Method createBackgroundImage

Source/Panels/SpectrogramPanel/SpectrumBackground.cpp:68–128

}

void SpectrumBackground::createBackgroundImage()
{
    // Get component bounds.
    auto bounds = getLocalBounds();
    if (bounds.isEmpty())
        return;

    // Create a new image with the current component size.
    cachedBackground = juce::Image(juce::Image::ARGB,
                                   juce::roundToInt(getWidth() * lastDisplayScale),
                                   juce::roundToInt(getHeight() * lastDisplayScale),
                                   true);
    // Create a graphics context to draw onto our new image.
    juce::Graphics g(cachedBackground);
    g.addTransform(juce::AffineTransform::scale(lastDisplayScale));

    // --- All original painting logic is moved here ---

    // Paint background color onto the image.
    g.setColour(COLOUR6);
    g.fillAll();

    // Set a scalable font size for the frequency labels.
    g.setFont(12.0f * scale);

    // Paint horizontal lines and frequency numbers.
    g.setColour(juce::Colours::lightgrey.withAlpha(0.2f));
    auto horizontalLineY = (float) bounds.getHeight() / 5.0f;
    g.drawHorizontalLine((int) horizontalLineY, 0.0f, (float) bounds.getWidth());

    for (const auto freq : frequenciesForLines)
    {
        float xPos = transformToLog(freq) * bounds.getWidth();
        g.drawVerticalLine((int) xPos, horizontalLineY, (float) bounds.getHeight());
    }

    // Loop 2: Draw ONLY the text labels using the sparse array.
    for (const auto freq : frequenciesForTextLabels)
    {
        float xPos = transformToLog(freq) * bounds.getWidth();

        const int scaledWidth = (int) (60 * scale);
        const int scaledXOffset = (int) (30 * scale);

        juce::Rectangle<int> textBounds((int) xPos - scaledXOffset, 0, scaledWidth, (int) horizontalLineY);

        juce::String text;
        if (freq >= 1000)
            text = juce::String(freq / 1000) + "k";
        else
            text = juce::String(freq);

        auto justification = juce::Justification::centred;
        if (freq == 20)
            justification = juce::Justification::right;
        else if (freq == 20000)
            justification = juce::Justification::left;