Okay, thanks for the info. Will try to fix them all. On Mon, Feb 1, 2016 at 5:51 AM, Oded Gabbay <oded.gab...@gmail.com> wrote:
> On Fri, Jan 22, 2016 at 11:41 AM, <spit...@gmail.com> wrote: > > > > From: Bill Spitzak <spit...@gmail.com> > > > > This is much more accurate and less blurry. In particular the filtering > does > > not change as the image is rotated. > > > > Signed-off-by: Bill Spitzak <spit...@gmail.com> > > --- > > demos/scale.c | 102 > +++++++++++++++++++++++++++++++++++----------------------- > > 1 file changed, 61 insertions(+), 41 deletions(-) > > > > diff --git a/demos/scale.c b/demos/scale.c > > index d00307e..0995ad0 100644 > > --- a/demos/scale.c > > +++ b/demos/scale.c > > @@ -55,50 +55,70 @@ get_widget (app_t *app, const char *name) > > return widget; > > } > > > > -static double > > -min4 (double a, double b, double c, double d) > > -{ > > - double m1, m2; > > - > > - m1 = MIN (a, b); > > - m2 = MIN (c, d); > > - return MIN (m1, m2); > > -} > > - > > -static double > > -max4 (double a, double b, double c, double d) > > -{ > > - double m1, m2; > > - > > - m1 = MAX (a, b); > > - m2 = MAX (c, d); > > - return MAX (m1, m2); > > -} > > - > > +/* Figure out the boundary of a diameter=1 circle transformed into an > ellipse > > + * by trans. Proof that this is the correct calculation: > > + * > > + * Transform x,y to u,v by this matrix calculation: > > + * > > + * |u| |a c| |x| > > + * |v| = |b d|*|y| > > + * > > + * Horizontal component: > > + * > > + * u = ax+cy (1) > > + * > > + * For each x,y on a radius-1 circle (p is angle to the point): > > + * > > + * x^2+y^2 = 1 > > + * x = cos(p) > > + * y = sin(p) > > + * dx/dp = -sin(p) = -y > > + * dy/dp = cos(p) = x > > + * > > + * Figure out derivative of (1) relative to p: > > + * > > + * du/dp = a(dx/dp) + c(dy/dp) > > + * = -ay + cx > > + * > > + * The min and max u are when du/dp is zero: > > + * > > + * -ay + cx = 0 > > + * cx = ay > > + * c = ay/x (2) > > + * y = cx/a (3) > > + * > > + * Substitute (2) into (1) and simplify: > > + * > > + * u = ax + ay^2/x > > + * = a(x^2+y^2)/x > > + * = a/x (because x^2+y^2 = 1) > > + * x = a/u (4) > > + * > > + * Substitute (4) into (3) and simplify: > > + * > > + * y = c(a/u)/a > > + * y = c/u (5) > > + * > > + * Square (4) and (5) and add: > > + * > > + * x^2+y^2 = (a^2+c^2)/u^2 > > + * > > + * But x^2+y^2 is 1: > > + * > > + * 1 = (a^2+c^2)/u^2 > > + * u^2 = a^2+c^2 > > + * u = hypot(a,c) > > + * > > + * Similarily the max/min of v is at: > > + * > > + * v = hypot(b,d) > > + * > > + */ > > static void > > compute_extents (pixman_f_transform_t *trans, double *sx, double *sy) > > { > > - double min_x, max_x, min_y, max_y; > > - pixman_f_vector_t v[4] = > > - { > > - { { 1, 1, 1 } }, > > - { { -1, 1, 1 } }, > > - { { -1, -1, 1 } }, > > - { { 1, -1, 1 } }, > > - }; > > - > > - pixman_f_transform_point (trans, &v[0]); > > - pixman_f_transform_point (trans, &v[1]); > > - pixman_f_transform_point (trans, &v[2]); > > - pixman_f_transform_point (trans, &v[3]); > > - > > - min_x = min4 (v[0].v[0], v[1].v[0], v[2].v[0], v[3].v[0]); > > - max_x = max4 (v[0].v[0], v[1].v[0], v[2].v[0], v[3].v[0]); > > - min_y = min4 (v[0].v[1], v[1].v[1], v[2].v[1], v[3].v[1]); > > - max_y = max4 (v[0].v[1], v[1].v[1], v[2].v[1], v[3].v[1]); > > - > > - *sx = (max_x - min_x) / 2.0; > > - *sy = (max_y - min_y) / 2.0; > > + *sx = hypot (trans->m[0][0], trans->m[0][1]) / trans->m[2][2]; > > + *sy = hypot (trans->m[1][0], trans->m[1][1]) / trans->m[2][2]; > > } > > > > typedef struct > > -- > > 1.9.1 > > > > _______________________________________________ > > Pixman mailing list > > Pixman@lists.freedesktop.org > > http://lists.freedesktop.org/mailman/listinfo/pixman > > Reviewed-by: Oded Gabbay <oded.gab...@gmail.com> > > p.s. if we have additional versions of this patch series, and patches > that got r-b are not modified, then please add my r-b to the patch so > I would know I don't need to spend even a second over that patch. > > Thanks >
_______________________________________________ Pixman mailing list Pixman@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/pixman