用C#制作“涂鸦板”的问题:如何实现自动重绘？

[引力场变动源]

要做的程序类似于一个Windows画图程序，也就是“涂鸦板”之类的，因为是基于象素操作的(不是规则几何图形)，所以无法把绘图代码放入onPaint事件中处理。现在采用的方法是，使用一个Bitmap作为绘图目标，在OnPaint事件中把这个Bitmap赋给PictureBox。虽然效果达到了，但是有一个问题，就是CPU占用率相当高(双核CPU占用率50%- -)，自己分析觉得，大概是onPaint事件中发生了频繁的数据复制之类的，但是找不到解决的方法，所以来向大家求助了。

[Red_angelX]

正常,gdi+的程序cpu动不动就是40%以上

[Red_angelX]

不过你可以考虑优化下绘图算法多用局部重绘

[北京的雾霾天]

给你个画图的例子(双缓冲),效果很好:
public partial class DrawLine : Form
{
class LineObj
{
private Point m_start;
private Point m_end;
public LineObj(Point start, Point end)
{
this.m_start = start;
this.m_end = end;
}
public void Draw(Graphics g, Pen pen)
{
g.DrawLine(pen, m_start, m_end);
}
}

private Point m_startPoint = Point.Empty;
List<LineObj> lineList = new List<LineObj>();
public DrawLine()
{
InitializeComponent();
}
private void drawLine(Graphics graphics, Point startPoint, Point endPoint)
{
BufferedGraphicsContext context = BufferedGraphicsManager.Current;
BufferedGraphics bg = context.Allocate(graphics, this.ClientRectangle);
bg.Graphics.Clear(this.BackColor);
foreach (LineObj line in this.lineList)
{
line.Draw(bg.Graphics, SystemPens.ControlText);
}
bg.Graphics.DrawLine(SystemPens.ControlText, startPoint, endPoint);
bg.Render();
bg.Dispose();
bg = null;
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
foreach (LineObj line in this.lineList)
{
line.Draw(e.Graphics, SystemPens.ControlText);
}
}
protected override void OnMouseDown(MouseEventArgs e)
{
base.OnMouseDown(e);
this.m_startPoint = new Point(e.X, e.Y);
}
protected override void OnMouseMove(MouseEventArgs e)
{
base.OnMouseMove(e);
if (e.Button == MouseButtons.Left)
{
this.drawLine(this.CreateGraphics(), this.m_startPoint, new Point(e.X, e.Y));
}
}
protected override void OnMouseUp(MouseEventArgs e)
{
base.OnMouseUp(e);
LineObj line = new LineObj(this.m_startPoint, e.Location);
this.lineList.Add(line);
}
}

[sly520]

帮顶，同时学习

[引力场变动源]

OTL一下，原来CPU使用率高是GDI＋的特性啊......

to hbxtlhx(平民百姓)：我去试一下，感谢～