[Pixman] [PATCH 10/15] pixman-filter: don't range-check impulse filter

[Oded Gabbay]

On Sat, Dec 12, 2015 at 8:06 PM,  <spitzak at gmail.com> wrote:
> From: Bill Spitzak <spitzak at gmail.com>
>
> The other filters don't range-check, so there is no need for this
> one to either. It is only called with x==0.

Actually, I tried to stop at this function in gdb and didn't manage to
do it (using the scale demo). I then looked at the code and it seems
to me that the only way to reach this function is when both
reconstruction and sample kernels are IMPLUSE. That's because:

1. If both reconstruction and sample are *not* IMPLUSE, then of course
we won't reach it.
2. If only one of them is IMPLUSE, than the code will immediately
return the value of the function of the other kernel, which is *not*
IMPLUSE.

However, when I put both of them to IMPLUSE in the scale demo, the
picture simply disappears *and* the impluse_kernel is still not
reached. Actually, in that case, the integral() func is never reached
as well.

What am I missing ?

       Oded

> ---
>  pixman/pixman-filter.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/pixman/pixman-filter.c b/pixman/pixman-filter.c
> index fbc657d..00126cd 100644
> --- a/pixman/pixman-filter.c
> +++ b/pixman/pixman-filter.c
> @@ -45,7 +45,7 @@ typedef struct
>  static double
>  impulse_kernel (double x)
>  {
> -    return (x == 0.0)? 1.0 : 0.0;
> +    return 1;
>  }
>
>  static double
> --
> 1.9.1
>
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