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gsk: Add some private transform apis

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Some of the graphene_matrix_transform apis don't work
correctly with projective matrices, so add our own
variants.
This commit is contained in:
Matthias Clasen 2020-09-01 08:36:45 -04:00
parent 9377ce984d
commit 99a7a2188a
2 changed files with 87 additions and 0 deletions
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77
gsk/gsktransform.c
View File

@ -2165,3 +2165,80 @@ gsk_transform_parse (const char *string,
return result;
}
/* Some of the graphene_matrix_transform apis yield unexpected
* results with projective matrices, since they silently drop
* the w component, so we provide working alternatives here.
*/
void
gsk_matrix_transform_point (const graphene_matrix_t *m,
const graphene_point_t *p,
graphene_point_t *res)
{
graphene_vec4_t vec4;
float w;
graphene_vec4_init (&vec4, p->x, p->y, 0.0f, 1.0f);
graphene_matrix_transform_vec4 (m, &vec4, &vec4);
w = graphene_vec4_get_w (&vec4);
res->x = graphene_vec4_get_x (&vec4) / w;
res->y = graphene_vec4_get_y (&vec4) / w;
}
void
gsk_matrix_transform_point3d (const graphene_matrix_t *m,
const graphene_point3d_t *p,
graphene_point3d_t *res)
{
graphene_vec4_t vec4;
float w;
graphene_vec4_init (&vec4, p->x, p->y, 0.0f, 1.0f);
graphene_matrix_transform_vec4 (m, &vec4, &vec4);
w = graphene_vec4_get_w (&vec4);
res->x = graphene_vec4_get_x (&vec4) / w;
res->y = graphene_vec4_get_y (&vec4) / w;
res->z = graphene_vec4_get_z (&vec4) / w;
}
void
gsk_matrix_transform_bounds (const graphene_matrix_t *m,
const graphene_rect_t *r,
graphene_rect_t *res)
{
graphene_point_t ret[4];
float min_x, min_y;
float max_x, max_y;
graphene_rect_t rr;
graphene_rect_normalize_r (r, &rr);
#define TRANSFORM_POINT(matrix, rect, corner, out_p) do {\
graphene_vec4_t __s; \
graphene_point_t __p; \
float w; \
graphene_rect_get_ ## corner (rect, &__p); \
graphene_vec4_init (&__s, __p.x, __p.y, 0.f, 1.f); \
graphene_matrix_transform_vec4 (matrix, &__s, &__s); \
w = graphene_vec4_get_w (&__s); \
out_p.x = graphene_vec4_get_x (&__s) / w; \
out_p.y = graphene_vec4_get_y (&__s) / w; } while (0)
TRANSFORM_POINT (m, &rr, top_left, ret[0]);
TRANSFORM_POINT (m, &rr, top_right, ret[1]);
TRANSFORM_POINT (m, &rr, bottom_right, ret[2]);
TRANSFORM_POINT (m, &rr, bottom_left, ret[3]);
#undef TRANSFORM_POINT
/* FIXME: graphene doesn't export a fast way to do this */
min_x = MIN (MIN (ret[0].x, ret[1].x), MIN (ret[2].x, ret[3].x));
min_y = MIN (MIN (ret[0].y, ret[1].y), MIN (ret[2].y, ret[3].y));
max_x = MAX (MAX (ret[0].x, ret[1].x), MAX (ret[2].x, ret[3].x));
max_y = MAX (MAX (ret[0].y, ret[1].y), MAX (ret[2].y, ret[3].y));
graphene_rect_init (res, min_x, min_y, max_x - min_x, max_y - min_y);
}

10
gsk/gsktransformprivate.h
View File

@ -32,6 +32,16 @@ G_BEGIN_DECLS
gboolean gsk_transform_parser_parse (GtkCssParser *parser,
GskTransform **out_transform);
void gsk_matrix_transform_point (const graphene_matrix_t *m,
const graphene_point_t *p,
graphene_point_t *res);
void gsk_matrix_transform_point3d (const graphene_matrix_t *m,
const graphene_point3d_t *p,
graphene_point3d_t *res);
void gsk_matrix_transform_bounds (const graphene_matrix_t *m,
const graphene_rect_t *r,
graphene_rect_t *res);
G_END_DECLS