Files
2025-04-07 07:44:27 -07:00

115 lines
3.8 KiB
C#

using System.Drawing;
using System.Windows.Forms;
namespace LibreHardwareMonitor.UI.Themes
{
public class ThemedHScrollIndicator : Control
{
private readonly HScrollBar _scrollbar;
private int _startValue = 0;
private int _startPos = 0;
private bool _isScrolling = false;
public static void AddToControl(Control control)
{
foreach (Control child in control.Controls)
{
if (child is HScrollBar scrollbar)
{
control.Controls.Add(new ThemedHScrollIndicator(scrollbar));
return;
}
}
}
public ThemedHScrollIndicator(HScrollBar scrollBar)
{
_scrollbar = scrollBar;
Height = 8;
SetStyle(ControlStyles.ResizeRedraw, true);
SetStyle(ControlStyles.AllPaintingInWmPaint, true);
SetStyle(ControlStyles.UserPaint, true);
SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
Left = 0;
Top = scrollBar.Parent.Height - Height;
Size = new Size(scrollBar.Parent.Width, Height);
Anchor = AnchorStyles.Right | AnchorStyles.Left | AnchorStyles.Bottom;
Visible = scrollBar.Visible;
scrollBar.VisibleChanged += (s, e) => Visible = (s as ScrollBar).Visible;
scrollBar.Scroll += (s, e) => Invalidate();
scrollBar.ValueChanged += (s, e) => Invalidate();
scrollBar.Height = 0;
this.MouseDown += OnMouseDown;
}
private void OnMouseDown(object sender, MouseEventArgs e)
{
if (_isScrolling)
return;
_isScrolling = true;
//note: this.Capture is true when the control is clicked, no need to handle this
_startPos = e.X;
_startValue = _scrollbar.Value;
this.MouseUp += OnMouseUp;
this.MouseMove += OnMouseMove;
}
private void OnMouseUp(object sender, MouseEventArgs e)
{
_isScrolling = false;
this.MouseUp -= OnMouseUp;
this.MouseMove -= OnMouseMove;
}
private void OnMouseMove(object sender, MouseEventArgs e)
{
if (!_isScrolling)
return;
//pixel to range scaling:
double totalRange = _scrollbar.Maximum - _scrollbar.Minimum;
if (totalRange <= 0)
return;
double scaleToPercent = totalRange / Bounds.Width;
double scrollValue = _startValue + (e.X - _startPos) * scaleToPercent;
if (scrollValue < _scrollbar.Minimum)
scrollValue = _scrollbar.Minimum;
if (scrollValue > (_scrollbar.Maximum - _scrollbar.LargeChange))
scrollValue = _scrollbar.Maximum - _scrollbar.LargeChange;
_scrollbar.Value = (int)scrollValue;
Refresh();
}
protected override void OnPaint(PaintEventArgs e)
{
Graphics g = e.Graphics;
using (SolidBrush brush = new SolidBrush(Theme.Current.ScrollbarBackground))
g.FillRectangle(brush, new Rectangle(0, 0, Bounds.Width, Bounds.Height));
int width = Bounds.Width;
int range = _scrollbar.Maximum - _scrollbar.Minimum;
if (range > 0)
{
int start = width * (_scrollbar.Value - _scrollbar.Minimum) / range;
int end = width * (_scrollbar.Value - _scrollbar.Minimum + _scrollbar.LargeChange) / range;
using (SolidBrush brush = new SolidBrush(Theme.Current.ScrollbarTrack))
g.FillRectangle(brush, new Rectangle(start, 2, end - start, Bounds.Height - 4));
}
}
}
}