Would using "iscale" (for inverse scale) work? Another is "tscale" because it is the scale from the transform matrix.
I really would like to use two different names for these variables as it is really confusing using the same one. On Fri, Mar 18, 2016 at 8:24 AM, Bill Spitzak <spit...@gmail.com> wrote: > > > On Thu, Mar 17, 2016 at 10:06 PM, Søren Sandmann <soren.sandm...@gmail.com > > wrote: > >> I suppose it's a little illogical that scale_x and scale_y really are the >> reciprocal values of how much the source image should be scaled. I don't >> remember exactly what I was thinking, but it might have something like >> "this allows you to just pass t[0][0] and t[1][1] if you have a pure >> scaling, which avoids a division". There is also kind of precedence in the >> Pixman API since the transformation given as in the dst->source direction. >> >> I don't really like "size" either though. It's not really the size of the >> filter that we are specifying; it just happens to be proportional to it. >> >> If it comes down to "size" and "scale", I prefer "scale". >> > > I tried "width" but it is not actually the filter width. How about "dx" > and "dy" since it is almost always the derivative of the x and y in the > input (or du,dv or dtx dtx) > >> >> >> Søren >> >> >> On Sun, Mar 6, 2016 at 8:06 PM, <spit...@gmail.com> wrote: >> >>> From: Bill Spitzak <spit...@gmail.com> >>> >>> This is to remove some confusion when reading the code. "scale" gets >>> larger >>> as the picture gets larger, while "size" (ie the size of the filter) gets >>> smaller. >>> >>> v14: Removed changes to integral function >>> >>> Signed-off-by: Bill Spitzak <spit...@gmail.com> >>> Reviewed-by: Oded Gabbay <oded.gab...@gmail.com> >>> --- >>> pixman/pixman-filter.c | 18 +++++++++--------- >>> pixman/pixman.h | 6 +++--- >>> 2 files changed, 12 insertions(+), 12 deletions(-) >>> >>> diff --git a/pixman/pixman-filter.c b/pixman/pixman-filter.c >>> index a29116a..c03a7f6 100644 >>> --- a/pixman/pixman-filter.c >>> +++ b/pixman/pixman-filter.c >>> @@ -221,7 +221,7 @@ static void >>> create_1d_filter (int width, >>> pixman_kernel_t reconstruct, >>> pixman_kernel_t sample, >>> - double scale, >>> + double size, >>> int n_phases, >>> pixman_fixed_t *p) >>> { >>> @@ -251,8 +251,8 @@ create_1d_filter (int width, >>> double pos = x + 0.5 - frac; >>> double rlow = - filters[reconstruct].width / 2.0; >>> double rhigh = rlow + filters[reconstruct].width; >>> - double slow = pos - scale * filters[sample].width / 2.0; >>> - double shigh = slow + scale * filters[sample].width; >>> + double slow = pos - size * filters[sample].width / 2.0; >>> + double shigh = slow + size * filters[sample].width; >>> double c = 0.0; >>> double ilow, ihigh; >>> >>> @@ -262,7 +262,7 @@ create_1d_filter (int width, >>> ihigh = MIN (shigh, rhigh); >>> >>> c = integral (reconstruct, ilow, >>> - sample, 1.0 / scale, ilow - pos, >>> + sample, 1.0 / size, ilow - pos, >>> ihigh - ilow); >>> } >>> >>> @@ -335,12 +335,12 @@ filter_width (pixman_kernel_t reconstruct, >>> pixman_kernel_t sample, double size) >>> } >>> >>> /* Create the parameter list for a SEPARABLE_CONVOLUTION filter >>> - * with the given kernels and scale parameters >>> + * with the given kernels and size parameters >>> */ >>> PIXMAN_EXPORT pixman_fixed_t * >>> pixman_filter_create_separable_convolution (int *n_values, >>> - pixman_fixed_t scale_x, >>> - pixman_fixed_t scale_y, >>> + pixman_fixed_t size_x, >>> + pixman_fixed_t size_y, >>> pixman_kernel_t >>> reconstruct_x, >>> pixman_kernel_t >>> reconstruct_y, >>> pixman_kernel_t sample_x, >>> @@ -348,8 +348,8 @@ pixman_filter_create_separable_convolution (int >>> *n_values, >>> int >>> subsample_bits_x, >>> int >>> subsample_bits_y) >>> { >>> - double sx = fabs (pixman_fixed_to_double (scale_x)); >>> - double sy = fabs (pixman_fixed_to_double (scale_y)); >>> + double sx = fabs (pixman_fixed_to_double (size_x)); >>> + double sy = fabs (pixman_fixed_to_double (size_y)); >>> pixman_fixed_t *params; >>> int subsample_x, subsample_y; >>> int width, height; >>> diff --git a/pixman/pixman.h b/pixman/pixman.h >>> index 509ba5e..b012a33 100644 >>> --- a/pixman/pixman.h >>> +++ b/pixman/pixman.h >>> @@ -845,12 +845,12 @@ typedef enum >>> } pixman_kernel_t; >>> >>> /* Create the parameter list for a SEPARABLE_CONVOLUTION filter >>> - * with the given kernels and scale parameters. >>> + * with the given kernels and size parameters. >>> */ >>> pixman_fixed_t * >>> pixman_filter_create_separable_convolution (int *n_values, >>> - pixman_fixed_t scale_x, >>> - pixman_fixed_t scale_y, >>> + pixman_fixed_t size_x, >>> + pixman_fixed_t size_y, >>> pixman_kernel_t >>> reconstruct_x, >>> pixman_kernel_t >>> reconstruct_y, >>> pixman_kernel_t sample_x, >>> -- >>> 1.9.1 >>> >>> _______________________________________________ >>> Pixman mailing list >>> Pixman@lists.freedesktop.org >>> https://lists.freedesktop.org/mailman/listinfo/pixman >>> >> >> >
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