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diff --git a/src/bezier.h b/src/bezier.h
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+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2016 Red Hat, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#ifndef BEZIER_H
+#define BEZIER_H
+
+#include <stdlib.h>
+#include <stdbool.h>
+
+struct bezier_control_point {
+	double x, y;
+};
+
+extern const struct bezier_control_point bezier_defaults[4];
+
+/**
+ * Given four control points in the range [(0.0/0.0), (1.0/1.0)]
+ * construct a Bézier curve.
+ *
+ *    ^
+ *1.0 |    c2 ______ c3
+ *    |     _/
+ *    |    /
+ *    |c1 /
+ *    |  /
+ *    | /
+ *    |/_________________>
+ *    c0           1.0
+ *
+ * This function requires that c[i].x <= c[i+1].x
+ *
+ * The curve is mapped into a canvas size [0, bezier_sz)². For each x
+ * coordinate in [0, bezier_sz), the matching y coordinate is thus
+ * bezier[x].
+ *
+ * In other words, if you have a range [0,2048) input possible values,
+ * the output is a list of 2048 points in a [0, 2048) range.
+ *
+ * @return true on success, false otherwise
+ */
+bool
+cubic_bezier(const struct bezier_control_point controls[4],
+	     int *bezier,
+	     size_t bezier_sz);
+#endif