InstaGrain/Source/WaveformDisplay.cpp

#include "WaveformDisplay.h"
#include "LookAndFeel.h"

WaveformDisplay::WaveformDisplay() {}

void WaveformDisplay::setBuffer (const juce::AudioBuffer<float>* buffer)
{
    audioBuffer = buffer;
    if (buffer != nullptr)
    {
        totalSourceSamples = buffer->getNumSamples();
        lastBufferSize = totalSourceSamples;
    }
    else
    {
        totalSourceSamples = 0;
        lastBufferSize = 0;
    }
    pathDirty = true;
    repaint();
}

void WaveformDisplay::setActiveGrains (const std::vector<GrainEngine::ActiveGrainInfo>& grains)
{
    activeGrains = grains;
    repaint();
}

void WaveformDisplay::resized()
{
    pathDirty = true;
}

void WaveformDisplay::rebuildWaveformPath (juce::Rectangle<float> bounds)
{
    cachedWaveformPath.clear();

    if (audioBuffer == nullptr || audioBuffer->getNumSamples() == 0)
        return;

    const int numSamples = audioBuffer->getNumSamples();
    const float width = bounds.getWidth();
    const float height = bounds.getHeight();
    const float midY = bounds.getCentreY();
    const float* data = audioBuffer->getReadPointer (0);

    // Build filled waveform path
    int blockSize = std::max (1, numSamples / (int) width);

    // Top line (max values)
    cachedWaveformPath.startNewSubPath (bounds.getX(), midY);
    for (int x = 0; x < (int) width; ++x)
    {
        int sampleIndex = (int) ((float) x / width * (float) numSamples);
        sampleIndex = juce::jlimit (0, numSamples - 1, sampleIndex);

        float maxVal = -1.0f;
        for (int j = 0; j < blockSize && (sampleIndex + j) < numSamples; ++j)
            maxVal = std::max (maxVal, data[sampleIndex + j]);

        float topY = midY - maxVal * (height * 0.45f);
        cachedWaveformPath.lineTo ((float) x + bounds.getX(), topY);
    }

    // Bottom line (min values, reversed)
    for (int x = (int) width - 1; x >= 0; --x)
    {
        int sampleIndex = (int) ((float) x / width * (float) numSamples);
        sampleIndex = juce::jlimit (0, numSamples - 1, sampleIndex);

        float minVal = 1.0f;
        for (int j = 0; j < blockSize && (sampleIndex + j) < numSamples; ++j)
            minVal = std::min (minVal, data[sampleIndex + j]);

        float botY = midY - minVal * (height * 0.45f);
        cachedWaveformPath.lineTo ((float) x + bounds.getX(), botY);
    }

    cachedWaveformPath.closeSubPath();
    lastWidth = getWidth();
    lastHeight = getHeight();
    pathDirty = false;
}

void WaveformDisplay::paint (juce::Graphics& g)
{
    auto bounds = getLocalBounds().toFloat();

    // Background gradient
    {
        juce::ColourGradient bgGrad (InstaGrainLookAndFeel::bgDark.darker (0.4f), 0, bounds.getY(),
                                      InstaGrainLookAndFeel::bgDark.darker (0.2f), 0, bounds.getBottom(), false);
        g.setGradientFill (bgGrad);
        g.fillRoundedRectangle (bounds, 4.0f);
    }

    // Border
    g.setColour (InstaGrainLookAndFeel::bgLight.withAlpha (0.3f));
    g.drawRoundedRectangle (bounds, 4.0f, 1.0f);

    // Grid lines
    g.setColour (InstaGrainLookAndFeel::bgLight.withAlpha (0.12f));
    for (int i = 1; i < 8; ++i)
    {
        float xLine = bounds.getX() + bounds.getWidth() * (float) i / 8.0f;
        g.drawVerticalLine ((int) xLine, bounds.getY(), bounds.getBottom());
    }

    // Center line
    g.setColour (InstaGrainLookAndFeel::bgLight.withAlpha (0.2f));
    float midY = bounds.getCentreY();
    g.drawHorizontalLine ((int) midY, bounds.getX(), bounds.getRight());

    if (audioBuffer == nullptr || audioBuffer->getNumSamples() == 0)
    {
        // "Drop sample here" text
        g.setColour (InstaGrainLookAndFeel::textSecondary);
        g.setFont (16.0f);
        g.drawText ("Drop a sample here or click Load Sample", bounds, juce::Justification::centred);
        return;
    }

    // Rebuild path if needed
    if (pathDirty || lastWidth != getWidth() || lastHeight != getHeight()
        || lastBufferSize != audioBuffer->getNumSamples())
    {
        lastBufferSize = audioBuffer->getNumSamples();
        rebuildWaveformPath (bounds);
    }

    // Scatter range highlight
    if (scatterRange > 0.001f)
    {
        float posX = bounds.getX() + grainPosition * bounds.getWidth();
        float rangeW = scatterRange * bounds.getWidth();
        float left = std::max (bounds.getX(), posX - rangeW);
        float right = std::min (bounds.getRight(), posX + rangeW);

        g.setColour (juce::Colour (0x1800ff88));
        g.fillRect (left, bounds.getY(), right - left, bounds.getHeight());
    }

    // Waveform fill + stroke
    juce::Colour waveColour (0xffff8844);
    g.setColour (waveColour.withAlpha (0.5f));
    g.fillPath (cachedWaveformPath);
    g.setColour (waveColour.withAlpha (0.9f));
    g.strokePath (cachedWaveformPath, juce::PathStrokeType (1.0f));

    // Active grain rectangles
    if (totalSourceSamples > 0)
    {
        for (const auto& grain : activeGrains)
        {
            if (grain.startSample < 0) continue;
            float gx = bounds.getX() + ((float) grain.startSample / (float) totalSourceSamples) * bounds.getWidth();
            float gw = ((float) grain.lengthSamples / (float) totalSourceSamples) * bounds.getWidth();
            gw = std::max (2.0f, gw);

            float alpha = 0.6f * (1.0f - grain.progress); // fade as grain progresses
            g.setColour (InstaGrainLookAndFeel::accent.withAlpha (alpha));
            g.fillRect (gx, bounds.getY() + 2, gw, bounds.getHeight() - 4);
        }
    }

    // Position indicator line
    {
        float posX = bounds.getX() + grainPosition * bounds.getWidth();
        g.setColour (InstaGrainLookAndFeel::accent);
        g.drawVerticalLine ((int) posX, bounds.getY(), bounds.getBottom());

        // Glow
        g.setColour (InstaGrainLookAndFeel::accent.withAlpha (0.3f));
        g.fillRect (posX - 2.0f, bounds.getY(), 5.0f, bounds.getHeight());
    }
}

void WaveformDisplay::updatePositionFromMouse (const juce::MouseEvent& e)
{
    auto bounds = getLocalBounds().toFloat();
    float pos = (float) (e.x - bounds.getX()) / bounds.getWidth();
    pos = juce::jlimit (0.0f, 1.0f, pos);
    grainPosition = pos;

    if (onPositionChanged)
        onPositionChanged (pos);

    repaint();
}

void WaveformDisplay::mouseDown (const juce::MouseEvent& e)
{
    if (audioBuffer != nullptr && audioBuffer->getNumSamples() > 0)
        updatePositionFromMouse (e);
}

void WaveformDisplay::mouseDrag (const juce::MouseEvent& e)
{
    if (audioBuffer != nullptr && audioBuffer->getNumSamples() > 0)
        updatePositionFromMouse (e);
}