static inline int
fill_linear_color_triangle(gx_device *dev, const gs_fill_attributes *fa,
const gs_fixed_point *p0, const gs_fixed_point *p1,
const gs_fixed_point *p2,
const frac31 *c0, const frac31 *c1, const frac31 *c2)
{ /* p0 must be the lowest vertex. */
int code;
gs_linear_color_edge e0, e1, e2;
int num_components = dev->color_info.num_components;
if (p0->y == p1->y)
return gx_default_fill_linear_color_trapezoid(dev, fa, p0, p2, p1, p2, c0, c2, c1, c2);
if (p1->y == p2->y)
return gx_default_fill_linear_color_trapezoid(dev, fa, p0, p2, p0, p1, c0, c2, c0, c1);
e0.start = *p0;
e0.end = *p2;
e0.c0 = c0;
e0.c1 = c2;
e0.clip_x = fa->clip->p.x;
e1.start = *p0;
e1.end = *p1;
e1.c0 = c0;
e1.c1 = c1;
e1.clip_x = fa->clip->q.x;
if (p0->y < p1->y && p1->y < p2->y) {
e2.start = *p1;
e2.end = *p2;
e2.c0 = c1;
e2.c1 = c2;
e2.clip_x = fa->clip->q.x;
if (check_gradient_overflow(&e0, &e1, num_components))
return 0;
if (check_gradient_overflow(&e0, &e2, num_components))
return 0;
code = fill_linear_color_trapezoid_nocheck(dev, fa, &e0, &e1);
if (code <= 0) /* Sic! */
return code;
return fill_linear_color_trapezoid_nocheck(dev, fa, &e0, &e2);
} else { /* p0->y < p2->y && p2->y < p1->y */
e2.start = *p2;
e2.end = *p1;
e2.c0 = c2;
e2.c1 = c1;
e2.clip_x = fa->clip->q.x;
if (check_gradient_overflow(&e0, &e1, num_components))
return 0;
if (check_gradient_overflow(&e2, &e1, num_components))
return 0;
code = fill_linear_color_trapezoid_nocheck(dev, fa, &e0, &e1);
if (code <= 0) /* Sic! */
return code;
return fill_linear_color_trapezoid_nocheck(dev, fa, &e2, &e1);
}
}
/* Fill a trapezoid with a linear color.
[p0 : p1] - left edge, from bottom to top.
[p2 : p3] - right edge, from bottom to top.
The filled area is within Y-spans of both edges.
This implemetation actually handles a bilinear color,
in which the generatrix keeps a parallelizm to the X axis.
In general a bilinear function doesn't keep the generatrix parallelizm,
so the caller must decompose/approximate such functions.
Return values :
1 - success;
0 - Too big. The area isn't filled. The client must decompose the area.
<0 - error.
*/
int
gx_default_fill_linear_color_trapezoid(gx_device *dev, const gs_fill_attributes *fa,
const gs_fixed_point *p0, const gs_fixed_point *p1,
const gs_fixed_point *p2, const gs_fixed_point *p3,
const frac31 *c0, const frac31 *c1,
const frac31 *c2, const frac31 *c3)
{
gs_linear_color_edge le, re;
le.start = *p0;
le.end = *p1;
le.c0 = c0;
le.c1 = c1;
le.clip_x = fa->clip->p.x;
re.start = *p2;
re.end = *p3;
re.c0 = c2;
re.c1 = c3;
re.clip_x = fa->clip->q.x;
if (check_gradient_overflow(&le, &re))
return 0;
return fill_linear_color_trapezoid_nocheck(dev, fa, &le, &re);
}