Two in one:

- Bugfix #25937
  Child-of constraint now behaves like regular parent-child
  relationship when all options are set. This prevents the 
  errors that can happen when decomposing non-uniform matrices.

- Todo item
  The area corner hotspots for splitting/merging were far too
  narrow. Now it uses a circular distance to detect whether
  the hotspot is active. Also cleaned up drawing code for it.

5 files changed, 85 insertions, 68 deletions

diff --git a/source/blender/blenkernel/intern/constraint.c b/source/blender/blenkernel/intern/constraint.c
index c61f3ba3683..e653a6198ca 100644
--- a/source/blender/blenkernel/intern/constraint.c
+++ b/source/blender/blenkernel/intern/constraint.c
@@ -834,54 +834,71 @@ static void childof_evaluate (bConstraint *con, bConstraintOb *cob, ListBase *ta
 	
 	/* only evaluate if there is a target */
 	if (VALID_CONS_TARGET(ct)) {
-		float parmat[4][4], invmat[4][4], tempmat[4][4];
-		float loc[3], eul[3], size[3];
-		float loco[3], eulo[3], sizo[3];
-		
-		/* get offset (parent-inverse) matrix */
-		copy_m4_m4(invmat, data->invmat);
-		
-		/* extract components of both matrices */
-		copy_v3_v3(loc, ct->matrix[3]);
-		mat4_to_eulO(eul, ct->rotOrder, ct->matrix);
-		mat4_to_size(size, ct->matrix);
-		
-		copy_v3_v3(loco, invmat[3]);
-		mat4_to_eulO(eulo, cob->rotOrder, invmat);
-		mat4_to_size(sizo, invmat);
-		
-		/* disable channels not enabled */
-		if (!(data->flag & CHILDOF_LOCX)) loc[0]= loco[0]= 0.0f;
-		if (!(data->flag & CHILDOF_LOCY)) loc[1]= loco[1]= 0.0f;
-		if (!(data->flag & CHILDOF_LOCZ)) loc[2]= loco[2]= 0.0f;
-		if (!(data->flag & CHILDOF_ROTX)) eul[0]= eulo[0]= 0.0f;
-		if (!(data->flag & CHILDOF_ROTY)) eul[1]= eulo[1]= 0.0f;
-		if (!(data->flag & CHILDOF_ROTZ)) eul[2]= eulo[2]= 0.0f;
-		if (!(data->flag & CHILDOF_SIZEX)) size[0]= sizo[0]= 1.0f;
-		if (!(data->flag & CHILDOF_SIZEY)) size[1]= sizo[1]= 1.0f;
-		if (!(data->flag & CHILDOF_SIZEZ)) size[2]= sizo[2]= 1.0f;
-		
-		/* make new target mat and offset mat */
-		loc_eulO_size_to_mat4(ct->matrix, loc, eul, size, ct->rotOrder);
-		loc_eulO_size_to_mat4(invmat, loco, eulo, sizo, cob->rotOrder);
-		
-		/* multiply target (parent matrix) by offset (parent inverse) to get 
-		 * the effect of the parent that will be exherted on the owner
-		 */
-		mul_m4_m4m4(parmat, invmat, ct->matrix);
+		float parmat[4][4];
 		
-		/* now multiply the parent matrix by the owner matrix to get the 
-		 * the effect of this constraint (i.e.  owner is 'parented' to parent)
-		 */
-		copy_m4_m4(tempmat, cob->matrix);
-		mul_m4_m4m4(cob->matrix, tempmat, parmat);
-
-		/* without this, changes to scale and rotation can change location
-		 * of a parentless bone or a disconnected bone. Even though its set
-		 * to zero above. */
-		if (!(data->flag & CHILDOF_LOCX)) cob->matrix[3][0]= tempmat[3][0];
-		if (!(data->flag & CHILDOF_LOCY)) cob->matrix[3][1]= tempmat[3][1];
-		if (!(data->flag & CHILDOF_LOCZ)) cob->matrix[3][2]= tempmat[3][2];	
+		/* simple matrix parenting */
+		if(data->flag == CHILDOF_ALL) {
+			
+			/* multiply target (parent matrix) by offset (parent inverse) to get 
+			 * the effect of the parent that will be exherted on the owner
+			 */
+			mul_m4_m4m4(parmat, data->invmat, ct->matrix);
+			
+			/* now multiply the parent matrix by the owner matrix to get the 
+			 * the effect of this constraint (i.e.  owner is 'parented' to parent)
+			 */
+			mul_m4_m4m4(cob->matrix, cob->matrix, parmat);
+		}
+		else {
+			float invmat[4][4], tempmat[4][4];
+			float loc[3], eul[3], size[3];
+			float loco[3], eulo[3], sizo[3];
+			
+			/* get offset (parent-inverse) matrix */
+			copy_m4_m4(invmat, data->invmat);
+			
+			/* extract components of both matrices */
+			copy_v3_v3(loc, ct->matrix[3]);
+			mat4_to_eulO(eul, ct->rotOrder, ct->matrix);
+			mat4_to_size(size, ct->matrix);
+			
+			copy_v3_v3(loco, invmat[3]);
+			mat4_to_eulO(eulo, cob->rotOrder, invmat);
+			mat4_to_size(sizo, invmat);
+			
+			/* disable channels not enabled */
+			if (!(data->flag & CHILDOF_LOCX)) loc[0]= loco[0]= 0.0f;
+			if (!(data->flag & CHILDOF_LOCY)) loc[1]= loco[1]= 0.0f;
+			if (!(data->flag & CHILDOF_LOCZ)) loc[2]= loco[2]= 0.0f;
+			if (!(data->flag & CHILDOF_ROTX)) eul[0]= eulo[0]= 0.0f;
+			if (!(data->flag & CHILDOF_ROTY)) eul[1]= eulo[1]= 0.0f;
+			if (!(data->flag & CHILDOF_ROTZ)) eul[2]= eulo[2]= 0.0f;
+			if (!(data->flag & CHILDOF_SIZEX)) size[0]= sizo[0]= 1.0f;
+			if (!(data->flag & CHILDOF_SIZEY)) size[1]= sizo[1]= 1.0f;
+			if (!(data->flag & CHILDOF_SIZEZ)) size[2]= sizo[2]= 1.0f;
+			
+			/* make new target mat and offset mat */
+			loc_eulO_size_to_mat4(ct->matrix, loc, eul, size, ct->rotOrder);
+			loc_eulO_size_to_mat4(invmat, loco, eulo, sizo, cob->rotOrder);
+			
+			/* multiply target (parent matrix) by offset (parent inverse) to get 
+			 * the effect of the parent that will be exherted on the owner
+			 */
+			mul_m4_m4m4(parmat, invmat, ct->matrix);
+			
+			/* now multiply the parent matrix by the owner matrix to get the 
+			 * the effect of this constraint (i.e.  owner is 'parented' to parent)
+			 */
+			copy_m4_m4(tempmat, cob->matrix);
+			mul_m4_m4m4(cob->matrix, tempmat, parmat);
+
+			/* without this, changes to scale and rotation can change location
+			 * of a parentless bone or a disconnected bone. Even though its set
+			 * to zero above. */
+			if (!(data->flag & CHILDOF_LOCX)) cob->matrix[3][0]= tempmat[3][0];
+			if (!(data->flag & CHILDOF_LOCY)) cob->matrix[3][1]= tempmat[3][1];
+			if (!(data->flag & CHILDOF_LOCZ)) cob->matrix[3][2]= tempmat[3][2];	
+		}
 	}
 }
 
diff --git a/source/blender/editors/screen/area.c b/source/blender/editors/screen/area.c
index 5ea5fe06c46..4784f19012e 100644
--- a/source/blender/editors/screen/area.c
+++ b/source/blender/editors/screen/area.c
@@ -164,27 +164,22 @@ void ED_area_overdraw_flush(ScrArea *sa, ARegion *ar)
 
 static void area_draw_azone(short x1, short y1, short x2, short y2)
 {
-	float xmin = x1;
-	float xmax = x2-2;
-	float ymin = y1-1;
-	float ymax = y2-3;
-	
-	float dx= 0.3f*(xmax-xmin);
-	float dy= 0.3f*(ymax-ymin);
+	int dx= floor(0.3f*(x2-x1));
+	int dy= floor(0.3f*(y2-y1));
 	
 	glColor4ub(255, 255, 255, 180);
-	fdrawline(xmin, ymax, xmax, ymin);
+	fdrawline(x1, y2, x2, y1);
 	glColor4ub(255, 255, 255, 130);
-	fdrawline(xmin, ymax-dy, xmax-dx, ymin);
+	fdrawline(x1, y2-dy, x2-dx, y1);
 	glColor4ub(255, 255, 255, 80);
-	fdrawline(xmin, ymax-2*dy, xmax-2*dx, ymin);
+	fdrawline(x1, y2-2*dy, x2-2*dx, y1);
 	
 	glColor4ub(0, 0, 0, 210);
-	fdrawline(xmin, ymax+1, xmax+1, ymin);
+	fdrawline(x1, y2+1, x2+1, y1);
 	glColor4ub(0, 0, 0, 180);
-	fdrawline(xmin, ymax-dy+1, xmax-dx+1, ymin);
+	fdrawline(x1, y2-dy+1, x2-dx+1, y1);
 	glColor4ub(0, 0, 0, 150);
-	fdrawline(xmin, ymax-2*dy+1, xmax-2*dx+1, ymin);
+	fdrawline(x1, y2-2*dy+1, x2-2*dx+1, y1);
 }
 
 
@@ -451,7 +446,6 @@ void ED_area_headerprint(ScrArea *sa, const char *str)
 /* ************************************************************ */
 
 
-#define AZONESPOT		12
 static void area_azone_initialize(ScrArea *sa) 
 {
 	AZone *az;
@@ -465,8 +459,8 @@ static void area_azone_initialize(ScrArea *sa)
 	az->type= AZONE_AREA;
 	az->x1= sa->totrct.xmin;
 	az->y1= sa->totrct.ymin;
-	az->x2= sa->totrct.xmin + AZONESPOT-1;
-	az->y2= sa->totrct.ymin + AZONESPOT-1;
+	az->x2= sa->totrct.xmin + AZONESPOT;
+	az->y2= sa->totrct.ymin + AZONESPOT;
 	BLI_init_rcti(&az->rect, az->x1, az->x2, az->y1, az->y2);
 	
 	az= (AZone *)MEM_callocN(sizeof(AZone), "actionzone");
@@ -474,13 +468,13 @@ static void area_azone_initialize(ScrArea *sa)
 	az->type= AZONE_AREA;
 	az->x1= sa->totrct.xmax+1;
 	az->y1= sa->totrct.ymax+1;
-	az->x2= sa->totrct.xmax-AZONESPOT+1;
-	az->y2= sa->totrct.ymax-AZONESPOT+1;
+	az->x2= sa->totrct.xmax-AZONESPOT;
+	az->y2= sa->totrct.ymax-AZONESPOT;
 	BLI_init_rcti(&az->rect, az->x1, az->x2, az->y1, az->y2);
 }
 
 #define AZONEPAD_EDGE	4
-#define AZONEPAD_ICON	8
+#define AZONEPAD_ICON	9
 static void region_azone_edge(AZone *az, ARegion *ar)
 {
 	switch(az->edge) {
diff --git a/source/blender/editors/screen/screen_intern.h b/source/blender/editors/screen/screen_intern.h
index 87b397382a3..ee448e70779 100644
--- a/source/blender/editors/screen/screen_intern.h
+++ b/source/blender/editors/screen/screen_intern.h
@@ -32,6 +32,8 @@
 struct wmWindow;
 struct Scene;
 
+#define AZONESPOT		12
+
 /* area.c */
 void		area_copy_data	(ScrArea *sa1, ScrArea *sa2, int swap_space);
 
diff --git a/source/blender/editors/screen/screen_ops.c b/source/blender/editors/screen/screen_ops.c
index b6c92982560..9267f4d4e80 100644
--- a/source/blender/editors/screen/screen_ops.c
+++ b/source/blender/editors/screen/screen_ops.c
@@ -474,7 +474,10 @@ AZone *is_in_area_actionzone(ScrArea *sa, int x, int y)
 	for(az= sa->actionzones.first; az; az= az->next) {
 		if(BLI_in_rcti(&az->rect, x, y)) {
 			if(az->type == AZONE_AREA) {
-				if(isect_point_tri_v2_int(az->x1, az->y1, az->x2, az->y2, x, y)) 
+				/* no triangle intersect but a hotspot circle based on corner */
+				int radius= (x-az->x1)*(x-az->x1) + (y-az->y1)*(y-az->y1);
+				
+				if(radius <= AZONESPOT*AZONESPOT)
 					break;
 			}
 			else if(az->type == AZONE_REGION) {
diff --git a/source/blender/makesdna/DNA_constraint_types.h b/source/blender/makesdna/DNA_constraint_types.h
index f9d6a70db48..275ffd93ae5 100644
--- a/source/blender/makesdna/DNA_constraint_types.h
+++ b/source/blender/makesdna/DNA_constraint_types.h
@@ -699,7 +699,8 @@ typedef enum eChildOf_Flags {
 	CHILDOF_ROTZ	= (1<<5),
 	CHILDOF_SIZEX	= (1<<6),
 	CHILDOF_SIZEY	= (1<<7),
-	CHILDOF_SIZEZ	= (1<<8)
+	CHILDOF_SIZEZ	= (1<<8),
+	CHILDOF_ALL		= 511
 } eChildOf_Flags;
 
 /* Pivot Constraint */