Patch T22084: Robert Penner Easing Equations for FCurves

This commit introduces support for a number of new interpolation types
which are useful for motion-graphics work. These define a number of
"easing equations" (basically, equations which define some preset
ways that one keyframe transitions to another) which reduce the amount
of manual work (inserting and tweaking keyframes) to achieve certain
common effects. For example, snappy movements, and fake-physics such
as bouncing/springing effects.

The additional interpolation types introduced in this commit can be found
in many packages and toolkits (notably Qt and all modern web browsers).
For more info and a few live demos, see [1] and [2].


Credits:
* Dan Eicher (dna)              - Original patch
* Thomas Beck (plasmasolutions) - Porting/updating patch to 2.70 codebase
* Joshua Leung (aligorith)      - Code review and a few polishing tweaks

Additional Resources:
[1] http://easings.net
[2] http://www.robertpenner.com/easing/

1 files changed, 66 insertions, 0 deletions

diff --git a/source/blender/editors/space_graph/graph_edit.c b/source/blender/editors/space_graph/graph_edit.c
index 93d103e11a6..0fa6edd0011 100644
--- a/source/blender/editors/space_graph/graph_edit.c
+++ b/source/blender/editors/space_graph/graph_edit.c
@@ -1502,6 +1502,72 @@ void GRAPH_OT_interpolation_type(wmOperatorType *ot)
 	ot->prop = RNA_def_enum(ot->srna, "type", beztriple_interpolation_mode_items, 0, "Type", "");
 }
 
+/* ******************** Set Easing Operator *********************** */
+
+static void seteasing_graph_keys(bAnimContext *ac, short mode)
+{
+	ListBase anim_data = {NULL, NULL};
+	bAnimListElem *ale;
+	int filter;
+	KeyframeEditFunc set_cb = ANIM_editkeyframes_easing(mode);
+	
+	/* filter data */
+	filter = (ANIMFILTER_DATA_VISIBLE | ANIMFILTER_CURVE_VISIBLE | ANIMFILTER_FOREDIT | ANIMFILTER_NODUPLIS);
+	ANIM_animdata_filter(ac, &anim_data, filter, ac->data, ac->datatype);
+	
+	/* loop through setting BezTriple easing
+	 * Note: we do not supply KeyframeEditData to the looper yet. Currently that's not necessary here...
+	 */
+	for (ale = anim_data.first; ale; ale = ale->next)
+		ANIM_fcurve_keyframes_loop(NULL, ale->key_data, NULL, set_cb, calchandles_fcurve);
+	
+	/* cleanup */
+	BLI_freelistN(&anim_data);
+}
+
+static int graphkeys_easing_exec(bContext *C, wmOperator *op)
+{
+	bAnimContext ac;
+	short mode;
+	
+	/* get editor data */
+	if (ANIM_animdata_get_context(C, &ac) == 0)
+		return OPERATOR_CANCELLED;
+	
+	/* get handle setting mode */
+	mode = RNA_enum_get(op->ptr, "type");
+	
+	/* set handle type */
+	seteasing_graph_keys(&ac, mode);
+	
+	/* validate keyframes after editing */
+	ANIM_editkeyframes_refresh(&ac);
+	
+	/* set notifier that keyframe properties have changed */
+	WM_event_add_notifier(C, NC_ANIMATION | ND_KEYFRAME_PROP, NULL);
+	
+	return OPERATOR_FINISHED;
+}
+
+void GRAPH_OT_easing_type(wmOperatorType *ot)
+{
+	/* identifiers */
+	ot->name = "Set Keyframe Easing Type";
+	ot->idname = "GRAPH_OT_easing_type";
+	ot->description = "Set easing type for the F-Curve segments starting from the selected keyframes";
+	
+	/* api callbacks */
+	ot->invoke = WM_menu_invoke;
+	ot->exec = graphkeys_easing_exec;
+	ot->poll = graphop_editable_keyframes_poll;
+	
+	/* flags */
+	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+	
+	/* id-props */
+	ot->prop = RNA_def_enum(ot->srna, "type", beztriple_interpolation_easing_items, 0, "Type", "");
+}
+
 /* ******************** Set Handle-Type Operator *********************** */
 
 /* this function is responsible for setting handle-type of selected keyframes */