From: nicolas Date: Sat, 13 Nov 2010 15:31:28 +0000 (+0000) Subject: (no commit message) X-Git-Tag: 7.0.1-0~8516 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=2d3579a0edd50f3aab45ba78e49f442fbdc19185;p=imagemagick --- diff --git a/ChangeLog b/ChangeLog index df285c448..ccb4d2bc4 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,8 @@ +2010-11-13 6.6.5-9 Nicolas robidoux + * LanczosSharp blur tweaked to minimize worst case scenario deviation + from "perfect preservation of images which only vary horizontally (or + vertically)" under no-op. + 2010-10-29 6.6.5-9 Glenn Randers-Pehrson * Revised PNG encoder to avoid emitting some spurious warnings. diff --git a/config/configure.xml b/config/configure.xml index aa56103ef..e836742cb 100644 --- a/config/configure.xml +++ b/config/configure.xml @@ -9,7 +9,7 @@ - + diff --git a/magick/resize.c b/magick/resize.c index 9eb279eed..84397cdaa 100644 --- a/magick/resize.c +++ b/magick/resize.c @@ -532,38 +532,36 @@ static MagickRealType Welsh(const MagickRealType x, % and rational (high Q) approximations, and will be used by default in % most cases. % -% Lanczos filter is a special 3-lobed Sinc windowed Sinc filter, -% (or cylindrical promoted Jinc-Jinc filter). This filter is -% probably the most popular windowed filter. +% Lanczos filter is a special 3-lobed Sinc-windowed Sinc filter +% (promoted to Jinc-windowed Jinc for cylindrical use). This is the +% most popular windowed filter. % -% LanczosSharp is a slightly sharpened (blur=0.98303932214489908) -% form of the Lanczos filter. It was designed specifically for +% LanczosSharp is a slightly sharpened (blur=0.9812505644269356) form +% of the Lanczos filter. It was designed specifically for % cylindrical EWA (Elliptical Weighted Average) distortion (as a -% Jinc-Jinc filter), but can used as a slightly sharper orthogonal -% Lanczos (Sinc-Sinc) filter. The chosen blur value comes as close as -% possible to satisfying the following condition without changing the -% character of the corresponding EWA filter: +% Jinc-Jinc filter); it can also be used as a slightly sharper +% orthogonal Lanczos (Sinc-Sinc) filter. The chosen blur value comes +% as close as possible to satisfying the following condition without +% changing the character of the corresponding EWA filter: % % 'No-Op' Vertical and Horizontal Line Preservation Condition: % Images with only vertical or horizontal features are preserved % when performing 'no-op" with EWA distortion. % -% The Lanczos2 and Lanczos2Sharp filters are simply 2-lobe versions -% of the Lanczos filters. The 'sharp' version uses a blur factor of +% The Lanczos2 and Lanczos2Sharp filters are 2-lobe versions of the +% Lanczos filters. The 'sharp' version uses a blur factor of % 0.958027803631219, again chosen because the resulting EWA filter -% comes as close as possible to preserving vertical and horizontal -% lines without changing its character. (There are other optimal -% values; we use the least sharpening one). +% comes as close as possible to satisfying the above condition. % % Robidoux is another filter tuned for EWA. It is the Keys cubic % filter defined by B=(228 - 108 sqrt(2))/199. Robidoux satisfies the % "'No-Op' Vertical and Horizontal Line Preservation Condition" -% exactly. It also seems to provide only minimal bluring of a low -% level 'pixel-hash' pattern in the 'No-Op Distort' case. It turns -% out to be close to both plain Mitchell and Lanczos2Sharp filters. -% For example, its first crossing is at (36 sqrt(2) + 123)/(72 -% sqrt(2) + 47) which is almost the same as the first crossing -% of the other two. +% exactly. Also, it minimally blurs high frequency 'pixel-hash' +% patterns in the 'No-Op Distort' case. Robidoux turns out to be +% close to both plain the Mitchell and Lanczos2Sharp filters. For +% example, its first crossing is at (36 sqrt(2) + 123)/(72 sqrt(2) + +% 47), almost the same as the first crossing of Mitchell and +% Lanczos2Sharp. % % % 'EXPERT' OPTIONS: diff --git a/magick/version.h b/magick/version.h index 013cd7b32..d4ca7e61e 100644 --- a/magick/version.h +++ b/magick/version.h @@ -33,8 +33,8 @@ extern "C" { #define MagickLibAddendum "-9" #define MagickLibInterface 4 #define MagickLibMinInterface 4 -#define MagickReleaseDate "2010-11-11" -#define MagickChangeDate "20101108" +#define MagickReleaseDate "2010-11-13" +#define MagickChangeDate "20101113" #define MagickAuthoritativeURL "http://www.imagemagick.org" #if defined(MAGICKCORE_OPENMP_SUPPORT) #define MagickOpenMPFeature "OpenMP "