<div dir="ltr"><div>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. </div> If it comes down to "size" and "scale", I prefer "scale". <div> </div><div>Søren </div><div> </div></div><div class="gmail_extra"> <div class="gmail_quote">On Sun, Mar 6, 2016 at 8:06 PM, <<a href="mailto:spitzak@gmail.com" target="_blank">spitzak@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">From: Bill Spitzak <<a href="mailto:spitzak@gmail.com">spitzak@gmail.com</a>> 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 <<a href="mailto:spitzak@gmail.com">spitzak@gmail.com</a>> Reviewed-by: Oded Gabbay <<a href="mailto:oded.gabbay@gmail.com">oded.gabbay@gmail.com</a>> --- 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 <a href="mailto:Pixman@lists.freedesktop.org">Pixman@lists.freedesktop.org</a> <a href="https://lists.freedesktop.org/mailman/listinfo/pixman" rel="noreferrer" target="_blank">https://lists.freedesktop.org/mailman/listinfo/pixman</a> </blockquote></div> </div>