Re: GtkCanvas requirements?

On Sun, 2007-04-22 at 21:16 +0100, Damon Chaplin wrote:

> In these days of 64-bit machines I don't think sizeof (double) is a big
> deal, if its just for a few coordinates per item. Anyway if we're using
> interfaces for items then the items can use whatever they like
> internally.

it's not a matter of space.

thinking 'in these days of 64-bit machines' would basically screw up all
of the people working on getting GTK+ to work on small devices which -
surprise! - have no FPU, hence perform like shit with doubles and
floats. in Clutter, for instance, most of the operations are done using
fixed point algebra and transforming doubles in the public API into
16.16 or 21.11 fixed point numbers internally; we also expose a fixed
point API to avoid using doubles altogether. is this hard? yes. is it
necessary? yes. should it be a part of the initial design and
implementation? hell, yes. because history teach us that starting with
"well, we have 64-bit machines nowadays, what's a double going to do" is
the perfect way to hit the wall of performance regressions.

cairo and pango developers and contributors went all the lengths to
reduce the floating point usage in their libraries; we shouldn't screw
the developers on embedded devices *again*.


Emmanuele Bassi,  E: ebassi gmail com

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