stitch_something/StitchATon/Controller.cs

using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.ObjectPool;
using OpenCvSharp;
using StitchATon.DTO;
using StitchATon.Services;
using StitchATon.Utility;

namespace StitchATon;

[ApiController]
[Route("api/image/")]
public class ImageController( ImageProvider ip, ObjectPool<PngNamedPipe> npPool, ILogger<Controller> logger ) : ControllerBase
{
  [HttpPost]
  [Route("generate")]
  public async Task<IActionResult> GetImage([FromBody] GenerateInput generateInput)
  {
    logger.LogInformation( $"GetImage requested at {generateInput.CanvasRect}" );
    
    var namedPipe = npPool.Get();
    var imagePath = namedPipe.PipeFullname;

    using var roiIm = await ip.GetImage(
      generateInput.ParsedCanvasRect(),
      generateInput.ParsedCropOffset(),
      generateInput.ParsedCropSize()
      );
    
    var scaledSize = new Size(
      roiIm.Cols * generateInput.OutputScale,
      roiIm.Rows * generateInput.OutputScale
    );
    Mat resizedIm = new();
    
    if( scaledSize == roiIm.Size() )
      resizedIm = roiIm;
    else
      Cv2.Resize( roiIm, resizedIm, scaledSize  );

    // Spawn new task to write to the named pipe
    Task.Run( () =>
    {
      Cv2.ImWrite( imagePath, resizedIm );
      resizedIm.Dispose();
    } );

    // Stream the named pipe as output
    var fileStream = new FileStream(
      imagePath, 
      FileMode.Open, 
      FileAccess.Read, 
      FileShare.Read, 
      4096, 
      FileOptions.Asynchronous | FileOptions.SequentialScan);
    
    return File(fileStream, "image/png");
  }
  
  [HttpGet]
  [Route("sanity")]
  public async Task<IActionResult> GetImageSanityTest()
  {
    var namedPipe = npPool.Get();
    var imagePath = namedPipe.PipeFullname;

    using var roiIm = await ip.GetImage(
      new Rect( new Point( 5, 6 ), new Size( 3, 3 ) ),
      new Point2f( .1f, .1f ),
      new Point2f( .8f, .8f ) );

    var mul = .7;
    var scaledSize = new Size(roiIm.Cols * mul , roiIm.Rows * mul);
    Mat resizedIm = new();
    
    if( scaledSize == roiIm.Size() )
      resizedIm = roiIm;
    else
      Cv2.Resize( roiIm, resizedIm, scaledSize  );

    // Spawn new task to write to the named pipe
    Task.Run( () =>
    {
      Cv2.ImWrite( imagePath, resizedIm );
      resizedIm.Dispose();
    } );

    // Stream the named pipe as output
    var fileStream = new FileStream(
      imagePath, 
      FileMode.Open, 
      FileAccess.Read, 
      FileShare.Read, 
      4096, 
      FileOptions.Asynchronous | FileOptions.SequentialScan);
    
    return File(fileStream, "image/png");
  }
}