wavetable.py 文件源码

def draw_wave(self, stream, force=False):
#        print stream.getnframes()
        if self.wavepath:
            self.scene().removeItem(self.wavepath)
            self.fitInView(0, 0, 1, 1)
        self.current_sampwidth = sampwidth = stream.getsampwidth()
        self.current_sampwidth_int = delta = 2**(8*sampwidth)
        if stream in self.cache and not force:
            self.current_data, wavepath = self.cache[stream]
        else:
            stream.rewind()
            frames = stream.getnframes()
            ratio = frames / 64
            if stream.getnchannels() == 2:
                data = audioop.tomono(stream.readframes(float('inf')), sampwidth, self.main.left_spin.value(), self.main.right_spin.value())
            else:
                data = stream.readframes(float('inf'))
            data = audioop.mul(data, sampwidth, self.main.gain)
            self.current_data = data
            wavepath = QtGui.QPainterPath()
            try:
                for frame_set in xrange(ratio):
                    frame_min = frame_max = 0
                    for frame in xrange(64):
                        try:
                            value = audioop.getsample(data, sampwidth, frame + frame_set * 64)
                            frame_min = min(frame_min, value)
                            frame_max = max(frame_max, value)
                        except:
                            break
                    if frame == 0:
                        break
                    wavepath.moveTo(frame_set, delta - frame_min)
                    wavepath.lineTo(frame_set, delta - frame_max)
            except:
                pass
            self.cache[stream] = data, wavepath
        self.wavepath = self.scene().addPath(wavepath)
        self.wavepath.setPen(self.wave_pen)
        self.wavepath.setY(-delta * .5)
        self.wavepath.setX(self.left_margin*2)
        self.fitInView(0, 0, self.zoom_values[self.zoom], delta)
        if not force:
            self.centerOn(self.wavepath)
        self.right_margin_item.setX(len(self.current_data)/self.current_sampwidth/64)

        visible = self.mapToScene(self.viewport().rect()).boundingRect()
        if visible.width() > self.wavepath.boundingRect().width():
            self.scene().setSceneRect(-self.left_margin, 0, visible.width(), delta)
        else:
            self.scene().setSceneRect(-self.left_margin, 0, self.wavepath.boundingRect().width(), delta)