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Re: Subpixel functions
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Re: Subpixel functions



Check out the docs.  

Font smoothing is a more generic term, but it turns on what wikipedia calls subpixel rendering.

If subpixel positioning is off, then each rendered glyph starts at a pixel boundary.

When subpixel positioning is on, if subpixel quantization is also on, then glyphs are constrained to only certain subpixel positions.  If I recall, it currently constraints glyphs to thirds of a pixel horizontally and whole pixels vertically.  This is a performance win, because it means that there are only three rasterized versions of each glyph, and these can be cached.  

In a typical window context, all three are on.  

-Ken


On Sat, Jan 1, 2011 at 3:50 PM, Glen Low <email@hidden> wrote:
Scott, All

On 01/01/2011, at 11:40 PM, Scott Thompson wrote:


On Jan 1, 2011, at 5:35 AM, Glen Low wrote:

What do the various subpixel functions do in iOS 4.0 etc.?

Specificially,

CGContextSetAllowsFontSmoothing
CGContextSetAllowsFontSubpixelPositioning
CGContextSetAllowsFontSubpixelQuantization


They adjust the settings related to subpixel antialiasing in bitmap contexts.

Yes but what is font smooting vs. subpixel positioning vs. subpixel quantization?




Cheers, Glen Low


---
pixelglow software | simply brilliant stuff
aim: pixglen
twitter: pixelglow


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References: 
 >Subpixel functions (From: Glen Low <email@hidden>)
 >Re: Subpixel functions (From: Scott Thompson <email@hidden>)
 >Re: Subpixel functions (From: Glen Low <email@hidden>)



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