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A function to convert an SVG path into a QPainterPath
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Kovid Goyal
parent
eb3eb615ec
commit
5d324e8e57
@ -43,4 +43,156 @@ class ReadOnlyFileBuffer(object):
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def close(self):
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pass
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def svg_path_to_painter_path(d):
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'''
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Convert a tiny SVG 1.2 path into a QPainterPath.
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:param d: The value of the d attribute of an SVG <path> tag
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'''
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from PyQt5.Qt import QPainterPath
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cmd = last_cmd = b''
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path = QPainterPath()
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moveto_abs, moveto_rel = b'Mm'
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closepath1, closepath2 = b'Zz'
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lineto_abs, lineto_rel = b'Ll'
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hline_abs, hline_rel = b'Hh'
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vline_abs, vline_rel = b'Vv'
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curveto_abs, curveto_rel = b'Cc'
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smoothcurveto_abs, smoothcurveto_rel = b'Ss'
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quadcurveto_abs, quadcurveto_rel = b'Qq'
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smoothquadcurveto_abs, smoothquadcurveto_rel = b'Tt'
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# Store the last parsed values
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# x/y = end position
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# x1/y1 and x2/y2 = bezier control points
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x = y = x1 = y1 = x2 = y2 = 0
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data = d.replace(b',', b' ').replace(b'\n', b' ')
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if isinstance(data, type('')):
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data = data.encode('ascii')
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end = len(data)
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data = ReadOnlyFileBuffer(data)
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def parse_float():
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chars = []
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while data.tell() < end:
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c = data.read(1)
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if c == b' ' and not chars:
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continue
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if c == b'-' or b'0' <= c[0] <= b'9' or c == b'.':
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chars.append(c[0])
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else:
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break
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if not chars:
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raise ValueError('Premature end of input while expecting a number')
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return float(b''.join(chars))
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def parse_floats(num, x_offset=0, y_offset=0):
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for i in xrange(num):
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val = parse_float()
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yield val + (x_offset if i % 2 == 0 else y_offset)
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repeated_command = None
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while data.tell() < end:
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last_cmd = cmd
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cmd = data.read(1) if repeated_command is None else repeated_command
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repeated_command = None
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if cmd == b' ':
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continue
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elif cmd == moveto_abs:
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x, y = parse_float(), parse_float()
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path.moveTo(x, y)
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elif cmd == moveto_rel:
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x += parse_float()
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y += parse_float()
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path.moveTo(x, y)
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elif cmd == closepath1 or cmd == closepath2:
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path.closeSubpath()
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elif cmd == lineto_abs:
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x, y = parse_floats(2)
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path.lineTo(x, y)
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elif cmd == lineto_rel:
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x += parse_float()
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y += parse_float()
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path.lineTo(x, y)
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elif cmd == hline_abs:
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x = parse_float()
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path.lineTo(x, y)
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elif cmd == hline_rel:
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x += parse_float()
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path.lineTo(x, y)
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elif cmd == vline_abs:
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y = parse_float()
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path.lineTo(x, y)
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elif cmd == vline_rel:
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y += parse_float()
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path.lineTo(x, y)
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elif cmd == curveto_abs:
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x1, y1, x2, y2, x, y = parse_floats(6)
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path.cubicTo(x1, y1, x2, y2, x, y)
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elif cmd == curveto_rel:
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x1, y1, x2, y2, x, y = parse_floats(6, x, y)
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path.cubicTo(x1, y1, x2, y2, x, y)
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elif cmd == smoothcurveto_abs:
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if last_cmd == curveto_abs or last_cmd == curveto_rel or last_cmd == smoothcurveto_abs or last_cmd == smoothcurveto_rel:
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x1 = 2 * x - x2
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y1 = 2 * y - y2
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else:
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x1, y1 = x, y
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x2, y2, x, y = parse_floats(4)
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path.cubicTo(x1, y1, x2, y2, x, y)
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elif cmd == smoothcurveto_rel:
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if last_cmd == curveto_abs or last_cmd == curveto_rel or last_cmd == smoothcurveto_abs or last_cmd == smoothcurveto_rel:
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x1 = 2 * x - x2
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y1 = 2 * y - y2
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else:
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x1, y1 = x, y
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x2, y2, x, y = parse_floats(4, x, y)
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path.cubicTo(x1, y1, x2, y2, x, y)
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elif cmd == quadcurveto_abs:
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x1, y1, x, y = parse_floats(4)
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path.quadTo(x1, y1, x, y)
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elif cmd == quadcurveto_rel:
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x1, y1, x, y = parse_floats(4, x, y)
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path.quadTo(x1, y1, x, y)
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elif cmd == smoothquadcurveto_abs:
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if last_cmd in (quadcurveto_abs, quadcurveto_rel, smoothquadcurveto_abs, smoothquadcurveto_rel):
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x1 = 2 * x - x1
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y1 = 2 * y - y1
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else:
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x1, y1 = x, y
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x, y = parse_floats(2)
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path.quadTo(x1, y1, x, y)
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elif cmd == smoothquadcurveto_rel:
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if last_cmd in (quadcurveto_abs, quadcurveto_rel, smoothquadcurveto_abs, smoothquadcurveto_rel):
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x1 = 2 * x - x1
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y1 = 2 * y - y1
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else:
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x1, y1 = x, y
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x, y = parse_floats(2, x, y)
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path.quadTo(x1, y1, x, y)
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elif cmd[0] in b'-.' or b'0' <= cmd[0] <= b'9':
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# A new number begins
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# In this case, multiple parameters tuples are specified for the last command
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# We rewind to reparse data correctly
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data.seek(-1, os.SEEK_CUR)
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# Handle extra parameters
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if last_cmd == moveto_abs:
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repeated_command = cmd = lineto_abs
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elif last_cmd == moveto_rel:
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repeated_command = cmd = lineto_rel
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elif last_cmd in (closepath1, closepath2):
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raise ValueError('Extra parameters after close path command')
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elif last_cmd in (
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lineto_abs, lineto_rel, hline_abs, hline_rel, vline_abs,
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vline_rel, curveto_abs, curveto_rel,smoothcurveto_abs,
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smoothcurveto_rel, quadcurveto_abs, quadcurveto_rel,
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smoothquadcurveto_abs, smoothquadcurveto_rel
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):
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repeated_command = cmd = last_cmd
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else:
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raise ValueError('Unknown path command: %s' % cmd)
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return path
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