71 lines
2.0 KiB
Dart
71 lines
2.0 KiB
Dart
import 'package:flutter/material.dart';
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/// カメラ画面右端の露出スライダーを描画する CustomPainter。
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///
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/// - 縦トラック（白半透明）
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/// - 中央基準線（0 EV を示すマーカー）
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/// - 現在値を示すノブ（影付き白丸）
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class ExposureSliderPainter extends CustomPainter {
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final double currentValue;
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final double minValue;
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final double maxValue;
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const ExposureSliderPainter({
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required this.currentValue,
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required this.minValue,
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required this.maxValue,
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});
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@override
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void paint(Canvas canvas, Size size) {
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final trackPaint = Paint()
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..color = Colors.white.withValues(alpha: 0.3)
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..strokeWidth = 4
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..strokeCap = StrokeCap.round;
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final centerLinePaint = Paint()
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..color = Colors.white54
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..strokeWidth = 2;
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final knobPaint = Paint()
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..color = Colors.white
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..style = PaintingStyle.fill;
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final knobShadowPaint = Paint()
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..color = Colors.black26
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..maskFilter = const MaskFilter.blur(BlurStyle.normal, 4);
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// 縦トラック（中央線）
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final trackX = size.width / 2;
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canvas.drawLine(
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Offset(trackX, 10),
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Offset(trackX, size.height - 10),
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trackPaint,
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);
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// 0 EV マーカー
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canvas.drawLine(
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Offset(trackX - 6, size.height / 2),
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Offset(trackX + 6, size.height / 2),
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centerLinePaint,
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);
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// ノブ位置を算出
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final range = maxValue - minValue;
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if (range > 0) {
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// minValue(下端) → 0.0、maxValue(上端) → 1.0 に正規化してY座標に変換
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final normalized = (currentValue - minValue) / range;
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final knobY = (size.height - 20) * (1.0 - normalized) + 10;
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canvas.drawCircle(Offset(trackX, knobY), 7, knobShadowPaint);
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canvas.drawCircle(Offset(trackX, knobY), 6, knobPaint);
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}
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}
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@override
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bool shouldRepaint(ExposureSliderPainter oldDelegate) {
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return oldDelegate.currentValue != currentValue ||
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oldDelegate.minValue != minValue ||
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oldDelegate.maxValue != maxValue;
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}
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}
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