Make toggle and hold snap method cohabit nicely.

Shift-Tab toggles the global toolsetting snap settings (both in and out of transform).
Holding down Ctrl inverts the snap setting in transform (turns it on when global snap is off and vice versa).
Ctrl-Shift-Tab to select snap mode (only outside of transform for now).

For old (pre 2.5) behavior, just keep global snap off and use Ctrl.

NOTE: transform modal events for snap have change a bit, saved keymap might not work anymore.

5 files changed, 105 insertions, 94 deletions

diff --git a/source/blender/editors/transform/transform.c b/source/blender/editors/transform/transform.c
index ffc6ea86835..1b450e48e31 100644
--- a/source/blender/editors/transform/transform.c
+++ b/source/blender/editors/transform/transform.c
@@ -507,8 +507,8 @@ static char *transform_to_undostr(TransInfo *t)
 #define TFM_MODAL_TRANSLATE		3
 #define TFM_MODAL_ROTATE		4
 #define TFM_MODAL_RESIZE		5
-#define TFM_MODAL_SNAP_ON		6
-#define TFM_MODAL_SNAP_OFF		7
+#define TFM_MODAL_SNAP_INV_ON	6
+#define TFM_MODAL_SNAP_INV_OFF	7
 #define TFM_MODAL_SNAP_TOGGLE	8
 #define TFM_MODAL_AXIS_X		9
 #define TFM_MODAL_AXIS_Y		10
@@ -529,8 +529,8 @@ void transform_modal_keymap(wmKeyConfig *keyconf)
 	{TFM_MODAL_TRANSLATE, "TRANSLATE", 0, "Translate", ""},
 	{TFM_MODAL_ROTATE, "ROTATE", 0, "Rotate", ""},
 	{TFM_MODAL_RESIZE, "RESIZE", 0, "Resize", ""},
-	{TFM_MODAL_SNAP_ON, "SNAP_ON", 0, "Snap On", ""},
-	{TFM_MODAL_SNAP_OFF, "SNAP_OFF", 0, "Snap Off", ""},
+	{TFM_MODAL_SNAP_INV_ON, "SNAP_INV_ON", 0, "Invert Snap On", ""},
+	{TFM_MODAL_SNAP_INV_OFF, "SNAP_INV_OFF", 0, "Invert Snap Off", ""},
 	{TFM_MODAL_SNAP_TOGGLE, "SNAP_TOGGLE", 0, "Snap Toggle", ""},
 	{TFM_MODAL_AXIS_X, "AXIS_X", 0, "Orientation X axis", ""},
 	{TFM_MODAL_AXIS_Y, "AXIS_Y", 0, "Orientation Y axis", ""},
@@ -560,7 +560,10 @@ void transform_modal_keymap(wmKeyConfig *keyconf)
 	WM_modalkeymap_add_item(keymap, RKEY, KM_PRESS, 0, 0, TFM_MODAL_ROTATE);
 	WM_modalkeymap_add_item(keymap, SKEY, KM_PRESS, 0, 0, TFM_MODAL_RESIZE);
 	
-	WM_modalkeymap_add_item(keymap, LEFTCTRLKEY, KM_CLICK, KM_ANY, 0, TFM_MODAL_SNAP_TOGGLE);
+	WM_modalkeymap_add_item(keymap, TABKEY, KM_PRESS, KM_SHIFT, 0, TFM_MODAL_SNAP_TOGGLE);
+
+	WM_modalkeymap_add_item(keymap, LEFTCTRLKEY, KM_PRESS, KM_ANY, 0, TFM_MODAL_SNAP_INV_ON);
+	WM_modalkeymap_add_item(keymap, LEFTCTRLKEY, KM_RELEASE, KM_ANY, 0, TFM_MODAL_SNAP_INV_OFF);
 	
 	WM_modalkeymap_add_item(keymap, AKEY, KM_PRESS, 0, 0, TFM_MODAL_ADD_SNAP);
 	WM_modalkeymap_add_item(keymap, AKEY, KM_PRESS, KM_ALT, 0, TFM_MODAL_REMOVE_SNAP);
@@ -651,12 +654,12 @@ int transformEvent(TransInfo *t, wmEvent *event)
 				}
 				break;
 				
-			case TFM_MODAL_SNAP_ON:
-				t->modifiers |= MOD_SNAP;
+			case TFM_MODAL_SNAP_INV_ON:
+				t->modifiers |= MOD_SNAP_INVERT;
 				t->redraw = 1;
 				break;
-			case TFM_MODAL_SNAP_OFF:
-				t->modifiers &= ~MOD_SNAP;
+			case TFM_MODAL_SNAP_INV_OFF:
+				t->modifiers &= ~MOD_SNAP_INVERT;
 				t->redraw = 1;
 				break;
 			case TFM_MODAL_SNAP_TOGGLE:
diff --git a/source/blender/editors/transform/transform.h b/source/blender/editors/transform/transform.h
index 1577c05cc88..d51cf9c864b 100644
--- a/source/blender/editors/transform/transform.h
+++ b/source/blender/editors/transform/transform.h
@@ -91,8 +91,8 @@ typedef struct TransSnapPoint {
 
 typedef struct TransSnap {
 	short	mode;
+	short	target;
 	short	modePoint;
-	short	modeTarget;
 	short	modeSelect;
 	short	align;
 	short	project;
@@ -382,7 +382,8 @@ typedef struct TransInfo {
 #define	MOD_CONSTRAINT_SELECT	0x01
 #define	MOD_PRECISION			0x02
 #define	MOD_SNAP				0x04
-#define	MOD_CONSTRAINT_PLANE	0x08
+#define	MOD_SNAP_INVERT			0x08
+#define	MOD_CONSTRAINT_PLANE	0x10
 
 
 /* ******************************************************************************** */
@@ -427,13 +428,6 @@ typedef struct TransInfo {
 #define POINT_INIT		4
 #define MULTI_POINTS	8
 
-/* transsnap->modeTarget */
-#define SNAP_CLOSEST		0
-#define SNAP_CENTER			1
-#define SNAP_MEDIAN			2
-#define SNAP_ACTIVE			3
-
-
 void TFM_OT_transform(struct wmOperatorType *ot);
 
 int initTransform(struct bContext *C, struct TransInfo *t, struct wmOperator *op, struct wmEvent *event, int mode);
@@ -597,6 +591,9 @@ typedef enum {
 void snapGrid(TransInfo *t, float *val);
 void snapGridAction(TransInfo *t, float *val, GearsType action);
 
+int activeSnap(TransInfo *t);
+int validSnap(TransInfo *t);
+
 void initSnapping(struct TransInfo *t, struct wmOperator *op);
 void applyProject(TransInfo *t);
 void applySnapping(TransInfo *t, float *vec);
diff --git a/source/blender/editors/transform/transform_constraints.c b/source/blender/editors/transform/transform_constraints.c
index 1a810d4adc3..1f42d9411f1 100644
--- a/source/blender/editors/transform/transform_constraints.c
+++ b/source/blender/editors/transform/transform_constraints.c
@@ -290,7 +290,7 @@ static void applyAxisConstraintVec(TransInfo *t, TransData *td, float in[3], flo
 		mul_m3_v3(t->con.pmtx, out);
 
 		// With snap, a projection is alright, no need to correct for view alignment
-		if (!(t->tsnap.mode != SCE_SNAP_MODE_INCREMENT && t->modifiers & MOD_SNAP)) {
+		if (!(t->tsnap.mode != SCE_SNAP_MODE_INCREMENT && activeSnap(t))) {
 			if (getConstraintSpaceDimension(t) == 2) {
 				if (out[0] != 0.0f || out[1] != 0.0f || out[2] != 0.0f) {
 					planeProjection(t, in, out);
diff --git a/source/blender/editors/transform/transform_ops.c b/source/blender/editors/transform/transform_ops.c
index 6ab2982b51e..ad4462a74cf 100644
--- a/source/blender/editors/transform/transform_ops.c
+++ b/source/blender/editors/transform/transform_ops.c
@@ -784,10 +784,10 @@ void transform_keymap_for_space(struct wmKeyConfig *keyconf, struct wmKeyMap *ke
 
 			km = WM_keymap_add_item(keymap, "TFM_OT_mirror", MKEY, KM_PRESS, KM_CTRL, 0);
 
-			km = WM_keymap_add_item(keymap, "WM_OT_context_toggle", LEFTCTRLKEY, KM_CLICK, 0, 0);
+			km = WM_keymap_add_item(keymap, "WM_OT_context_toggle", TABKEY, KM_PRESS, KM_SHIFT, 0);
 			RNA_string_set(km->ptr, "path", "scene.tool_settings.snap");
 
-			km = WM_keymap_add_item(keymap, "TFM_OT_snap_type", LEFTCTRLKEY, KM_CLICK, KM_SHIFT, 0);
+			km = WM_keymap_add_item(keymap, "TFM_OT_snap_type", TABKEY, KM_PRESS, KM_SHIFT|KM_CLICK, 0);
 
 			break;
 		case SPACE_ACTION:
@@ -861,7 +861,7 @@ void transform_keymap_for_space(struct wmKeyConfig *keyconf, struct wmKeyMap *ke
 
 			km = WM_keymap_add_item(keymap, "TFM_OT_mirror", MKEY, KM_PRESS, KM_CTRL, 0);
 
-			km = WM_keymap_add_item(keymap, "WM_OT_context_toggle", LEFTCTRLKEY, KM_CLICK, 0, 0);
+			km = WM_keymap_add_item(keymap, "WM_OT_context_toggle", TABKEY, KM_PRESS, KM_SHIFT, 0);
 			RNA_string_set(km->ptr, "path", "scene.tool_settings.snap");
 			break;
 		default:
diff --git a/source/blender/editors/transform/transform_snap.c b/source/blender/editors/transform/transform_snap.c
index ae28986017f..b8ea49110fc 100644
--- a/source/blender/editors/transform/transform_snap.c
+++ b/source/blender/editors/transform/transform_snap.c
@@ -90,7 +90,7 @@
 
 /********************* PROTOTYPES ***********************/
 
-void setSnappingCallback(TransInfo *t, short snap_target);
+void setSnappingCallback(TransInfo *t);
 
 void ApplySnapTranslation(TransInfo *t, float vec[3]);
 void ApplySnapRotation(TransInfo *t, float *vec);
@@ -123,15 +123,20 @@ int BIF_snappingSupported(Object *obedit)
 	return status;
 }
 
-int validSnap(TransInfo *t) {
+int validSnap(TransInfo *t)
+{
 	return (t->tsnap.status & (POINT_INIT|TARGET_INIT)) == (POINT_INIT|TARGET_INIT) ||
 			(t->tsnap.status & (MULTI_POINTS|TARGET_INIT)) == (MULTI_POINTS|TARGET_INIT);
 }
 
+int activeSnap(TransInfo *t)
+{
+	return (t->modifiers & (MOD_SNAP|MOD_SNAP_INVERT)) == MOD_SNAP || (t->modifiers & (MOD_SNAP|MOD_SNAP_INVERT)) == MOD_SNAP_INVERT;
+}
+
 void drawSnapping(const struct bContext *C, TransInfo *t)
 {
-	if (validSnap(t) &&
-		(t->modifiers & MOD_SNAP))
+	if (validSnap(t) && activeSnap(t))
 		{
 		
 		char col[4] = {1, 0, 1};
@@ -232,7 +237,7 @@ int  handleSnapping(TransInfo *t, wmEvent *event)
 void applyProject(TransInfo *t)
 {
 	/* XXX FLICKER IN OBJECT MODE */
-	if ((t->tsnap.project) && (t->modifiers & MOD_SNAP) && (t->modifiers & MOD_SNAP))
+	if ((t->tsnap.project) && activeSnap(t))
 	{
 		TransData *td = t->data;
 		float tvec[3];
@@ -268,7 +273,7 @@ void applyProject(TransInfo *t)
 			
 			project_float(t->ar, iloc, mval);
 			
-			if (snapObjectsTransform(t, mval, &dist, loc, no, t->tsnap.modeTarget))
+			if (snapObjectsTransform(t, mval, &dist, loc, no, t->tsnap.target))
 			{
 //				if(t->flag & (T_EDIT|T_POSE)) {
 //					mul_m4_v3(imat, loc);
@@ -298,8 +303,7 @@ void applySnapping(TransInfo *t, float *vec)
 	
 		t->tsnap.applySnap(t, vec);
 	}
-	else if ((t->tsnap.mode != SCE_SNAP_MODE_INCREMENT) &&
-		(t->modifiers & MOD_SNAP))
+	else if ((t->tsnap.mode != SCE_SNAP_MODE_INCREMENT) && activeSnap(t))
 	{
 		double current = PIL_check_seconds_timer();
 		
@@ -325,7 +329,7 @@ void resetSnapping(TransInfo *t)
 	t->tsnap.align = 0;
 	t->tsnap.mode = 0;
 	t->tsnap.modeSelect = 0;
-	t->tsnap.modeTarget = 0;
+	t->tsnap.target = 0;
 	t->tsnap.last = 0;
 	t->tsnap.applySnap = NULL;
 
@@ -352,11 +356,67 @@ int validSnappingNormal(TransInfo *t)
 	return 0;
 }
 
-void initSnapping(TransInfo *t, wmOperator *op)
+void initSnappingMode(TransInfo *t)
 {
 	ToolSettings *ts = t->settings;
 	Object *obedit = t->obedit;
 	Scene *scene = t->scene;
+
+	resetSnapping(t);
+
+	/* force project off when not supported */
+	if (ts->snap_mode != SCE_SNAP_MODE_FACE)
+	{
+		t->tsnap.project = 0;
+	}
+
+	t->tsnap.mode = ts->snap_mode;
+
+	if ((t->spacetype == SPACE_VIEW3D || t->spacetype == SPACE_IMAGE) && // Only 3D view or UV
+			(t->flag & T_CAMERA) == 0) { // Not with camera selected in camera view
+		setSnappingCallback(t);
+
+		/* Edit mode */
+		if (t->tsnap.applySnap != NULL && // A snapping function actually exist
+			(obedit != NULL && ELEM3(obedit->type, OB_MESH, OB_ARMATURE, OB_CURVE)) ) // Temporary limited to edit mode meshes, armature, curves
+		{
+			if (t->flag & T_PROP_EDIT)
+			{
+				t->tsnap.modeSelect = SNAP_NOT_OBEDIT;
+			}
+			else
+			{
+				t->tsnap.modeSelect = SNAP_ALL;
+			}
+		}
+		/* Particles edit mode*/
+		else if (t->tsnap.applySnap != NULL && // A snapping function actually exist
+			(obedit == NULL && BASACT && BASACT->object && BASACT->object->mode & OB_MODE_PARTICLE_EDIT ))
+		{
+			t->tsnap.modeSelect = SNAP_ALL;
+		}
+		/* Object mode */
+		else if (t->tsnap.applySnap != NULL && // A snapping function actually exist
+			(obedit == NULL) ) // Object Mode
+		{
+			t->tsnap.modeSelect = SNAP_NOT_SELECTED;
+		}
+		else
+		{
+			/* Grid if snap is not possible */
+			t->tsnap.mode = SCE_SNAP_MODE_INCREMENT;
+		}
+	}
+	else
+	{
+		/* Always grid outside of 3D view */
+		t->tsnap.mode = SCE_SNAP_MODE_INCREMENT;
+	}
+}
+
+void initSnapping(TransInfo *t, wmOperator *op)
+{
+	ToolSettings *ts = t->settings;
 	short snap_target = t->settings->snap_target;
 	
 	resetSnapping(t);
@@ -405,76 +465,27 @@ void initSnapping(TransInfo *t, wmOperator *op)
 		t->tsnap.peel = ((t->settings->snap_flag & SCE_SNAP_PROJECT) == SCE_SNAP_PROJECT);
 	}
 	
-	/* force project off when not supported */
-	if (ts->snap_mode != SCE_SNAP_MODE_FACE)
-	{
-		t->tsnap.project = 0;
-	}
-	
-	t->tsnap.mode = ts->snap_mode;
+	t->tsnap.target = snap_target;
 
-	if ((t->spacetype == SPACE_VIEW3D || t->spacetype == SPACE_IMAGE) && // Only 3D view or UV
-			(t->flag & T_CAMERA) == 0) { // Not with camera selected in camera view
-		setSnappingCallback(t, snap_target);
-
-		/* Edit mode */
-		if (t->tsnap.applySnap != NULL && // A snapping function actually exist
-			(obedit != NULL && ELEM3(obedit->type, OB_MESH, OB_ARMATURE, OB_CURVE)) ) // Temporary limited to edit mode meshes, armature, curves
-		{
-			if (t->flag & T_PROP_EDIT)
-			{
-				t->tsnap.modeSelect = SNAP_NOT_OBEDIT;
-			}
-			else
-			{
-				t->tsnap.modeSelect = SNAP_ALL;
-			}
-		}
-		/* Particles edit mode*/
-		else if (t->tsnap.applySnap != NULL && // A snapping function actually exist
-			(obedit == NULL && BASACT && BASACT->object && BASACT->object->mode & OB_MODE_PARTICLE_EDIT ))
-		{
-			t->tsnap.modeSelect = SNAP_ALL;
-		}
-		/* Object mode */
-		else if (t->tsnap.applySnap != NULL && // A snapping function actually exist
-			(obedit == NULL) ) // Object Mode
-		{
-			t->tsnap.modeSelect = SNAP_NOT_SELECTED;
-		}
-		else
-		{	
-			/* Grid if snap is not possible */
-			t->tsnap.mode = SCE_SNAP_MODE_INCREMENT;
-		}
-	}
-	else
-	{
-		/* Always grid outside of 3D view */
-		t->tsnap.mode = SCE_SNAP_MODE_INCREMENT;
-	}
+	initSnappingMode(t);
 }
 
-void setSnappingCallback(TransInfo *t, short snap_target)
+void setSnappingCallback(TransInfo *t)
 {
 	t->tsnap.calcSnap = CalcSnapGeometry;
 
-	switch(snap_target)
+	switch(t->tsnap.target)
 	{
 		case SCE_SNAP_TARGET_CLOSEST:
-			t->tsnap.modeTarget = SNAP_CLOSEST;
 			t->tsnap.targetSnap = TargetSnapClosest;
 			break;
 		case SCE_SNAP_TARGET_CENTER:
-			t->tsnap.modeTarget = SNAP_CENTER;
 			t->tsnap.targetSnap = TargetSnapCenter;
 			break;
 		case SCE_SNAP_TARGET_MEDIAN:
-			t->tsnap.modeTarget = SNAP_MEDIAN;
 			t->tsnap.targetSnap = TargetSnapMedian;
 			break;
 		case SCE_SNAP_TARGET_ACTIVE:
-			t->tsnap.modeTarget = SNAP_ACTIVE;
 			t->tsnap.targetSnap = TargetSnapActive;
 			break;
 
@@ -491,8 +502,8 @@ void setSnappingCallback(TransInfo *t, short snap_target)
 		t->tsnap.distance = RotationBetween;
 		
 		// Can't do TARGET_CENTER with rotation, use TARGET_MEDIAN instead
-		if (snap_target == SCE_SNAP_TARGET_CENTER) {
-			t->tsnap.modeTarget = SNAP_MEDIAN;
+		if (t->tsnap.target == SCE_SNAP_TARGET_CENTER) {
+			t->tsnap.target = SCE_SNAP_TARGET_MEDIAN;
 			t->tsnap.targetSnap = TargetSnapMedian;
 		}
 		break;
@@ -501,8 +512,8 @@ void setSnappingCallback(TransInfo *t, short snap_target)
 		t->tsnap.distance = ResizeBetween;
 		
 		// Can't do TARGET_CENTER with resize, use TARGET_MEDIAN instead
-		if (snap_target == SCE_SNAP_TARGET_CENTER) {
-			t->tsnap.modeTarget = SNAP_MEDIAN;
+		if (t->tsnap.target == SCE_SNAP_TARGET_CENTER) {
+			t->tsnap.target = SCE_SNAP_TARGET_MEDIAN;
 			t->tsnap.targetSnap = TargetSnapMedian;
 		}
 		break;
@@ -569,7 +580,7 @@ void ApplySnapTranslation(TransInfo *t, float vec[3])
 
 void ApplySnapRotation(TransInfo *t, float *vec)
 {
-	if (t->tsnap.modeTarget == SNAP_CLOSEST) {
+	if (t->tsnap.target == SCE_SNAP_TARGET_CLOSEST) {
 		*vec = t->tsnap.dist;
 	}
 	else {
@@ -581,7 +592,7 @@ void ApplySnapRotation(TransInfo *t, float *vec)
 
 void ApplySnapResize(TransInfo *t, float vec[3])
 {
-	if (t->tsnap.modeTarget == SNAP_CLOSEST) {
+	if (t->tsnap.target == SCE_SNAP_TARGET_CLOSEST) {
 		vec[0] = vec[1] = vec[2] = t->tsnap.dist;
 	}
 	else {
@@ -887,7 +898,7 @@ void TargetSnapActive(TransInfo *t)
 		/* No active, default to median */
 		else
 		{
-			t->tsnap.modeTarget = SNAP_MEDIAN;
+			t->tsnap.target = SCE_SNAP_TARGET_MEDIAN;
 			t->tsnap.targetSnap = TargetSnapMedian;
 			TargetSnapMedian(t);
 		}		
@@ -1907,10 +1918,10 @@ void snapGrid(TransInfo *t, float *val) {
 		invert = U.flag & USER_AUTOGRABGRID;
 
 	if(invert) {
-		action = (t->modifiers & MOD_SNAP) ? NO_GEARS: BIG_GEARS;
+		action = activeSnap(t) ? NO_GEARS: BIG_GEARS;
 	}
 	else {
-		action = (t->modifiers & MOD_SNAP) ? BIG_GEARS : NO_GEARS;
+		action = activeSnap(t) ? BIG_GEARS : NO_GEARS;
 	}
 
 	if (action == BIG_GEARS && (t->modifiers & MOD_PRECISION)) {