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author | Matthew Barnes <mbarnes@redhat.com> | 2010-06-14 06:37:27 +0800 |
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committer | Matthew Barnes <mbarnes@redhat.com> | 2010-06-14 09:31:58 +0800 |
commit | e6972011f01eab9f8d0a4584f32ee1e2a00f3231 (patch) | |
tree | 69e2a5e846965c3b369724b825f5b35c6d88056a /libart_lgpl/art_rgb_affine_private.c | |
parent | 7f3377c78a560aa762e04d596b79f847c4acd870 (diff) | |
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Embed libart_lgpl and libgnomecanvas.
Both of these modules are deprecated and going away in GNOME 3 but we
still rely heavily on them for GnomeCalendar and ETable. So, welcome
to the island of unwanted libraries...
Diffstat (limited to 'libart_lgpl/art_rgb_affine_private.c')
-rw-r--r-- | libart_lgpl/art_rgb_affine_private.c | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/libart_lgpl/art_rgb_affine_private.c b/libart_lgpl/art_rgb_affine_private.c new file mode 100644 index 0000000000..679e114c14 --- /dev/null +++ b/libart_lgpl/art_rgb_affine_private.c @@ -0,0 +1,127 @@ +/* Libart_LGPL - library of basic graphic primitives + * Copyright (C) 1998 Raph Levien + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Library General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Library General Public License for more details. + * + * You should have received a copy of the GNU Library General Public + * License along with this library; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 02111-1307, USA. + */ + +#include "config.h" +#include "art_rgb_affine_private.h" + +#include <math.h> +#include "art_misc.h" +#include "art_point.h" +#include "art_affine.h" + +/* Private functions for the rgb affine image compositors - primarily, + the determination of runs, eliminating the need for source image + bbox calculation in the inner loop. */ + +/* Determine a "run", such that the inverse affine of all pixels from + (x0, y) inclusive to (x1, y) exclusive fit within the bounds + of the source image. + + Initial values of x0, x1, and result values stored in first two + pointer arguments. +*/ + +#define EPSILON 1e-6 + +void +art_rgb_affine_run (int *p_x0, int *p_x1, int y, + int src_width, int src_height, + const double affine[6]) +{ + int x0, x1; + double z; + double x_intercept; + int xi; + + x0 = *p_x0; + x1 = *p_x1; + + /* do left and right edges */ + if (affine[0] > EPSILON) + { + z = affine[2] * (y + 0.5) + affine[4]; + x_intercept = -z / affine[0]; + xi = ceil (x_intercept + EPSILON - 0.5); + if (xi > x0) + x0 = xi; + x_intercept = (-z + src_width) / affine[0]; + xi = ceil (x_intercept - EPSILON - 0.5); + if (xi < x1) + x1 = xi; + } + else if (affine[0] < -EPSILON) + { + z = affine[2] * (y + 0.5) + affine[4]; + x_intercept = (-z + src_width) / affine[0]; + xi = ceil (x_intercept + EPSILON - 0.5); + if (xi > x0) + x0 = xi; + x_intercept = -z / affine[0]; + xi = ceil (x_intercept - EPSILON - 0.5); + if (xi < x1) + x1 = xi; + } + else + { + z = affine[2] * (y + 0.5) + affine[4]; + if (z < 0 || z >= src_width) + { + *p_x1 = *p_x0; + return; + } + } + + /* do top and bottom edges */ + if (affine[1] > EPSILON) + { + z = affine[3] * (y + 0.5) + affine[5]; + x_intercept = -z / affine[1]; + xi = ceil (x_intercept + EPSILON - 0.5); + if (xi > x0) + x0 = xi; + x_intercept = (-z + src_height) / affine[1]; + xi = ceil (x_intercept - EPSILON - 0.5); + if (xi < x1) + x1 = xi; + } + else if (affine[1] < -EPSILON) + { + z = affine[3] * (y + 0.5) + affine[5]; + x_intercept = (-z + src_height) / affine[1]; + xi = ceil (x_intercept + EPSILON - 0.5); + if (xi > x0) + x0 = xi; + x_intercept = -z / affine[1]; + xi = ceil (x_intercept - EPSILON - 0.5); + if (xi < x1) + x1 = xi; + } + else + { + z = affine[3] * (y + 0.5) + affine[5]; + if (z < 0 || z >= src_height) + { + *p_x1 = *p_x0; + return; + } + } + + *p_x0 = x0; + *p_x1 = x1; +} |