如何在图片框中绘制图纸

在图片中绘制图片使用c＃拖动鼠标

Answer 1

将PictureBox放在表单上，​​并将其BackColor设置为白色。 然后将此代码添加到您的表单中（您必须实际连接下面的鼠标事件，即您不能将此代码复制并粘贴到您的表单中）：

private Point? _Previous = null; private void pictureBox1_MouseDown(object sender, MouseEventArgs e) { _Previous = e.Location; pictureBox1_MouseMove(sender, e); } private void pictureBox1_MouseMove(object sender, MouseEventArgs e) { if (_Previous != null) { if (pictureBox1.Image == null) { Bitmap bmp = new Bitmap(pictureBox1.Width, pictureBox1.Height); using (Graphics g = Graphics.FromImage(bmp)) { g.Clear(Color.White); } pictureBox1.Image = bmp; } using (Graphics g = Graphics.FromImage(pictureBox1.Image)) { g.DrawLine(Pens.Black, _Previous.Value, e.Location); } pictureBox1.Invalidate(); _Previous = e.Location; } } private void pictureBox1_MouseUp(object sender, MouseEventArgs e) { _Previous = null; } 

然后抽离！

如果您愿意，可以通过设置Graphics对象的SmoothingMode属性来稍微提高绘制图像的质量。

更新： .Net CF没有Pens集合，而且MoustEventArgs没有Location ，所以这里是CF友好版本：

 private Point? _Previous = null; private Pen _Pen = new Pen(Color.Black); private void pictureBox1_MouseDown(object sender, MouseEventArgs e) { _Previous = new Point(eX, eY); pictureBox1_MouseMove(sender, e); } private void pictureBox1_MouseMove(object sender, MouseEventArgs e) { if (_Previous != null) { if (pictureBox1.Image == null) { Bitmap bmp = new Bitmap(pictureBox1.Width, pictureBox1.Height); using (Graphics g = Graphics.FromImage(bmp)) { g.Clear(Color.White); } pictureBox1.Image = bmp; } using (Graphics g = Graphics.FromImage(pictureBox1.Image)) { g.DrawLine(_Pen, _Previous.Value.X, _Previous.Value.Y, eX, eY); } pictureBox1.Invalidate(); _Previous = new Point(eX, eY); } } private void pictureBox1_MouseUp(object sender, MouseEventArgs e) { _Previous = null; } 

Answer 2

这里，pictureBox1 ==签名。 我以这种方式翻译成vb：

全球：

 Dim _previous As Point = Nothing Dim _pen As Pen = New Pen(Color.Black) Dim drawing As Boolean = False ''' 
 ''' This handles the signature drawing events (drawing) ''' 
 '''  '''  '''  Private Sub signature_MouseMove(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles signature.MouseMove If drawing = True Then If signature.Image Is Nothing Then Dim bmp As Bitmap = New Bitmap(signature.Width, signature.Height) Using g As Graphics = Graphics.FromImage(bmp) g.Clear(Color.White) End Using signature.Image = bmp End If Using g As Graphics = Graphics.FromImage(signature.Image) g.DrawLine(_pen, _previous.X, _previous.Y, eX, eY) End Using signature.Invalidate() _previous = New Point(eX, eY) End If End Sub ''' 
 ''' this indicates somebody is going to write a signature ''' 
 '''  '''  '''  Private Sub signature_MouseDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles signature.MouseDown _previous = New Point(eX, eY) drawing = True signature_MouseMove(sender, e) End Sub ''' 
 ''' the signature is done. ''' 
 '''  '''  '''  Private Sub signature_MouseUp(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles signature.MouseUp _previous = Nothing drawing = False End Sub 

Answer 3

您可以通过捕获图片框的mousemove事件然后从图片框中获取图片来实现。

图形g = pictureBox.CreateGraphics（）; 那么你可以使用这个图形对象绘制你想要绘制的任何东西