[cairo] Engaging 64 bit precision

Kai-Uwe Behrmann ku.b at gmx.de
Wed Aug 11 21:05:26 PDT 2010

Am 12.08.10, 14:25 +1200 schrieb Richard Procter:
> On 12/08/2010, at 9:14 AM, Richard Procter wrote:

> FWIW, here's is my beginner's successfully compiled but untested first 
> attempt to boost CAIRO_FIXED_BITS to the maximum 64 bit double precision of 
> 52 bits.

Maybe only a semantic irritation, maybe not.

You imagine to use double in terms of IEEE double precision floats but 
your actual used type is uint64_t. Then you switch the CAIRO_FIXED_BITS 
from 32 to 52. It does not fit well. uint64_t is 64 bit not 52. INT64_MIN 
is for uint64_t and so on.

Why do you think the _cairo_fixed_from_double() trick might be necessary?

kind regards
Kai-Uwe Behrmann
developing for colour management 
www.behrmann.name + www.oyranos.org

disclaimer: I am not a expert in Cairo's mathematical internals.

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