java - 尽管我使用了 Swing Timer，但在 JPanel 上从动画绘制 Wave 时 GUI 卡住

Question

请查看我的代码片段，它有什么问题，当 Swing 计时器统计信息重复绘制在 jpnael 上时，它会卡住 GUI ??

class WaveformPanel extends JPanel {

        Timer graphTimer = null;
        AudioInfo helper = null;

        WaveformPanel() {
            setPreferredSize(new Dimension(200, 80));
            setBorder(BorderFactory.createLineBorder(Color.BLACK));
            graphTimer = new Timer(15, new TimerDrawing());
        }

        /**
         * 
         */
        private static final long serialVersionUID = 969991141812736791L;
        protected final Color BACKGROUND_COLOR = Color.white;
        protected final Color REFERENCE_LINE_COLOR = Color.black;
        protected final Color WAVEFORM_COLOR = Color.red;

        protected void paintComponent(Graphics g) {

            super.paintComponent(g);

            int lineHeight = getHeight() / 2;
            g.setColor(REFERENCE_LINE_COLOR);
            g.drawLine(0, lineHeight, (int) getWidth(), lineHeight);

            if (helper == null) {
                return;
            }

            drawWaveform(g, helper.getAudio(0));

        }

        protected void drawWaveform(Graphics g, int[] samples) {

            if (samples == null) {
                return;
            }

            int oldX = 0;
            int oldY = (int) (getHeight() / 2);
            int xIndex = 0;

            int increment = helper.getIncrement(helper
                    .getXScaleFactor(getWidth()));
            g.setColor(WAVEFORM_COLOR);

            int t = 0;

            for (t = 0; t < increment; t += increment) {
                g.drawLine(oldX, oldY, xIndex, oldY);
                xIndex++;
                oldX = xIndex;
            }

            for (; t < samples.length; t += increment) {
                double scaleFactor = helper.getYScaleFactor(getHeight());
                double scaledSample = samples[t] * scaleFactor;
                int y = (int) ((getHeight() / 2) - (scaledSample));
                g.drawLine(oldX, oldY, xIndex, y);

                xIndex++;
                oldX = xIndex;
                oldY = y;
            }
        }

        public void setAnimation(boolean turnon) {
            if (turnon) {
                graphTimer.start();
            } else {
                graphTimer.stop();
            }
        }

        class TimerDrawing implements ActionListener {

            @Override
            public void actionPerformed(ActionEvent e) {

                byte[] bytes = captureThread.getTempBuffer();

                if (helper != null) {
                    helper.setBytes(bytes);
                } else {
                    helper = new AudioInfo(bytes);
                }
                repaint();
            }
        }

    }

我正在从其父类调用 WaveFormPanel 的 setAnimation。当动画开始时，它不会绘制任何东西，但会卡住。请给我解决方案。

谢谢 米希尔·帕克

Answer 1

java.swingx.Timer 在 EDT 中调用 ActionPerformed。接下来的问题是，什么需要时间来渲染。这可能是对 captureThread.getTempBuffer 的调用，也可能是帮助的构建，但我怀疑这只是您尝试绘制的数据共享量。

最近在玩这个，处理波形需要相当多的时间。

一个建议可能是减少绘制的样本数量。与其绘制每个样本点，不如根据组件的宽度每隔一秒或第四个样本点绘制一次。你仍然应该得到同样的笑话，但没有所有的工作......

已更新

所有样本，2.18 秒

每 4 个样本，0.711 秒

每第 8 个样本，0.450 秒

与其响应计时器进行绘制，也许您需要响应批量数据进行绘制。

由于您的加载程序线程有一个数据“ block ”，因此可能会绘制它。

正如 HoverCraftFullOfEels 所建议的，您可以先将其绘制到 BufferedImage，然后再将其绘制到屏幕...

SwingWorker或许可以为您实现这一目标

已更新

这是我用来绘制上述示例的代码。

// Samples is a 2D int array (int[][]), where the first index is the channel, the second is the sample for that channel
if (samples != null) {

    Graphics2D g2d = (Graphics2D) g;

    int length = samples[0].length;

    int width = getWidth() - 1;
    int height = getHeight() - 1;

    int oldX = 0;
    int oldY = height / 2;
    int frame = 0;

    // min, max is the min/max range of the samples, ie the highest and lowest samples
    int range = max + (min * -2);
    float scale = (float) height / (float) range;

    int minY = Math.round(((height / 2) + (min * scale)));
    int maxY = Math.round(((height / 2) + (max * scale)));

    LinearGradientPaint lgp = new LinearGradientPaint(
            new Point2D.Float(0, minY),
            new Point2D.Float(0, maxY),
            new float[]{0f, 0.5f, 1f},
            new Color[]{Color.BLUE, Color.RED, Color.BLUE});
    g2d.setPaint(lgp);
    for (int sample : samples[0]) {

        if (sample % 64 == 0) {

            int x = Math.round(((float) frame / (float) length) * width);
            int y = Math.round((height / 2) + (sample * scale));

            g2d.drawLine(oldX, oldY, x, y);

            oldX = x;
            oldY = y;

        }

        frame++;

    }

}

我使用 AudioStream 流加载 Wav 文件并生成 2D 样本。