Any suggestions on how to "onion skinning"?
mark at maseurope.net
Thu Nov 29 09:25:11 EST 2007
Well, one alternative that also seems to work is to map the 24bit
value of each pixel to an 8bit value :
function makeGS @inData
repeat with n = 1 to length(inData) - 3 step 4
get binarydecode("M", char n to n+3 of inData, tPix)
put numtochar(tPix div 65536) into tv
put null & tv & tv & tv after outData
It's maybe 25% quicker than dealing with each color component
On 29 Nov 2007, at 09:48, Wilhelm Sanke wrote:
> Mark Smith mark at maseurope.net wrote:
>> This is sort of interesting:
>> if you simply take one of the color bytes of each pixel, and copy
>> it to the other two color bytes, you get a gray-scale result.
>> The brightness/contrast varies with which color you choose. For
>> the few images I've tried, it seems to be red =brighter/less
>> contrast to blue= darker/more contrast. This may be no surprise
>> to the pro image wranglers among us, but seemed intriguing to me.
> And Chipp Walters chipp at chipp.com wrote:
>> Unless you average the 3, your gray-scale result may not work
>> properly. Try it on an image with 3 circles: 100%R, 100%G, 100%B and
>> you'll see what I mean.
> My experience is that with most photos you get a very nice
> grayscale image using the red pixel and copying the value to the
> other two pixels like Mark suggested.
> The last public version of my "Imagedata Toolkit Preview 3" (update
> of April 17)
> contains both grayscale routines using "average" and those with
> copying one color pixel to the other two - implemented for all
> three colors.
> Speed for "average gray" and a 640X480 image (on a 2 GHz machine)
> is about 1.1 seconds and for "gray from red" about 600 milliseconds.-
> The next update of the Imagedata Toolkit, which will be the last
> with a restriction to an enforced image size of 640X480, will
> probably be released before Xmas and contain a number of major
> enhancements (among them: scripted Rev emulation of cubic
> enlargement, integration and expanding of some new Gluas filters
> from Gimp - translated into Revolution - "stretch contrast",
> "compress contrast", enhancement of "jitter" filters with various
> multi-pixel jitters, another despeckle filter based on minimum
> differences between surrounding pixel pairs [this is another Gimp/
> Gluas development that is identical in effectiveness to the
> "median" approach, but somewhat slower], exchanging color values
> within a defined range by clicking on image and/or color scale,
> copying - and enlarging or shrinking - and pasting oval or
> rectangular portions of an image into the same or another image
> with variable fringe and/or overall blending into the basic image).
> Best regards,
> Wilhelm Sanke
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