Directly select animation curves in the graph editor

Hi!

In Blender, in the graph editor, it is for now impossible to select a curve directly without selecting a keyframe of that curve.
This can sometimes be a bit frustrating, especially for people coming from softwares where this is possible. Being able to select curves directly allows to hide or lock them a bit faster, for instance.

This patch enables the user to **directly select animation curves with the usual selection operators**. When doing a selection, the usual keyframe selection is first performed, and if no keyframe could be found, then it tries selecting the curve. This is done on a per-curve basis (per-channel), which means that the user may select both a keyframe for a curve A, and a curve B with no keyframe. I found it to be more intuitive, but maybe this is something that should change.

The selection of the curves is done by sampling them in the interval defined by the xmin and the xmax of the selection area, and checking if those points are inside of this area.

Selecting curve is available in the **box selection** operator, the **lasso**, and the **circle selection** operators.

{F8892684}

Reviewed By: sybren, zeddb, looch

Differential Revision: https://developer.blender.org/D8687

source/blender/editors/space_graph/graph_select.c

@@ -512,16 +512,19 @@ static rctf initialize_box_select_coords(const bAnimContext *ac, const rctf *rec
   return rectf;
 }
 
-static ListBase initialize_box_select_anim_data(const SpaceGraph *sipo, bAnimContext *ac)
+static int initialize_filter(const SpaceGraph *sipo)
 {
-  ListBase anim_data = {NULL, NULL};
-
   int filter = (ANIMFILTER_DATA_VISIBLE | ANIMFILTER_CURVE_VISIBLE | ANIMFILTER_NODUPLIS);
   if (sipo->flag & SIPO_SELCUVERTSONLY) {
     filter |= ANIMFILTER_FOREDIT | ANIMFILTER_SELEDIT;
   }
-  ANIM_animdata_filter(ac, &anim_data, filter, ac->data, ac->datatype);
+  return filter;
+}
 
+static ListBase initialize_box_select_anim_data(const int filter, bAnimContext *ac)
+{
+  ListBase anim_data = {NULL, NULL};
+  ANIM_animdata_filter(ac, &anim_data, filter, ac->data, ac->datatype);
   return anim_data;
 }
 
@@ -583,7 +586,8 @@ static void box_select_graphkeys(bAnimContext *ac,
 {
   const rctf rectf = initialize_box_select_coords(ac, rectf_view);
   SpaceGraph *sipo = (SpaceGraph *)ac->sl;
-  ListBase anim_data = initialize_box_select_anim_data(sipo, ac);
+  const int filter = initialize_filter(sipo);
+  ListBase anim_data = initialize_box_select_anim_data(filter, ac);
   rctf scaled_rectf;
   KeyframeEditData ked;
   int mapping_flag;
@@ -655,6 +659,112 @@ static void box_select_graphkeys(bAnimContext *ac,
   ANIM_animdata_freelist(&anim_data);
 }
 
+/* This function checks whether a keyframe is already selected. */
+static bool is_key_already_selected(const ListBase *anim_data)
+{
+  for (bAnimListElem *ale = anim_data->first; ale; ale = ale->next) {
+    const FCurve *fcu = (FCurve *)ale->key_data;
+    BezTriple *bezt;
+    uint i;
+    for (bezt = fcu->bezt, i = 0; i < fcu->totvert; bezt++, i++) {
+      if (BEZT_ISSEL_ANY(bezt)) {
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+/* Perform a box selection of the curves themselves. If check_for_keys is true,
+ * no curves will be selected if a keyframe is already selected by the user. */
+static void box_select_graphcurves(bAnimContext *ac,
+                                   const rctf *rectf_view,
+                                   short mode,
+                                   bool incl_handles,
+                                   void *data,
+                                   bool check_for_key_selection)
+{
+  const rctf rectf = initialize_box_select_coords(ac, rectf_view);
+  SpaceGraph *sipo = (SpaceGraph *)ac->sl;
+  const int filter = initialize_filter(sipo);
+  ListBase anim_data = initialize_box_select_anim_data(filter, ac);
+  rctf scaled_rectf;
+  KeyframeEditData ked;
+  int mapping_flag;
+  initialize_box_select_key_editing_data(
+      sipo, incl_handles, mode, ac, data, &scaled_rectf, &ked, &mapping_flag);
+
+  /* Curve selection should only be done if there is no keyframe already selected, unless
+   * the user has chosen not to care about already selected keys. */
+  if (check_for_key_selection && is_key_already_selected(&anim_data)) {
+    return;
+  }
+
+  FCurve *selected_curve = NULL;
+  uint selected_count = 0;
+
+  for (bAnimListElem *ale = anim_data.first; ale; ale = ale->next) {
+    AnimData *adt = ANIM_nla_mapping_get(ac, ale);
+    FCurve *fcu = (FCurve *)ale->key_data;
+    float offset;
+    const float unit_scale = ANIM_unit_mapping_get_factor(
+        ac->scene, ale->id, fcu, mapping_flag, &offset);
+
+    /* Apply NLA mapping to all the keyframes, since it's easier than trying to
+     * guess when a callback might use something different.
+     */
+    if (adt) {
+      ANIM_nla_mapping_apply_fcurve(adt, ale->key_data, 0, incl_handles == 0);
+    }
+
+    scaled_rectf.xmin = rectf.xmin;
+    scaled_rectf.xmax = rectf.xmax;
+    scaled_rectf.ymin = rectf.ymin / unit_scale - offset;
+    scaled_rectf.ymax = rectf.ymax / unit_scale - offset;
+
+    /* Set horizontal range (if applicable).
+     * NOTE: these values are only used for x-range and y-range but not region
+     *      (which uses ked.data, i.e. rectf)
+     */
+    if (mode != BEZT_OK_VALUERANGE) {
+      ked.f1 = rectf.xmin;
+      ked.f2 = rectf.xmax;
+    }
+    else {
+      ked.f1 = rectf.ymin;
+      ked.f2 = rectf.ymax;
+    }
+
+    const float step = (rectf.xmax - rectf.xmin) / 30.0f;
+    float x = rectf.xmin;
+
+    /* Sample points on the given fcurve in the interval defined by the
+     * xmin and xmax of the selected rectangle.
+     * For each point, check if it is inside of the selection box. If it is, then
+     * stop the loop and select this curve.
+     */
+    while (x < rectf.xmax) {
+      float current_point[2];
+      current_point[0] = x;
+      current_point[1] = (evaluate_fcurve(fcu, x) + offset) * unit_scale;
+
+      if (BLI_rctf_isect_pt_v(&rectf, current_point)) {
+        fcu->flag |= FCURVE_SELECTED;
+        selected_curve = fcu;
+        selected_count++;
+        break;
+      }
+      x += step;
+    }
+  }
+
+  /* If only one curve is selected, then make it active so that it's easier to
+   * add curve modifiers for instance. */
+  if (selected_count == 1) {
+    ANIM_set_active_channel(ac, ac->data, ac->datatype, filter, selected_curve, ANIMTYPE_FCURVE);
+  }
+}
+
 /* ------------------- */
 
 static int graphkeys_box_select_invoke(bContext *C, wmOperator *op, const wmEvent *event)
@@ -700,6 +810,8 @@ static int graphkeys_box_select_exec(bContext *C, wmOperator *op)
   /* 'include_handles' from the operator specifies whether to include handles in the selection. */
   const bool incl_handles = RNA_boolean_get(op->ptr, "include_handles");
 
+  const bool enable_curves_selection = RNA_boolean_get(op->ptr, "select_curves");
+
   /* Get settings from operator. */
   WM_operator_properties_border_to_rcti(op, &rect);
 
@@ -727,6 +839,10 @@ static int graphkeys_box_select_exec(bContext *C, wmOperator *op)
 
   /* Apply box_select action. */
   box_select_graphkeys(&ac, &rect_fl, mode, selectmode, incl_handles, NULL);
+  if (enable_curves_selection) {
+    box_select_graphcurves(&ac, &rect_fl, mode, incl_handles, NULL, true);
+  }
+
   /* Send notifier that keyframe selection has changed. */
   WM_event_add_notifier(C, NC_ANIMATION | ND_KEYFRAME | NA_SELECTED, NULL);
 
@@ -767,6 +883,13 @@ void GRAPH_OT_select_box(wmOperatorType *ot)
       ot->srna, "tweak", 0, "Tweak", "Operator has been activated using a tweak event");
   RNA_def_property_flag(prop, PROP_SKIP_SAVE);
 
+  prop = RNA_def_boolean(ot->srna,
+                         "select_curves",
+                         1,
+                         "Select Curves",
+                         "Are curves directly selectable? If no, only keyframes are selected");
+  RNA_def_property_flag(prop, PROP_SKIP_SAVE);
+
   WM_operator_properties_gesture_box(ot);
   WM_operator_properties_select_operation_simple(ot);
 }
@@ -810,12 +933,18 @@ static int graphkeys_lassoselect_exec(bContext *C, wmOperator *op)
     }
   }
 
+  const bool enable_curves_selection = RNA_boolean_get(op->ptr, "select_curves");
+
   /* Get settings from operator. */
   BLI_lasso_boundbox(&rect, data_lasso.mcoords, data_lasso.mcoords_len);
   BLI_rctf_rcti_copy(&rect_fl, &rect);
 
   /* Apply box_select action. */
   box_select_graphkeys(&ac, &rect_fl, BEZT_OK_REGION_LASSO, selectmode, incl_handles, &data_lasso);
+  if (enable_curves_selection) {
+    box_select_graphcurves(
+        &ac, &rect_fl, BEZT_OK_REGION_LASSO, incl_handles, &data_lasso, true);
+  }
 
   MEM_freeN((void *)data_lasso.mcoords);
 
@@ -845,6 +974,13 @@ void GRAPH_OT_select_lasso(wmOperatorType *ot)
   /* Properties. */
   WM_operator_properties_gesture_lasso(ot);
   WM_operator_properties_select_operation_simple(ot);
+  PropertyRNA *prop = RNA_def_boolean(
+      ot->srna,
+      "select_curves",
+      1,
+      "Select Curves",
+      "Are curves directly selectable? If no, only keyframes are selected");
+  RNA_def_property_flag(prop, PROP_SKIP_SAVE);
 }
 
 /* ------------------- */
@@ -869,6 +1005,8 @@ static int graph_circle_select_exec(bContext *C, wmOperator *op)
   const eSelectOp sel_op = ED_select_op_modal(RNA_enum_get(op->ptr, "mode"),
                                               WM_gesture_is_modal_first(op->customdata));
   const short selectmode = (sel_op != SEL_OP_SUB) ? SELECT_ADD : SELECT_SUBTRACT;
+  const bool enable_curves_selection = RNA_boolean_get(op->ptr, "select_curves");
+
   if (SEL_OP_USE_PRE_DESELECT(sel_op)) {
     deselect_graph_keys(&ac, 0, SELECT_SUBTRACT, true);
   }
@@ -895,6 +1033,10 @@ static int graph_circle_select_exec(bContext *C, wmOperator *op)
 
   /* Apply box_select action. */
   box_select_graphkeys(&ac, &rect_fl, BEZT_OK_REGION_CIRCLE, selectmode, incl_handles, &data);
+  if (enable_curves_selection) {
+    box_select_graphcurves(
+        &ac, &rect_fl, BEZT_OK_REGION_CIRCLE, incl_handles, &data, true);
+  }
 
   /* Send notifier that keyframe selection has changed. */
   WM_event_add_notifier(C, NC_ANIMATION | ND_KEYFRAME | NA_SELECTED, NULL);
@@ -920,6 +1062,13 @@ void GRAPH_OT_select_circle(wmOperatorType *ot)
   /* properties */
   WM_operator_properties_gesture_circle(ot);
   WM_operator_properties_select_operation_simple(ot);
+  PropertyRNA *prop = RNA_def_boolean(
+      ot->srna,
+      "select_curves",
+      1,
+      "Select Curves",
+      "Are curves directly selectable? If no, only keyframes are selected");
+  RNA_def_property_flag(prop, PROP_SKIP_SAVE);
 }
 
 /* ******************** Column Select Operator **************************** */