[gtk/matthiasc/lottie-tests] Add a path editor demo
- From: Matthias Clasen <matthiasc src gnome org>
- To: commits-list gnome org
- Cc:
- Subject: [gtk/matthiasc/lottie-tests] Add a path editor demo
- Date: Sun, 29 Nov 2020 05:49:41 +0000 (UTC)
commit 238e210d8bfb2bb767371b2db70ed1992ef711cf
Author: Matthias Clasen <mclasen redhat com>
Date: Thu Nov 19 13:41:21 2020 -0500
Add a path editor demo
Add a simple demo for editing a poly-Bezier curve.
It does not handle conic segments yet.
tests/curve-editor.c | 1811 ++++++++++++++++++++++++++++++++++++++++++++++++++
tests/curve-editor.h | 33 +
tests/curve.c | 184 +++++
tests/meson.build | 1 +
4 files changed, 2029 insertions(+)
---
diff --git a/tests/curve-editor.c b/tests/curve-editor.c
new file mode 100644
index 0000000000..d7fd811afd
--- /dev/null
+++ b/tests/curve-editor.c
@@ -0,0 +1,1811 @@
+#include "curve-editor.h"
+
+#include <gtk/gtk.h>
+
+#define DRAW_RADIUS 5
+#define CLICK_RADIUS 8
+
+/* {{{ Types and structures */
+typedef enum
+{
+ MOVE,
+ LINE,
+ CURVE
+} Operation;
+
+static const char *
+op_to_string (Operation op)
+{
+ switch (op)
+ {
+ case MOVE:
+ return "move";
+ case LINE:
+ return "line";
+ case CURVE:
+ return "curve";
+ default:
+ g_assert_not_reached ();
+ }
+}
+
+static Operation
+op_from_string (const char *s)
+{
+ if (strcmp (s, "move") == 0)
+ return MOVE;
+ else if (strcmp (s, "line") == 0)
+ return LINE;
+ else if (strcmp (s, "curve") == 0)
+ return CURVE;
+ else
+ g_assert_not_reached ();
+}
+
+typedef enum
+{
+ CUSP,
+ SMOOTH,
+ SYMMETRIC,
+ AUTO
+} PointType;
+
+static const char *
+point_type_to_string (PointType type)
+{
+ switch (type)
+ {
+ case CUSP:
+ return "cusp";
+ case SMOOTH:
+ return "smooth";
+ case SYMMETRIC:
+ return "symmetric";
+ case AUTO:
+ return "auto";
+ default:
+ g_assert_not_reached ();
+ }
+}
+
+static PointType
+point_type_from_string (const char *s)
+{
+ if (strcmp (s, "cusp") == 0)
+ return CUSP;
+ else if (strcmp (s, "smooth") == 0)
+ return SMOOTH;
+ else if (strcmp (s, "symmetric") == 0)
+ return SYMMETRIC;
+ else if (strcmp (s, "auto") == 0)
+ return AUTO;
+ else
+ g_assert_not_reached ();
+}
+
+/* We don't store Bezier segments, but an array of points on
+ * the line. Each point comes with its two neighboring control
+ * points, so each Bezier segment contains p[1] and p[2] from
+ * one point, and p[0] and p[1] from the next.
+ *
+ * The control points are irrelevant for MOVE and LINE segments.
+ */
+typedef struct
+{
+ /* 0 and 2 are control points, 1 is the point on the line */
+ graphene_point_t p[3];
+ PointType type;
+ gboolean edit;
+ int dragged;
+ int hovered;
+ /* refers to the segment following the point */
+ Operation op;
+} PointData;
+
+struct _CurveEditor
+{
+ GtkWidget parent_instance;
+ GArray *points;
+ int dragged;
+ int context;
+ gboolean edit;
+ int molded;
+
+ GtkWidget *menu;
+ GActionMap *actions;
+ GskStroke *stroke;
+ GdkRGBA color;
+};
+
+struct _CurveEditorClass
+{
+ GtkWidgetClass parent_class;
+};
+
+G_DEFINE_TYPE (CurveEditor, curve_editor, GTK_TYPE_WIDGET)
+/* }}} */
+/* {{{ Misc. geometry */
+/* Set q to the projection of p onto the line through a and b */
+static void
+closest_point (const graphene_point_t *p,
+ const graphene_point_t *a,
+ const graphene_point_t *b,
+ graphene_point_t *q)
+{
+ graphene_vec2_t n;
+ graphene_vec2_t ap;
+ float t;
+
+ graphene_vec2_init (&n, b->x - a->x, b->y - a->y);
+ graphene_vec2_init (&ap, p->x - a->x, p->y - a->y);
+
+ t = graphene_vec2_dot (&ap, &n) / graphene_vec2_dot (&n, &n);
+
+ q->x = a->x + t * (b->x - a->x);
+ q->y = a->y + t * (b->y - a->y);
+}
+
+/* Determine if p is on the line through a and b */
+static gboolean
+collinear (const graphene_point_t *p,
+ const graphene_point_t *a,
+ const graphene_point_t *b)
+{
+ graphene_point_t q;
+
+ closest_point (p, a, b, &q);
+
+ return graphene_point_near (p, &q, 0.0001);
+}
+
+/* Set q to the point on the line through p and a that is
+ * at a distance of d from p, on the opposite side
+ */
+static void
+opposite_point (const graphene_point_t *p,
+ const graphene_point_t *a,
+ float d,
+ graphene_point_t *q)
+{
+ graphene_vec2_t ap;
+ float t;
+
+ graphene_vec2_init (&ap, p->x - a->x, p->y - a->y);
+ t = - sqrt (d * d / graphene_vec2_dot (&ap, &ap));
+
+ q->x = p->x + t * (a->x - p->x);
+ q->y = p->y + t * (a->y - p->y);
+}
+
+/* Set q to the point on the line through p and a that is
+ * at a distance of d from p, on the same side
+ */
+static void
+scale_point (const graphene_point_t *p,
+ const graphene_point_t *a,
+ float d,
+ graphene_point_t *q)
+{
+ graphene_vec2_t ap;
+ float t;
+
+ graphene_vec2_init (&ap, p->x - a->x, p->y - a->y);
+ t = sqrt (d * d / graphene_vec2_dot (&ap, &ap));
+
+ q->x = p->x + t * (a->x - p->x);
+ q->y = p->y + t * (a->y - p->y);
+}
+
+/* Set p to the intersection of the lines through a, b
+ * and c, d
+ */
+static void
+line_intersection (const graphene_point_t *a,
+ const graphene_point_t *b,
+ const graphene_point_t *c,
+ const graphene_point_t *d,
+ graphene_point_t *p)
+{
+ double a1 = b->y - a->y;
+ double b1 = a->x - b->x;
+ double c1 = a1*a->x + b1*a->y;
+
+ double a2 = d->y - c->y;
+ double b2 = c->x - d->x;
+ double c2 = a2*c->x+ b2*c->y;
+
+ double det = a1*b2 - a2*b1;
+
+ if (det == 0)
+ {
+ p->x = NAN;
+ p->y = NAN;
+ }
+ else
+ {
+ p->x = (b2*c1 - b1*c2) / det;
+ p->y = (a1*c2 - a2*c1) / det;
+ }
+}
+
+/* Given 3 points, determine the center of a circle that
+ * passes through all of them.
+ */
+static void
+circle_through_points (const graphene_point_t *a,
+ const graphene_point_t *b,
+ const graphene_point_t *c,
+ graphene_point_t *center)
+{
+ graphene_point_t ab;
+ graphene_point_t ac;
+ graphene_point_t ab2;
+ graphene_point_t ac2;
+
+ ab.x = (a->x + b->x) / 2;
+ ab.y = (a->y + b->y) / 2;
+ ac.x = (a->x + c->x) / 2;
+ ac.y = (a->y + c->y) / 2;
+
+ ab2.x = ab.x + a->y - b->y;
+ ab2.y = ab.y + b->x - a->x;
+ ac2.x = ac.x + a->y - c->y;
+ ac2.y = ac.y + c->x - a->x;
+
+ line_intersection (&ab, &ab2, &ac, &ac2, center);
+}
+
+/* Return the cosine of the angle between b1 - a and b2 - a */
+static double
+three_point_angle (const graphene_point_t *a,
+ const graphene_point_t *b1,
+ const graphene_point_t *b2)
+{
+ graphene_vec2_t u;
+ graphene_vec2_t v;
+
+ graphene_vec2_init (&u, b1->x - a->x, b1->y - a->y);
+ graphene_vec2_init (&v, b2->x - a->x, b2->y - a->y);
+ graphene_vec2_normalize (&u, &u);
+ graphene_vec2_normalize (&v, &v);
+
+ return graphene_vec2_dot (&u, &v);
+}
+/* }}} */
+/* {{{ Misc. Bezier math */
+/* Given Bezier control points and a t value between 0 and 1,
+ * return new Bezier control points for two segments in left
+ * and right that are obtained by splitting the curve at the
+ * point for t.
+ *
+ * Note that the points in the right array are in returned in
+ * reverse order.
+ */
+static void
+split_bezier (graphene_point_t *points,
+ int length,
+ float t,
+ graphene_point_t *left,
+ int *left_pos,
+ graphene_point_t *right,
+ int *right_pos)
+{
+ if (length == 1)
+ {
+ left[*left_pos] = points[0];
+ (*left_pos)++;
+ right[*right_pos] = points[0];
+ (*right_pos)++;
+ }
+ else
+ {
+ graphene_point_t *newpoints;
+ int i;
+
+ newpoints = g_alloca (sizeof (graphene_point_t) * (length - 1));
+ for (i = 0; i < length - 1; i++)
+ {
+ if (i == 0)
+ {
+ left[*left_pos] = points[i];
+ (*left_pos)++;
+ }
+ if (i + 1 == length - 1)
+ {
+ right[*right_pos] = points[i + 1];
+ (*right_pos)++;
+ }
+ graphene_point_interpolate (&points[i], &points[i + 1], t, &newpoints[i]);
+ }
+ split_bezier (newpoints, length - 1, t, left, left_pos, right, right_pos);
+ }
+}
+
+static double
+projection_ratio (double t)
+{
+ double top, bottom;
+
+ if (t == 0 || t == 1)
+ return t;
+
+ top = pow (1 - t, 3),
+ bottom = pow (t, 3) + top;
+
+ return top / bottom;
+}
+
+static double
+abc_ratio (double t)
+{
+ double top, bottom;
+
+ if (t == 0 || t == 1)
+ return t;
+
+ bottom = pow (t, 3) + pow (1 - t, 3);
+ top = bottom - 1;
+
+ return fabs (top / bottom);
+}
+
+static void
+find_control_points (double t,
+ const graphene_point_t *A,
+ const graphene_point_t *B,
+ const graphene_point_t *C,
+ const graphene_point_t *S,
+ const graphene_point_t *E,
+ graphene_point_t *C1,
+ graphene_point_t *C2)
+{
+ double angle;
+ double dist;
+ double bc;
+ double de1;
+ double de2;
+ graphene_point_t c;
+ graphene_point_t t0, t1;
+ double tlength;
+ double dx, dy;
+ graphene_point_t e1, e2;
+ graphene_point_t v1, v2;
+
+ dist = graphene_point_distance (S, E, NULL, NULL);
+ angle = atan2 (E->y - S->y, E->x - S->x) - atan2 (B->y - S->y, B->x - S->x);
+ bc = (angle < 0 || angle > M_PI ? -1 : 1) * dist / 3;
+ de1 = t * bc;
+ de2 = (1 - t) * bc;
+
+ circle_through_points (S, B, E, &c);
+
+ t0.x = B->x - (B->y - c.y);
+ t0.y = B->y + (B->x - c.x);
+ t1.x = B->x + (B->y - c.y);
+ t1.y = B->y - (B->x - c.x);
+
+ tlength = graphene_point_distance (&t0, &t1, NULL, NULL);
+ dx = (t1.x - t0.x) / tlength;
+ dy = (t1.y - t0.y) / tlength;
+
+ e1.x = B->x + de1 * dx;
+ e1.y = B->y + de1 * dy;
+ e2.x = B->x - de2 * dx;
+ e2.y = B->y - de2 * dy;
+
+ v1.x = A->x + (e1.x - A->x) / (1 - t);
+ v1.y = A->y + (e1.y - A->y) / (1 - t);
+
+ v2.x = A->x + (e2.x - A->x) / t;
+ v2.y = A->y + (e2.y - A->y) / t;
+
+ C1->x = S->x + (v1.x - S->x) / t;
+ C1->y = S->y + (v1.y - S->y) / t;
+
+ C2->x = E->x + (v2.x - E->x) / (1 - t);
+ C2->y = E->y + (v2.y - E->y) / (1 - t);
+}
+
+/* Given points S, B, E, determine control
+ * points C1, C2 such that B lies on the
+ * Bezier segment given bY S, C1, C2, E.
+ */
+static void
+bezier_through (const graphene_point_t *S,
+ const graphene_point_t *B,
+ const graphene_point_t *E,
+ graphene_point_t *C1,
+ graphene_point_t *C2)
+{
+ double d1, d2, t;
+ double u, um, s;
+ graphene_point_t A, C;
+
+ d1 = graphene_point_distance (S, B, NULL, NULL);
+ d2 = graphene_point_distance (E, B, NULL, NULL);
+ t = d1 / (d1 + d2);
+
+ u = projection_ratio (t);
+ um = 1 - u;
+
+ C.x = u * S->x + um * E->x;
+ C.y = u * S->y + um * E->y;
+
+ s = abc_ratio (t);
+
+ A.x = B->x + (B->x - C.x) / s;
+ A.y = B->y + (B->y - C.y) / s;
+
+ find_control_points (t, &A, B, &C, S, E, C1, C2);
+}
+/* }}} */
+/* {{{ Utilities */
+static PointData *
+get_point (CurveEditor *self,
+ int point)
+{
+ point = point % self->points->len;
+ if (point < 0)
+ point += self->points->len;
+ return &g_array_index (self->points, PointData, point);
+}
+
+static gboolean
+point_is_visible (CurveEditor *self,
+ int point,
+ int point1)
+{
+ PointData *pd;
+
+ if (!self->edit)
+ return FALSE;
+
+ pd = get_point (self, point);
+ switch (point1)
+ {
+ case 0:
+ if (!pd->edit)
+ return FALSE;
+ else
+ return get_point (self, point - 1)->op == CURVE;
+ case 1: /* point on curve */
+ return TRUE;
+ case 2:
+ if (!pd->edit)
+ return FALSE;
+ else
+ return pd->op == CURVE;
+ default:
+ g_assert_not_reached ();
+ }
+}
+
+static void
+maintain_smoothness (CurveEditor *self,
+ int point)
+{
+ PointData *pd;
+ Operation op, op1;
+ graphene_point_t *p, *c, *c2, *p2;
+ float d;
+
+ pd = get_point (self, point);
+
+ if (pd->type == CUSP)
+ return;
+
+ op = pd->op;
+ op1 = get_point (self, point - 1)->op;
+
+ p = &pd->p[1];
+ c = &pd->p[0];
+ c2 = &pd->p[2];
+
+ if (op == CURVE && op1 == CURVE)
+ {
+ d = graphene_point_distance (c, p, NULL, NULL);
+ opposite_point (p, c2, d, c);
+ }
+ else if (op == CURVE && op1 == LINE)
+ {
+ p2 = &get_point (self, point - 1)->p[1];
+ d = graphene_point_distance (c2, p, NULL, NULL);
+ opposite_point (p, p2, d, c2);
+ }
+ else if (op == LINE && op1 == CURVE)
+ {
+ p2 = &get_point (self, point + 1)->p[1];
+ d = graphene_point_distance (c, p, NULL, NULL);
+ opposite_point (p, p2, d, c);
+ }
+}
+
+static void
+maintain_symmetry (CurveEditor *self,
+ int point)
+{
+ PointData *pd;
+ graphene_point_t *p, *c, *c2;
+ double l1, l2, l;
+
+ pd = get_point (self, point);
+
+ if (pd->type != SYMMETRIC)
+ return;
+
+ c = &pd->p[0];
+ p = &pd->p[1];
+ c2 = &pd->p[2];
+
+ l1 = graphene_point_distance (p, c, NULL, NULL);
+ l2 = graphene_point_distance (p, c2, NULL, NULL);
+
+ if (l1 != l2)
+ {
+ l = (l1 + l2) / 2;
+
+ scale_point (p, c, l, c);
+ scale_point (p, c2, l, c2);
+ }
+}
+
+/* Make the line through the control points perpendicular
+ * to the line bisecting the angle between neighboring
+ * points, and make the lengths 1/3 of the distance to
+ * the corresponding neighboring points.
+ */
+static void
+update_automatic (CurveEditor *self,
+ int point)
+{
+ PointData *pd, *pd1, *pd2;
+ double l1, l2;
+ graphene_point_t a;
+
+ pd = get_point (self, point);
+
+ if (pd->type != AUTO)
+ return;
+
+ pd1 = get_point (self, point - 1);
+ pd2 = get_point (self, point + 1);
+
+ l1 = graphene_point_distance (&pd->p[1], &pd1->p[1], NULL, NULL);
+ l2 = graphene_point_distance (&pd->p[1], &pd2->p[1], NULL, NULL);
+
+ a.x = pd2->p[1].x + (pd->p[1].x - pd1->p[1].x);
+ a.y = pd2->p[1].y + (pd->p[1].y - pd1->p[1].y);
+
+ scale_point (&pd->p[1], &a, l2/3, &pd->p[2]);
+ opposite_point (&pd->p[1], &a, l1/3, &pd->p[0]);
+}
+
+static void
+maintain_automatic (CurveEditor *self,
+ int point)
+{
+ if (get_point (self, point)->op != CURVE ||
+ get_point (self, point - 1)->op != CURVE)
+ return;
+
+ update_automatic (self, point);
+ update_automatic (self, point - 1);
+ update_automatic (self, point + 1);
+}
+
+/* Check if the points arount point currently satisfy
+ * smoothness conditions. Set PointData.type accordingly.
+ */
+static void
+check_smoothness (CurveEditor *self,
+ int point)
+{
+ Operation op, op1;
+ graphene_point_t *p1, *p2;
+ PointData *pd;
+
+ pd = get_point (self, point);
+ op = pd->op;
+ op1 = get_point (self, point - 1)->op;
+
+ if (op == CURVE)
+ p2 = &pd->p[2];
+ else if (op == LINE)
+ p2 = &get_point (self, point + 1)->p[1];
+ else
+ p2 = NULL;
+
+ if (op1 == CURVE)
+ p1 = &pd->p[0];
+ else if (op1 == LINE)
+ p1 = &get_point (self, point - 1)->p[1];
+ else
+ p1 = NULL;
+
+ if (!p1 || !p2 || !collinear (&pd->p[1], p1, p2))
+ pd->type = CUSP;
+ else
+ pd->type = SMOOTH;
+}
+
+static void
+insert_point (CurveEditor *self,
+ int point,
+ double pos)
+{
+ PointData *pd, *pd1, *pd2;
+ graphene_point_t points[4];
+ PointData np;
+
+ pd = get_point (self, point);
+ if (pd->op == MOVE)
+ return;
+
+ pd1 = get_point (self, point + 1);
+ points[0] = pd->p[1];
+ points[1] = pd->p[2];
+ points[2] = pd1->p[0];
+ points[3] = pd1->p[1];
+
+ g_array_insert_val (self->points, point + 1, np);
+
+ pd = get_point (self, point);
+ pd1 = get_point (self, point + 1);
+ pd2 = get_point (self, point + 2);
+
+ pd1->type = SMOOTH;
+ pd1->hovered = -1;
+ pd1->dragged = -1;
+
+ if (pd->op == LINE)
+ {
+ pd1->op = LINE;
+ graphene_point_interpolate (&points[0], &points[3], pos, &pd1->p[1]);
+ }
+ else if (pd->op == CURVE)
+ {
+ graphene_point_t left[4];
+ graphene_point_t right[4];
+ int left_pos = 0;
+ int right_pos = 0;
+
+ pd1->op = CURVE;
+
+ split_bezier (points, 4, pos, left, &left_pos, right, &right_pos);
+
+ pd->p[1] = left[0];
+ pd->p[2] = left[1];
+ pd1->p[0] = left[2];
+ pd1->p[1] = left[3];
+ pd1->p[2] = right[2];
+ pd2->p[0] = right[1];
+ pd2->p[1] = right[0];
+ }
+ else
+ g_assert_not_reached ();
+
+ maintain_smoothness (self, point + 1);
+ maintain_automatic (self, point + 1);
+
+ gtk_widget_queue_draw (GTK_WIDGET (self));
+}
+
+static void
+remove_point (CurveEditor *self,
+ int point)
+{
+ g_array_remove_index (self->points, point);
+
+ maintain_smoothness (self, point);
+ maintain_automatic (self, point);
+}
+
+/* }}} */
+/* {{{ GskPath helpers */
+static void
+curve_editor_add_segment (CurveEditor *self,
+ GskPathBuilder *builder,
+ int point)
+{
+ PointData *pd1, *pd;
+
+ pd1 = get_point (self, point);
+ pd = get_point (self, point + 1);
+
+ gsk_path_builder_move_to (builder, pd1->p[1].x, pd1->p[1].y);
+
+ switch (pd1->op)
+ {
+ case LINE:
+ gsk_path_builder_line_to (builder, pd->p[1].x, pd->p[1].y);
+ break;
+
+ case CURVE:
+ gsk_path_builder_curve_to (builder,
+ pd1->p[2].x, pd1->p[2].y,
+ pd->p[0].x, pd->p[0].y,
+ pd->p[1].x, pd->p[1].y);
+ break;
+
+ case MOVE:
+ default:
+ break;
+ }
+}
+
+static void
+curve_editor_add_path (CurveEditor *self,
+ GskPathBuilder *builder)
+{
+ int i;
+
+ for (i = 0; i < self->points->len; i++)
+ {
+ PointData *pd1, *pd;
+
+ pd1 = get_point (self, i);
+ pd = get_point (self, i + 1);
+
+ if (i == 0)
+ gsk_path_builder_move_to (builder, pd1->p[1].x, pd1->p[1].y);
+
+ switch (pd1->op)
+ {
+ case MOVE:
+ gsk_path_builder_move_to (builder, pd->p[1].x, pd->p[1].y);
+ break;
+
+ case LINE:
+ gsk_path_builder_line_to (builder, pd->p[1].x, pd->p[1].y);
+ break;
+
+ case CURVE:
+ gsk_path_builder_curve_to (builder,
+ pd1->p[2].x, pd1->p[2].y,
+ pd->p[0].x, pd->p[0].y,
+ pd->p[1].x, pd->p[1].y);
+ break;
+
+ default:
+ g_assert_not_reached ();
+ }
+ }
+}
+
+static gboolean
+find_closest_segment (CurveEditor *self,
+ graphene_point_t *point,
+ float threshold,
+ graphene_point_t *p,
+ int *segment,
+ float *pos)
+{
+ graphene_point_t pp;
+ float t;
+ int seg;
+ gboolean found = FALSE;
+ int i;
+
+ for (i = 0; i < self->points->len; i++)
+ {
+ GskPathBuilder *builder;
+ GskPath *path;
+ GskPathMeasure *measure;
+ float t1;
+ graphene_point_t pp1;
+
+ builder = gsk_path_builder_new ();
+ curve_editor_add_segment (self, builder, i);
+ path = gsk_path_builder_free_to_path (builder);
+ measure = gsk_path_measure_new (path);
+
+ if (gsk_path_measure_get_closest_point_full (measure, point, threshold, &threshold, &pp1, &t1, NULL))
+ {
+ seg = i;
+ t = t1 / gsk_path_measure_get_length (measure);
+ pp = pp1;
+ found = TRUE;
+ }
+
+ gsk_path_measure_unref (measure);
+ gsk_path_unref (path);
+ }
+
+ if (found)
+ {
+ if (segment)
+ *segment = seg;
+ if (pos)
+ *pos = t;
+ if (p)
+ *p = pp;
+ }
+
+ return found;
+}
+/* }}} */
+/* {{{ Drag implementation */
+static void
+drag_begin (GtkGestureDrag *gesture,
+ double start_x,
+ double start_y,
+ CurveEditor *self)
+{
+ int i, j;
+ graphene_point_t p = GRAPHENE_POINT_INIT (start_x, start_y);
+ float t;
+ int point;
+
+ if (!self->edit)
+ return;
+
+ for (i = 0; i < self->points->len; i++)
+ {
+ PointData *pd = get_point (self, i);
+
+ for (j = 0; j < 3; j++)
+ {
+ if (graphene_point_distance (&pd->p[j], &p, NULL, NULL) < CLICK_RADIUS)
+ {
+ if (point_is_visible (self, i, j))
+ {
+ self->dragged = i;
+ pd->dragged = j;
+ gtk_widget_queue_draw (GTK_WIDGET (self));
+ }
+ return;
+ }
+ }
+ }
+
+ if (find_closest_segment (self, &p, CLICK_RADIUS, NULL, &point, &t))
+ {
+ /* Can't bend a straight line */
+ get_point (self, point)->op = CURVE;
+ self->molded = point;
+ return;
+ }
+
+ gtk_gesture_set_state (GTK_GESTURE (gesture), GTK_EVENT_SEQUENCE_DENIED);
+}
+
+static void
+drag_control_point (CurveEditor *self,
+ double x,
+ double y)
+{
+ double dx, dy;
+ graphene_point_t *c, *p, *d;
+ double l1, l2;
+ PointData *pd;
+
+ pd = get_point (self, self->dragged);
+ d = &pd->p[pd->dragged];
+
+ /* before moving the point, record the distances to its neighbors, since
+ * we may want to preserve those
+ */
+ l1 = graphene_point_distance (&pd->p[1], &pd->p[0], NULL, NULL);
+ l2 = graphene_point_distance (&pd->p[1], &pd->p[2], NULL, NULL);
+
+ dx = x - d->x;
+ dy = y - d->y;
+
+ if (pd->dragged == 1)
+ {
+ /* dragged point is on curve */
+
+ Operation op, op1, op11, op2;
+ PointData *pd1, *pd2;
+
+ /* first move the point itself */
+ d->x = x;
+ d->y = y;
+
+ /* adjust control points as needed */
+ pd1 = get_point (self, self->dragged - 1);
+ pd2 = get_point (self, self->dragged + 1);
+
+ op = pd->op;
+ op1 = pd1->op;
+ op2 = pd2->op;
+
+ if (op1 == LINE)
+ {
+ /* the other endpoint of the line */
+ p = &pd1->p[1];
+
+ if (op == CURVE && pd->type != CUSP)
+ {
+ /* adjust the control point after the line segment */
+ opposite_point (d, p, l2, &pd->p[2]);
+ }
+ else
+ {
+ pd->p[2].x += dx;
+ pd->p[2].y += dy;
+ }
+
+ pd->p[0].x += dx;
+ pd->p[0].y += dy;
+
+ op11 = get_point (self, self->dragged - 2)->op;
+
+ if (op11 == CURVE && pd1->type != CUSP)
+ {
+ double l;
+
+ /* adjust the control point before the line segment */
+ l = graphene_point_distance (&pd1->p[0], p, NULL, NULL);
+ opposite_point (p, d, l, &pd1->p[0]);
+ }
+ }
+
+ if (op == LINE)
+ {
+ /* the other endpoint of the line */
+ p = &pd2->p[1];
+
+ if (op1 == CURVE && pd->type != CUSP)
+ {
+ /* adjust the control point before the line segment */
+ opposite_point (d, p, l1, &pd->p[0]);
+ }
+ else
+ {
+ pd->p[0].x += dx;
+ pd->p[0].y += dy;
+ }
+
+ pd->p[2].x += dx;
+ pd->p[2].y += dy;
+
+ if (op2 == CURVE && pd2->type != CUSP)
+ {
+ double l;
+
+ /* adjust the control point after the line segment */
+ l = graphene_point_distance (&pd2->p[2], p, NULL, NULL);
+ opposite_point (p, d, l, &pd2->p[2]);
+ }
+ }
+
+ if (op1 != LINE && op != LINE)
+ {
+ pd->p[0].x += dx;
+ pd->p[0].y += dy;
+ pd->p[2].x += dx;
+ pd->p[2].y += dy;
+ }
+
+ maintain_automatic (self, self->dragged);
+ }
+ else
+ {
+ /* dragged point is a control point */
+
+ graphene_point_t *p1;
+ Operation op, op1;
+
+ if (pd->dragged == 0)
+ {
+ c = &pd->p[2];
+ p = &pd->p[1];
+
+ op = get_point (self, self->dragged - 1)->op;
+ op1 = get_point (self, self->dragged)->op;
+ p1 = &get_point (self, self->dragged + 1)->p[1];
+ }
+ else if (pd->dragged == 2)
+ {
+ c = &pd->p[0];
+ p = &pd->p[1];
+
+ op = get_point (self, self->dragged)->op;
+ op1 = get_point (self, self->dragged - 1)->op;
+ p1 = &get_point (self, self->dragged - 1)->p[1];
+ }
+ else
+ g_assert_not_reached ();
+
+ if (op == CURVE && pd->type != CUSP)
+ {
+ if (op1 == CURVE)
+ {
+ double l;
+
+ /* first move the point itself */
+ d->x = x;
+ d->y = y;
+
+ /* then adjust the other control point */
+ if (pd->type == SYMMETRIC)
+ l = graphene_point_distance (d, p, NULL, NULL);
+ else
+ l = graphene_point_distance (c, p, NULL, NULL);
+
+ opposite_point (p, d, l, c);
+ }
+ else if (op1 == LINE)
+ {
+ graphene_point_t m = GRAPHENE_POINT_INIT (x, y);
+ closest_point (&m, p, p1, d);
+ }
+ else
+ {
+ d->x = x;
+ d->y = y;
+ }
+ }
+ else
+ {
+ d->x = x;
+ d->y = y;
+ }
+ }
+}
+
+static void
+drag_curve (CurveEditor *self,
+ double x,
+ double y)
+{
+ PointData *pd, *pd1, *pd2, *pd3;
+ graphene_point_t *S, *E;
+ graphene_point_t B, C1, C2;
+ double l;
+
+ pd = get_point (self, self->molded);
+ pd1 = get_point (self, self->molded + 1);
+ pd2 = get_point (self, self->molded - 1);
+ pd3 = get_point (self, self->molded + 2);
+
+ S = &pd->p[1];
+ B = GRAPHENE_POINT_INIT (x, y);
+ E = &pd1->p[1];
+
+ bezier_through (S, &B, E, &C1, &C2);
+
+ pd->p[2] = C1;
+ pd1->p[0] = C2;
+
+ /* When the neighboring segments are lines, we can't actually
+ * use C1 and C2 as-is, since we need control points to lie
+ * on the line. So we just use their distance. This makes our
+ * point B not quite match anymore, but we're overconstrained.
+ */
+ if (pd2->op == LINE)
+ {
+ l = graphene_point_distance (&pd->p[1], &pd->p[2], NULL, NULL);
+ if (three_point_angle (&pd->p[1], &pd2->p[1], &B) > 0)
+ scale_point (&pd->p[1], &pd2->p[1], l, &pd->p[2]);
+ else
+ opposite_point (&pd->p[1], &pd2->p[1], l, &pd->p[2]);
+ }
+
+ if (pd1->op == LINE)
+ {
+ l = graphene_point_distance (&pd1->p[1], &pd1->p[0], NULL, NULL);
+ if (three_point_angle (&pd1->p[1], &pd3->p[1], &B) > 0)
+ scale_point (&pd1->p[1], &pd3->p[1], l, &pd1->p[0]);
+ else
+ opposite_point (&pd1->p[1], &pd3->p[1], l, &pd1->p[0]);
+ }
+
+ /* Maintain smoothness and symmetry */
+ if (pd->type != CUSP)
+ {
+ if (pd->type == SYMMETRIC)
+ l = graphene_point_distance (&pd->p[1], &pd->p[2], NULL, NULL);
+ else
+ l = graphene_point_distance (&pd->p[1], &pd->p[0], NULL, NULL);
+ opposite_point (&pd->p[1], &pd->p[2], l, &pd->p[0]);
+ }
+
+ if (pd1->type != CUSP)
+ {
+ if (pd1->type == SYMMETRIC)
+ l = graphene_point_distance (&pd1->p[1], &pd1->p[0], NULL, NULL);
+ else
+ l = graphene_point_distance (&pd1->p[1], &pd1->p[2], NULL, NULL);
+ opposite_point (&pd1->p[1], &pd1->p[0], l, &pd1->p[2]);
+ }
+}
+
+static void
+drag_update (GtkGestureDrag *gesture,
+ double offset_x,
+ double offset_y,
+ CurveEditor *self)
+{
+ double x, y;
+
+ gtk_gesture_drag_get_start_point (gesture, &x, &y);
+
+ x += offset_x;
+ y += offset_y;
+
+ if (self->dragged != -1)
+ {
+ gtk_gesture_set_state (GTK_GESTURE (gesture), GTK_EVENT_SEQUENCE_CLAIMED);
+ drag_control_point (self, x, y);
+ gtk_widget_queue_draw (GTK_WIDGET (self));
+ }
+ else if (self->molded != -1)
+ {
+ gtk_gesture_set_state (GTK_GESTURE (gesture), GTK_EVENT_SEQUENCE_CLAIMED);
+ drag_curve (self, x, y);
+ gtk_widget_queue_draw (GTK_WIDGET (self));
+ }
+}
+
+static void
+drag_end (GtkGestureDrag *gesture,
+ double offset_x,
+ double offset_y,
+ CurveEditor *self)
+{
+ drag_update (gesture, offset_x, offset_y, self);
+ self->dragged = -1;
+ self->molded = -1;
+}
+/* }}} */
+/* {{{ Action callbacks */
+static void
+set_point_type (GSimpleAction *action,
+ GVariant *value,
+ gpointer data)
+{
+ CurveEditor *self = CURVE_EDITOR (data);
+
+ get_point (self, self->context)->type = point_type_from_string (g_variant_get_string (value, NULL));
+
+ maintain_smoothness (self, self->context);
+ maintain_symmetry (self, self->context);
+ maintain_automatic (self, self->context);
+
+ gtk_widget_queue_draw (GTK_WIDGET (self));
+}
+
+static void
+set_operation (GSimpleAction *action,
+ GVariant *value,
+ gpointer data)
+{
+ CurveEditor *self = CURVE_EDITOR (data);
+
+ get_point (self, self->context)->op = op_from_string (g_variant_get_string (value, NULL));
+
+ maintain_smoothness (self, self->context);
+ maintain_smoothness (self, self->context + 1);
+ maintain_symmetry (self, self->context);
+ maintain_symmetry (self, self->context + 1);
+
+ gtk_widget_queue_draw (GTK_WIDGET (self));
+}
+
+static void
+remove_current_point (GSimpleAction *action,
+ GVariant *value,
+ gpointer data)
+{
+ CurveEditor *self = CURVE_EDITOR (data);
+
+ remove_point (self, self->context);
+
+ gtk_widget_queue_draw (GTK_WIDGET (self));
+ }
+/* }}} */
+/* {{{ Event handlers */
+static void
+pressed (GtkGestureClick *gesture,
+ int n_press,
+ double x,
+ double y,
+ CurveEditor *self)
+{
+ graphene_point_t m = GRAPHENE_POINT_INIT (x, y);
+ int i;
+ int button = gtk_gesture_single_get_current_button (GTK_GESTURE_SINGLE (gesture));
+
+ if (!self->edit)
+ return;
+
+ if (button == GDK_BUTTON_SECONDARY)
+ {
+ for (i = 0; i < self->points->len; i++)
+ {
+ PointData *pd = get_point (self, i);
+
+ if (graphene_point_distance (&pd->p[1], &m, NULL, NULL) < CLICK_RADIUS)
+ {
+ GAction *action;
+
+ self->context = i;
+
+ action = g_action_map_lookup_action (self->actions, "type");
+ g_simple_action_set_state (G_SIMPLE_ACTION (action), g_variant_new_string
(point_type_to_string (pd->type)));
+
+ action = g_action_map_lookup_action (self->actions, "operation");
+ g_simple_action_set_state (G_SIMPLE_ACTION (action), g_variant_new_string (op_to_string
(pd->op)));
+
+ gtk_popover_set_pointing_to (GTK_POPOVER (self->menu),
+ &(const GdkRectangle){ x, y, 1, 1 });
+ gtk_popover_popup (GTK_POPOVER (self->menu));
+ return;
+ }
+ }
+ }
+}
+
+static void
+released (GtkGestureClick *gesture,
+ int n_press,
+ double x,
+ double y,
+ CurveEditor *self)
+{
+ graphene_point_t m = GRAPHENE_POINT_INIT (x, y);
+ int button = gtk_gesture_single_get_current_button (GTK_GESTURE_SINGLE (gesture));
+ int i;
+
+ if (!self->edit)
+ return;
+
+ for (i = 0; i < self->points->len; i++)
+ {
+ PointData *pd = get_point (self, i);
+
+ if (graphene_point_distance (&pd->p[1], &m, NULL, NULL) < CLICK_RADIUS)
+ {
+ if (button == GDK_BUTTON_PRIMARY)
+ {
+ pd->edit = !pd->edit;
+ gtk_widget_queue_draw (GTK_WIDGET (self));
+ return;
+ }
+ }
+ }
+
+ if (button == GDK_BUTTON_PRIMARY)
+ {
+ float t;
+ int point;
+
+ if (find_closest_segment (self, &m, CLICK_RADIUS, NULL, &point, &t))
+ {
+ self->dragged = -1;
+ self->molded = -1;
+ insert_point (self, point, t);
+ }
+ }
+}
+
+static void
+motion (GtkEventControllerMotion *controller,
+ double x,
+ double y,
+ CurveEditor *self)
+{
+ graphene_point_t m = GRAPHENE_POINT_INIT (x, y);
+ int i, j;
+ gboolean changed = FALSE;
+
+ if (self->edit)
+ {
+ for (i = 0; i < self->points->len; i++)
+ {
+ PointData *pd = get_point (self, i);
+ int hovered = -1;
+
+ for (j = 0; j < 3; j++)
+ {
+ if (!point_is_visible (self, i, j))
+ continue;
+
+ if (graphene_point_distance (&pd->p[j], &m, NULL, NULL) < CLICK_RADIUS)
+ {
+ hovered = j;
+ break;
+ }
+ }
+ if (pd->hovered != hovered)
+ {
+ pd->hovered = hovered;
+ changed = TRUE;
+ }
+ }
+ }
+
+ if (changed)
+ gtk_widget_queue_draw (GTK_WIDGET (self));
+}
+
+static void
+leave (GtkEventController *controller,
+ CurveEditor *self)
+{
+ int i;
+ gboolean changed = FALSE;
+
+ for (i = 0; i < self->points->len; i++)
+ {
+ PointData *pd = get_point (self, i);
+ if (pd->hovered != -1)
+ {
+ pd->hovered = -1;
+ changed = TRUE;
+ }
+ }
+
+ if (changed)
+ gtk_widget_queue_draw (GTK_WIDGET (self));
+}
+/* }}} */
+/* {{{ Snapshot */
+static void
+curve_editor_snapshot (GtkWidget *widget,
+ GtkSnapshot *snapshot)
+{
+ CurveEditor *self = (CurveEditor *)widget;
+ GskPathBuilder *builder;
+ GskPath *path;
+ GskStroke *stroke;
+ int i, j, k;
+ float width;
+ float height;
+
+ if (self->points->len == 0)
+ return;
+
+ width = gtk_widget_get_width (widget);
+ height = gtk_widget_get_width (widget);
+
+ /* Add the curve itself */
+
+ builder = gsk_path_builder_new ();
+
+ curve_editor_add_path (self, builder);
+
+ path = gsk_path_builder_free_to_path (builder);
+ gtk_snapshot_push_stroke (snapshot, path, self->stroke);
+ gsk_path_unref (path);
+
+ gtk_snapshot_append_color (snapshot,
+ &self->color,
+ &GRAPHENE_RECT_INIT (0, 0, width, height ));
+
+ gtk_snapshot_pop (snapshot);
+
+ if (self->edit)
+ {
+ /* Add the skeleton */
+
+ builder = gsk_path_builder_new ();
+
+ for (i = 0; i < self->points->len; i++)
+ {
+ PointData *pd = get_point (self, i);
+ gboolean need_move = TRUE;
+
+ if (point_is_visible (self, i, 0))
+ {
+ gsk_path_builder_move_to (builder, pd->p[0].x, pd->p[0].y);
+ gsk_path_builder_line_to (builder, pd->p[1].x, pd->p[1].y);
+ need_move = FALSE;
+ }
+ if (point_is_visible (self, i, 2))
+ {
+ if (need_move)
+ gsk_path_builder_move_to (builder, pd->p[1].x, pd->p[1].y);
+ gsk_path_builder_line_to (builder, pd->p[2].x, pd->p[2].y);
+ }
+ }
+
+ path = gsk_path_builder_free_to_path (builder);
+ stroke = gsk_stroke_new (1);
+ gtk_snapshot_push_stroke (snapshot, path, stroke);
+ gsk_stroke_free (stroke);
+ gsk_path_unref (path);
+
+ gtk_snapshot_append_color (snapshot,
+ &(GdkRGBA){ 0, 0, 0, 1 },
+ &GRAPHENE_RECT_INIT (0, 0, width, height ));
+
+ gtk_snapshot_pop (snapshot);
+
+ /* Draw the circles, in several passes, one for each color */
+
+ const char *colors[] = {
+ "white", /* hovered */
+ "red", /* smooth curve points */
+ "green", /* sharp curve points */
+ "blue" /* control points */
+ };
+ GdkRGBA color;
+
+ for (k = 0; k < 4; k++)
+ {
+ builder = gsk_path_builder_new ();
+
+ for (i = 0; i < self->points->len; i++)
+ {
+ PointData *pd = get_point (self, i);
+
+ for (j = 0; j < 3; j++)
+ {
+ switch (k)
+ {
+ case 0:
+ if (j != pd->hovered)
+ continue;
+ break;
+
+ case 1:
+ if (j == pd->hovered)
+ continue;
+
+ if (!(j == 1 && pd->type != CUSP))
+ continue;
+ break;
+
+ case 2:
+ if (j == pd->hovered)
+ continue;
+
+ if (!(j == 1 && pd->type == CUSP))
+ continue;
+ break;
+
+ case 3:
+ if (j == pd->hovered)
+ continue;
+
+ if (j == 1)
+ continue;
+
+ if (!point_is_visible (self, i, j))
+ continue;
+ break;
+
+ default:
+ g_assert_not_reached ();
+ }
+
+ gsk_path_builder_add_circle (builder, &pd->p[j], DRAW_RADIUS);
+ }
+ }
+
+ path = gsk_path_builder_free_to_path (builder);
+
+ gtk_snapshot_push_fill (snapshot, path, GSK_FILL_RULE_WINDING);
+ gdk_rgba_parse (&color, colors[k]);
+ gtk_snapshot_append_color (snapshot,
+ &color,
+ &GRAPHENE_RECT_INIT (0, 0, width, height));
+ gtk_snapshot_pop (snapshot);
+
+ stroke = gsk_stroke_new (1.0);
+ gtk_snapshot_push_stroke (snapshot, path, stroke);
+ gsk_stroke_free (stroke);
+
+ gtk_snapshot_append_color (snapshot,
+ &(GdkRGBA){ 0, 0, 0, 1 },
+ &GRAPHENE_RECT_INIT (0, 0, width, height));
+ gtk_snapshot_pop (snapshot);
+
+ gsk_path_unref (path);
+ }
+ }
+}
+/* }}} */
+/* {{{ GtkWidget boilerplate */
+static void
+curve_editor_measure (GtkWidget *widget,
+ GtkOrientation orientation,
+ int for_size,
+ int *minimum_size,
+ int *natural_size,
+ int *minimum_baseline,
+ int *natural_baseline)
+{
+ *minimum_size = 100;
+ *natural_size = 200;
+}
+
+static void
+curve_editor_size_allocate (GtkWidget *widget,
+ int width,
+ int height,
+ int baseline)
+{
+ CurveEditor *self = CURVE_EDITOR (widget);
+
+ gtk_native_check_resize (GTK_NATIVE (self->menu));
+}
+/* }}} */
+/* {{{ GObject boilerplate */
+static void
+curve_editor_dispose (GObject *object)
+{
+ CurveEditor *self = CURVE_EDITOR (object);
+
+ g_clear_pointer (&self->points, g_array_unref);
+ g_clear_pointer (&self->menu, gtk_widget_unparent);
+ g_clear_object (&self->actions);
+
+ G_OBJECT_CLASS (curve_editor_parent_class)->dispose (object);
+}
+
+static void
+curve_editor_class_init (CurveEditorClass *class)
+{
+ GObjectClass *object_class = G_OBJECT_CLASS (class);
+ GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (class);
+
+ object_class->dispose = curve_editor_dispose;
+
+ widget_class->snapshot = curve_editor_snapshot;
+ widget_class->measure = curve_editor_measure;
+ widget_class->size_allocate = curve_editor_size_allocate;
+}
+/* }}} */
+/* {{{ Setup */
+static void
+curve_editor_init (CurveEditor *self)
+{
+ GtkEventController *controller;
+ GMenu *menu;
+ GMenu *section;
+ GMenuItem *item;
+ GSimpleAction *action;
+
+ self->points = g_array_new (FALSE, FALSE, sizeof (PointData));
+ self->dragged = -1;
+ self->molded = -1;
+ self->edit = FALSE;
+ self->stroke = gsk_stroke_new (1.0);
+ self->color = (GdkRGBA){ 0, 0, 0, 1 };
+
+ controller = GTK_EVENT_CONTROLLER (gtk_gesture_drag_new ());
+ gtk_gesture_single_set_button (GTK_GESTURE_SINGLE (controller), GDK_BUTTON_PRIMARY);
+ g_signal_connect (controller, "drag-begin", G_CALLBACK (drag_begin), self);
+ g_signal_connect (controller, "drag-update", G_CALLBACK (drag_update), self);
+ g_signal_connect (controller, "drag-end", G_CALLBACK (drag_end), self);
+ gtk_widget_add_controller (GTK_WIDGET (self), controller);
+
+ controller = GTK_EVENT_CONTROLLER (gtk_gesture_click_new ());
+ gtk_gesture_single_set_button (GTK_GESTURE_SINGLE (controller), 0);
+ g_signal_connect (controller, "pressed", G_CALLBACK (pressed), self);
+ g_signal_connect (controller, "released", G_CALLBACK (released), self);
+ gtk_widget_add_controller (GTK_WIDGET (self), controller);
+
+ controller = gtk_event_controller_motion_new ();
+ g_signal_connect (controller, "motion", G_CALLBACK (motion), self);
+ g_signal_connect (controller, "leave", G_CALLBACK (leave), self);
+ gtk_widget_add_controller (GTK_WIDGET (self), controller);
+
+ self->actions = G_ACTION_MAP (g_simple_action_group_new ());
+
+ action = g_simple_action_new_stateful ("type", G_VARIANT_TYPE_STRING, g_variant_new_string ("smooth"));
+ g_signal_connect (action, "change-state", G_CALLBACK (set_point_type), self);
+ g_action_map_add_action (G_ACTION_MAP (self->actions), G_ACTION (action));
+ gtk_widget_insert_action_group (GTK_WIDGET (self), "point", G_ACTION_GROUP (self->actions));
+
+ action = g_simple_action_new_stateful ("operation", G_VARIANT_TYPE_STRING, g_variant_new_string ("curve"));
+ g_signal_connect (action, "change-state", G_CALLBACK (set_operation), self);
+ g_action_map_add_action (G_ACTION_MAP (self->actions), G_ACTION (action));
+
+ action = g_simple_action_new ("remove", NULL);
+ g_signal_connect (action, "activate", G_CALLBACK (remove_current_point), self);
+ g_action_map_add_action (G_ACTION_MAP (self->actions), G_ACTION (action));
+
+ gtk_widget_insert_action_group (GTK_WIDGET (self), "point", G_ACTION_GROUP (self->actions));
+
+ menu = g_menu_new ();
+
+ section = g_menu_new ();
+
+ item = g_menu_item_new ("Cusp", "point.type::cusp");
+ g_menu_append_item (section, item);
+ g_object_unref (item);
+
+ item = g_menu_item_new ("Smooth", "point.type::smooth");
+ g_menu_append_item (section, item);
+ g_object_unref (item);
+
+ item = g_menu_item_new ("Symmetric", "point.type::symmetric");
+ g_menu_append_item (section, item);
+ g_object_unref (item);
+
+ item = g_menu_item_new ("Automatic", "point.type::auto");
+ g_menu_append_item (section, item);
+ g_object_unref (item);
+
+
+ g_menu_append_section (menu, NULL, G_MENU_MODEL (section));
+ g_object_unref (section);
+
+ section = g_menu_new ();
+
+ item = g_menu_item_new ("Move", "point.operation::move");
+ g_menu_append_item (section, item);
+ g_object_unref (item);
+
+ item = g_menu_item_new ("Line", "point.operation::line");
+ g_menu_append_item (section, item);
+ g_object_unref (item);
+
+ item = g_menu_item_new ("Curve", "point.operation::curve");
+ g_menu_append_item (section, item);
+ g_object_unref (item);
+
+ g_menu_append_section (menu, NULL, G_MENU_MODEL (section));
+ g_object_unref (section);
+
+ section = g_menu_new ();
+
+ item = g_menu_item_new ("Remove", "point.remove");
+ g_menu_append_item (section, item);
+ g_object_unref (item);
+
+ g_menu_append_section (menu, NULL, G_MENU_MODEL (section));
+ g_object_unref (section);
+
+ self->menu = gtk_popover_menu_new_from_model (G_MENU_MODEL (menu));
+ g_object_unref (menu);
+
+ gtk_widget_set_parent (self->menu, GTK_WIDGET (self));
+}
+
+/* }}} */
+/* {{{ API */
+GtkWidget *
+curve_editor_new (void)
+{
+ return g_object_new (curve_editor_get_type (), NULL);
+}
+
+void
+curve_editor_set_edit (CurveEditor *self,
+ gboolean edit)
+{
+ int i;
+
+ self->edit = edit;
+ if (!self->edit)
+ {
+ for (i = 0; i < self->points->len; i++)
+ {
+ PointData *pd = get_point (self, i);
+ pd->edit = FALSE;
+ pd->hovered = -1;
+ }
+ }
+
+ gtk_widget_queue_draw (GTK_WIDGET (self));
+}
+
+static gboolean
+copy_segments (GskPathOperation op,
+ const graphene_point_t *pts,
+ gsize n_pts,
+ float weight,
+ gpointer data)
+{
+ CurveEditor *self = data;
+ PointData *pd;
+ PointData *pd1;
+ PointData np;
+
+ switch (op)
+ {
+ case GSK_PATH_MOVE:
+ if (self->points->len > 0)
+ {
+ pd = &g_array_index (self->points, PointData, self->points->len - 1);
+ pd->op = MOVE;
+ }
+
+ np.p[1] = pts[0];
+ g_array_append_val (self->points, np);
+ break;
+
+ case GSK_PATH_CLOSE:
+ pd = &g_array_index (self->points, PointData, self->points->len - 1);
+ pd1 = &g_array_index (self->points, PointData, 0);
+ if (graphene_point_near (&pd->p[1], &pd1->p[1], 0.001))
+ {
+ pd1->p[0] = pd->p[0];
+ g_array_remove_index (self->points, self->points->len - 1);
+ }
+ break;
+
+ case GSK_PATH_LINE:
+ pd = &g_array_index (self->points, PointData, self->points->len - 1);
+ pd->op = LINE;
+ np.p[1] = pts[1];
+ g_array_append_val (self->points, np);
+ break;
+
+ case GSK_PATH_CURVE:
+ pd = &g_array_index (self->points, PointData, self->points->len - 1);
+ pd->op = CURVE;
+ pd->p[2] = pts[1];
+ np.p[0] = pts[2];
+ np.p[1] = pts[3];
+ g_array_append_val (self->points, np);
+ break;
+
+ case GSK_PATH_CONIC:
+ /* FIXME */
+
+ default:
+ g_assert_not_reached ();
+ }
+
+ return TRUE;
+}
+void
+curve_editor_set_path (CurveEditor *self,
+ GskPath *path)
+{
+ int i;
+
+ g_array_set_size (self->points, 0);
+
+ gsk_path_foreach (path, copy_segments, self);
+
+ for (i = 0; i < self->points->len; i++)
+ {
+ get_point (self, i)->hovered = -1;
+ check_smoothness (self, i);
+ }
+
+ gtk_widget_queue_draw (GTK_WIDGET (self));
+}
+
+GskPath *
+curve_editor_get_path (CurveEditor *self)
+{
+ GskPathBuilder *builder;
+
+ builder = gsk_path_builder_new ();
+
+ curve_editor_add_path (self, builder);
+
+ return gsk_path_builder_free_to_path (builder);
+}
+
+void
+curve_editor_set_stroke (CurveEditor *self,
+ GskStroke *stroke)
+{
+ gsk_stroke_free (self->stroke);
+ self->stroke = gsk_stroke_copy (stroke);
+
+ gtk_widget_queue_draw (GTK_WIDGET (self));
+}
+
+const GskStroke *
+curve_editor_get_stroke (CurveEditor *self)
+{
+ return self->stroke;
+}
+
+void
+curve_editor_set_color (CurveEditor *self,
+ GdkRGBA *color)
+{
+ self->color = *color;
+
+ gtk_widget_queue_draw (GTK_WIDGET (self));
+}
+
+const GdkRGBA *
+curve_editor_get_color (CurveEditor *self)
+{
+ return &self->color;
+}
+/* }}} */
+/* vim:set foldmethod=marker expandtab: */
diff --git a/tests/curve-editor.h b/tests/curve-editor.h
new file mode 100644
index 0000000000..215adf449f
--- /dev/null
+++ b/tests/curve-editor.h
@@ -0,0 +1,33 @@
+#pragma once
+
+#include <gtk/gtk.h>
+
+G_BEGIN_DECLS
+
+#define CURVE_TYPE_EDITOR (curve_editor_get_type ())
+G_DECLARE_FINAL_TYPE (CurveEditor, curve_editor, CURVE, EDITOR, GtkWidget)
+
+GtkWidget * curve_editor_new (void);
+
+void curve_editor_set_edit (CurveEditor *self,
+ gboolean edit);
+
+void curve_editor_set_path (CurveEditor *self,
+ GskPath *path);
+
+GskPath * curve_editor_get_path (CurveEditor *self);
+
+void curve_editor_set_stroke (CurveEditor *self,
+ GskStroke *stroke);
+
+const GskStroke *
+ curve_editor_get_stroke (CurveEditor *self);
+
+
+void curve_editor_set_color (CurveEditor *self,
+ GdkRGBA *color);
+
+const GdkRGBA *
+ curve_editor_get_color (CurveEditor *self);
+
+G_END_DECLS
diff --git a/tests/curve.c b/tests/curve.c
new file mode 100644
index 0000000000..45b08c89ab
--- /dev/null
+++ b/tests/curve.c
@@ -0,0 +1,184 @@
+#include <gtk/gtk.h>
+#include "curve-editor.h"
+
+
+static GskPath *
+make_circle_path (void)
+{
+ float w = 200;
+ float h = 200;
+ float cx = w / 2;
+ float cy = h / 2;
+ float pad = 20;
+ float r = (w - 2 * pad) / 2;
+ float k = 0.55228;
+ float kr = k * r;
+ GskPathBuilder *builder;
+
+ builder = gsk_path_builder_new ();
+
+ gsk_path_builder_move_to (builder, cx, pad);
+ gsk_path_builder_curve_to (builder, cx + kr, pad,
+ w - pad, cy - kr,
+ w - pad, cy);
+ gsk_path_builder_curve_to (builder, w - pad, cy + kr,
+ cx + kr, h - pad,
+ cx, h - pad);
+ gsk_path_builder_curve_to (builder, cx - kr, h - pad,
+ pad, cy + kr,
+ pad, cy);
+ gsk_path_builder_curve_to (builder, pad, cy - kr,
+ cx - kr, pad,
+ cx, pad);
+ gsk_path_builder_close (builder);
+
+ return gsk_path_builder_free_to_path (builder);
+}
+
+static void
+edit_changed (GtkToggleButton *button,
+ GParamSpec *pspec,
+ CurveEditor *editor)
+{
+ curve_editor_set_edit (editor, gtk_toggle_button_get_active (button));
+}
+
+static void
+reset (GtkButton *button,
+ CurveEditor *editor)
+{
+ GskPath *path;
+
+ path = make_circle_path ();
+ curve_editor_set_path (editor, path);
+ gsk_path_unref (path);
+}
+
+static void
+width_changed (GtkRange *range,
+ CurveEditor *editor)
+{
+ GskStroke *stroke;
+
+ stroke = gsk_stroke_copy (curve_editor_get_stroke (editor));
+ gsk_stroke_set_line_width (stroke, gtk_range_get_value (range));
+ curve_editor_set_stroke (editor, stroke);
+ gsk_stroke_free (stroke);
+}
+
+static void
+cap_changed (GtkDropDown *combo,
+ GParamSpec *pspec,
+ CurveEditor *editor)
+{
+ GskStroke *stroke;
+
+ stroke = gsk_stroke_copy (curve_editor_get_stroke (editor));
+ gsk_stroke_set_line_cap (stroke, (GskLineCap)gtk_drop_down_get_selected (combo));
+ curve_editor_set_stroke (editor, stroke);
+ gsk_stroke_free (stroke);
+}
+
+static void
+join_changed (GtkDropDown *combo,
+ GParamSpec *pspec,
+ CurveEditor *editor)
+{
+ GskStroke *stroke;
+
+ stroke = gsk_stroke_copy (curve_editor_get_stroke (editor));
+ gsk_stroke_set_line_join (stroke, (GskLineJoin)gtk_drop_down_get_selected (combo));
+ curve_editor_set_stroke (editor, stroke);
+ gsk_stroke_free (stroke);
+}
+
+static void
+color_changed (GtkColorChooser *chooser,
+ CurveEditor *editor)
+{
+ GdkRGBA color;
+
+ gtk_color_chooser_get_rgba (chooser, &color);
+ curve_editor_set_color (editor, &color);
+}
+
+int
+main (int argc, char *argv[])
+{
+ GtkWindow *window;
+ GtkWidget *demo;
+ GtkWidget *edit_toggle;
+ GtkWidget *reset_button;
+ GtkWidget *titlebar;
+ GtkWidget *scale;
+ GtkWidget *stroke_button;
+ GtkWidget *popover;
+ GtkWidget *grid;
+ GtkWidget *cap_combo;
+ GtkWidget *join_combo;
+ GtkWidget *color_button;
+
+ gtk_init ();
+
+ window = GTK_WINDOW (gtk_window_new ());
+ gtk_window_set_default_size (GTK_WINDOW (window), 250, 250);
+
+ edit_toggle = gtk_toggle_button_new ();
+ gtk_button_set_icon_name (GTK_BUTTON (edit_toggle), "document-edit-symbolic");
+
+ reset_button = gtk_button_new_from_icon_name ("edit-undo-symbolic");
+
+ stroke_button = gtk_menu_button_new ();
+ gtk_menu_button_set_icon_name (GTK_MENU_BUTTON (stroke_button), "open-menu-symbolic");
+ popover = gtk_popover_new ();
+ gtk_menu_button_set_popover (GTK_MENU_BUTTON (stroke_button), popover);
+
+ grid = gtk_grid_new ();
+ gtk_grid_set_row_spacing (GTK_GRID (grid), 6);
+ gtk_grid_set_column_spacing (GTK_GRID (grid), 6);
+ gtk_popover_set_child (GTK_POPOVER (popover), grid);
+
+ gtk_grid_attach (GTK_GRID (grid), gtk_label_new ("Line Width:"), 0, 0, 1, 1);
+ scale = gtk_scale_new_with_range (GTK_ORIENTATION_HORIZONTAL, 1, 10, 1);
+ gtk_widget_set_size_request (scale, 60, -1);
+ gtk_grid_attach (GTK_GRID (grid), scale, 1, 0, 1, 1);
+
+ gtk_grid_attach (GTK_GRID (grid), gtk_label_new ("Line cap:"), 0, 1, 1, 1);
+ cap_combo = gtk_drop_down_new_from_strings ((const char *[]){"Butt", "Round", "Square", NULL});
+ gtk_grid_attach (GTK_GRID (grid), cap_combo, 1, 1, 1, 1);
+
+ gtk_grid_attach (GTK_GRID (grid), gtk_label_new ("Line join:"), 0, 2, 1, 1);
+ join_combo = gtk_drop_down_new_from_strings ((const char *[]){"Miter", "Round", "Bevel", NULL});
+ gtk_grid_attach (GTK_GRID (grid), join_combo, 1, 2, 1, 1);
+
+ gtk_grid_attach (GTK_GRID (grid), gtk_label_new ("Stroke color:"), 0, 3, 1, 1);
+ color_button = gtk_color_button_new_with_rgba (&(GdkRGBA){ 0., 0., 0., 1.});
+ gtk_grid_attach (GTK_GRID (grid), color_button, 1, 3, 1, 1);
+
+ titlebar = gtk_header_bar_new ();
+ gtk_header_bar_pack_start (GTK_HEADER_BAR (titlebar), edit_toggle);
+ gtk_header_bar_pack_start (GTK_HEADER_BAR (titlebar), reset_button);
+ gtk_header_bar_pack_start (GTK_HEADER_BAR (titlebar), stroke_button);
+
+ gtk_window_set_titlebar (GTK_WINDOW (window), titlebar);
+
+ demo = curve_editor_new ();
+
+ g_signal_connect (edit_toggle, "notify::active", G_CALLBACK (edit_changed), demo);
+ g_signal_connect (reset_button, "clicked", G_CALLBACK (reset), demo);
+ g_signal_connect (scale, "value-changed", G_CALLBACK (width_changed), demo);
+ g_signal_connect (cap_combo, "notify::selected", G_CALLBACK (cap_changed), demo);
+ g_signal_connect (join_combo, "notify::selected", G_CALLBACK (join_changed), demo);
+ g_signal_connect (color_button, "color-set", G_CALLBACK (color_changed), demo);
+
+ reset (NULL, CURVE_EDITOR (demo));
+
+ gtk_window_set_child (window, demo);
+
+ gtk_window_present (window);
+
+ while (g_list_model_get_n_items (gtk_window_get_toplevels ()) > 0)
+ g_main_context_iteration (NULL, TRUE);
+
+ return 0;
+}
diff --git a/tests/meson.build b/tests/meson.build
index 42c492b67f..5a90ce07b1 100644
--- a/tests/meson.build
+++ b/tests/meson.build
@@ -1,5 +1,6 @@
gtk_tests = [
# testname, optional extra sources
+ ['curve', ['curve.c', 'curve-editor.c']],
['curve2'],
['testupload'],
['testtransform'],
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