title: Supported formats for libvips CLI output to Windows stdout
body: <p>I use <code>libvips</code> to convert <code>HEIC</code> images to a more tractable format and pipe the result to another process without writing to disk. I can do that using <code>PNG</code> as an intermediate format:</p>
  <pre><code>vips copy input.heic .png
  </code></pre>
  <p>However the next process in my chain only accepts either <code>BMP</code> images or raw RGB data. If I replace <code>.png</code> with <code>.bmp</code> in the above command I get this error:</p>
  <pre><code>input.heic: bad seek to 1811903
  VipsForeignSave: &quot;.bmp&quot; is not a known target format
  </code></pre>
  <p>This happens with many other formats including the native <code>.vips</code>. The conversion works fine with all formats if I write to disk instead of to <code>stdout</code>.</p>
  <p>It will help being able to convert either to <code>BMP</code> or to a list of integers with the RGB information.</p>