将所有绘制的对象保存到位图中

找到解决方法,这将在我的pictureBox/Canvas中保存图形。

private void button2_Click(object sender, EventArgs e)
    {
        SaveFileDialog save = new SaveFileDialog();

            //Creates a filter fir saving the Project File
            save.Filter = "Image Files(*.jpg; *.jpeg; *.gif; *.bmp); *.PNG|*.jpg; *.jpeg; *.gif; *.bmp; *.PNG";     
            save.DefaultExt = ".bmp";
            save.AddExtension = true;

            if (save.ShowDialog() == DialogResult.OK)
            {
                using (var bmp = new Bitmap(pictureBox_Canvass.Width, pictureBox_Canvass.Height))
                {
                    pictureBox_Canvass.DrawToBitmap(bmp, new Rectangle(0, 0, bmp.Width, bmp.Height));
                    bmp.Save(save.FileName);
                }
            }
    }

Graphics 是一个 "device context" 对象它将图形处理到计算机上 Bitmap ,但无法将其转换回 位图 .

然而,你可以复制已经画在你的窗户上的部分,然后画在你的窗户上 绘图

protected override void OnMouseClick(MouseEventArgs e)
{
    base.OnMouseClick(e);

    //get the screen coordinates for this window
    var rect = this.RectangleToScreen(this.ClientRectangle);

    //copy bits from screen to bitmap
    using (var bmp = new Bitmap(rect.Width, rect.Height))
    {
        var gr = Graphics.FromImage(bmp);
        gr.CopyFromScreen(rect.Left, rect.Top, 0, 0, rect.Size);

        //save to file
        bmp.Save(@"c:\test\test.bmp");
    }
}

或者,您可以在响应Windows消息绘制后立即执行此操作,但您必须调用 Graphics::Flush 当您完成绘制时,让Windows知道。此方法假定目标窗口可见。命令之间可能存在延迟,或者部分窗口不可见,并且无法获得所需的输出。

在另一个答案中建议了一个更好的解决方案:创建一个内存位图并利用它。

public void do_all_paintings(Graphics gr)
{
    //paint something random, add all other drawings
    gr.Clear(Color.Red);
}

现在绘制以响应Windows绘制请求:

protected override void OnPaint(PaintEventArgs e)
{
    base.OnPaint(e);
    do_all_paintings(e.Graphics);
}

使用相同的 do_all_paintings 函数创建文件以响应命令:

protected override void OnMouseClick(MouseEventArgs e)
{
    base.OnMouseClick(e);

    var rect = this.RectangleToScreen(this.ClientRectangle);
    using (var bmp = new Bitmap(rect.Width, rect.Height))
    {
        do_all_paintings(Graphics.FromImage(bmp));
        bmp.Save(@"c:\test\test.bmp");
    }
}