def thread_func(start, end):
try:
mlsl.grayify(img, img_type, src_col_offset,
src_row_offset + start,
src_col_stride, src_row_stride,
src_chan_stride, dst_col_offset,
dst_row_offset + start,
dst_col_stride, dst_row_stride,
cols, end-start, chans,
weights, gamma, output)
finally:
done.release()
def grayify(img, img_type, src_col_offset, src_row_offset,
src_col_stride, src_row_stride, src_chan_stride,
dst_col_offset, dst_row_offset,
dst_col_stride, dst_row_stride, cols, rows, chans,
weights, gamma, output=None, threads=2):
if threads < 1:
raise Error('the argument threads must be positive')
if threads < 2:
return mlsl.grayify(img, img_type, src_col_offset, src_row_offset,
src_col_stride, src_row_stride, src_chan_stride,
dst_col_offset, dst_row_offset,
dst_col_stride, dst_row_stride,
cols, rows, chans,
weights, gamma, output)
if threads > rows:
threads = rows
# create output buffer
output_is_array = False
if output is None:
output_size = (struct.calcsize('f') +
dst_col_stride*(dst_col_offset+cols-1) +
dst_row_stride*(dst_row_offset+rows-1))
output = array.array('f', output_size*'\x00')
output_is_array = True
done = threading.Semaphore(0)
def thread_func(start, end):
try:
mlsl.grayify(img, img_type, src_col_offset,
src_row_offset + start,
src_col_stride, src_row_stride,
src_chan_stride, dst_col_offset,
dst_row_offset + start,
dst_col_stride, dst_row_stride,
cols, end-start, chans,
weights, gamma, output)
finally:
done.release()
starts = [int(round(1.0*x*rows/threads)) for x in range(threads)]
starts.append(cols)
for j in range(len(starts)-1):
start = starts[j]
end = starts[j+1]
thread.start_new_thread(thread_func, (start,end))
for j in range(len(starts)-1):
done.acquire()
if output_is_array:
output = output.tostring()
return output
