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diff --git a/freetype/docs/reference/ft2-cff_driver.html b/freetype/docs/reference/ft2-cff_driver.html index f1de5661a..f9113ba46 100644 --- a/freetype/docs/reference/ft2-cff_driver.html +++ b/freetype/docs/reference/ft2-cff_driver.html @@ -3,7 +3,7 @@ <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> -<title>FreeType-2.5.5 API Reference</title> +<title>FreeType-2.7 API Reference</title> <style type="text/css"> a:link { color: #0000EF; } a:visited { color: #51188E; } @@ -100,13 +100,14 @@ <body> <table class="index-toc-link"><tr><td class="left">[<a href="ft2-index.html">Index</a>]</td><td class="right">[<a href="ft2-toc.html">TOC</a>]</td></tr></table> -<h1>FreeType-2.5.5 API Reference</h1> +<h1>FreeType-2.7 API Reference</h1> -<h1>The CFF driver</h1> +<h1 id="cff_driver">The CFF driver</h1> <h2>Synopsis</h2> <table class="synopsis"> -<tr><td><a href="#hinting-engine">hinting-engine</a></td><td><a href="#darkening-parameters">darkening-parameters</a></td><td><a href="#FT_CFF_HINTING_XXX">FT_CFF_HINTING_XXX</a></td></tr> -<tr><td><a href="#no-stem-darkening">no-stem-darkening</a></td><td> </td><td></td></tr> +<tr><td><a href="#hinting-engine(cff)">hinting-engine</a></td><td> </td></tr> +<tr><td><a href="#no-stem-darkening(cff)">no-stem-darkening</a></td><td><a href="#FT_CFF_HINTING_XXX">FT_CFF_HINTING_XXX</a></td></tr> +<tr><td><a href="#darkening-parameters(cff)">darkening-parameters</a></td><td></td></tr> </table> @@ -117,12 +118,12 @@ <p>There are two principles behind this approach.</p> <p>1) No hinting in the horizontal direction: Unlike ‘superhinted’ TrueType, which changes glyph widths to accommodate regular inter-glyph spacing, Adobe's approach is ‘faithful to the design’ in representing both the glyph width and the inter-glyph spacing designed for the font. This makes the screen display as close as it can be to the result one would get with infinite resolution, while preserving what is considered the key characteristics of each glyph. Note that the distances between unhinted and grid-fitted positions at small sizes are comparable to kerning values and thus would be noticeable (and distracting) while reading if hinting were applied.</p> <p>One of the reasons to not hint horizontally is antialiasing for LCD screens: The pixel geometry of modern displays supplies three vertical sub-pixels as the eye moves horizontally across each visible pixel. On devices where we can be certain this characteristic is present a rasterizer can take advantage of the sub-pixels to add increments of weight. In Western writing systems this turns out to be the more critical direction anyway; the weights and spacing of vertical stems (see above) are central to Armenian, Cyrillic, Greek, and Latin type designs. Even when the rasterizer uses greyscale antialiasing instead of color (a necessary compromise when one doesn't know the screen characteristics), the unhinted vertical features preserve the design's weight and spacing much better than aliased type would.</p> -<p>2) Aligment in the vertical direction: Weights and spacing along the y axis are less critical; what is much more important is the visual alignment of related features (like cap-height and x-height). The sense of alignment for these is enhanced by the sharpness of grid-fit edges, while the cruder vertical resolution (full pixels instead of 1/3 pixels) is less of a problem.</p> +<p>2) Alignment in the vertical direction: Weights and spacing along the y axis are less critical; what is much more important is the visual alignment of related features (like cap-height and x-height). The sense of alignment for these is enhanced by the sharpness of grid-fit edges, while the cruder vertical resolution (full pixels instead of 1/3 pixels) is less of a problem.</p> <p>On the technical side, horizontal alignment zones for ascender, x-height, and other important height values (traditionally called ‘blue zones’) as defined in the font are positioned independently, each being rounded to the nearest pixel edge, taking care of overshoot suppression at small sizes, stem darkening, and scaling.</p> <p>Hstems (this is, hint values defined in the font to help align horizontal features) that fall within a blue zone are said to be ‘captured’ and are aligned to that zone. Uncaptured stems are moved in one of four ways, top edge up or down, bottom edge up or down. Unless there are conflicting hstems, the smallest movement is taken to minimize distortion.</p> <div class="section"> -<h3 id="hinting-engine">hinting-engine</h3> +<h3 id="hinting-engine(cff)">hinting-engine</h3> <p>Thanks to Adobe, which contributed a new hinting (and parsing) engine, an application can select between ‘freetype’ and ‘adobe’ if compiled with CFF_CONFIG_OPTION_OLD_ENGINE. If this configuration macro isn't defined, ‘hinting-engine’ does nothing.</p> <p>The default engine is ‘freetype’ if CFF_CONFIG_OPTION_OLD_ENGINE is defined, and ‘adobe’ otherwise.</p> @@ -140,12 +141,13 @@ <h4>note</h4> <p>This property can be used with <a href="ft2-module_management.html#FT_Property_Get">FT_Property_Get</a> also.</p> +<p>This property can be set via the ‘FREETYPE_PROPERTIES’ environment variable (using values ‘adobe’ or ‘freetype’).</p> <hr> <table class="index-toc-link"><tr><td class="left">[<a href="ft2-index.html">Index</a>]</td><td class="middle">[<a href="#">Top</a>]</td><td class="right">[<a href="ft2-toc.html">TOC</a>]</td></tr></table></div> <div class="section"> -<h3 id="no-stem-darkening">no-stem-darkening</h3> +<h3 id="no-stem-darkening(cff)">no-stem-darkening</h3> <p>By default, the Adobe CFF engine darkens stems at smaller sizes, regardless of hinting, to enhance contrast. This feature requires a rendering system with proper gamma correction. Setting this property, stem darkening gets switched off.</p> <p>Note that stem darkening is never applied if <a href="ft2-base_interface.html#FT_LOAD_XXX">FT_LOAD_NO_SCALE</a> is set.</p> @@ -162,12 +164,13 @@ <h4>note</h4> <p>This property can be used with <a href="ft2-module_management.html#FT_Property_Get">FT_Property_Get</a> also.</p> +<p>This property can be set via the ‘FREETYPE_PROPERTIES’ environment variable (using values 1 and 0 for ‘on’ and ‘off’, respectively).</p> <hr> <table class="index-toc-link"><tr><td class="left">[<a href="ft2-index.html">Index</a>]</td><td class="middle">[<a href="#">Top</a>]</td><td class="right">[<a href="ft2-toc.html">TOC</a>]</td></tr></table></div> <div class="section"> -<h3 id="darkening-parameters">darkening-parameters</h3> +<h3 id="darkening-parameters(cff)">darkening-parameters</h3> <p>By default, the Adobe CFF engine darkens stems as follows (if the ‘no-stem-darkening’ property isn't set):</p> <pre class="colored"> @@ -194,19 +197,24 @@ <h4>note</h4> <p>This property can be used with <a href="ft2-module_management.html#FT_Property_Get">FT_Property_Get</a> also.</p> +<p>This property can be set via the ‘FREETYPE_PROPERTIES’ environment variable, using eight comma-separated integers without spaces. Here the above example, using ‘\’ to break the line for readability.</p> +<pre class="colored"> + FREETYPE_PROPERTIES=\ + cff:darkening-parameters=500,300,1000,200,1500,100,2000,0 +</pre> <hr> <table class="index-toc-link"><tr><td class="left">[<a href="ft2-index.html">Index</a>]</td><td class="middle">[<a href="#">Top</a>]</td><td class="right">[<a href="ft2-toc.html">TOC</a>]</td></tr></table></div> <div class="section"> <h3 id="FT_CFF_HINTING_XXX">FT_CFF_HINTING_XXX</h3> -<p>Defined in FT_CFF_DRIVER_H (ftcffdrv.h).</p> +<p>Defined in FT_CFF_DRIVER_H (freetype/ftcffdrv.h).</p> <pre> #define <a href="ft2-cff_driver.html#FT_CFF_HINTING_FREETYPE">FT_CFF_HINTING_FREETYPE</a> 0 #define <a href="ft2-cff_driver.html#FT_CFF_HINTING_ADOBE">FT_CFF_HINTING_ADOBE</a> 1 </pre> -<p>A list of constants used for the <a href="ft2-cff_driver.html#hinting-engine">hinting-engine</a> property to select the hinting engine for CFF fonts.</p> +<p>A list of constants used for the <a href="ft2-cff_driver.html#hinting-engine(cff)">hinting-engine</a> property to select the hinting engine for CFF fonts.</p> <h4>values</h4> <table class="fields"> |