[Pixman] [PATCH pixman 01/15] demos/scale: Compute filter size using boundary of xformed ellipse, not rectangle
This is much more accurate and less blurry. In particular the filtering does
not change as the image is rotated.
---
demos/scale.c | 43 ++-
1 file changed, 2 insertions(+), 41 deletions(-)
diff --git a/demos/scale.c b/demos/scale.c
index d00307e..71c7791 100644
--- a/demos/scale.c
+++ b/demos/scale.c
@@ -55,50 +55,11 @@ 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);
-}
-
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
--
1.7.9.5
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[Pixman] [PATCH pixman 01/15] demos/scale: Compute filter size using boundary of xformed ellipse, not rectangle
This is much more accurate and less blurry. In particular the filtering does
not change as the image is rotated.
---
demos/scale.c | 43 ++-
1 file changed, 2 insertions(+), 41 deletions(-)
diff --git a/demos/scale.c b/demos/scale.c
index d00307e..71c7791 100644
--- a/demos/scale.c
+++ b/demos/scale.c
@@ -55,50 +55,11 @@ 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);
-}
-
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
--
1.7.9.5
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