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Re: [ft] what's the mean of CEIL( x )?
From: |
David Turner |
Subject: |
Re: [ft] what's the mean of CEIL( x )? |
Date: |
Fri, 19 May 2006 09:18:02 +0200 |
User-agent: |
Thunderbird 1.5 (Windows/20051201) |
luoyi a écrit :
sorry, but:
#define CEIL( x ) ( ( (x) + 63 ) >> 6 )
obviously doesn't do what the C language "ceil()" function do....
if x is a fixed-point 26.6 number, the macro returns the smallest
integer that is greater
or equal to it, so it's very comparable to ceil()
ex:
x=240 corresponds to value 3.75 CEIL(240) => 4
x=64 corresponds to value 1.0 CEIL(64) => 1
x=32 corresponds to value 0.5 CEIL(32) => 1
x =1 corresponds to value 0.015625 CEIL(1) => 1
x = 0 corresponds to value 0. CEIL(0) => 0
x = -1 corresponds to value -0.015625 CEIL(-1) => 0
x = -32 corresponds to value -0.5 CEIL(-32) => 0
x = -64 corresponds to value -1. CEIL(-64) => -1
etc...
Regards,
- David Turner
- The FreeType Project (www.freetype.org)
"Peter Montgomery" <address@hidden> ??????:address@hidden
luoyi,
Looks like the fixed point (26.6) version of the C language "ceil( )"
function. Here's a page if you're not familiar with it.
http://www.cplusplus.com/ref/cmath/ceil.html
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