mirror
/
msdfgen
mirror of https://github.com/Chlumsky/msdfgen.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

Better edge deconverge procedure

This commit is contained in:
Chlumsky 2024-05-07 17:17:32 +02:00
parent 5dc5f6260b
commit d7ac1e084d
4 changed files with 22 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
core/Shape.cpp
View File

@ -4,6 +4,8 @@
#include <cstdlib>
#include "arithmetics.hpp"
#define DECONVERGE_OVERSHOOT 1.11111111111111111 // moves control points slightly more than necessary to account for floating-point errors
namespace msdfgen {
Shape::Shape() : inverseYAxis(false) { }
@ -39,13 +41,23 @@ bool Shape::validate() const {
return true;
}
static void deconvergeEdge(EdgeHolder &edgeHolder, int param) {
static void deconvergeEdge(EdgeHolder &edgeHolder, int param, Vector2 vector) {
switch (edgeHolder->type()) {
case (int) QuadraticSegment::EDGE_TYPE:
edgeHolder = static_cast<const QuadraticSegment *>(&*edgeHolder)->convertToCubic();
// fallthrough
case (int) CubicSegment::EDGE_TYPE:
static_cast<CubicSegment *>(&*edgeHolder)->deconverge(param, MSDFGEN_DECONVERGENCE_FACTOR);
{
Point2 *p = static_cast<CubicSegment *>(&*edgeHolder)->p;
switch (param) {
case 0:
p[1] += (p[1]-p[0]).length()*vector;
break;
case 1:
p[2] += (p[2]-p[3]).length()*vector;
break;
}
}
}
}
@ -59,13 +71,19 @@ void Shape::normalize() {
contour->edges.push_back(EdgeHolder(parts[1]));
contour->edges.push_back(EdgeHolder(parts[2]));
} else {
// Push apart convergent edge segments
EdgeHolder *prevEdge = &contour->edges.back();
for (std::vector<EdgeHolder>::iterator edge = contour->edges.begin(); edge != contour->edges.end(); ++edge) {
Vector2 prevDir = (*prevEdge)->direction(1).normalize();
Vector2 curDir = (*edge)->direction(0).normalize();
if (dotProduct(prevDir, curDir) < MSDFGEN_CORNER_DOT_EPSILON-1) {
deconvergeEdge(*prevEdge, 1);
deconvergeEdge(*edge, 0);
double factor = DECONVERGE_OVERSHOOT*sqrt(1-(MSDFGEN_CORNER_DOT_EPSILON-1)*(MSDFGEN_CORNER_DOT_EPSILON-1))/(MSDFGEN_CORNER_DOT_EPSILON-1);
Vector2 axis = factor*(curDir-prevDir).normalize();
// Determine curve ordering using third-order derivative (t = 0) of crossProduct((*prevEdge)->point(1-t)-p0, (*edge)->point(t)-p0) where p0 is the corner (*edge)->point(0)
if (crossProduct((*prevEdge)->directionChange(1), (*edge)->direction(0))+crossProduct((*edge)->directionChange(0), (*prevEdge)->direction(1)) < 0)
axis = -axis;
deconvergeEdge(*prevEdge, 1, axis.getOrthogonal(true));
deconvergeEdge(*edge, 0, axis.getOrthogonal(false));
}
prevEdge = &*edge;
}

2
core/Shape.h
View File

@ -9,8 +9,6 @@ namespace msdfgen {
// Threshold of the dot product of adjacent edge directions to be considered convergent.
#define MSDFGEN_CORNER_DOT_EPSILON .000001
// The proportional amount by which a curve's control point will be adjusted to eliminate convergent corners.
#define MSDFGEN_DECONVERGENCE_FACTOR .000001
/// Vector shape representation.
class Shape {

14
core/edge-segments.cpp
View File

@ -524,18 +524,4 @@ EdgeSegment *QuadraticSegment::convertToCubic() const {
return new CubicSegment(p[0], mix(p[0], p[1], 2/3.), mix(p[1], p[2], 1/3.), p[2], color);
}
void CubicSegment::deconverge(int param, double amount) {
Vector2 dir = direction(param);
Vector2 normal = dir.getOrthonormal();
double h = dotProduct(directionChange(param)-dir, normal);
switch (param) {
case 0:
p[1] += amount*(dir+sign(h)*sqrt(fabs(h))*normal);
break;
case 1:
p[2] -= amount*(dir-sign(h)*sqrt(fabs(h))*normal);
break;
}
}
}

2
core/edge-segments.h
View File

@ -141,8 +141,6 @@ public:
void moveEndPoint(Point2 to);
void splitInThirds(EdgeSegment *&part0, EdgeSegment *&part1, EdgeSegment *&part2) const;
void deconverge(int param, double amount);
};
}