加载的图片编辑

Question

我应该从一个文件中加载一个图像，这个图像应该覆盖pictureBox的80%，然后在上面绘制一些东西…使用加载没有问题，但是尝试在上面绘制任何内容都会导致错误，该错误具有不正确的参数(g.FillRectangle...)。

我在堆栈上找到了刷新pictureBox的建议，但它什么也改变不了……

我不知道该怎么解决这个问题。

private void button1_Click_1(object sender, EventArgs e)
{
    pictureBox1.Width = (int)(Width * 0.80);
    pictureBox1.Height = (int)(Height * 0.80);

    // open file dialog 
    OpenFileDialog open = new OpenFileDialog();
    // image filters
    open.Filter = "Image Files(*.jpg; *.jpeg; *.gif; *.bmp)|*.jpg; *.jpeg; *.gif; *.bmp";
    if (open.ShowDialog() == DialogResult.OK)
    {
        // display image in picture box
        pictureBox1.Image = new Bitmap(open.FileName);
        // image file path
        //  textBox1.Text = open.FileName;
        g.FillRectangle(Brushes.Red, 0, 0, 20, 50);
        pictureBox1.Refresh();
    }
}

Answer 1

使用Graphics.FromImage或Control.CreateGraphics方法在图像上绘制：

var img = new Bitmap(open.FileName);
using (Graphics g = Graphics.FromImage(img))
{
    g.FillRectangle(Brushes.Red, 0, 0, 20, 50);  
}
pictureBox1.Image = img;

或者通过Paint事件直接在PictureBox上绘制(例如使用Anonymous Methods)：

pictureBox1.Paint += (s, e) => e.Graphics.FillRectangle(Brushes.Red, 0, 0, 20, 50);

Answer 2

下面的代码对我来说工作得很好...你能试一下同样的吗？

private void button1_Click(object sender, EventArgs e)
        {
            pictureBox1.Width = (int)(Width * 0.80);
            pictureBox1.Height = (int)(Height * 0.80);


            // open file dialog 
            OpenFileDialog open = new OpenFileDialog();

            // image filters
            open.Filter = "Image Files(*.jpg; *.jpeg; *.gif; *.bmp)|*.jpg; *.jpeg; *.gif; *.bmp";
            if (open.ShowDialog() == DialogResult.OK)
            {
                // display image in picture box
                pictureBox1.Image = new Bitmap(open.FileName);
                // image file path
                //  textBox1.Text = open.FileName;
                Graphics g = Graphics.FromImage(pictureBox1.Image);
                g.FillRectangle(Brushes.Red, 0, 0, 20, 50);
                pictureBox1.Refresh();
            }
        }