waveform_canvas_renderer.h

// SPDX-FileCopyrightText: © 2026 Alexandros Theodotou <alex@zrythm.org>
// SPDX-License-Identifier: LicenseRef-ZrythmLicense
 
#pragma once
 
#include <vector>
 
#include <QColor>
#include <QtCanvasPainter/qcanvaspainter.h>
#include <QtCanvasPainter/qcanvaspainteritemrenderer.h>
 
#include "juce_wrapper.h"
 
namespace zrythm::gui::qquick
{
 
class WaveformCanvasItem;

class WaveformCanvasRenderer : public QCanvasPainterItemRenderer
{
public:
  WaveformCanvasRenderer () = default;
  ~WaveformCanvasRenderer () override = default;
 
  void initializeResources (QCanvasPainter * painter) override;
  void synchronize (QCanvasPainterItem * item) override;
  void paint (QCanvasPainter * painter) override;
 
private:
  struct Peak
  {
    float min; // normalized 0-1
    float max; // normalized 0-1
  };
 
  using ChannelPeaks = std::vector<Peak>;
 
  void compute_peaks ();
 
  // Cached visual state from the item
  QColor waveform_color_;
  QColor outline_color_;
  float  canvas_width_ = 0.0f;
  float  canvas_height_ = 0.0f;
 
  // Cached pointer to the item's serialized audio buffer (owned by the item)
  const juce::AudioSampleBuffer * audio_buffer_ = nullptr;
 
  // Cached peak data
  std::vector<ChannelPeaks> peaks_;
  int                       num_channels_ = 0;
 
  // Change detection
  uint64_t prev_generation_ = 0;
  float    prev_width_ = 0.0f;
  float    prev_height_ = 0.0f;
};
 
} // namespace zrythm::gui::qquick