The canvas.export appears to have serious issues. I presume it is related to the "calling CIContext().drawImage" known issues, and certainly exporting a complex canvas takes forever, especially after they build up for a while, and lock the Mac up quite effectively, and produce incorrect results.
In my case, I am generating a set of 6 512x512 images, each constructed from a variety of relatively complex canvases, however the canvases are added in as:
outcanvas.append( canvas.flatten())
such that there should only be about a dozen layers in the output canvas. But performance results were still terrible and after the first couple of output images the results were also totally broken.
However, in my case I solved the issue by changing from:
Performance dramatically improved and correct images resulted. This might be helpful in debugging, or alternatively, might be helpful for others with problems exporting coreimage images.
canvas.export issues
Posted by Peter N Lewis on Mar 06, 2009The canvas.export appears to have serious issues. I presume it is related to the "calling CIContext().drawImage" known issues, and certainly exporting a complex canvas takes forever, especially after they build up for a while, and lock the Mac up quite effectively, and produce incorrect results.
such that there should only be about a dozen layers in the output canvas. But performance results were still terrible and after the first couple of output images the results were also totally broken.In my case, I am generating a set of 6 512x512 images, each constructed from a variety of relatively complex canvases, however the canvases are added in as:
However, in my case I solved the issue by changing from:toPerformance dramatically improved and correct images resulted. This might be helpful in debugging, or alternatively, might be helpful for others with problems exporting coreimage images.