scripts/startup/bl_ui/space_graph.py

@@ -329,6 +329,7 @@ class GRAPH_MT_slider(Menu):
         layout.operator("graph.breakdown", text="Breakdown")
         layout.operator("graph.blend_to_neighbor", text="Blend to Neighbor")
         layout.operator("graph.blend_to_default", text="Blend to Default Value")
+        layout.operator("graph.blend_to_ease", text="Blend to Ease")
         layout.operator("graph.ease", text="Ease")
         layout.operator("graph.gaussian_smooth", text="Smooth")
 

source/blender/editors/animation/keyframes_general.c

@@ -491,6 +491,75 @@ void ease_fcurve_segment(FCurve *fcu, FCurveSegment *segment, const float factor
 
 /* ---------------- */
 
+static float s_curve(float x, float slope, float width, float height, float xshift, float yshift)
+{
+  /* Formula for 'S' curve we use for the "ease" sliders. The shift values move the curve verticaly
+   * or horizontaly. The range of the curve used is from 0 to 1 on "x" and "y" so we can scale it
+   * (width and height) and move it (xshift and y yshift) to crop the part of the curve we need.
+   * Slope determins how curvy the shape is */
+  float y = height * pow((x - xshift), slope) /
+                (pow((x - xshift), slope) + pow((width - (x - xshift)), slope)) +
+            yshift;
+
+  /* The curve has some noise beyond our margins so we clamp the values */
+  if (x > xshift + width) {
+    y = height + yshift;
+  }
+  else if (x < xshift) {
+    y = yshift;
+  }
+  return y;
+}
+
+void blend_to_ease_fcurve_segment(FCurve *fcu, FCurveSegment *segment, const float factor)
+{
+  const BezTriple *left_key = fcurve_segment_start_get(fcu, segment->start_index);
+  const BezTriple *right_key = fcurve_segment_end_get(fcu, segment->start_index + segment->length);
+
+  const float key_x_range = right_key->vec[1][0] - left_key->vec[1][0];
+  const float key_y_range = right_key->vec[1][1] - left_key->vec[1][1];
+
+  /* Happens if there is only 1 key on the FCurve. Needs to be skipped because it
+   * would be a divide by 0. */
+  if (IS_EQF(key_x_range, 0.0f)) {
+    return;
+  }
+
+  const float slope = 3.0;
+  /* By doubling the size of the "S" curve we just one side of it, a "C" shape. */
+  const float width = 2.0;
+  const float height = 2.0;
+  float xy_shift;
+  float y_delta;
+
+  /* Shifting the x and y values we can decide what side of the "S" shape to use. */
+  if (factor > 0) {
+    xy_shift = -1.0;
+  }
+  else {
+    xy_shift = 0.0;
+  }
+
+  for (int i = segment->start_index; i < segment->start_index + segment->length; i++) {
+
+    const float x = (fcu->bezt[i].vec[1][0] - left_key->vec[1][0]) / key_x_range;
+    const float ease = s_curve(x, slope, width, height, xy_shift, xy_shift);
+    const float base = left_key->vec[1][1] + key_y_range * ease;
+
+    if (factor > 0) {
+      y_delta = base - fcu->bezt[i].vec[1][1];
+    }
+    else {
+      y_delta = fcu->bezt[i].vec[1][1] - base;
+    }
+
+    const float key_y_value = fcu->bezt[i].vec[1][1] + y_delta * factor;
+    move_key(&fcu->bezt[i], key_y_value);
+  }
+}
+
+/* ---------------- */
+
 void breakdown_fcurve_segment(FCurve *fcu, FCurveSegment *segment, const float factor)
 {
   const BezTriple *left_bezt = fcurve_segment_start_get(fcu, segment->start_index);

source/blender/editors/include/ED_keyframes_edit.h

@@ -437,6 +437,7 @@ void smooth_fcurve_segment(struct FCurve *fcu,
                            int kernel_size,
                            double *kernel);
 void ease_fcurve_segment(struct FCurve *fcu, struct FCurveSegment *segment, float factor);
+void blend_to_ease_fcurve_segment(struct FCurve *fcu, struct FCurveSegment *segment, float factor);
 bool decimate_fcurve(struct bAnimListElem *ale, float remove_ratio, float error_sq_max);
 void blend_to_default_fcurve(struct PointerRNA *id_ptr, struct FCurve *fcu, float factor);
 /**

source/blender/editors/space_graph/graph_intern.h

@@ -114,6 +114,7 @@ void GRAPH_OT_clean(struct wmOperatorType *ot);
 void GRAPH_OT_blend_to_neighbor(struct wmOperatorType *ot);
 void GRAPH_OT_breakdown(struct wmOperatorType *ot);
 void GRAPH_OT_ease(struct wmOperatorType *ot);
+void GRAPH_OT_blend_to_ease(struct wmOperatorType *ot);
 void GRAPH_OT_decimate(struct wmOperatorType *ot);
 void GRAPH_OT_blend_to_default(struct wmOperatorType *ot);
 void GRAPH_OT_gaussian_smooth(struct wmOperatorType *ot);

source/blender/editors/space_graph/graph_ops.c

@@ -463,6 +463,7 @@ void graphedit_operatortypes(void)
   WM_operatortype_append(GRAPH_OT_blend_to_neighbor);
   WM_operatortype_append(GRAPH_OT_breakdown);
   WM_operatortype_append(GRAPH_OT_ease);
+  WM_operatortype_append(GRAPH_OT_blend_to_ease);
   WM_operatortype_append(GRAPH_OT_blend_to_default);
   WM_operatortype_append(GRAPH_OT_gaussian_smooth);
   WM_operatortype_append(GRAPH_OT_euler_filter);

source/blender/editors/space_graph/graph_slider_ops.c

@@ -1060,6 +1060,133 @@ void GRAPH_OT_ease(wmOperatorType *ot)
                        1.0f);
 }
 
+/* -------------------------------------------------------------------- */
+/** \name Blend to Ease Operator
+ * \{ */
+
+static void blend_to_ease_graph_keys(bAnimContext *ac, const float factor)
+{
+  ListBase anim_data = {NULL, NULL};
+
+  ANIM_animdata_filter(ac, &anim_data, OPERATOR_DATA_FILTER, ac->data, ac->datatype);
+  LISTBASE_FOREACH (bAnimListElem *, ale, &anim_data) {
+    FCurve *fcu = (FCurve *)ale->key_data;
+    ListBase segments = find_fcurve_segments(fcu);
+
+    LISTBASE_FOREACH (FCurveSegment *, segment, &segments) {
+      blend_to_ease_fcurve_segment(fcu, segment, factor);
+    }
+
+    ale->update |= ANIM_UPDATE_DEFAULT;
+    BLI_freelistN(&segments);
+  }
+
+  ANIM_animdata_update(ac, &anim_data);
+  ANIM_animdata_freelist(&anim_data);
+}
+
+static void blend_to_ease_draw_status_header(bContext *C, tGraphSliderOp *gso)
+{
+  char status_str[UI_MAX_DRAW_STR];
+  char mode_str[32];
+  char slider_string[UI_MAX_DRAW_STR];
+
+  ED_slider_status_string_get(gso->slider, slider_string, UI_MAX_DRAW_STR);
+
+  strcpy(mode_str, TIP_("Blend to Ease Keys"));
+
+  if (hasNumInput(&gso->num)) {
+    char str_ofs[NUM_STR_REP_LEN];
+
+    outputNumInput(&gso->num, str_ofs, &gso->scene->unit);
+
+    BLI_snprintf(status_str, sizeof(status_str), "%s: %s", mode_str, str_ofs);
+  }
+  else {
+    BLI_snprintf(status_str, sizeof(status_str), "%s: %s", mode_str, slider_string);
+  }
+
+  ED_workspace_status_text(C, status_str);
+}
+
+static void blend_to_ease_modal_update(bContext *C, wmOperator *op)
+{
+  tGraphSliderOp *gso = op->customdata;
+
+  blend_to_ease_draw_status_header(C, gso);
+
+  /* Reset keyframes to the state at invoke. */
+  reset_bezts(gso);
+  const float factor = slider_factor_get_and_remember(op);
+  blend_to_ease_graph_keys(&gso->ac, factor);
+  WM_event_add_notifier(C, NC_ANIMATION | ND_KEYFRAME | NA_EDITED, NULL);
+}
+
+static int blend_to_ease_invoke(bContext *C, wmOperator *op, const wmEvent *event)
+{
+  const int invoke_result = graph_slider_invoke(C, op, event);
+
+  if (invoke_result == OPERATOR_CANCELLED) {
+    return invoke_result;
+  }
+
+  tGraphSliderOp *gso = op->customdata;
+  gso->modal_update = blend_to_ease_modal_update;
+  gso->factor_prop = RNA_struct_find_property(op->ptr, "factor");
+  blend_to_ease_draw_status_header(C, gso);
+  ED_slider_allow_overshoot_set(gso->slider, false);
+  ED_slider_is_bidirectional_set(gso->slider, true);
+  ED_slider_factor_set(gso->slider, 0.0f);
+
+  return invoke_result;
+}
+
+static int blend_to_ease_exec(bContext *C, wmOperator *op)
+{
+  bAnimContext ac;
+
+  /* Get editor data. */
+  if (ANIM_animdata_get_context(C, &ac) == 0) {
+    return OPERATOR_CANCELLED;
+  }
+
+  const float factor = RNA_float_get(op->ptr, "factor");
+
+  blend_to_ease_graph_keys(&ac, factor);
+
+  /* Set notifier that keyframes have changed. */
+  WM_event_add_notifier(C, NC_ANIMATION | ND_KEYFRAME | NA_EDITED, NULL);
+
+  return OPERATOR_FINISHED;
+}
+
+void GRAPH_OT_blend_to_ease(wmOperatorType *ot)
+{
+  /* Identifiers. */
+  ot->name = "Blend to Ease Keyframes";
+  ot->idname = "GRAPH_OT_blend_to_ease";
+  ot->description = "Blends keyframes from current state to an ease-in or ease-out curve";
+
+  /* API callbacks. */
+  ot->invoke = blend_to_ease_invoke;
+  ot->modal = graph_slider_modal;
+  ot->exec = blend_to_ease_exec;
+  ot->poll = graphop_editable_keyframes_poll;
+
+  /* Flags. */
+  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+
+  RNA_def_float_factor(ot->srna,
+                       "factor",
+                       0.0f,
+                       -FLT_MAX,
+                       FLT_MAX,
+                       "Curve Bend",
+                       "Control the bend of the curve",
+                       -1.0f,
+                       1.0f);
+}
+
 /** \} */
 /* -------------------------------------------------------------------- */
 /** \name Gauss Smooth Operator