DISTRHO-Ports/libs/drowaudio/source/dRowAudio/gui/dRowAudio_AudioOscilloscope.cpp

/*
  ==============================================================================

  This file is part of the dRowAudio JUCE module
  Copyright 2004-13 by dRowAudio.

  ------------------------------------------------------------------------------

  dRowAudio is provided under the terms of The MIT License (MIT):

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 
  SOFTWARE.

  ==============================================================================
*/



AudioOscilloscope::AudioOscilloscope()
    : verticalZoomFactor (1.0f),
      horizontalZoomFactor (1.0f),
      backgroundColour(Colours::black),
      traceColour(Colours::green)
{
    lastBufferPos = bufferPos = 0;
    bufferSize = 2048;		// Needs to be a power of 2 and larger than the width of your scope!
    bufferSizeMask = bufferSize - 1;
    circularBufferMax.calloc(bufferSize);
    circularBufferMin.calloc(bufferSize);
    clear();
    currentMin = bufferLastMin = 1.0e6f;
    currentMax = bufferLastMax = -currentMin;
    numSamplesIn = 0;
    
    setOpaque (true);
    resized();                  // initialise image
    startTimer (1000 / 60);     // repaint every 1/50 of a second
}

AudioOscilloscope::~AudioOscilloscope()
{
}

//==============================================================================
void AudioOscilloscope::processBlock (const float* inputChannelData,
                                      int numSamples)
{
    if (inputChannelData != 0)
    {
        for (int i = 0; i < numSamples; ++i)
            addSample (inputChannelData [i]);
    }
}

void AudioOscilloscope::clear()
{
    zeromem (circularBufferMax, sizeof (float) * bufferSize);
    zeromem (circularBufferMin, sizeof (float) * bufferSize);
}

//==============================================================================
void AudioOscilloscope::resized()
{
    Image oldImage (waveformImage);
    waveformImage = Image (Image::RGB, 
                           jmax (1, getWidth()), jmax (1, getHeight()),
                           true);
    waveformImage.clear(waveformImage.getBounds(), Colours::black);
    
    if (oldImage.isValid())
        waveformImage = oldImage.rescaled (waveformImage.getWidth(), waveformImage.getHeight());
}

void AudioOscilloscope::paint (Graphics& g)
{
    g.drawImageAt (waveformImage, 0, 0);
}

void AudioOscilloscope::timerCallback()
{
    const int width = getWidth();
    const float halfHeight = getHeight() * 0.5f;

    const int numPixelsToDraw = bufferPos - lastBufferPos;
    const int newSectionStart = width - numPixelsToDraw;

    // shuffle image along
    waveformImage.moveImageSection (0, 0,
                                    numPixelsToDraw, 0,
                                    newSectionStart, waveformImage.getHeight());

    // draw new section
    Graphics g (waveformImage);
    
    g.setColour (backgroundColour);
    g.fillRect (newSectionStart, 0, numPixelsToDraw, waveformImage.getHeight());
    g.setColour (traceColour);
    
    const int bp = bufferPos + bufferSize;
    
    for (int x = width; --x >= newSectionStart;)
    {
        const int samplesAgo = width - x;
        
        float max = circularBufferMax [(bp - samplesAgo) &bufferSizeMask];
        float min = circularBufferMin [(bp - samplesAgo) &bufferSizeMask];
        
        if (min > bufferLastMax)
            min = bufferLastMax;
        if (max < bufferLastMin)
            max = bufferLastMin;
        
        bufferLastMax = max;
        bufferLastMin = min;
        
        g.drawLine ((float) x, halfHeight + (halfHeight * verticalZoomFactor * max),
                    (float) x, halfHeight + (halfHeight * verticalZoomFactor * min));
    }
    
    lastBufferPos = bufferPos;

    repaint();
}

void AudioOscilloscope::addSample (const float sample)
{
    if (sample > currentMax)
        currentMax = sample;
    if (sample < currentMin)
        currentMin = sample;
    
    const int samplesToAverage = 1 + (int) (127.0 * horizontalZoomFactor);
    
    if (++numSamplesIn > samplesToAverage)
    {
        bufferPos = bufferPos & bufferSizeMask;
        circularBufferMax [bufferPos] = currentMax;
        circularBufferMin [bufferPos] = currentMin;
        bufferPos++;
        
        numSamplesIn = 0;
        currentMin = 1.0e6f;
        currentMax = -currentMin;
    }
}