Package: gimp Version: 2.8.16-1 Severity: minor Dear maintainer,
The automatic threshold computation is available in Colors > Threshold and then "auto" button. When applied on an image already binarized (with all pixels either black or white) it computes a threshold of 0, thus making all the pixels white. It seems that this feature use the Otsu's method to determine the threshold. This method determine two peaks in the histogram and separate them. I'm not sure I understand completely Otsu's thresholding algorithm, but I think the implementation only lacks a "+1" on the choosen threshold. It seems to me that the code returns the last value that should be black while the actual binarization code takes the threshold as the first value to be white. Thus a "+1" should be the only thing needed. Moreover the current code doesn't seem to be able to return a value 255. So it should be all good. Best regards, Celelibi -- System Information: Debian Release: stretch/sid APT prefers testing APT policy: (990, 'testing'), (500, 'unstable'), (500, 'stable'), (1, 'experimental') Architecture: i386 (x86_64) Kernel: Linux 3.10.11 (SMP w/2 CPU cores; PREEMPT) Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/bash Init: sysvinit (via /sbin/init) Versions of packages gimp depends on: ii gimp-data 2.8.16-1 ii libaa1 1.4p5-44 ii libatk1.0-0 2.18.0-1 ii libbabl-0.1-0 0.1.14-1 ii libbz2-1.0 1.0.6-8 ii libc6 2.21-6 ii libcairo2 1.14.4-1 ii libdbus-1-3 1.10.6-1 ii libdbus-glib-1-2 0.102-1 ii libexif12 0.6.21-2 ii libexpat1 2.1.0-7 ii libfontconfig1 2.11.0-6.3 ii libfreetype6 2.6.1-0.1 ii libgdk-pixbuf2.0-0 2.32.3-1 ii libgegl-0.3-0 0.3.4-1 ii libgimp2.0 2.8.16-1 ii libglib2.0-0 2.46.2-3 ii libgs9 9.16~dfsg-2 ii libgtk2.0-0 2.24.29-1 ii libgudev-1.0-0 230-2 ii libice6 2:1.0.9-1+b1 ii libjasper1 1.900.1-debian1-2.4 ii libjpeg62-turbo 1:1.4.1-2 ii libjson-glib-1.0-0 1.0.4-2 ii liblcms2-2 2.6-3+b3 ii libmng1 1.0.10+dfsg-3.1+b3 ii libpango-1.0-0 1.38.1-1 ii libpangocairo-1.0-0 1.38.1-1 ii libpangoft2-1.0-0 1.38.1-1 ii libpng12-0 1.2.54-1 ii libpoppler-glib8 0.38.0-2 ii librsvg2-2 2.40.11-2 ii libsm6 2:1.2.2-1+b1 ii libtiff5 4.0.6-1 ii libwmf0.2-7 0.2.8.4-10.4 ii libx11-6 2:1.6.3-1 ii libxcursor1 1:1.1.14-1+b1 ii libxext6 2:1.3.3-1 ii libxfixes3 1:5.0.1-2+b2 ii libxmu6 2:1.1.2-2 ii libxpm4 1:3.5.11-1+b1 ii libxt6 1:1.1.5-1 ii python-gtk2 2.24.0-4 ii python2.7 2.7.11-2 pn python:any <none> ii zlib1g 1:1.2.8.dfsg-2+b1 Versions of packages gimp recommends: ii ghostscript 9.16~dfsg-2 Versions of packages gimp suggests: pn gimp-data-extras <none> pn gimp-help-en | gimp-help <none> pn gvfs-backends <none> ii libasound2 1.0.29-1 -- no debconf information
