static int merged_svg(gstack_t *ross, svg_t *svg)
{
svg_stop_t ss;
rgbop_stop_t ros;
while (gstack_pop(ross, &ros) == 0)
{
ss.colour.red = svg_it_rgb(ros.r);
ss.colour.green = svg_it_rgb(ros.g);
ss.colour.blue = svg_it_rgb(ros.b);
ss.opacity = svg_it_op(ros.op);
ss.value = svg_it_z(ros.z);
svg_append(ss,svg);
}
return 0;
}
static gstack_t* merge(gstack_t *rss, gstack_t *oss)
{
gstack_t *ross;
int err = 0;
size_t n = gstack_size(rss) + gstack_size(oss);
/* get the first two of each type of stop */
rgb_stop_t rs0, rs1;
err += gstack_pop(rss, &rs0);
err += gstack_pop(rss, &rs1);
if (err)
{
btrace("%i errors rgb", err);
return NULL;
}
op_stop_t os0, os1;
err += gstack_pop(oss, &os0);
err += gstack_pop(oss, &os1);
if (err)
{
btrace("%i errors op", err);
return NULL;
}
if ((rs0.z != 0) || (os0.z != 0))
{
btrace("nonzero initial stop");
btrace("RGB %.3f", svg_it_z(rs0.z));
btrace("Opacity %.3f", svg_it_z(os0.z));
return NULL;
}
/* merged stack to return */
if ((ross = gstack_new(sizeof(rgbop_stop_t), n, n)) == NULL)
return NULL;
rgbop_stop_t ros;
while (1)
{
ros = stop_merge(rs0, os0);
gstack_push(ross, &ros);
if (rs1.z > os1.z)
{
rs0 = rgb_stop_interp(rs0, rs1, os1.z);
os0 = os1;
if (gstack_pop(oss, &os1) != 0)
{
btrace("early termination of opacity channel");
break;
}
}
else if (rs1.z < os1.z)
{
os0 = op_stop_interp(os0, os1, rs1.z);
rs0 = rs1;
if (gstack_pop(rss, &rs1) != 0)
{
btrace("early termination of rgb channel");
break;
}
}
else
{
rs0 = rs1;
os0 = os1;
int
odone = gstack_pop(oss, &os1),
rdone = gstack_pop(rss, &rs1);
if (odone && rdone)
{
ros = stop_merge(rs0, os0);
gstack_push(ross, &ros);
gstack_reverse(ross);
return ross;
}
else if (odone && !rdone)
{
btrace("early termination of opacity channel");
break;
}
else if (rdone && ! odone)
{
btrace("early termination of rgb channel");
break;
}
else
{
/* OK, so now we continue */
}
}
}
/* something has gone pear-shaped */
gstack_destroy(ross);
btrace("merge failed");
return NULL;
}
