Adding improve corner radius.
diff --git a/include/rive/math/vec2d.hpp b/include/rive/math/vec2d.hpp
index 21dcdd4..f2e7ec3 100644
--- a/include/rive/math/vec2d.hpp
+++ b/include/rive/math/vec2d.hpp
@@ -46,6 +46,7 @@
static Vec2D transformDir(const Vec2D& a, const Mat2D& m);
static float dot(Vec2D a, Vec2D b) { return a.x * b.x + a.y * b.y; }
+ static float cross(Vec2D a, Vec2D b) { return a.x * b.y - a.y * b.x; }
static Vec2D scaleAndAdd(Vec2D a, Vec2D b, float scale) {
return {
a.x + b.x * scale,
diff --git a/src/shapes/path.cpp b/src/shapes/path.cpp
index f6090fd..af2b688 100644
--- a/src/shapes/path.cpp
+++ b/src/shapes/path.cpp
@@ -1,15 +1,26 @@
#include "rive/shapes/path.hpp"
-#include "rive/math/circle_constant.hpp"
#include "rive/renderer.hpp"
#include "rive/shapes/cubic_vertex.hpp"
#include "rive/shapes/cubic_detached_vertex.hpp"
#include "rive/shapes/path_vertex.hpp"
#include "rive/shapes/shape.hpp"
#include "rive/shapes/straight_vertex.hpp"
+#include "rive/math/math_types.hpp"
#include <cassert>
using namespace rive;
+/// Compute an ideal control point distance to create a curve of the given
+/// radius.
+static float
+computeIdealControlPointDistance(const Vec2D& toPrev, const Vec2D& toNext, float radius) {
+ // Get the angle between next and prev
+ float angle = fabs(atan2(Vec2D::cross(toPrev, toNext), Vec2D::dot(toPrev, toNext)));
+
+ return (4.0f / 3.0f) * tan(math::PI / (2.0f * ((2.0f * math::PI) / angle))) * radius *
+ (angle < math::PI / 2 ? 1 + cos(angle) : 2.0f - sin(angle));
+}
+
StatusCode Path::onAddedClean(CoreContext* context) {
StatusCode code = Super::onAddedClean(context);
if (code != StatusCode::Ok) {
@@ -89,13 +100,15 @@
pos;
auto toNextLength = toNext.normalizeLength();
- float renderRadius = std::min(toPrevLength, std::min(toNextLength, radius));
+ float renderRadius =
+ std::min(toPrevLength / 2.0f, std::min(toNextLength / 2.0f, radius));
+ float idealDistance = computeIdealControlPointDistance(toPrev, toNext, renderRadius);
startIn = start = Vec2D::scaleAndAdd(pos, toPrev, renderRadius);
commandPath.move(startIn);
- Vec2D outPoint = Vec2D::scaleAndAdd(pos, toPrev, icircleConstant * renderRadius);
- Vec2D inPoint = Vec2D::scaleAndAdd(pos, toNext, icircleConstant * renderRadius);
+ Vec2D outPoint = Vec2D::scaleAndAdd(pos, toPrev, renderRadius - idealDistance);
+ Vec2D inPoint = Vec2D::scaleAndAdd(pos, toNext, renderRadius - idealDistance);
out = Vec2D::scaleAndAdd(pos, toNext, renderRadius);
commandPath.cubic(outPoint, inPoint, out);
prevIsCubic = false;
@@ -122,7 +135,10 @@
Vec2D pos = point.renderTranslation();
auto radius = point.radius();
if (radius > 0.0f) {
- Vec2D toPrev = out - pos;
+ auto prev = vertices[i - 1];
+ Vec2D toPrev = (prev->is<CubicVertex>() ? prev->as<CubicVertex>()->renderOut()
+ : prev->renderTranslation()) -
+ pos;
auto toPrevLength = toPrev.normalizeLength();
auto next = vertices[(i + 1) % length];
@@ -132,7 +148,10 @@
pos;
auto toNextLength = toNext.normalizeLength();
- float renderRadius = std::min(toPrevLength, std::min(toNextLength, radius));
+ float renderRadius =
+ std::min(toPrevLength / 2.0f, std::min(toNextLength / 2.0f, radius));
+ float idealDistance =
+ computeIdealControlPointDistance(toPrev, toNext, renderRadius);
Vec2D translation = Vec2D::scaleAndAdd(pos, toPrev, renderRadius);
if (prevIsCubic) {
@@ -141,8 +160,8 @@
commandPath.line(translation);
}
- Vec2D outPoint = Vec2D::scaleAndAdd(pos, toPrev, icircleConstant * renderRadius);
- Vec2D inPoint = Vec2D::scaleAndAdd(pos, toNext, icircleConstant * renderRadius);
+ Vec2D outPoint = Vec2D::scaleAndAdd(pos, toPrev, renderRadius - idealDistance);
+ Vec2D inPoint = Vec2D::scaleAndAdd(pos, toNext, renderRadius - idealDistance);
out = Vec2D::scaleAndAdd(pos, toNext, renderRadius);
commandPath.cubic(outPoint, inPoint, out);
prevIsCubic = false;
@@ -260,11 +279,13 @@
Vec2D toNext = nextPoint - pos;
auto toNextLength = toNext.normalizeLength();
- auto renderRadius =
- std::min(toPrevLength, std::min(toNextLength, point.radius()));
+ auto renderRadius = std::min(toPrevLength / 2.0f,
+ std::min(toNextLength / 2.0f, point.radius()));
+ float idealDistance =
+ computeIdealControlPointDistance(toPrev, toNext, renderRadius);
Vec2D translation = Vec2D::scaleAndAdd(pos, toPrev, renderRadius);
- Vec2D out = Vec2D::scaleAndAdd(pos, toPrev, icircleConstant * renderRadius);
+ Vec2D out = Vec2D::scaleAndAdd(pos, toPrev, renderRadius - idealDistance);
{
auto v1 = new DisplayCubicVertex(translation, out, translation);
flat->addVertex(v1, transform);
@@ -273,7 +294,7 @@
translation = Vec2D::scaleAndAdd(pos, toNext, renderRadius);
- Vec2D in = Vec2D::scaleAndAdd(pos, toNext, icircleConstant * renderRadius);
+ Vec2D in = Vec2D::scaleAndAdd(pos, toNext, renderRadius - idealDistance);
auto v2 = new DisplayCubicVertex(in, translation, translation);
flat->addVertex(v2, transform);
@@ -330,4 +351,4 @@
}
}
-#endif
+#endif
\ No newline at end of file
