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• About image opacity

  23 octobre 2013, par Mikko Koppanen — Imagick

  There is a common misconception that Imagick::setImageOpacity() would work to reduce the opacity of the image. However, as the name says the method actually sets the opacity throughout the image and thus affects also transparent areas.

  To demonstrate let’s first look at this image of a red circle on a transparent background :

  

  Now, let’s apply setImageOpacity on the image :

  php

  < view plain text >

  1. < ?php
  2. $im = new Imagick (’red-circle.png’) ;
  3. $im->setImageOpacity (0.5) ;
  4. $im->writeImage (’red-circle-setopacity.png’) ;
  5.  ?>

  

  As we can see from the resulting image the transparent background is affected as well.

  In order to actually reduce the opacity of the opaque parts Imagick::evaluateImage can be used instead :

  php

  < view plain text >

  1. < ?php
  2. $im = new Imagick (’red-circle.png’) ;
  3.  
  4. /* Divide the alpha channel value by 2 */
  5. $im->evaluateImage(Imagick: :EVALUATE_DIVIDE, 2, Imagick: :CHANNEL_ALPHA) ;
  6. $im->writeImage (’red-circle-divide.png’) ;
  7.  ?>

  And here are the results :

  

  As the background is already fully transparent so the divide operation causes no changes to it.

  Similar example is available in the PHP manual http://php.net/imagick.evaluateimage and I added a note to setImageOpacity page as well (at the time of writing it has not synced to documentation mirrors yet).

• XDCam EX gets some friends

  21 octobre 2009

  Sony has announced a couple new additions to the XDCamEX family - the PMW-350 and the PMW-EX1R.

  The 350 is a shouldermount camera with interchangeable lenses and 2/3" chips. That puts it somewhere between the 1/2" PDW-F355 and the 2/3" 4:2:2 PDW-700.

  

  The EX1R is a minor bump to the EX1, adding features that users have asked for, like a dedicated viewfinder and a DVCam recording mode.

  For me, the most interesting bit of news is that Sony is launching the "MEAD-MS01," an SXS to MemoryStick adapter. I guess Sony noticed that many EX1 and EX3 users have been using SD adapters, and decided to get into that market. And of course, they had to use everyone’s least favorite flash format, Memorystick. I’ll stick to my SD cards for now, but it’s nice to see Sony "legitimize" that recording option a bit.

• d3d11va : Check WINAPI_FAMILY instead of HAVE_LOADLIBRARY

  4 juillet 2017, par Martin Storsjö

  d3d11va : Check WINAPI_FAMILY instead of HAVE_LOADLIBRARY
  If using the winstore compat library, a fallback LoadLibrary
  
  function does exist, that only calls LoadPackagedLibrary though
  
  (which doesn’t work for dynamically loading d3d11 DLLs).
  Therefore explicitly check the targeted API family instead.
  Make this check a reusable HAVE_* component which other parts
  
  of the libraries can check when necessary as well.
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DBH] configure
  • [DBH] libavutil/hwcontext_d3d11va.c