Mercurial > ift6266
diff pycaptcha/Captcha/data/fonts/vera/RELEASENOTES.TXT @ 87:4775b4195b4b
code pour la generation de captchas
author | goldfinger |
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date | Thu, 11 Feb 2010 05:09:46 -0500 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/pycaptcha/Captcha/data/fonts/vera/RELEASENOTES.TXT Thu Feb 11 05:09:46 2010 -0500 @@ -0,0 +1,162 @@ +Bitstream Vera Fonts - April 16, 2003 +===================================== + +The version number of these fonts is 1.10 to distinguish them from the +beta test fonts. + +Note that the Vera copyright is incorporated in the fonts themselves. +The License field in the fonts contains the copyright license as it +appears below. The TrueType copyright field is not large enough to +contain the full license, so the license is incorporated (as you might +think if you thought about it) into the license field, which +unfortunately can be obscure to find. (In pfaedit, see: Element->Font +Info->TTFNames->License). + +Our apologies for it taking longer to complete the fonts than planned. +Beta testers requested a tighter line spacing (less leading) and Jim +Lyles redesigned Vera's accents to bring its line spacing to more +typical of other fonts. This took additional time and effort. Our +thanks to Jim for this effort above and beyond the call of duty. + +There are four monospace and sans faces (normal, oblique, bold, bold +oblique) and two serif faces (normal and bold). Fontconfig/Xft2 (see +www.fontconfig.org) can artificially oblique the serif faces for you: +this loses hinting and distorts the faces slightly, but is visibly +different than normal and bold, and reasonably pleasing. + +On systems with fontconfig 2.0 or 2.1 installed, making your sans, +serif and monospace fonts default to these fonts is very easy. Just +drop the file local.conf into your /etc/fonts directory. This will +make the Bitstream fonts your default fonts for all applications using +fontconfig (if sans, serif, or monospace names are used, as they often +are as default values in many desktops). The XML in local.conf may +need modification to enable subpixel decimation, if appropriate, +however, the commented out phrase does so for XFree86 4.3, in the case +that the server does not have sufficient information to identify the +use of a flat panel. Fontconfig 2.2 adds Vera to the list of font +families and will, by default use it as the default sans, serif and +monospace fonts. + +During the testing of the final Vera fonts, we learned that screen +fonts in general are only typically hinted to work correctly at +integer pixel sizes. Vera is coded internally for integer sizes only. +We need to investigate further to see if there are commonly used fonts +that are hinted to be rounded but are not rounded to integer sizes due +to oversights in their coding. + +Most fonts work best at 8 pixels and below if anti-aliased only, as +the amount of work required to hint well at smaller and smaller sizes +becomes astronomical. GASP tables are typically used to control +whether hinting is used or not, but Freetype/Xft does not currently +support GASP tables (which are present in Vera). + +To mitigate this problem, both for Vera and other fonts, there will be +(very shortly) a new fontconfig 2.2 release that will, by default not +apply hints if the size is below 8 pixels. if you should have a font +that in fact has been hinted more agressively, you can use fontconfig +to note this exception. We believe this should improve many hinted +fonts in addition to Vera, though implemeting GASP support is likely +the right long term solution. + +Font rendering in Gnome or KDE is the combination of algorithms in +Xft2 and Freetype, along with hinting in the fonts themselves. It is +vital to have sufficient information to disentangle problems that you +may observe. + +Note that having your font rendering system set up correctly is vital +to proper judgement of problems of the fonts: + + * Freetype may or may not be configured to in ways that may + implement execution of possibly patented (in some parts of the world) + TrueType hinting algorithms, particularly at small sizes. Best + results are obtained while using these algorithms. + + * The freetype autohinter (used when the possibly patented + algorithms are not used) continues to improve with each release. If + you are using the autohinter, please ensure you are using an up to + date version of freetype before reporting problems. + + * Please identify what version of freetype you are using in any + bug reports, and how your freetype is configured. + + * Make sure you are not using the freetype version included in + XFree86 4.3, as it has bugs that significantly degrade most fonts, + including Vera. if you build XFree86 4.3 from source yourself, you may + have installed this broken version without intending it (as I + did). Vera was verified with the recently released Freetype 2.1.4. On + many systems, 'ldd" can be used to see which freetype shared library + is actually being used. + + * Xft/X Render does not (yet) implement gamma correction. This + causes significant problems rendering white text on a black background + (causing partial pixels to be insufficiently shaded) if the gamma of + your monitor has not been compensated for, and minor problems with + black text on a while background. The program "xgamma" can be used to + set a gamma correction value in the X server's color pallette. Most + monitors have a gamma near 2. + + * Note that the Vera family uses minimal delta hinting. Your + results on other systems when not used anti-aliased may not be + entirely satisfying. We are primarily interested in reports of + problems on open source systems implementing Xft2/fontconfig/freetype + (which implements antialiasing and hinting adjustements, and + sophisticated subpixel decimation on flatpanels). Also, the + algorithms used by Xft2 adjust the hints to integer widths and the + results are crisper on open source systems than on Windows or + MacIntosh. + + * Your fontconfig may (probably does) predate the release of + fontconfig 2.2, and you may see artifacts not present when the font is + used at very small sizes with hinting enabled. "vc-list -V" can be + used to see what version you have installed. + +We believe and hope that these fonts will resolve the problems +reported during beta test. The largest change is the reduction of +leading (interline spacing), which had annoyed a number of people, and +reduced Vera's utility for some applcations. The Vera monospace font +should also now make '0' and 'O' and '1' and 'l' more clearly +distinguishable. + +The version of these fonts is version 1.10. Fontconfig should be +choosing the new version of the fonts if both the released fonts and +beta test fonts are installed (though please discard them: they have +names of form tt20[1-12]gn.ttf). Note that older versions of +fontconfig sometimes did not rebuild their cache correctly when new +fonts are installed: please upgrade to fontconfig 2.2. "fc-cache -f" +can be used to force rebuilding fontconfig's cache files. + +If you note problems, please send them to fonts at gnome dot org, with +exactly which face and size and unicode point you observe the problem +at. The xfd utility from XFree86 CVS may be useful for this (e.g. "xfd +-fa sans"). A possibly more useful program to examine fonts at a +variety of sizes is the "waterfall" program found in Keith Packard's +CVS. + + $ cvs -d :pserver:anoncvs@keithp.com:/local/src/CVS login + Logging in to :pserver:anoncvs@keithp.com:2401/local/src/CVS + CVS password: <hit return> + $ cvs -d :pserver:anoncvs@keithp.com:/local/src/CVS co waterfall + $ cd waterfall + $ xmkmf -a + $ make + # make install + # make install.man + +Again, please make sure you are running an up-to-date freetype, and +that you are only examining integer sizes. + +Reporting Problems +================== + +Please send problem reports to fonts at gnome org, with the following +information: + + 1. Version of Freetype, Xft2 and fontconfig + 2. Whether TT hinting is being used, or the autohinter + 3. Application being used + 4. Character/Unicode code point that has problems (if applicable) + 5. Version of which operating system + 6. Please include a screenshot, when possible. + +Please check the fonts list archives before reporting problems to cut +down on duplication.