cedric pushed a commit to branch master.
http://git.enlightenment.org/core/efl.git/commit/?id=ddb8515930c2da8364d7be6f363faafcaa7ea334
commit ddb8515930c2da8364d7be6f363faafcaa7ea334
Author: Subhransu Mohanty <sub.moha...@samsung.com>
Date: Wed Apr 8 14:13:15 2015 +0900
eina: add Eina_Bezier infrastructure for manipulating cubic bezier curves.
---
src/Makefile_Eina.am | 6 +-
src/lib/eina/Eina.h | 1 +
src/lib/eina/eina_bezier.c | 275 +++++++++++++++++++++++++++++++++++++++++++++
src/lib/eina/eina_bezier.h | 146 ++++++++++++++++++++++++
4 files changed, 426 insertions(+), 2 deletions(-)
diff --git a/src/Makefile_Eina.am b/src/Makefile_Eina.am
index aab92e2..0f1542d 100644
--- a/src/Makefile_Eina.am
+++ b/src/Makefile_Eina.am
@@ -92,7 +92,8 @@ lib/eina/eina_crc.h \
lib/eina/eina_inline_crc.x \
lib/eina/eina_evlog.h \
lib/eina/eina_util.h \
-lib/eina/eina_quaternion.h
+lib/eina/eina_quaternion.h \
+lib/eina/eina_bezier.h
lib_eina_libeina_la_SOURCES = \
lib/eina/eina_abi.c \
@@ -161,7 +162,8 @@ lib/eina/eina_debug.h \
lib/eina/eina_private.h \
lib/eina/eina_share_common.h \
lib/eina/eina_strbuf_common.h \
-lib/eina/eina_quaternion.c
+lib/eina/eina_quaternion.c \
+lib/eina/eina_bezier.c
if HAVE_WIN32
lib_eina_libeina_la_SOURCES += lib/eina/eina_file_win32.c
diff --git a/src/lib/eina/Eina.h b/src/lib/eina/Eina.h
index 9e1918c..97cdd3d 100644
--- a/src/lib/eina/Eina.h
+++ b/src/lib/eina/Eina.h
@@ -267,6 +267,7 @@ extern "C" {
#include <eina_evlog.h>
#include <eina_util.h>
#include <eina_quaternion.h>
+#include <eina_bezier.h>
#undef EAPI
#define EAPI
diff --git a/src/lib/eina/eina_bezier.c b/src/lib/eina/eina_bezier.c
new file mode 100644
index 0000000..4e8ffca
--- /dev/null
+++ b/src/lib/eina/eina_bezier.c
@@ -0,0 +1,275 @@
+/* EINA - EFL data type library
+ * Copyright (C) 2015 Subhransu Mohanty
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library;
+ * if not, see <http://www.gnu.org/licenses/>.
+ */
+#include "eina_private.h"
+#include "eina_bezier.h"
+
+#include <math.h>
+#include <float.h>
+
+#define FLOAT_CMP(a, b) (fabs(a - b) <= 0.01/* DBL_MIN */)
+
+static void
+_eina_bezier_1st_derivative(const Eina_Bezier *bz,
+ double t,
+ double *px, double *py)
+{
+ // p'(t) = 3 * (-(1-2t+t^2) * p0 + (1 - 4 * t + 3 * t^2) * p1 + (2 * t - 3
* t^2) * p2 + t^2 * p3)
+
+ double m_t = 1. - t;
+
+ double d = t * t;
+ double a = -m_t * m_t;
+ double b = 1 - 4 * t + 3 * d;
+ double c = 2 * t - 3 * d;
+
+ *px = 3 * ( a * bz->start.x + b * bz->ctrl_start.x + c * bz->ctrl_end.x + d
* bz->end.x);
+ *py = 3 * ( a * bz->start.y + b * bz->ctrl_start.y + c * bz->ctrl_end.y + d
* bz->end.y);
+}
+
+// approximate sqrt(x*x + y*y) using alpha max plus beta min algorithm.
+// With alpha = 1, beta = 3/8, giving results with a largest error less
+// than 7% compared to the exact value.
+static double
+_line_length(double x1, double y1, double x2, double y2)
+{
+ double x = x2 - x1;
+ double y = y2 - y1;
+
+ x = x < 0 ? -x : x;
+ y = y < 0 ? -y : y;
+
+ return (x > y ? x + 0.375 * y : y + 0.375 * x);
+}
+
+static void
+_eina_bezier_split(const Eina_Bezier *b,
+ Eina_Bezier *first, Eina_Bezier *second)
+{
+ double c = (b->ctrl_start.x + b->ctrl_end.x) * 0.5;
+
+ first->ctrl_start.x = (b->start.x + b->ctrl_start.x) * 0.5;
+ second->ctrl_end.x = (b->ctrl_end.x + b->end.x) * 0.5;
+ first->start.x = b->start.x;
+ second->end.x = b->end.x;
+ first->ctrl_end.x = (first->ctrl_start.x + c) * 0.5;
+ second->ctrl_start.x = (second->ctrl_end.x + c) * 0.5;
+ first->end.x = second->start.x = (first->ctrl_end.x + second->ctrl_start.x)
* 0.5;
+
+ c = (b->ctrl_start.y + b->ctrl_end.y) / 2;
+ first->ctrl_start.y = (b->start.y + b->ctrl_start.y) * 0.5;
+ second->ctrl_end.y = (b->ctrl_end.y + b->end.y) * 0.5;
+ first->start.y = b->start.y;
+ second->end.y = b->end.y;
+ first->ctrl_end.y = (first->ctrl_start.y + c) * 0.5;
+ second->ctrl_start.y = (second->ctrl_end.y + c) * 0.5;
+ first->end.y = second->start.y = (first->ctrl_end.y + second->ctrl_start.y)
* 0.5;
+}
+
+static void
+_eina_bezier_length_helper(const Eina_Bezier *b,
+ double *length)
+{
+ Eina_Bezier left, right; /* bez poly splits */
+ double len = 0.0; /* arc length */
+ double chord; /* chord length */
+
+ len = len + _line_length(b->start.x, b->start.y, b->ctrl_start.x,
b->ctrl_start.y);
+ len = len + _line_length(b->ctrl_start.x, b->ctrl_start.y, b->ctrl_end.x,
b->ctrl_end.y);
+ len = len + _line_length(b->ctrl_end.x, b->ctrl_end.y, b->end.x, b->end.y);
+
+ chord = _line_length(b->start.x, b->start.y, b->end.x, b->end.y);
+
+ if (!FLOAT_CMP(len, chord)) {
+ _eina_bezier_split(b, &left, &right); /* split in two */
+ _eina_bezier_length_helper(&left, length); /* try left side */
+ _eina_bezier_length_helper(&right, length); /* try right side */
+ return;
+ }
+
+ *length = *length + len;
+
+ return;
+}
+
+EAPI void
+eina_bezier_values_set(Eina_Bezier *b,
+ double start_x, double start_y,
+ double ctrl_start_x, double ctrl_start_y,
+ double ctrl_end_x, double ctrl_end_y,
+ double end_x, double end_y)
+{
+ b->start.x = start_x;
+ b->start.y = start_y;
+ b->ctrl_start.x = ctrl_start_x;
+ b->ctrl_start.y = ctrl_start_y;
+ b->ctrl_end.x = ctrl_end_x;
+ b->ctrl_end.y = ctrl_end_y;
+ b->end.x = end_x;
+ b->end.y = end_y;
+}
+
+EAPI void
+eina_bezier_values_get(const Eina_Bezier *b,
+ double *start_x, double *start_y,
+ double *ctrl_start_x, double *ctrl_start_y,
+ double *ctrl_end_x, double *ctrl_end_y,
+ double *end_x, double *end_y)
+{
+ if (start_x) *start_x = b->start.x;
+ if (start_y) *start_y = b->start.y;
+ if (ctrl_start_x) *ctrl_start_x = b->ctrl_start.x;
+ if (ctrl_start_y) *ctrl_start_y = b->ctrl_start.y;
+ if (ctrl_end_x) *ctrl_end_x = b->ctrl_end.x;
+ if (ctrl_end_y) *ctrl_end_y = b->ctrl_end.y;
+ if (end_x) *end_x = b->end.x;
+ if (end_y) *end_y = b->end.y;
+}
+
+
+EAPI void
+eina_bezier_point_at(const Eina_Bezier *bz, double t, double *px, double *py)
+{
+ double m_t = 1.0 - t;
+
+ if (px)
+ {
+ double a = bz->start.x * m_t + bz->ctrl_start.x * t;
+ double b = bz->ctrl_start.x * m_t + bz->ctrl_end.x * t;
+ double c = bz->ctrl_end.x * m_t + bz->end.x * t;
+
+ a = a * m_t + b * t;
+ b = b * m_t + c * t;
+ *px = a * m_t + b * t;
+ }
+
+ if (py)
+ {
+ double a = bz->start.y * m_t + bz->ctrl_start.y * t;
+ double b = bz->ctrl_start.y * m_t + bz->ctrl_end.y * t;
+ double c = bz->ctrl_end.y * m_t + bz->end.y * t;
+
+ a = a * m_t + b * t;
+ b = b * m_t + c * t;
+ *py = a * m_t + b * t;
+ }
+}
+
+EAPI double
+eina_bezier_angle_at(const Eina_Bezier *b, double t)
+{
+ double x, y;
+ double theta;
+ double theta_normalized;
+
+ _eina_bezier_1st_derivative(b, t, &x, &y);
+ theta = atan2(y, x) * 360.0 / (M_PI * 2);
+ theta_normalized = theta < 0 ? theta + 360 : theta;
+
+ return theta_normalized;
+}
+
+EAPI double
+eina_bezier_length_get(const Eina_Bezier *b)
+{
+ double length = 0.0;
+
+ _eina_bezier_length_helper(b, &length);
+
+ return length;
+}
+
+static void
+_eina_bezier_split_left(Eina_Bezier *b, double t, Eina_Bezier *left)
+{
+ Eina_Bezier local;
+
+ if (!left) left = &local;
+
+ left->start.x = b->start.x;
+ left->start.y = b->start.y;
+
+ left->ctrl_start.x = b->start.x + t * ( b->ctrl_start.x - b->start.x );
+ left->ctrl_start.y = b->start.y + t * ( b->ctrl_start.y - b->start.y );
+
+ left->ctrl_end.x = b->ctrl_start.x + t * ( b->ctrl_end.x - b->ctrl_start.x
); // temporary holding spot
+ left->ctrl_end.y = b->ctrl_start.y + t * ( b->ctrl_end.y - b->ctrl_start.y
); // temporary holding spot
+
+ b->ctrl_end.x = b->ctrl_end.x + t * ( b->end.x - b->ctrl_end.x );
+ b->ctrl_end.y = b->ctrl_end.y + t * ( b->end.y - b->ctrl_end.y );
+
+ b->ctrl_start.x = left->ctrl_end.x + t * ( b->ctrl_end.x -
left->ctrl_end.x);
+ b->ctrl_start.y = left->ctrl_end.y + t * ( b->ctrl_end.y -
left->ctrl_end.y);
+
+ left->ctrl_end.x = left->ctrl_start.x + t * ( left->ctrl_end.x -
left->ctrl_start.x );
+ left->ctrl_end.y = left->ctrl_start.y + t * ( left->ctrl_end.y -
left->ctrl_start.y );
+
+ left->end.x = b->start.x = left->ctrl_end.x + t * (b->ctrl_start.x -
left->ctrl_end.x);
+ left->end.y = b->start.y = left->ctrl_end.y + t * (b->ctrl_start.y -
left->ctrl_end.y);
+}
+
+EAPI double
+eina_bezier_t_at(const Eina_Bezier *b, double l)
+{
+ double len = eina_bezier_length_get(b);
+ double biggest = 1.0;
+ double t = 1.0;
+
+ if (l > len || (FLOAT_CMP(len, l)))
+ return t;
+
+ t *= 0.5;
+
+ while (1)
+ {
+ Eina_Bezier right = *b;
+ Eina_Bezier left;
+ double ll;
+
+ _eina_bezier_split_left(&right, t, &left);
+ ll = eina_bezier_length_get(&left);
+
+ if (FLOAT_CMP(ll, l))
+ break;
+
+ if (ll < l)
+ {
+ t += (biggest - t) * 0.5;
+ }
+ else
+ {
+ biggest = t;
+ t -= t * 0.5;
+ }
+ }
+
+ return t;
+}
+
+EAPI void
+eina_bezier_split_at_length(const Eina_Bezier *b, double len,
+ Eina_Bezier *left, Eina_Bezier *right)
+{
+ Eina_Bezier local;
+ double t;
+
+ if (!right) right = &local;
+ *right = *b;
+
+ t = eina_bezier_t_at(right, len);
+ _eina_bezier_split_left(right, t, left);
+}
diff --git a/src/lib/eina/eina_bezier.h b/src/lib/eina/eina_bezier.h
new file mode 100644
index 0000000..e15acc2
--- /dev/null
+++ b/src/lib/eina/eina_bezier.h
@@ -0,0 +1,146 @@
+/* EINA - EFL data type library
+ * Copyright (C) 2015 Subhransu Mohanty
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library;
+ * if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef EINA_BEZIER_H
+#define EINA_BEZIER_H
+
+/**
+ * Floating point cubic bezier curve
+ */
+typedef struct _Eina_Bezier Eina_Bezier;
+
+struct _Eina_Bezier
+{
+ struct {
+ double x; /**< x coordinate of start point */
+ double y; /**< y coordinate of start point */
+ } start;
+
+ struct {
+ double x; /**< x coordinate of 1st control point */
+ double y; /**< y coordinate of 1st control point */
+ } ctrl_start;
+
+ struct {
+ double x; /**< coordinate of 2nd control point */
+ double y; /**< y coordinate of 2nd control point */
+ } ctrl_end;
+
+ struct {
+ double x; /**< x coordinate of end point */
+ double y; /**< y coordinate of end point */
+ } end;
+};
+
+/**
+ * @brief Set the values of the points of the given floating
+ * point cubic bezier curve.
+ *
+ * @param b The floating point bezier.
+ * @param start_x x coordinate of start point.
+ * @param start_y y coordinate of start point.
+ * @param ctrl_start_x x coordinate of 1st control point.
+ * @param ctrl_start_y y coordinate of 1st control point.
+ * @param ctrl_end_x x coordinate of 2nd control point.
+ * @param ctrl_end_y y coordinate of 2nd control point.
+ * @param end_x x coordinate of end point.
+ * @param end_y y coordinate of end point.
+ *
+ * @p b. No check is done on @p b.
+ *
+ */
+EAPI void eina_bezier_values_set(Eina_Bezier *b, double start_x, double
start_y, double ctrl_start_x, double ctrl_start_y, double ctrl_end_x, double
ctrl_end_y, double end_x, double end_y) EINA_ARG_NONNULL(1);
+
+/**
+ * @brief Get the values of the points of the given floating
+ * point cubic bezier curve.
+ *
+ * @param b The floating point bezier.
+ * @param start_x x coordinate of start point.
+ * @param start_y y coordinate of start point.
+ * @param ctrl_start_x x coordinate of 1st control point.
+ * @param ctrl_start_y y coordinate of 1st control point.
+ * @param ctrl_end_x x coordinate of 2nd control point.
+ * @param ctrl_end_y y coordinate of 2nd control point.
+ * @param end_x x coordinate of end point.
+ * @param end_y y coordinate of end point.
+ *
+ * @p b. No check is done on @p b.
+ *
+ */
+EAPI void eina_bezier_values_get(const Eina_Bezier *b, double *start_x, double
*start_y, double *ctrl_start_x, double *ctrl_start_y, double *ctrl_end_x,
double *ctrl_end_y, double *end_x, double *end_y) EINA_ARG_NONNULL(1);
+
+/**
+ * @brief Returns the length of the given floating
+ * point cubic bezier curve.
+ *
+ * @param b The floating point bezier.
+ *
+ * @p b. No check is done on @p b.
+ *
+ */
+EAPI double eina_bezier_length_get(const Eina_Bezier *b) EINA_ARG_NONNULL(1);
+
+/**
+ * @brief Returns the position of the given bezier
+ * at given length.
+ *
+ * @param b The floating point bezier.
+ * @param len The given length.
+ *
+ * @p b. No check is done on @p b.
+ *
+ */
+EAPI double eina_bezier_t_at(const Eina_Bezier *b, double len)
EINA_ARG_NONNULL(1);
+
+/**
+ * @brief Gets the point on the bezier curve at
+ * position t.
+ *
+ * @param b The floating point bezier.
+ * @param t The floating point position.
+ *
+ * @p b. No check is done on @p b.
+ *
+ */
+EAPI void eina_bezier_point_at(const Eina_Bezier *b, double t, double *px,
double *py) EINA_ARG_NONNULL(1);
+
+/**
+ * @brief Returns the slope of the bezier
+ * at given length.
+ *
+ * @param b The floating point bezier.
+ * @param len The given length.
+ *
+ * @p b. No check is done on @p b.
+ *
+ */
+EAPI double eina_bezier_angle_at(const Eina_Bezier *b, double t)
EINA_ARG_NONNULL(1);
+
+/**
+ * @brief split the bezier at given length.
+ *
+ * @param b The floating point bezier.
+ * @param len The given length.
+ *
+ * @p b. No check is done on @p b.
+ *
+ */
+EAPI void eina_bezier_split_at_length(const Eina_Bezier *b, double len,
Eina_Bezier *left, Eina_Bezier *right) EINA_ARG_NONNULL(1);
+
+#endif // EINA_BEZIER_H
--
