first commit

dxf.py

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+from math import *
+from svg import *
+
+def parse_dxf(fn):
+    f = open(fn)
+
+    # skip to entities section
+    s = f.next()
+    while s.strip() != 'ENTITIES':
+        s = f.next()
+
+    in_line = False
+    in_circle = False
+
+    pt_list = []
+    cir_list = []
+
+    for line in f:
+        line = line.strip()
+        # In ENTITIES section, iteration can cease when ENDSEC is reached
+        if line == 'ENDSEC':
+            break
+
+        elif in_line:
+            keys = dict.fromkeys(['8','10','20','30','11','21','31'], 0.0)
+            while line != '0':
+                if line in keys:
+                    keys[line] = float(f.next().strip())
+                line = f.next().strip()
+            pt_list.append( ((keys['10'], keys['20']), (keys['11'], keys['21'])) )
+            in_line = False
+
+        elif in_circle:
+            keys = dict.fromkeys(['8','10','20','30','40'], 0.0)
+            while line != '0':
+                if line in keys:
+                    keys[line] = float(f.next().strip())
+                line = f.next().strip()
+            cir_list.append([[keys['10'], keys['20'], keys['30']], keys['40']])
+            in_circle = False
+
+        else:
+            if line == 'LINE':
+                in_line = True
+            elif line == 'CIRCLE' or line == 'ARC':
+                in_circle = True
+    f.close()
+    return pt_list, cir_list
+
+def is_circle(path):
+    points = len(path)
+    if points < 9:
+        return None
+    for i in range(points) :
+        p1 = path[0]
+        p2 = path[int(points /3 )]
+        p3 = path[int(points * 2 / 3)]
+        if p1[0] != p2[0] and p2[0] != p3[0]:
+            ma = (p2[1] - p1[1]) / (p2[0] - p1[0])
+            mb = (p3[1] - p2[1]) / (p3[0] - p2[0])
+            if ma == mb:
+                return None
+            x = (ma * mb *(p1[1] - p3[1]) + mb * (p1[0] + p2[0]) - ma * (p2[0] + p3[0])) / (2 * (mb - ma))
+            if ma == 0:
+                y = -(x - (p2[0] + p3[0]) / 2) / mb + (p2[1] + p3[1]) / 2
+            else:
+                y = -(x - (p1[0] + p2[0]) / 2) / ma + (p1[1] + p2[1]) / 2
+            r = sqrt((p1[0] - x) * (p1[0] - x) + (p1[1] - y) * (p1[1] - y))
+            for p in path:
+                if abs(sqrt((p[0] - x) * (p[0] - x) + (p[1] - y) * (p[1] - y)) - r) > 0.1:
+                    #print "error too big", abs(sqrt((p[0] - x) * (p[0] - x) + (p[1] - y) * (p[1] - y)) - r), points, 2 * r
+                    #print p, path
+                    return None
+            return [x,y, 2 * r, points]
+        path = path[1:] + path[:1]                  #rotate and try again
+    return None
+
+def dxf_to_svg(fn):
+    ptList, cirList = parse_dxf(fn)
+
+    loops = []
+    for pt1, pt2 in ptList:
+        found = False
+        for i in range(len(loops)):
+            loop = loops[i]
+            p0 = loop[0]
+            p1 = loop[-1]
+            if pt1 == p0:
+                loops[i] = [pt2] + loop; found = True
+            elif pt2 == p0:
+                loops[i] = [pt1] + loop; found = True
+            elif pt1 == p1:
+                loops[i] = loop + [pt2]; found = True
+            elif pt2 == p1:
+                loops[i] = loop + [pt2]; found = True
+        if not found:
+            loops.append([pt1, pt2])
+
+    xmax = ymax = 0
+    xmin = ymin = 99999999
+    for loop in loops:
+        if len(loop) < 4 or loop[0] != loop[-1]:
+            raise Exception, "loop not closed " + str(loop)
+        for point in loop:
+            if point[0] > xmax: xmax = point[0]
+            if point[0] < xmin: xmin = point[0]
+            if point[1] > ymax: ymax = point[1]
+            if point[1] < ymin: ymin = point[1]
+
+    def p(x, y): return (x - xmin, ymax - y)
+
+    print xmin, ymin, xmax, ymax
+    scene = Scene(fn[:-4], ceil(ymax - ymin + 10), ceil(xmax - xmin + 10))
+    for loop in loops:
+        circle = is_circle(loop)
+        if circle:
+            x ,y, d, n = circle
+            scene.add(Circle(p(x, y), d / 2, (255,0,0)))
+            scene.add(Line( p(x + d, y), p(x - d, y) ))
+            scene.add(Line( p(x, y + d), p(x, y - d) ))
+            scene.add(Text( p(x + d / 2, y + d / 2), str(round(d,1)) ))
+            #scene.add(Text( p(x + d, y - d - 3), "[%0.1f, %0.1f]" % (x, y), 12 ))
+        else:
+            last = loop[-1]
+            for point in loop:
+                scene.add(Line(p(last[0],last[1]),p(point[0],point[1])))
+                last = point
+    scene.write_svg()
+
+if __name__ == '__main__':
+    import sys
+    dxf_to_svg(sys.argv[1])