reasampler/src/core/ui/component_geometry.cpp

// component_geometry — pure implementation. See component_geometry.h.

#include "core/ui/component_geometry.h"

namespace reasampler::ui {

bool hitTestBox(int px, int py, const KitBox& box) {
    if (box.empty()) return false;
    return px >= box.x && px < box.x + box.width &&
           py >= box.y && py < box.y + box.height;
}

KitButtonBox computeButtonBox(const KitBox& cell, int padding) {
    if (cell.empty()) return {};
    if (padding < 0) padding = 0;
    KitBox b;
    b.x = cell.x + padding;
    b.y = cell.y + padding;
    b.width = cell.width - 2 * padding;
    b.height = cell.height - 2 * padding;
    if (b.empty()) return {};
    return KitButtonBox{b};
}

SliderGeometry computeSlider(const KitBox& control, double value,
                             int handleSize, int trackThickness) {
    if (control.empty() || handleSize <= 0 || trackThickness <= 0) return {};
    if (control.width < handleSize || control.height < handleSize) return {};

    if (value < 0.0) value = 0.0;
    if (value > 1.0) value = 1.0;

    const int half = handleSize / 2;

    KitBox track;
    track.x = control.x + half;
    track.width = control.width - handleSize;  // travel span for the handle centre
    if (track.width < 0) track.width = 0;
    track.height = trackThickness;
    track.y = control.y + (control.height - trackThickness) / 2;

    const int centre = track.x + static_cast<int>(value * track.width + 0.5);
    KitBox handle;
    handle.x = centre - half;
    handle.y = control.y + (control.height - handleSize) / 2;
    handle.width = handleSize;
    handle.height = handleSize;

    KitBox filled;
    filled.x = track.x;
    filled.y = track.y;
    filled.width = centre - track.x;
    if (filled.width < 0) filled.width = 0;
    filled.height = track.height;

    return SliderGeometry{track, filled, handle};
}

double sliderValueAt(int px, const KitBox& control, int handleSize) {
    if (control.empty() || handleSize <= 0) return 0.0;
    if (control.width < handleSize) return 0.0;

    const int half = handleSize / 2;
    const int trackStart = control.x + half;
    const int trackSpan = control.width - handleSize;  // matches computeSlider's travel
    if (trackSpan <= 0) return 0.0;

    if (px <= trackStart) return 0.0;
    if (px >= trackStart + trackSpan) return 1.0;
    return static_cast<double>(px - trackStart) / static_cast<double>(trackSpan);
}

ListRowBox computeListRow(const KitBox& list, int index, int rowHeight) {
    if (list.empty() || rowHeight <= 0 || index < 0) return {};
    const int top = list.y + index * rowHeight;
    if (top >= list.y + list.height) return {};
    KitBox b;
    b.x = list.x;
    b.y = top;
    b.width = list.width;
    b.height = rowHeight;
    return ListRowBox{index, b};
}

int hitTestListRow(int px, int py, const KitBox& list, int rowHeight, int rowCount) {
    if (list.empty() || rowHeight <= 0 || rowCount <= 0) return -1;
    if (px < list.x || px >= list.x + list.width ||
        py < list.y || py >= list.y + list.height)
        return -1;
    const int row = (py - list.y) / rowHeight;
    if (row < 0 || row >= rowCount) return -1;
    return row;
}

int waveformColumnCount(const KitBox& box) {
    const int w = box.width - 4;  // fixed 2px inset each side (matches drawWaveform)
    return w > 0 ? w : 0;
}

WaveformBand waveformBand(int bandTop, int bandHeight) {
    WaveformBand b;
    b.top = bandTop;
    b.height = bandHeight;
    b.midY = bandTop + bandHeight / 2;
    // matches drawWaveform's 2px vertical breathing room; clamped at 0 so a degenerate band
    // (height <= 3, where this would otherwise go negative) can't flip a positive peak below
    // the zero line.
    const int rawHalfSpan = (bandHeight / 2) - 2;
    b.halfSpan = rawHalfSpan > 0 ? rawHalfSpan : 0;
    // lo/hi (waveformColumnSpan) are midY-height/2 .. midY+height/2-1 — asymmetric by one px for
    // even heights. Unreachable while |compressAmplitudeForDisplay| <= 1, so left as-is.
    return b;
}

WaveformColumnSpan waveformColumnSpan(const WaveformBand& band,
                                      double compressedMax, double compressedMin) {
    const int lo = band.top;
    const int hi = band.top + band.height - 1;

    WaveformColumnSpan s;
    s.top = band.midY - static_cast<int>(compressedMax * band.halfSpan);
    s.bottom = band.midY - static_cast<int>(compressedMin * band.halfSpan);
    s.topF = band.midY - compressedMax * band.halfSpan;
    s.bottomF = band.midY - compressedMin * band.halfSpan;

    if (s.top < lo) s.top = lo;
    if (s.bottom > hi) s.bottom = hi;
    if (s.topF < lo) s.topF = lo;
    if (s.bottomF > hi) s.bottomF = hi;
    return s;
}

} // namespace reasampler::ui