NLA SoC: Proper poll callbacks for Graph Editor

For now, some of these polls may be a bit too restrictive, but at least we have some unified+cleaned bases to work from now (instead of relying on the generic ED_operator_area_active).

7 files changed, 325 insertions, 96 deletions

diff --git a/source/blender/editors/space_graph/graph_buttons.c b/source/blender/editors/space_graph/graph_buttons.c
index ea4f017c9bb..f2dcd297866 100644
--- a/source/blender/editors/space_graph/graph_buttons.c
+++ b/source/blender/editors/space_graph/graph_buttons.c
@@ -1000,34 +1000,6 @@ static void graph_panel_modifiers(const bContext *C, Panel *pa)
 
 /* ******************* general ******************************** */
 
-/* Find 'active' F-Curve. It must be editable, since that's the purpose of these buttons (subject to change).  
- * We return the 'wrapper' since it contains valuable context info (about hierarchy), which will need to be freed 
- * when the caller is done with it.
- */
-// TODO: move this to anim api with another name?
-bAnimListElem *get_active_fcurve_channel (bAnimContext *ac)
-{
-	ListBase anim_data = {NULL, NULL};
-	int filter= (ANIMFILTER_VISIBLE | ANIMFILTER_FOREDIT | ANIMFILTER_ACTIVE | ANIMFILTER_CURVESONLY);
-	int items = ANIM_animdata_filter(ac, &anim_data, filter, ac->data, ac->datatype);
-	
-	/* We take the first F-Curve only, since some other ones may have had 'active' flag set
-	 * if they were from linked data.
-	 */
-	if (items) {
-		bAnimListElem *ale= (bAnimListElem *)anim_data.first;
-		
-		/* remove first item from list, then free the rest of the list and return the stored one */
-		BLI_remlink(&anim_data, ale);
-		BLI_freelistN(&anim_data);
-		
-		return ale;
-	}
-	
-	/* no active F-Curve */
-	return NULL;
-}
-
 void graph_buttons_register(ARegionType *art)
 {
 	PanelType *pt;
diff --git a/source/blender/editors/space_graph/graph_draw.c b/source/blender/editors/space_graph/graph_draw.c
index 6393b6877b9..66168f2ed87 100644
--- a/source/blender/editors/space_graph/graph_draw.c
+++ b/source/blender/editors/space_graph/graph_draw.c
@@ -775,46 +775,6 @@ void graph_draw_ghost_curves (bAnimContext *ac, SpaceIpo *sipo, ARegion *ar, Vie
 	glDisable(GL_BLEND);
 }
 
-/* check if any FModifiers to draw controls for  - fcm is 'active' modifier */
-static short fcurve_needs_draw_fmodifier_controls (FCurve *fcu, FModifier *fcm)
-{
-	/* don't draw if there aren't any modifiers at all */
-	if (fcu->modifiers.first == NULL) 
-		return 0;
-	
-	/* if there's an active modifier - don't draw if it doesn't drastically
-	 * alter the curve...
-	 */
-	if (fcm) {
-		switch (fcm->type) {
-			/* clearly harmless */
-			case FMODIFIER_TYPE_CYCLES:
-				return 0;
-				
-			/* borderline... */
-			case FMODIFIER_TYPE_NOISE:
-				return 0;
-		}
-	}
-	
-	/* if only one modifier - don't draw if it is muted or disabled */
-	if (fcu->modifiers.first == fcu->modifiers.last) {
-		fcm= fcu->modifiers.first;
-		if (fcm->flag & (FMODIFIER_FLAG_DISABLED|FMODIFIER_FLAG_MUTED)) 
-			return 0;
-	}
-	
-	/* if only active modifier - don't draw if it is muted or disabled */
-	if (fcm) {
-		if (fcm->flag & (FMODIFIER_FLAG_DISABLED|FMODIFIER_FLAG_MUTED)) 
-			return 0;
-	}
-	
-	/* if we're still here, this means that there are modifiers with controls to be drawn */
-	// FIXME: what happens if all the modifiers were muted/disabled
-	return 1;
-}
-
 /* This is called twice from space_graph.c -> graph_main_area_draw()
  * Unselected then selected F-Curves are drawn so that they do not occlude each other.
  */
diff --git a/source/blender/editors/space_graph/graph_edit.c b/source/blender/editors/space_graph/graph_edit.c
index 4ea14a365e4..ca47e69cc75 100644
--- a/source/blender/editors/space_graph/graph_edit.c
+++ b/source/blender/editors/space_graph/graph_edit.c
@@ -189,7 +189,7 @@ void GRAPH_OT_previewrange_set (wmOperatorType *ot)
 	
 	/* api callbacks */
 	ot->exec= graphkeys_previewrange_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_visible_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
@@ -236,7 +236,7 @@ void GRAPH_OT_view_all (wmOperatorType *ot)
 	
 	/* api callbacks */
 	ot->exec= graphkeys_viewall_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_visible_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
@@ -347,7 +347,7 @@ void GRAPH_OT_ghost_curves_create (wmOperatorType *ot)
 	
 	/* api callbacks */
 	ot->exec= graphkeys_create_ghostcurves_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_visible_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
@@ -390,7 +390,7 @@ void GRAPH_OT_ghost_curves_clear (wmOperatorType *ot)
 	
 	/* api callbacks */
 	ot->exec= graphkeys_clear_ghostcurves_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= ED_operator_ipo_active;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
@@ -488,7 +488,7 @@ void GRAPH_OT_insert_keyframe (wmOperatorType *ot)
 	/* api callbacks */
 	ot->invoke= WM_menu_invoke;
 	ot->exec= graphkeys_insertkey_exec;
-	ot->poll= ED_operator_ipo_active; // xxx
+	ot->poll= graphop_editable_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
@@ -575,7 +575,7 @@ void GRAPH_OT_click_insert (wmOperatorType *ot)
 	/* api callbacks */
 	ot->invoke= graphkeys_click_insert_invoke;
 	ot->exec= graphkeys_click_insert_exec;
-	ot->poll= ED_operator_areaactive; // XXX active + editable poll
+	ot->poll= graphop_active_fcurve_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
@@ -657,7 +657,7 @@ void GRAPH_OT_copy (wmOperatorType *ot)
 	
 	/* api callbacks */
 	ot->exec= graphkeys_copy_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_editable_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
@@ -696,7 +696,7 @@ void GRAPH_OT_paste (wmOperatorType *ot)
 	
 	/* api callbacks */
 	ot->exec= graphkeys_paste_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_editable_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
@@ -764,7 +764,7 @@ void GRAPH_OT_duplicate (wmOperatorType *ot)
 	/* api callbacks */
 	ot->invoke= graphkeys_duplicate_invoke;
 	ot->exec= graphkeys_duplicate_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_editable_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
@@ -825,7 +825,7 @@ void GRAPH_OT_delete (wmOperatorType *ot)
 	/* api callbacks */
 	ot->invoke= WM_operator_confirm;
 	ot->exec= graphkeys_delete_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_editable_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
@@ -886,7 +886,7 @@ void GRAPH_OT_clean (wmOperatorType *ot)
 	/* api callbacks */
 	//ot->invoke=  // XXX we need that number popup for this! 
 	ot->exec= graphkeys_clean_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_editable_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
@@ -967,7 +967,7 @@ void GRAPH_OT_bake (wmOperatorType *ot)
 	/* api callbacks */
 	ot->invoke= WM_operator_confirm; // FIXME...
 	ot->exec= graphkeys_bake_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_editable_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
@@ -1092,7 +1092,7 @@ void GRAPH_OT_sample (wmOperatorType *ot)
 	
 	/* api callbacks */
 	ot->exec= graphkeys_sample_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_editable_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
@@ -1167,7 +1167,7 @@ void GRAPH_OT_extrapolation_type (wmOperatorType *ot)
 	/* api callbacks */
 	ot->invoke= WM_menu_invoke;
 	ot->exec= graphkeys_expo_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_editable_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
@@ -1235,7 +1235,7 @@ void GRAPH_OT_interpolation_type (wmOperatorType *ot)
 	/* api callbacks */
 	ot->invoke= WM_menu_invoke;
 	ot->exec= graphkeys_ipo_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_editable_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
@@ -1322,7 +1322,7 @@ void GRAPH_OT_handletype (wmOperatorType *ot)
 	/* api callbacks */
 	ot->invoke= WM_menu_invoke;
 	ot->exec= graphkeys_handletype_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_editable_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
@@ -1411,7 +1411,7 @@ void GRAPH_OT_euler_filter (wmOperatorType *ot)
 	
 	/* api callbacks */
 	ot->exec= graphkeys_euler_filter_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_editable_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
@@ -1438,7 +1438,7 @@ static int graphkeys_framejump_exec(bContext *C, wmOperator *op)
 	memset(&bed, 0, sizeof(BeztEditData));
 	
 	/* loop over action data, averaging values */
-	filter= (ANIMFILTER_VISIBLE | ANIMFILTER_CURVEVISIBLE| ANIMFILTER_CURVESONLY);
+	filter= (ANIMFILTER_VISIBLE | ANIMFILTER_CURVEVISIBLE | ANIMFILTER_CURVESONLY);
 	ANIM_animdata_filter(&ac, &anim_data, filter, ac.data, ac.datatype);
 	
 	for (ale= anim_data.first; ale; ale= ale->next) {
@@ -1476,7 +1476,7 @@ void GRAPH_OT_frame_jump (wmOperatorType *ot)
 	
 	/* api callbacks */
 	ot->exec= graphkeys_framejump_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_visible_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
@@ -1568,7 +1568,7 @@ void GRAPH_OT_snap (wmOperatorType *ot)
 	/* api callbacks */
 	ot->invoke= WM_menu_invoke;
 	ot->exec= graphkeys_snap_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_editable_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
@@ -1679,7 +1679,7 @@ void GRAPH_OT_mirror (wmOperatorType *ot)
 	/* api callbacks */
 	ot->invoke= WM_menu_invoke;
 	ot->exec= graphkeys_mirror_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_editable_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
@@ -1732,7 +1732,7 @@ void GRAPH_OT_smooth (wmOperatorType *ot)
 	
 	/* api callbacks */
 	ot->exec= graphkeys_smooth_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_editable_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
@@ -1795,7 +1795,7 @@ void GRAPH_OT_fmodifier_add (wmOperatorType *ot)
 	/* api callbacks */
 	ot->invoke= WM_menu_invoke;
 	ot->exec= graph_fmodifier_add_exec;
-	ot->poll= ED_operator_areaactive; // XXX need active F-Curve
+	ot->poll= graphop_active_fcurve_poll; 
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
diff --git a/source/blender/editors/space_graph/graph_intern.h b/source/blender/editors/space_graph/graph_intern.h
index d520a63c126..fd7fe7cc6c9 100644
--- a/source/blender/editors/space_graph/graph_intern.h
+++ b/source/blender/editors/space_graph/graph_intern.h
@@ -141,8 +141,17 @@ void GRAPH_OT_ghost_curves_clear(struct wmOperatorType *ot);
 void GRAPH_OT_properties(struct wmOperatorType *ot);
 void graph_buttons_register(struct ARegionType *art);
 
+/* ***************************************** */
+/* graph_utils.c */
+
 struct bAnimListElem *get_active_fcurve_channel(struct bAnimContext *ac);
 
+short fcurve_needs_draw_fmodifier_controls(struct FCurve *fcu, struct FModifier *fcm);
+
+int graphop_visible_keyframes_poll(struct bContext *C);
+int graphop_editable_keyframes_poll(struct bContext *C);
+int graphop_active_fcurve_poll(struct bContext *C);
+
 /* ***************************************** */
 /* graph_ops.c */
 void graphedit_keymap(struct wmWindowManager *wm);
diff --git a/source/blender/editors/space_graph/graph_ops.c b/source/blender/editors/space_graph/graph_ops.c
index 012bfd944b4..d5e93dafaf0 100644
--- a/source/blender/editors/space_graph/graph_ops.c
+++ b/source/blender/editors/space_graph/graph_ops.c
@@ -92,7 +92,7 @@ void GRAPH_OT_view_togglehandles (wmOperatorType *ot)
 	
 	/* callbacks */
 	ot->exec= view_toggle_handles_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= ED_operator_ipo_active;
 }
 
 /* ************************** registration - operator types **********************************/
diff --git a/source/blender/editors/space_graph/graph_select.c b/source/blender/editors/space_graph/graph_select.c
index afe66ed179e..11af86ca83b 100644
--- a/source/blender/editors/space_graph/graph_select.c
+++ b/source/blender/editors/space_graph/graph_select.c
@@ -182,7 +182,7 @@ void GRAPH_OT_select_all_toggle (wmOperatorType *ot)
 	
 	/* api callbacks */
 	ot->exec= graphkeys_deselectall_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_visible_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER/*|OPTYPE_UNDO*/;
@@ -316,7 +316,7 @@ void GRAPH_OT_select_border(wmOperatorType *ot)
 	ot->exec= graphkeys_borderselect_exec;
 	ot->modal= WM_border_select_modal;
 	
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_visible_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER/*|OPTYPE_UNDO*/;
@@ -506,7 +506,7 @@ void GRAPH_OT_select_column (wmOperatorType *ot)
 	
 	/* api callbacks */
 	ot->exec= graphkeys_columnselect_exec;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_visible_keyframes_poll;
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER/*|OPTYPE_UNDO*/;
@@ -926,7 +926,7 @@ void GRAPH_OT_clickselect (wmOperatorType *ot)
 	
 	/* api callbacks */
 	ot->invoke= graphkeys_clickselect_invoke;
-	ot->poll= ED_operator_areaactive;
+	ot->poll= graphop_visible_keyframes_poll;
 	
 	/* id-props */
 	// XXX should we make this into separate operators?
diff --git a/source/blender/editors/space_graph/graph_utils.c b/source/blender/editors/space_graph/graph_utils.c
new file mode 100644
index 00000000000..b1ec795a089
--- /dev/null
+++ b/source/blender/editors/space_graph/graph_utils.c
@@ -0,0 +1,288 @@
+/**
+ * $Id:
+ *
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version. 
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *
+ * The Original Code is Copyright (C) 2009 Blender Foundation.
+ * All rights reserved.
+ *
+ * 
+ * Contributor(s): Blender Foundation, Joshua Leung
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+#include <string.h>
+#include <stdio.h>
+#include <math.h>
+#include <float.h>
+
+#include "DNA_anim_types.h"
+#include "DNA_action_types.h"
+#include "DNA_object_types.h"
+#include "DNA_space_types.h"
+#include "DNA_scene_types.h"
+#include "DNA_screen_types.h"
+#include "DNA_userdef_types.h"
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_arithb.h"
+#include "BLI_blenlib.h"
+#include "BLI_editVert.h"
+#include "BLI_rand.h"
+
+#include "BKE_animsys.h"
+#include "BKE_action.h"
+#include "BKE_context.h"
+#include "BKE_curve.h"
+#include "BKE_customdata.h"
+#include "BKE_depsgraph.h"
+#include "BKE_fcurve.h"
+#include "BKE_object.h"
+#include "BKE_global.h"
+#include "BKE_scene.h"
+#include "BKE_screen.h"
+#include "BKE_utildefines.h"
+
+#include "BIF_gl.h"
+
+#include "WM_api.h"
+#include "WM_types.h"
+
+#include "RNA_access.h"
+#include "RNA_define.h"
+
+#include "ED_anim_api.h"
+#include "ED_keyframing.h"
+#include "ED_screen.h"
+#include "ED_types.h"
+#include "ED_util.h"
+
+#include "UI_interface.h"
+#include "UI_resources.h"
+#include "UI_view2d.h"
+
+#include "graph_intern.h"	// own include
+
+/* ************************************************************** */
+/* Active F-Curve */
+
+/* Find 'active' F-Curve. It must be editable, since that's the purpose of these buttons (subject to change).  
+ * We return the 'wrapper' since it contains valuable context info (about hierarchy), which will need to be freed 
+ * when the caller is done with it.
+ */
+bAnimListElem *get_active_fcurve_channel (bAnimContext *ac)
+{
+	ListBase anim_data = {NULL, NULL};
+	int filter= (ANIMFILTER_VISIBLE | ANIMFILTER_FOREDIT | ANIMFILTER_ACTIVE | ANIMFILTER_CURVESONLY);
+	int items = ANIM_animdata_filter(ac, &anim_data, filter, ac->data, ac->datatype);
+	
+	/* We take the first F-Curve only, since some other ones may have had 'active' flag set
+	 * if they were from linked data.
+	 */
+	if (items) {
+		bAnimListElem *ale= (bAnimListElem *)anim_data.first;
+		
+		/* remove first item from list, then free the rest of the list and return the stored one */
+		BLI_remlink(&anim_data, ale);
+		BLI_freelistN(&anim_data);
+		
+		return ale;
+	}
+	
+	/* no active F-Curve */
+	return NULL;
+}
+
+/* ************************************************************** */
+/* Operator Polling Callbacks */
+
+/* check if any FModifiers to draw controls for  - fcm is 'active' modifier 
+ * used for the polling callbacks + also for drawing
+ */
+short fcurve_needs_draw_fmodifier_controls (FCurve *fcu, FModifier *fcm)
+{
+	/* don't draw if there aren't any modifiers at all */
+	if (fcu->modifiers.first == NULL) 
+		return 0;
+	
+	/* if there's an active modifier - don't draw if it doesn't drastically
+	 * alter the curve...
+	 */
+	if (fcm) {
+		switch (fcm->type) {
+			/* clearly harmless */
+			case FMODIFIER_TYPE_CYCLES:
+				return 0;
+				
+			/* borderline... */
+			case FMODIFIER_TYPE_NOISE:
+				return 0;
+		}
+	}
+	
+	/* if only one modifier - don't draw if it is muted or disabled */
+	if (fcu->modifiers.first == fcu->modifiers.last) {
+		fcm= fcu->modifiers.first;
+		if (fcm->flag & (FMODIFIER_FLAG_DISABLED|FMODIFIER_FLAG_MUTED)) 
+			return 0;
+	}
+	
+	/* if only active modifier - don't draw if it is muted or disabled */
+	if (fcm) {
+		if (fcm->flag & (FMODIFIER_FLAG_DISABLED|FMODIFIER_FLAG_MUTED)) 
+			return 0;
+	}
+	
+	/* if we're still here, this means that there are modifiers with controls to be drawn */
+	// FIXME: what happens if all the modifiers were muted/disabled
+	return 1;
+}
+
+/* ------------------- */
+
+/* Check if there are any visible keyframes (for selection tools) */
+int graphop_visible_keyframes_poll (bContext *C)
+{
+	bAnimContext ac;
+	bAnimListElem *ale;
+	ListBase anim_data = {NULL, NULL};
+	ScrArea *sa= CTX_wm_area(C);
+	int filter, items;
+	short found = 0;
+	
+	/* firstly, check if in Graph Editor */
+	// TODO: also check for region?
+	if ((sa == NULL) || (sa->spacetype != SPACE_IPO))
+		return 0;
+		
+	/* try to init Anim-Context stuff ourselves and check */
+	if (ANIM_animdata_get_context(C, &ac) == 0)
+		return 0;
+	
+	/* loop over the visible (selection doesn't matter) F-Curves, and see if they're suitable
+	 * stopping on the first successful match
+	 */
+	filter= (ANIMFILTER_VISIBLE | ANIMFILTER_CURVESONLY);
+	items = ANIM_animdata_filter(&ac, &anim_data, filter, ac.data, ac.datatype);
+	if (items == 0) 
+		return 0;
+	
+	for (ale = anim_data.first; ale; ale= ale->next) {
+		FCurve *fcu= (FCurve *)ale->data;
+		FModifier *fcm;
+		
+		/* visible curves for selection must fulfull the following criteria:
+		 *	- it has bezier keyframes
+		 *	- F-Curve modifiers do not interfere with the result too much 
+		 *	  (i.e. the modifier-control drawing check returns false)
+		 */
+		if (fcu->bezt == NULL)
+			continue;
+		fcm= fcurve_find_active_modifier(fcu);
+		
+		found= (fcurve_needs_draw_fmodifier_controls(fcu, fcm) == 0);
+		if (found) break;
+	}
+	
+	/* cleanup and return findings */
+	BLI_freelistN(&anim_data);
+	return found;
+}
+
+/* Check if there are any visible + editable keyframes (for editing tools) */
+int graphop_editable_keyframes_poll (bContext *C)
+{
+	bAnimContext ac;
+	bAnimListElem *ale;
+	ListBase anim_data = {NULL, NULL};
+	ScrArea *sa= CTX_wm_area(C);
+	int filter, items;
+	short found = 0;
+	
+	/* firstly, check if in Graph Editor */
+	// TODO: also check for region?
+	if ((sa == NULL) || (sa->spacetype != SPACE_IPO))
+		return 0;
+		
+	/* try to init Anim-Context stuff ourselves and check */
+	if (ANIM_animdata_get_context(C, &ac) == 0)
+		return 0;
+	
+	/* loop over the editable (selected + editable) F-Curves, and see if they're suitable
+	 * stopping on the first successful match
+	 */
+	filter= (ANIMFILTER_VISIBLE | ANIMFILTER_SEL | ANIMFILTER_FOREDIT | ANIMFILTER_CURVESONLY);
+	items = ANIM_animdata_filter(&ac, &anim_data, filter, ac.data, ac.datatype);
+	if (items == 0) 
+		return 0;
+	
+	for (ale = anim_data.first; ale; ale= ale->next) {
+		FCurve *fcu= (FCurve *)ale->data;
+		FModifier *fcm;
+		
+		/* editable curves must fulfull the following criteria:
+		 *	- it has bezier keyframes
+		 *	- it must not be protected from editing (this is already checked for with the foredit flag
+		 *	- F-Curve modifiers do not interfere with the result too much 
+		 *	  (i.e. the modifier-control drawing check returns false)
+		 */
+		if (fcu->bezt == NULL)
+			continue;
+		fcm= fcurve_find_active_modifier(fcu);
+		
+		found= (fcurve_needs_draw_fmodifier_controls(fcu, fcm) == 0);
+		if (found) break;
+	}
+	
+	/* cleanup and return findings */
+	BLI_freelistN(&anim_data);
+	return found;
+}
+
+/* has active F-Curve that's editable */
+int graphop_active_fcurve_poll (bContext *C)
+{
+	bAnimContext ac;
+	bAnimListElem *ale;
+	ScrArea *sa= CTX_wm_area(C);
+	short has_fcurve= 0;
+	
+	/* firstly, check if in Graph Editor */
+	// TODO: also check for region?
+	if ((sa == NULL) || (sa->spacetype != SPACE_IPO))
+		return 0;
+		
+	/* try to init Anim-Context stuff ourselves and check */
+	if (ANIM_animdata_get_context(C, &ac) == 0)
+		return 0;
+		
+	/* try to get the Active F-Curve */
+	ale= get_active_fcurve_channel(&ac);
+	if (ale == NULL)
+		return 0;
+		
+	/* free temp data... */
+	has_fcurve= ((ale->data) && (ale->type == ANIMTYPE_FCURVE));
+	MEM_freeN(ale);
+	
+	/* return success */
+	return has_fcurve;
+}
+
+/* ************************************************************** */