering
    Byte ordering of source image data. The following are values defined in ByteOrdering:

    • BigEndian
    • LittleEndian
  • GreenGain: double
  • RedGain: double

See Also

• PixelViewer
• Scripting in Application (C#)
• Image Rendering Script