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| Direktori : /lib/calibre/calibre/utils/ |
| Current File : //lib/calibre/calibre/utils/speedups.py |
#!/usr/bin/env python3
# License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
import os
class ReadOnlyFileBuffer:
''' A zero copy implementation of a file like object. Uses memoryviews for efficiency. '''
def __init__(self, raw):
self.sz, self.mv = len(raw), (raw if isinstance(raw, memoryview) else memoryview(raw))
self.pos = 0
def tell(self):
return self.pos
def read(self, n=None):
if n is None:
ans = self.mv[self.pos:]
self.pos = self.sz
return ans
ans = self.mv[self.pos:self.pos+n]
self.pos = min(self.pos + n, self.sz)
return ans
def seek(self, pos, whence=os.SEEK_SET):
if whence == os.SEEK_SET:
self.pos = pos
elif whence == os.SEEK_END:
self.pos = self.sz + pos
else:
self.pos += pos
self.pos = max(0, min(self.pos, self.sz))
return self.pos
def getvalue(self):
return self.mv
def close(self):
pass
def svg_path_to_painter_path(d):
'''
Convert a tiny SVG 1.2 path into a QPainterPath.
:param d: The value of the d attribute of an SVG <path> tag
'''
from qt.core import QPainterPath
cmd = last_cmd = b''
path = QPainterPath()
moveto_abs, moveto_rel = b'M', b'm'
closepath1, closepath2 = b'Z', b'z'
lineto_abs, lineto_rel = b'L', b'l'
hline_abs, hline_rel = b'H', b'h'
vline_abs, vline_rel = b'V', b'v'
curveto_abs, curveto_rel = b'C', b'c'
smoothcurveto_abs, smoothcurveto_rel = b'S', b's'
quadcurveto_abs, quadcurveto_rel = b'Q', b'q'
smoothquadcurveto_abs, smoothquadcurveto_rel = b'T', b't'
# Store the last parsed values
# x/y = end position
# x1/y1 and x2/y2 = bezier control points
x = y = x1 = y1 = x2 = y2 = 0
if isinstance(d, str):
d = d.encode('ascii')
d = d.replace(b',', b' ').replace(b'\n', b' ')
end = len(d)
pos = [0]
def read_byte():
p = pos[0]
pos[0] += 1
return d[p:p+1]
def parse_float():
chars = []
while pos[0] < end:
c = read_byte()
if c == b' ' and not chars:
continue
if c in b'-.0123456789':
chars.append(c)
else:
break
if not chars:
raise ValueError('Premature end of input while expecting a number')
return float(b''.join(chars))
def parse_floats(num, x_offset=0, y_offset=0):
for i in range(num):
val = parse_float()
yield val + (x_offset if i % 2 == 0 else y_offset)
repeated_command = None
while pos[0] < end:
last_cmd = cmd
cmd = read_byte() if repeated_command is None else repeated_command
repeated_command = None
if cmd == b' ':
continue
if cmd == moveto_abs:
x, y = parse_float(), parse_float()
path.moveTo(x, y)
elif cmd == moveto_rel:
x += parse_float()
y += parse_float()
path.moveTo(x, y)
elif cmd == closepath1 or cmd == closepath2:
path.closeSubpath()
elif cmd == lineto_abs:
x, y = parse_floats(2)
path.lineTo(x, y)
elif cmd == lineto_rel:
x += parse_float()
y += parse_float()
path.lineTo(x, y)
elif cmd == hline_abs:
x = parse_float()
path.lineTo(x, y)
elif cmd == hline_rel:
x += parse_float()
path.lineTo(x, y)
elif cmd == vline_abs:
y = parse_float()
path.lineTo(x, y)
elif cmd == vline_rel:
y += parse_float()
path.lineTo(x, y)
elif cmd == curveto_abs:
x1, y1, x2, y2, x, y = parse_floats(6)
path.cubicTo(x1, y1, x2, y2, x, y)
elif cmd == curveto_rel:
x1, y1, x2, y2, x, y = parse_floats(6, x, y)
path.cubicTo(x1, y1, x2, y2, x, y)
elif cmd == smoothcurveto_abs:
if last_cmd == curveto_abs or last_cmd == curveto_rel or last_cmd == smoothcurveto_abs or last_cmd == smoothcurveto_rel:
x1 = 2 * x - x2
y1 = 2 * y - y2
else:
x1, y1 = x, y
x2, y2, x, y = parse_floats(4)
path.cubicTo(x1, y1, x2, y2, x, y)
elif cmd == smoothcurveto_rel:
if last_cmd == curveto_abs or last_cmd == curveto_rel or last_cmd == smoothcurveto_abs or last_cmd == smoothcurveto_rel:
x1 = 2 * x - x2
y1 = 2 * y - y2
else:
x1, y1 = x, y
x2, y2, x, y = parse_floats(4, x, y)
path.cubicTo(x1, y1, x2, y2, x, y)
elif cmd == quadcurveto_abs:
x1, y1, x, y = parse_floats(4)
path.quadTo(x1, y1, x, y)
elif cmd == quadcurveto_rel:
x1, y1, x, y = parse_floats(4, x, y)
path.quadTo(x1, y1, x, y)
elif cmd == smoothquadcurveto_abs:
if last_cmd in (quadcurveto_abs, quadcurveto_rel, smoothquadcurveto_abs, smoothquadcurveto_rel):
x1 = 2 * x - x1
y1 = 2 * y - y1
else:
x1, y1 = x, y
x, y = parse_floats(2)
path.quadTo(x1, y1, x, y)
elif cmd == smoothquadcurveto_rel:
if last_cmd in (quadcurveto_abs, quadcurveto_rel, smoothquadcurveto_abs, smoothquadcurveto_rel):
x1 = 2 * x - x1
y1 = 2 * y - y1
else:
x1, y1 = x, y
x, y = parse_floats(2, x, y)
path.quadTo(x1, y1, x, y)
elif cmd in b'-.0123456789':
# A new number begins
# In this case, multiple parameters tuples are specified for the last command
# We rewind to reparse data correctly
pos[0] -= 1
# Handle extra parameters
if last_cmd == moveto_abs:
repeated_command = cmd = lineto_abs
elif last_cmd == moveto_rel:
repeated_command = cmd = lineto_rel
elif last_cmd in (closepath1, closepath2):
raise ValueError('Extra parameters after close path command')
elif last_cmd in (
lineto_abs, lineto_rel, hline_abs, hline_rel, vline_abs,
vline_rel, curveto_abs, curveto_rel,smoothcurveto_abs,
smoothcurveto_rel, quadcurveto_abs, quadcurveto_rel,
smoothquadcurveto_abs, smoothquadcurveto_rel
):
repeated_command = cmd = last_cmd
else:
raise ValueError('Unknown path command: %s' % cmd)
return path