Reported by: Anders Lindgren <andlind <at> gmail.com>
Date: Sat, 22 Jan 2011 18:39:02 UTC
Severity: normal
Done: Jan Djärv <jan.h.d <at> swipnet.se>
Bug is archived. No further changes may be made.
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From: help-debbugs <at> gnu.org (GNU bug Tracking System) To: Anders Lindgren <andlind <at> gmail.com> Subject: bug#7887: closed (Re: bug#7887: Emacs will render some fonts under Mac OS X one pixel too tall (patch supplied)) Date: Sat, 29 Jan 2011 10:31:02 +0000
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Your bug report #7887: Emacs will render some fonts under Mac OS X one pixel too tall (patch supplied) which was filed against the emacs,ns package, has been closed. The explanation is attached below, along with your original report. If you require more details, please reply to 7887 <at> debbugs.gnu.org. -- 7887: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=7887 GNU Bug Tracking System Contact help-debbugs <at> gnu.org with problems
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From: Jan Djärv <jan.h.d <at> swipnet.se> To: Anders Lindgren <andlind <at> gmail.com>, 7887-done <at> debbugs.gnu.org Subject: Re: bug#7887: Emacs will render some fonts under Mac OS X one pixel too tall (patch supplied) Date: Sat, 29 Jan 2011 11:39:09 +0100Anders Lindgren skrev 2011-01-25 18.18: > > My original suggesten simply said that anything in the range -2.0 - > -2.0001 should be treated as -2. The motivation behind this is that > often a floating-point error is only in the lowest bit or bits. (In > the case I found, the bits that were set corresponds to the least > significant mantissa bits of a 32 bit floating-point number, even > though the number had been converted to 64 bit number along the way.) > If it only to handle fp errors, then I guess 0.0001 is OK. Patch checked in. I don't have any fonts to test with, so if you can confirm that it is fixed, that would be great. Thanks, Jan D. > On Tue, Jan 25, 2011 at 5:12 PM, Jan Djärv <jan.h.d <at> swipnet.se> wrote: >> > Sounds like a job for round then. >> > >> > Jan D. >> > >> > >> > Anders Lindgren skrev 2011-01-25 15.45: >>> >> >>> >> No, that won't work. Descents are always negative, "floor" is used to >>> >> treat, for example, -2.5 as -3.0, to avoid clipping. The problem is >>> >> that is also converts -2.000001 to -3. >>> >> >>> >> What I suggested was that we continue to round -2.5 down to -3, but >>> >> round values very close to -2.0 up to -2. >>> >> >>> >> I don't know if this is a general problem, only related to FontForge >>> >> (an open-source font editor). If it's only related to FontForge, then >>> >> another solution would be to fix it instead of Emacs. >>> >> >>> >> -- Anders >>> >> >>> >>
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From: Anders Lindgren <andlind <at> gmail.com> To: bug-gnu-emacs <at> gnu.org Subject: Emacs will render some fonts under Mac OS X one pixel too tall (patch supplied) Date: Sat, 22 Jan 2011 10:43:39 +0100Hi! I have notices that Emacs will render some fonts under Mac OS X one pixel too tall. The current implementation for handling fonts under NextStep always round the descender to the next full integer, to avoid clipping. (As descenders under NextStep are negative, this is done using the function "floor"). Unfortunately, some fonts do not specify the descender as exactly as desired. Concretely, a 6x8 bitmap font could report a descender of -2.0000040531158447 (represented by 0xc000000220000000), which Emacs rounds to -3. The result is that the font will be drawn one pixel taller than expected. The patch below is one example of how to handle this, it will circumvent the problem by adding a small value to the descender, making sure that values close enough to an integer will be rounded to that integer. -- Anders Lindgren 2011-01-22 Anders Lindgren <andlind <at> gmail.com> * nsfont.m (nsfont_open): Ensure that fonts with inexact descenders would not become one pixel too tall. === modified file 'src/nsfont.m' --- src/nsfont.m 2011-01-19 22:11:33 +0000 +++ src/nsfont.m 2011-01-22 09:03:56 +0000 @@ -809,6 +809,15 @@ const char *fontName = [[nsfont fontName] UTF8String]; int len = strlen (fontName); + /* The values specified by fonts are not always exact. For + * example, a 6x8 font could specify that the descender is + * -2.00000405... (represented by 0xc000000220000000). Without + * adjustment, the code below would round the descender to -3, + * resulting in a font that would be one pixel higher than + * intended. */ + + CGFloat adjusted_descender = [sfont descender] + 0.0001; + #ifdef NS_IMPL_GNUSTEP font_info->nsfont = sfont; #else @@ -830,7 +839,7 @@ brect = [sfont boundingRectForFont]; full_height = brect.size.height; - min_height = [sfont ascender] - [sfont descender]; + min_height = [sfont ascender] - adjusted_descender; hd = full_height - min_height; /* standard height, similar to Carbon. Emacs.app: was 0.5 by default. */ @@ -845,10 +854,10 @@ /* max bounds */ font_info->max_bounds.ascent = lrint (hshrink * [sfont ascender] + expand * hd/2); - /* [sfont descender] is usually negative. Use floor to avoid - clipping descenders. */ + /* Descender is usually negative. Use floor to avoid clipping + descenders. */ font_info->max_bounds.descent = - -lrint (floor(hshrink* [sfont descender] - expand*hd/2)); + -lrint (floor(hshrink * adjusted_descender - expand * hd/2)); font_info->height = font_info->max_bounds.ascent + font_info->max_bounds.descent; font_info->max_bounds.width = lrint (font_info->width); @@ -884,7 +893,7 @@ /* set up metrics portion of font struct */ font->ascent = lrint([sfont ascender]); - font->descent = -lrint(floor([sfont descender])); + font->descent = -lrint(floor(adjusted_descender)); font->min_width = ns_char_width(sfont, '|'); font->space_width = lrint (ns_char_width (sfont, ' ')); font->average_width = lrint (font_info->width); In GNU Emacs 24.0.50.1 (x86_64-apple-darwin10.5.0, NS apple-appkit-1038.35) of 2011-01-14 on macpro.local Windowing system distributor `Apple', version 10.3.1038 configured using `configure '--with-ns'' Important settings: value of $LC_ALL: nil value of $LC_COLLATE: nil value of $LC_CTYPE: nil value of $LC_MESSAGES: nil value of $LC_MONETARY: nil value of $LC_NUMERIC: nil value of $LC_TIME: nil value of $LANG: nil value of $XMODIFIERS: nil locale-coding-system: nil default enable-multibyte-characters: t Major mode: ObjC/lw Minor modes in effect: diff-auto-refine-mode: t subword-mode: t global-auto-revert-mode: t global-cwarn-mode: t minibuffer-electric-file-mode: t recentf-mode: t msb-mode: t display-time-mode: t tooltip-mode: t mouse-wheel-mode: t menu-bar-mode: t file-name-shadow-mode: t global-font-lock-mode: t font-lock-mode: t auto-composition-mode: t auto-encryption-mode: t auto-compression-mode: t column-number-mode: t line-number-mode: t transient-mark-mode: t abbrev-mode: t Recent input: <down> <down> <down> <down> <down> <down> <down> <down> <down> <down> <down> <down> <down> <down> <down> <down> <down> <down> <down> <down> <down> <down> <down> <down> <down> <down> <down> C-SPC <down> C-w <down> C-SPC <down> <down> <down> C-w <up> C-e <left> <left> <left> <M-backspace> <backspace> <backspace> <backspace> C-a C-x C-s C-M-a C-s e p s C-a C-x C-f s a <backspace> l a s j . <backspace> <backspace> k . c <return> <C-tab> C-x o <C-S-tab> C-x p C-M-a <up> <up> <up> <up> <up> <up> <up> <up> <up> C-SPC <down> <down> <down> <down> <down> <down> <down> C-w C-x C-s C-x o C-y C-x p <down> C-v C-l C-v <down> <down-mouse-1> <mouse-1> C-a C-SPC <down> <down> <down> <down> <down> <down> <down> C-w C-x C-s C-x o C-y C-x C-s C-x p <down-mouse-1> <mouse-1> M-d M-d M-d c o u l y <backspace> d SPC <backspace> M-f <backspace> <backspace> <backspace> y <escape> q <M-left> <M-left> <M-backspace> <escape> q <down> <down> M-f M-f M-f <M-backspace> t h e SPC d e s c M-- <escape> q C-x C-s <down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> <backspace> C-a C-x C-s <down-mouse-1> <mouse-1> SPC <down-mouse-1> <mouse-1> SPC C-a C-x C-s <down-mouse-1> <mouse-1> SPC <down-mouse-1> <mouse-1> SPC C-a C-x C-s <down-mouse-1> <mouse-1> C-a <down> SPC <backspace> <down> <down> <down> <down> <down> <up> SPC <backspace> C-a C-x C-s <up> <up> <up> <up> M-f <right> <right> C-s C-w C-s C-a <down-mouse-1> <mouse-1> a <backspace> a d j u s t m e n t <escape> d <escape> q <up> <up> <up> C-a C-SPC <down> <down> <down> <down> <down> <down> <escape> x i s p l l <backspace> <backspace> e l l - r e g <tab> ' <backspace> <return> q <up> C-g <up> <down-mouse-1> <mouse-1> c <escape> q <down-mouse-1> <mouse-1> C-d <backspace> <backspace> <backspace> i f y C-a C-x C-s <menu-bar> <help-menu> <send-emacs -bug-report> Recent messages: Wrote /Users/anders/build/emacs/trunk/src/nsfont.m Mark saved where search started Mark set Starting new Ispell process [default] ... Entering debugger... Back to top level. Quit Auto-saving...done Saving file /Users/anders/build/emacs/trunk/src/nsfont.m... Wrote /Users/anders/build/emacs/trunk/src/nsfont.m Load-path shadows: ~/emacs/lisp/table hides /Applications/Emacs24.app/Contents/Resources/lisp/textmodes/table ~/emacs/lisp/ruby-mode hides /Applications/Emacs24.app/Contents/Resources/lisp/progmodes/ruby-mode ~/emacs/src/asm-mode-new/src/asm-mode hides /Applications/Emacs24.app/Contents/Resources/lisp/progmodes/asm-mode Features: (ispell smerge-mode diff-mode texinfo autoconf autoconf-mode conf-mode shadow sort gnus-util mail-extr message rfc822 mml mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mailabbrev mail-utils gmm-utils mailheader emacsbug subword newcomment ctypes grep compile etags jka-compr find-func follow my-end-of-buffer-log c-electric-operator c-indent-operator dired-aux dired vc-bzr sha1 hex-util add-log vc-dispatcher vc-svn pp apropos multi-isearch debug dabbrev help-mode eldoc ps-print ps-def lpr autorevert folding-isearch folding view rdebug cwarn prepaint cc-mode cc-fonts cc-menus cc-cmds cc-styles cc-align cc-engine cc-vars cc-defs tempo edg-mode split-nways toggle-file-read-only lockdir uniquify ange-ftp comint regexp-opt ring paren mic-paren iso-insert minibuf-elfile easy-mmode recentf tree-widget wid-edit easymenu msb edmacro kmacro warnings disp-table time advice help-fns advice-preload cl tooltip ediff-hook vc-hooks lisp-float-type mwheel ns-win tool-bar dnd fontset image fringe lisp-mode register page menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock font-lock syntax facemenu font-core frame cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean japanese hebrew greek romanian slovak czech european ethiopic indian cyrillic chinese case-table epa-hook jka-cmpr-hook help simple abbrev loaddefs button minibuffer faces cus-face files text-properties overlay md5 base64 format env code-pages mule custom widget hashtable-print-readable backquote make-network-process ns multi-tty emacs)
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