Implement asymmetric and free handles type for masks

Summary:
The title actually says it all, it's just possible to
have independent free handles for mask splines. Also
it's now possible to have aligned handles displayed
as independent handles.

Required changes in quite a few places, but they're
rather straightforward.

From user perspective there's one really visible change
which is removed Handle Type menu from the panel. With
asymmetric handles it's not clear which handle type to
display there. So now the only way to change handle type
is via V-key menu.

Rewrote normal evaluation function to make it deal
with new type of handles we support. Now it works in
the following way:

- Offset the original spline by maximal weight
- Calculate vector between corresponding U positions
  on offset and original spline
- Normalize this vector.

Seems to be giving more adequate results and doesn't
tend to self-intersect as much as old behavior used to,

There're still some changes which needed to be done, but
which are planned for further patch:

- Support colors and handle size via themes.
- Make handles color-coded, just the same as done for
  regular bezier splines in 3D viewport.

Additional changes to make roto workflow even better:
- Use circles to draw handles
- Support AA for handles
- Change click-create-drag to change curvature of the
  spline instead of adjusting point position.

Reviewers: campbellbarton

CC: sebastian_k, hype, cronk

Differential Revision: http://developer.blender.org/D121

1 files changed, 42 insertions, 106 deletions

diff --git a/source/blender/editors/mask/mask_add.c b/source/blender/editors/mask/mask_add.c
index 7fa41c361bb..2e1d5221b56 100644
--- a/source/blender/editors/mask/mask_add.c
+++ b/source/blender/editors/mask/mask_add.c
@@ -182,15 +182,13 @@ static int find_nearest_diff_point(const bContext *C, Mask *mask, const float no
 /******************** add vertex *********************/
 
 static void setup_vertex_point(Mask *mask, MaskSpline *spline, MaskSplinePoint *new_point,
-                               const float point_co[2], const float tangent[2], const float u,
-                               MaskSplinePoint *reference_point, const short reference_adjacent,
-                               const float view_zoom)
+                               const float point_co[2], const float u,
+                               MaskSplinePoint *reference_point, const short reference_adjacent)
 {
 	MaskSplinePoint *prev_point = NULL;
 	MaskSplinePoint *next_point = NULL;
 	BezTriple *bezt;
 	float co[3];
-	const float len = 10.0; /* default length of handle in pixel space */
 
 	copy_v2_v2(co, point_co);
 	co[2] = 0.0f;
@@ -201,7 +199,41 @@ static void setup_vertex_point(Mask *mask, MaskSpline *spline, MaskSplinePoint *
 	bezt->h1 = bezt->h2 = HD_ALIGN;
 
 	if (reference_point) {
-		bezt->h1 = bezt->h2 = MAX2(reference_point->bezt.h2, reference_point->bezt.h1);
+		if (reference_point->bezt.h1 == HD_VECT && reference_point->bezt.h2 == HD_VECT) {
+			/* If the reference point is sharp try using some smooth point as reference
+			 * for handles.
+			 */
+			int point_index = reference_point - spline->points;
+			int delta = new_point == spline->points ? 1 : -1;
+			int i = 0;
+			for (i = 0; i < spline->tot_point - 1; ++i) {
+				MaskSplinePoint *current_point;
+
+				point_index += delta;
+				if (point_index == -1 || point_index >= spline->tot_point) {
+					if (spline->flag & MASK_SPLINE_CYCLIC) {
+						if (point_index == -1) {
+							point_index = spline->tot_point - 1;
+						}
+						else if (point_index >= spline->tot_point) {
+							point_index = 0;
+						}
+					}
+					else {
+						break;
+					}
+				}
+
+				current_point = &spline->points[point_index];
+				if (current_point->bezt.h1 != HD_VECT || current_point->bezt.h2 != HD_VECT) {
+					bezt->h1 = bezt->h2 = MAX2(current_point->bezt.h2, current_point->bezt.h1);
+					break;
+				}
+			}
+		}
+		else {
+			bezt->h1 = bezt->h2 = MAX2(reference_point->bezt.h2, reference_point->bezt.h1);
+		}
 	}
 	else if (reference_adjacent) {
 		if (spline->tot_point != 1) {
@@ -219,83 +251,11 @@ static void setup_vertex_point(Mask *mask, MaskSpline *spline, MaskSplinePoint *
 	copy_v3_v3(bezt->vec[1], co);
 	copy_v3_v3(bezt->vec[2], co);
 
-	/* initial offset for handles */
-	if (spline->tot_point == 1) {
-		/* first point of splien is aligned horizontally */
-		bezt->vec[0][0] -= len * view_zoom;
-		bezt->vec[2][0] += len * view_zoom;
-	}
-	else if (tangent) {
-		float vec[2];
-
-		copy_v2_v2(vec, tangent);
-
-		mul_v2_fl(vec, len);
-
-		sub_v2_v2(bezt->vec[0], vec);
-		add_v2_v2(bezt->vec[2], vec);
-
-		if (reference_adjacent) {
-			BKE_mask_calc_handle_adjacent_interp(spline, new_point, u);
-		}
-	}
-	else {
-
-		/* calculating auto handles works much nicer */
-#if 0
-		/* next points are aligning in the direction of previous/next point */
-		MaskSplinePoint *point;
-		float v1[2], v2[2], vec[2];
-		float dir = 1.0f;
-
-		if (new_point == spline->points) {
-			point = new_point + 1;
-			dir = -1.0f;
-		}
-		else
-			point = new_point - 1;
-
-		if (spline->tot_point < 3) {
-			v1[0] = point->bezt.vec[1][0] * width;
-			v1[1] = point->bezt.vec[1][1] * height;
-
-			v2[0] = new_point->bezt.vec[1][0] * width;
-			v2[1] = new_point->bezt.vec[1][1] * height;
-		}
-		else {
-			if (new_point == spline->points) {
-				v1[0] = spline->points[1].bezt.vec[1][0] * width;
-				v1[1] = spline->points[1].bezt.vec[1][1] * height;
-
-				v2[0] = spline->points[spline->tot_point - 1].bezt.vec[1][0] * width;
-				v2[1] = spline->points[spline->tot_point - 1].bezt.vec[1][1] * height;
-			}
-			else {
-				v1[0] = spline->points[0].bezt.vec[1][0] * width;
-				v1[1] = spline->points[0].bezt.vec[1][1] * height;
-
-				v2[0] = spline->points[spline->tot_point - 2].bezt.vec[1][0] * width;
-				v2[1] = spline->points[spline->tot_point - 2].bezt.vec[1][1] * height;
-			}
-		}
-
-		sub_v2_v2v2(vec, v1, v2);
-		mul_v2_fl(vec, len * dir / len_v2(vec));
-
-		vec[0] /= width;
-		vec[1] /= height;
-
-		add_v2_v2(bezt->vec[0], vec);
-		sub_v2_v2(bezt->vec[2], vec);
-#else
-		BKE_mask_calc_handle_point_auto(spline, new_point, TRUE);
+	BKE_mask_parent_init(&new_point->parent);
+	if (spline->tot_point != 1) {
 		BKE_mask_calc_handle_adjacent_interp(spline, new_point, u);
-
-#endif
 	}
 
-	BKE_mask_parent_init(&new_point->parent);
-
 	/* select new point */
 	MASKPOINT_SEL_ALL(new_point);
 	ED_mask_select_flush_all(mask);
@@ -382,7 +342,7 @@ static int add_vertex_subdivide(const bContext *C, Mask *mask, const float co[2]
 
 		new_point = &spline->points[point_index + 1];
 
-		setup_vertex_point(mask, spline, new_point, co, tangent, u, NULL, TRUE, 1.0f);
+		setup_vertex_point(mask, spline, new_point, co, u, NULL, TRUE);
 
 		/* TODO - we could pass the spline! */
 		BKE_mask_layer_shape_changed_add(masklay, BKE_mask_layer_shape_spline_to_index(masklay, spline) + point_index + 1, true, true);
@@ -409,7 +369,6 @@ static int add_vertex_extrude(const bContext *C, Mask *mask, MaskLayer *masklay,
 	float tangent_point[2];
 	float tangent_co[2];
 	bool do_cyclic_correct = false;
-	bool do_recalc_src = false;  /* when extruding from endpoints only */
 	bool do_prev;                /* use prev point rather then next?? */
 
 	if (!masklay) {
@@ -440,11 +399,9 @@ static int add_vertex_extrude(const bContext *C, Mask *mask, MaskLayer *masklay,
 	}
 	else if (((spline->flag & MASK_SPLINE_CYCLIC) == 0) && (point_index == 0)) {
 		do_prev = TRUE;
-		do_recalc_src = TRUE;
 	}
 	else if (((spline->flag & MASK_SPLINE_CYCLIC) == 0) && (point_index == spline->tot_point - 1)) {
 		do_prev = FALSE;
-		do_recalc_src = TRUE;
 	}
 	else {
 		do_prev = FALSE;  /* quiet warning */
@@ -482,18 +439,13 @@ static int add_vertex_extrude(const bContext *C, Mask *mask, MaskLayer *masklay,
 
 	masklay->act_point = new_point;
 
-	setup_vertex_point(mask, spline, new_point, co, NULL, 0.5f, ref_point, FALSE, 1.0f);
+	setup_vertex_point(mask, spline, new_point, co, 0.5f, ref_point, FALSE);
 
 	if (masklay->splines_shapes.first) {
 		point_index = (((int)(new_point - spline->points) + 0) % spline->tot_point);
 		BKE_mask_layer_shape_changed_add(masklay, BKE_mask_layer_shape_spline_to_index(masklay, spline) + point_index, true, true);
 	}
 
-	if (do_recalc_src) {
-		/* TODO, update keyframes in time */
-		BKE_mask_calc_handle_point_auto(spline, ref_point, FALSE);
-	}
-
 	WM_event_add_notifier(C, NC_MASK | NA_EDITED, mask);
 
 	return TRUE;
@@ -504,7 +456,6 @@ static int add_vertex_new(const bContext *C, Mask *mask, MaskLayer *masklay, con
 	MaskSpline *spline;
 	MaskSplinePoint *point;
 	MaskSplinePoint *new_point = NULL, *ref_point = NULL;
-	float view_zoom;
 
 	if (!masklay) {
 		/* if there's no masklay currently operationg on, create new one */
@@ -529,22 +480,7 @@ static int add_vertex_new(const bContext *C, Mask *mask, MaskLayer *masklay, con
 
 	masklay->act_point = new_point;
 
-	{
-		ScrArea *sa = CTX_wm_area(C);
-		ARegion *ar = CTX_wm_region(C);
-
-		float zoom_x, zoom_y;
-		/* calc view zoom in a simplistic way */
-		ED_mask_zoom(sa, ar, &zoom_x, &zoom_y);
-
-		view_zoom = zoom_x + zoom_y / 2.0f;
-		view_zoom = 1.0f / view_zoom;
-
-		/* arbitrary but gives good results */
-		view_zoom /= 500.0f;
-	}
-
-	setup_vertex_point(mask, spline, new_point, co, NULL, 0.5f, ref_point, FALSE, view_zoom);
+	setup_vertex_point(mask, spline, new_point, co, 0.5f, ref_point, FALSE);
 
 	{
 		int point_index = (((int)(new_point - spline->points) + 0) % spline->tot_point);