New battery slider

2026-02-23 13:00:52 +01:00 · 2023-03-28 20:11:30 +02:00
parent fbed195194
commit 14dc1741f7
4 changed files with 198 additions and 38 deletions
--- a/app/Slider.cs
+++ b/app/Slider.cs
@@ -0,0 +1,168 @@
+using System.Diagnostics;
+using System.Drawing.Drawing2D;
+
+namespace WinFormsSliderBar
+{
+    public static class GraphicsExtensions
+    {
+        public static void DrawCircle(this Graphics g, Pen pen,
+                                      float centerX, float centerY, float radius)
+        {
+            g.DrawEllipse(pen, centerX - radius, centerY - radius,
+                          radius + radius, radius + radius);
+        }
+
+        public static void FillCircle(this Graphics g, Brush brush,
+                                      float centerX, float centerY, float radius)
+        {
+            g.FillEllipse(brush, centerX - radius, centerY - radius,
+                          radius + radius, radius + radius);
+        }
+    }
+
+    public class Slider : Control
+    {
+        private float _radius;
+        private PointF _thumbPos;
+        private SizeF _barSize;
+        private PointF _barPos;
+
+        private int _step = 5;
+
+        public Color accentColor = Color.FromArgb(255, 58, 174, 239);
+
+        public event EventHandler ValueChanged;
+
+        public Slider()
+        {
+            // This reduces flicker
+            DoubleBuffered = true;
+        }
+
+        private int _min = 0;
+        public int Min
+        {
+            get => _min;
+            set
+            {
+                _min = value;
+                RecalculateParameters();
+            }
+        }
+
+        private int _max = 100;
+        public int Max
+        {
+            get => _max;
+            set
+            {
+                _max = value;
+                RecalculateParameters();
+            }
+        }
+
+        private int _value = 50;
+        public int Value
+        {
+            get => _value;
+            set
+            {
+
+                value = (int)Math.Round(value / (float)_step) * _step;
+
+                if (_value != value)
+                {
+                    _value = value;
+                    ValueChanged?.Invoke(this, EventArgs.Empty);
+                    RecalculateParameters();
+                }
+            }
+        }
+
+        protected override void OnPaint(PaintEventArgs e)
+        {
+            base.OnPaint(e);
+
+            Brush brushAccent = new SolidBrush(accentColor);
+            Brush brushEmpty = new SolidBrush(Color.Gray);
+            Brush brushBorder = new SolidBrush(Color.White);
+
+            e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
+            e.Graphics.FillRectangle(brushEmpty,
+                _barPos.X, _barPos.Y, _barSize.Width, _barSize.Height);
+            e.Graphics.FillRectangle(brushAccent,
+                _barPos.X, _barPos.Y, _thumbPos.X - _barPos.X, _barSize.Height);
+
+            e.Graphics.FillCircle(brushBorder, _thumbPos.X, _thumbPos.Y, _radius);
+            e.Graphics.FillCircle(brushAccent, _thumbPos.X, _thumbPos.Y, 0.7f * _radius);
+        }
+
+        protected override void OnResize(EventArgs e)
+        {
+            base.OnResize(e);
+            RecalculateParameters();
+        }
+
+        private void RecalculateParameters()
+        {
+            _radius = 0.45F * ClientSize.Height;
+            _barSize = new SizeF(ClientSize.Width - 4 * _radius, ClientSize.Height*0.15F);
+            _barPos = new PointF(_radius, (ClientSize.Height - _barSize.Height) / 2);
+            _thumbPos = new PointF(
+                _barSize.Width / (Max - Min) * (Value-Min) + _barPos.X,
+                _barPos.Y + 0.5f * _barSize.Height);
+            Invalidate();
+        }
+
+        bool _moving = false;
+        SizeF _delta;
+
+        protected override void OnMouseDown(MouseEventArgs e)
+        {
+            base.OnMouseDown(e);
+
+            // Difference between tumb and mouse position.
+            _delta = new SizeF(e.Location.X - _thumbPos.X, e.Location.Y - _thumbPos.Y);
+            if (_delta.Width * _delta.Width + _delta.Height * _delta.Height <= _radius * _radius)
+            {
+                // Clicking inside thumb.
+                _moving = true;
+            }
+
+            _calculateValue(e);
+
+        }
+
+        private void _calculateValue(MouseEventArgs e)
+        {
+            float thumbX = e.Location.X; // - _delta.Width;
+            if (thumbX < _barPos.X)
+            {
+                thumbX = _barPos.X;
+            }
+            else if (thumbX > _barPos.X + _barSize.Width)
+            {
+                thumbX = _barPos.X + _barSize.Width;
+            }
+            Value = (int)Math.Round(Min + (thumbX - _barPos.X) * (Max - Min) / _barSize.Width);
+            
+        }
+
+        protected override void OnMouseMove(MouseEventArgs e)
+        {
+            base.OnMouseMove(e);
+            if (_moving)
+            {
+                _calculateValue(e);
+            }
+        }
+
+        protected override void OnMouseUp(MouseEventArgs e)
+        {
+            base.OnMouseUp(e);
+            _moving = false;
+        }
+
+    }
+
+}