cyf
74 lines
2.6 KiB
C#
74 lines
2.6 KiB
C#
using System;
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using System.Collections.Generic;
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using System.ComponentModel;
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using System.Diagnostics;
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using System.Drawing;
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using System.Drawing.Drawing2D;
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using System.Linq;
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using System.Text;
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using System.Windows.Forms;
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namespace Lskj.Main.Control
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{
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public partial class BackgroundPanel :Panel
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{
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private Image _originalBackgroundImage;
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// 公开属性：设置/获取背景图片
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public Image BackgroundImageCustom
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{
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get => _originalBackgroundImage;
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set
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{
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_originalBackgroundImage = value;
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Invalidate(); // 设置图片后立即重绘
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}
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}
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public BackgroundPanel()
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{
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// 关键设置：关闭Panel默认背景，启用双缓冲减少闪烁
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this.BackgroundImage = null;
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this.DoubleBuffered = true;
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this.SetStyle(ControlStyles.UserPaint |
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ControlStyles.AllPaintingInWmPaint |
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ControlStyles.OptimizedDoubleBuffer, true);
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}
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// 重写OnPaint方法，手动绘制背景图
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protected override void OnPaint(PaintEventArgs e)
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{
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base.OnPaint(e);
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// 图片为空时直接返回
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if (_originalBackgroundImage == null) return;
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// 1. 计算等比缩放比例（以Panel的ClientSize为基准）
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float scaleX = (float)this.ClientSize.Width / _originalBackgroundImage.Width;
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float scaleY = (float)this.ClientSize.Height / _originalBackgroundImage.Height;
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float scale = Math.Min(scaleX, scaleY); // 取较小值，避免图片超出Panel
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// 2. 计算图片绘制的位置（居中显示）
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int newWidth = (int)(_originalBackgroundImage.Width * scale);
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int newHeight = (int)(_originalBackgroundImage.Height * scale);
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int x = (this.ClientSize.Width - newWidth) / 2;
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int y = (this.ClientSize.Height - newHeight) / 2;
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// 3. 高质量绘制图片（抗锯齿、高清缩放）
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e.Graphics.SmoothingMode = SmoothingMode.HighQuality;
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e.Graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
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e.Graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
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e.Graphics.DrawImage(_originalBackgroundImage, new Rectangle(x, y, newWidth, newHeight));
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}
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// Panel大小变化时触发重绘
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protected override void OnResize(EventArgs e)
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{
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base.OnResize(e);
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Invalidate(); // 标记控件需要重绘
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}
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}
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}
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