在python librosa中创建图形ctxt对象时出错

Question

我正在尝试使用librosa绘制一些.wav数据，但遇到一些异常问题，在谷歌搜索“创建图形ctxt对象的python librosa错误”中找不到很多问题

def plot_waves(sound_names, raw_sounds):
    i = 1
    fig = plt.figure(figsize=(25, 60), dpi=900)
    for n, f in zip(sound_names, raw_sounds):
        print "plot_waves:", i
        plt.subplot(10, 1, i)
        librosa.display.waveplot(np.array(f), sr=22050)
        plt.title(n.title())
        i += 1
    print "plot_waves_loop_end"


    plt.suptitle("Figure 1: Waveplot", x=0.5, y=0.915, fontsize=18)

    #THIS LINE CAUSES THE ERROR
    plt.show()

可能与macOS有关。

我已经在virtualenv和外部尝试过，两种情况都存在相同的错误。

pip install {matplotlib，librosa，numpy}在virtualenv和外部都显示为不需要更新

错误消息（超出此范围并锁定python-必须强制退出）

2017-03-24 22:15:03.393 python[62870:25289530] _initWithWindowNumber: error creating graphics ctxt object for ctxt:0x3653b, window:0x9754
2017-03-24 22:15:03.393 python[62870:25289530] _initWithWindowNumber: error creating graphics ctxt object for ctxt:0x3653b, window:0x9754
Mar 24 22:15:03  python[62870] <Error>: CGContextSetFillColorWithColor: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.
Mar 24 22:15:03  python[62870] <Error>: CGContextSetStrokeColorWithColor: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.
Mar 24 22:15:03  python[62870] <Error>: CGContextGetCompositeOperation: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.
Mar 24 22:15:03  python[62870] <Error>: CGContextSetCompositeOperation: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.
Mar 24 22:15:03  python[62870] <Error>: CGContextFillRects: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.
Mar 24 22:15:03  python[62870] <Error>: CGContextSetCompositeOperation: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.
Mar 24 22:15:03  python[62870] <Error>: CGContextGetCTM: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.
Mar 24 22:15:03  python[62870] <Error>: CGContextGetDefaultUserSpaceToDeviceSpaceTransform: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.
Mar 24 22:15:03  python[62870] <Error>: CGContextSaveGState: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.
Mar 24 22:15:03  python[62870] <Error>: CGContextConcatCTM: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.
Mar 24 22:15:03  python[62870] <Error>: CGContextSetCompositeOperation: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.
Mar 24 22:15:03  python[62870] <Error>: CGContextSaveGState: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.
Mar 24 22:15:03  python[62870] <Error>: CGContextSetCompositeOperation: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.

Answer 1

我认为问题不是dpi设置太高（900可能太过分了！），而不是删除行（根据您的评论）。 尝试将其减少（例如减少到30），它应该可以工作。

def plot_waves(sound_names, raw_sounds):
    i = 1
    fig = plt.figure(figsize=(25, 60), dpi=30)  ## changed from 900 to 30
    for n, f in zip(sound_names, raw_sounds):
        print "plot_waves:", i
        plt.subplot(10, 1, i)
        librosa.display.waveplot(np.array(f), sr=22050)
        plt.title(n.title())
        i += 1
    print "plot_waves_loop_end"


    plt.suptitle("Figure 1: Waveplot", x=0.5, y=0.915, fontsize=18)

    plt.show()