def draw(self, context):
"""Redraw the drawing area.
Keywords:
context surface used for drawing actions.
"""
context.set_source_rgb(0, 0, 0)
context.rectangle(-1, -1, 2, 2)
context.fill()
fill = self.fill
data = self.data
group = len(data) / 256
data = [sum(seq) / len(seq) for seq in batch(data, group)]
# color stuff.
context.set_source_rgb(.8, .8, .8)
# actual rendering.
width = 2 / len(data)
context.set_line_width(width)
x = -1 + width / 2
context.move_to(x, 0)
for value in data:
y = -value
context.line_to(x, y)
x += width
context.line_to(1 - width / 2, 0)
if fill:
context.fill()
else:
context.stroke()
def draw(self, context):
"""Redraw the drawing area.
Keywords:
context surface used for drawing actions.
"""
context.set_source_rgb(0, 0, 0)
context.rectangle(-1, -1, 2, 2)
context.fill()
threshold = self.threshold
bands = self.bands
data = self.data
# compute the fft and trasform it in decibel notation:
# - add 1e-15 in order to prevent log10(0).
# - we divide by 1 because it is supposed to be the highest peak.
data = 20 * log10(abs(fft(data) + 1e-15) / 1)
# how many values we have to merge in order to achieve the desired
# number of bands
group = len(data) / bands
data = [sum(seq) / len(seq) for seq in batch(data, group)]
# is it possible to obtain more values that needed; we simply ignore
# them (they refer to high value of frequencies.
data[:] = data[:bands]
## data = 20 * log10(abs(fft(data[:512]) + 1e-15) / 1)
## temp = []
## data = [max(data[2 ** i:2 ** (i + 1)]) for i in xrange(8)]
# color stuff.
context.set_source_rgb(.8, .8, .8)
# actual rendering.
width = 2 / len(data)
context.set_line_width(width)
x = -1 + width / 2
for value in data:
context.move_to(x, 1)
if value < threshold:
value = threshold
y = 1 - (value - threshold) / (-threshold) * 2
context.line_to(x, y)
context.stroke()
x += width