[cairo] Floating point API in Pixman
jcrml at mxm.eu
Wed Aug 11 01:50:47 PDT 2010
Le 11/08/2010 08:00, M Joonas Pihlaja a écrit :
> On Wed, 11 Aug 2010, Soeren Sandmann wrote:
>> For the matrix in pixman_image_t, I think we need to just move to
>> single precision floating point unconditionally. There are several
>> cases where 16.16 fixed point simply doesn't have enough either range
>> or precision.
> Before deciding on the kind of floating point, could we think very
> hard about the precision and accuracy guarantees pixman would like to
> make for each of its operations? Single precision floating point is
> not very far off from 16.16 after all, so I worry that we'll be in the
> same boat very quickly again if we're not careful.
Please don't forget that Cairo is used on some processors that don't
have FPU (such as ARM processors). So if you introduce floating point,
it MUST be optional.
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