viewport_projection.hpp

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#pragma once
 
#include <cstdint>
 
#include <pulp/runtime/result.hpp>
#include <pulp/timebase/tick.hpp>
 
namespace pulp::timeline_editor {

struct PixelSpan {
    float origin = 0.0f;
    float extent = 0.0f;
 
    constexpr bool operator==(const PixelSpan&) const = default;
};
 
enum class ViewportProjectionError : std::uint8_t {
    NonFinitePixelSpan,
    NonPositivePixelExtent,
    NonPositiveTickDuration,
    TickRangeOverflow,
    InvalidPitchRange,
};

class TickProjection {
  public:
    static runtime::Result<TickProjection, ViewportProjectionError>
    create(timebase::TickPosition visible_start, timebase::TickDuration visible_duration,
           PixelSpan pixels) noexcept;
 
    [[nodiscard]] float x_at(timebase::TickPosition tick) const noexcept;
    [[nodiscard]] timebase::TickPosition tick_at(float x) const noexcept;
 
    [[nodiscard]] constexpr timebase::TickPosition visible_start() const noexcept {
        return visible_start_;
    }
    [[nodiscard]] constexpr timebase::TickDuration visible_duration() const noexcept {
        return visible_duration_;
    }
    [[nodiscard]] constexpr timebase::TickPosition visible_end() const noexcept {
        return {visible_start_.value + visible_duration_.value};
    }
    [[nodiscard]] constexpr PixelSpan pixels() const noexcept {
        return pixels_;
    }
 
  private:
    constexpr TickProjection(timebase::TickPosition visible_start,
                             timebase::TickDuration visible_duration, PixelSpan pixels) noexcept
        : visible_start_(visible_start), visible_duration_(visible_duration), pixels_(pixels) {}
 
    timebase::TickPosition visible_start_{};
    timebase::TickDuration visible_duration_{};
    PixelSpan pixels_{};
};

class PitchProjection {
  public:
    static runtime::Result<PitchProjection, ViewportProjectionError>
    create(std::uint8_t lowest_pitch, std::uint8_t highest_pitch, PixelSpan pixels) noexcept;
 
    [[nodiscard]] float y_at(std::uint8_t pitch) const noexcept;
    [[nodiscard]] std::uint8_t pitch_at(float y) const noexcept;
    [[nodiscard]] float row_height() const noexcept;
 
    [[nodiscard]] constexpr std::uint8_t lowest_pitch() const noexcept {
        return lowest_pitch_;
    }
    [[nodiscard]] constexpr std::uint8_t highest_pitch() const noexcept {
        return highest_pitch_;
    }
    [[nodiscard]] constexpr PixelSpan pixels() const noexcept {
        return pixels_;
    }
 
  private:
    constexpr PitchProjection(std::uint8_t lowest_pitch, std::uint8_t highest_pitch,
                              PixelSpan pixels) noexcept
        : lowest_pitch_(lowest_pitch), highest_pitch_(highest_pitch), pixels_(pixels) {}
 
    std::uint8_t lowest_pitch_ = 0;
    std::uint8_t highest_pitch_ = 127;
    PixelSpan pixels_{};
};
 
} // namespace pulp::timeline_editor