Hi again! On Wed, Oct 4, 2017 at 1:01 PM, Elle Stone <ellestone@xxxxxxxxxxxxxxxxxxxx> wrote: > On 10/03/2017 09:33 PM, Jehan Pagès wrote: >> >> I don't know how this info is computed in GIMP code (i.e. does it >> check for actual memory size or does it do some basic maths as I am >> about to do), but assuming your image is 8 bits per channel, and all 7 >> layers are the size of the image and have no alpha, that makes: >> 4000*6000*7*24 = 4 032 000 000 / 1024^3 ~ 3.8GB!:-) > > > Hi, > > Actually the image is at 32-bit floating point precision, all the layers > have alpha channels, most of the layers have masks, and there are a couple > extra channels (saved masks) in the channels dialog. > > Ignoring the masks and the extra saved channels, and assuming I'm doing the > right math, this would be: > > 4000*6000*7*32*4 = 21 504 000 000 / 1024^3 ~ 20 GB Sorry I was stupid earlier. By multiplying by 24 (or here 32), we get the size in bits, we want in bytes (instead, we must multiply by 3 bytes for 32 bits). So a single mono-channel image should be 4000*6000*3 bytes. So assuming each layer has alpha and mask, that makes 5 channels per layer and each channel uses 3 bytes: 4000*6000*3*7*5 ~ 2.34 GB. Hopefully I didn't make too many errors this time. :P You also said that there were a few extra channels. Selection is a channel as well, so if you have one, it must be taken into account. This said, I am wondering if the channels are all 3-bytes precision in a 32-bit image? Jehan > As an experiment, I followed Simon's suggestion and made a new document, > same size, 7 layers, and filled each layer with random LCH noise. This > brought the %m value up to 4.8 GB. > > Removing all operations from the Undo history brought the %m value down to > 2.9 GB. Saved to disk, the size is 1.6 GB. I guess random noise also > compresses? > > Best, > Elle -- ZeMarmot open animation film http://film.zemarmot.net Patreon: https://patreon.com/zemarmot Tipeee: https://www.tipeee.com/zemarmot _______________________________________________ gimp-developer-list mailing list List address: gimp-developer-list@xxxxxxxxx List membership: https://mail.gnome.org/mailman/listinfo/gimp-developer-list List archives: https://mail.gnome.org/archives/gimp-developer-list
