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diff --git a/tikzit-1/src/common/RegularPolyShape.m b/tikzit-1/src/common/RegularPolyShape.m
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+++ b/tikzit-1/src/common/RegularPolyShape.m
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+//
+//  RegularPolyShape.m
+//  TikZiT
+//  
+//  Copyright 2011 Aleks Kissinger
+//  Copyright 2012 Alex Merry
+//  All rights reserved.
+//  
+//  This file is part of TikZiT.
+//  
+//  TikZiT 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 3 of the License, or
+//  (at your option) any later version.
+//  
+//  TikZiT 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 TikZiT.  If not, see <http://www.gnu.org/licenses/>.
+//  
+
+#import "RegularPolyShape.h"
+#import "Node.h"
+#import "Edge.h"
+#import "util.h"
+
+@implementation RegularPolyShape
+
+- (id)initWithSides:(int)sides rotation:(int)rotation {
+	self = [super init];
+	if (self == nil)
+		return nil;
+
+	// TikZ draws regular polygons using a radius inscribed
+	// _inside_ the shape (touching middles of edges), not
+	// outside (touching points)
+	const float innerRadius = 0.2f;
+
+	NSMutableArray *nodes = [NSMutableArray arrayWithCapacity:sides];
+	NSMutableArray *edges = [NSMutableArray arrayWithCapacity:sides];
+
+	float dtheta = (M_PI * 2.0f) / ((float)sides);
+	float theta = (dtheta/2.0f) - (M_PI / 2.0f);
+	theta += degreesToRadians(rotation);
+	// radius of the outer circle
+	float radius = ABS(innerRadius / cos(dtheta));
+
+	for (int i = 0; i < sides; ++i) {
+		NSPoint p;
+		p.x = radius * cos(theta);
+		p.y = radius * sin(theta);
+		
+		[nodes addObject:[Node nodeWithPoint:p]];
+		theta += dtheta;
+	}
+
+	for (int i = 0; i < sides; ++i) {
+		[edges addObject:[Edge edgeWithSource:[nodes objectAtIndex:i]
+									andTarget:[nodes objectAtIndex:(i+1)%sides]]];
+	}
+
+	paths = [[NSSet alloc] initWithObjects:edges,nil];
+
+	styleTikz = [[NSString alloc] initWithFormat:
+		@"regular polygon,regular polygon sides=%d,shape border rotate=%d",
+		sides, rotation];
+
+	return self;
+}
+
+@end
+
+// vi:ft=objc:ts=4:noet:sts=4:sw=4