Well if there are 4x 8 bit values (RGB+alpha) =32 bits trying to be encoded/decoded into a single precision float, there will be loss of fidelity.
It amazes me that it works for encoding 24 bit values (I tested it for RGB only and can send a demo patch, or check the one Katja posted here: http://lists.puredata.info/pipermail/pd-list/2015-12/112694.html ) Check out Katja's page and video about "Pd Double" for the best explanation of this problem. I personally wish there was a 32 bit integer data type in Pd for counters and binary registers and such, which I know will never get converted into floats, and risk strange rounding errors or noise in the Least Significant Bits. On Thursday, December 31, 2015, João Pais <[email protected]> wrote: > Ok. Do you know what should be done to convert to Pd's rgb format? > >> I'm pretty sure the 4th value is alpha >> >> Sent from my iPhone >> >>> On Dec 31, 2015, at 7:53 AM, João Pais <[email protected]> wrote: >>> >>> Hello list, >>> >>> I'm trying to use [pix_data] to get the RGB values from an image, and color a canvas using them. But the results come out a bit weird, as not all colors match. >>> >>> I can try to some a more detailed patch in a couple of days, but wanted to ask first the there is any example of how to use the values coming out of [pix_data]: >>> - should the gray value be used? >>> - the middle outlet should send a list of RGB values, but I noticed that instead a list of 4 values comes out. This isn't documented, what is the 4th value? >>> >>> Attached are 2 pictures that should exemplifiy the issue: >>> - rgb.tif - a rgb palette >>> - rgb-conv.tif - the result after my interpretation of the data >>> >>> Best, >>> >>> Joao >>> <rgb.tif> >>> <rgb-conv.tif> >>> _______________________________________________ >>> [email protected] mailing list >>> UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list > > _______________________________________________ > [email protected] mailing list > UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list > -- -- May you, and all beings be happy and free from suffering :) -- ancient Buddhist Prayer (Metta)
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