[英]How to move a certain part of a picture box using Visual Studio c#
[英]How do I properly select a certain part of an image inside a picture box in C# and highlight it?
我一直在尝试编写一个程序,以便能够在窗体上加载图像并选择一个矩形,然后将该矩形加载到另一个图片框(pictureBox2)上,并且我还想突出显示我拥有的内容当我移动鼠标时,在原始图片上的pictureBox1中选择。
到目前为止,我已经有了这段代码,但是它无法正确响应mouseMove事件,没有正确选择我突出显示的矩形。 问题是什么?
public partial class Form1 : Form
{
Bitmap original;
bool isSelecting;
int x0, y0, x1, y1;
public Form1()
{
InitializeComponent();
pictureBox1.MouseDown += new MouseEventHandler(picOriginal_MouseDown);
pictureBox1.MouseMove += new MouseEventHandler(picOriginal_MouseMove);
pictureBox1.MouseUp += new MouseEventHandler(picOriginal_MouseUp);
}
#region helpder methods
// Start selecting the rectangle.
private void picOriginal_MouseDown(object sender, MouseEventArgs e)
{
if(original != null)
{
isSelecting = true;
// Save the start point.
x0 = e.X;
y0 = e.Y;
}
}
// Continue selecting.
private void picOriginal_MouseMove(object sender, MouseEventArgs e)
{
if(original != null)
{
// Do nothing it we're not selecting an area.
if(!isSelecting) return;
// Save the new point.
x1 = e.X;
y1 = e.Y;
// Make a Bitmap to display the selection rectangle.
Bitmap bm = new Bitmap(original);
// Draw the rectangle.
using(Graphics gr = Graphics.FromImage(bm))
{
gr.DrawRectangle(Pens.Red,
Math.Min(x0, x1), Math.Min(y0, y1),
Math.Abs(x0 - x1), Math.Abs(y0 - y1)
);
}
// Display the temporary bitmap.
pictureBox1.Image = new Bitmap(bm, new Size(pictureBox1.Width, pictureBox1.Height));
}
}
// Finish selecting the area.
private void picOriginal_MouseUp(object sender, MouseEventArgs e)
{
if(original != null)
{
// Do nothing it we're not selecting an area.
if(!isSelecting) return;
isSelecting = false;
// Display the original image.
pictureBox1.Image = original;
// Copy the selected part of the image.
int wid = Math.Abs(x0 - x1);
int hgt = Math.Abs(y0 - y1);
if((wid < 1) || (hgt < 1)) return;
Bitmap area = new Bitmap(wid, hgt);
using(Graphics gr = Graphics.FromImage(area))
{
Rectangle source_rectangle =
new Rectangle(Math.Min(x0, x1), Math.Min(y0, y1),
wid, hgt);
Rectangle dest_rectangle =
new Rectangle(0, 0, wid, hgt);
gr.DrawImage(original, dest_rectangle,
source_rectangle, GraphicsUnit.Pixel);
}
// Display the result.
pictureBox2.Image = area;
}
}
#endregion
private void button1_Click(object sender, EventArgs e)
{
if(original != null)
{
}
}
private void button2_Click(object sender, EventArgs e)
{
OpenFileDialog dialog = new OpenFileDialog();
dialog.Filter = "jpg files (*.jpg)|*.jpg|All files(*.*)|*.*";
if(dialog.ShowDialog() == DialogResult.OK)
{
original = new Bitmap(dialog.FileName);
pictureBox1.Image = new Bitmap(original, new Size(pictureBox1.Width, pictureBox1.Height));
}
dialog.Dispose();
}
}
我认为您的问题是“原始”图像尺寸与图片框尺寸不同。 尝试使用以下代码来补偿“原始”图像和图片框尺寸之间的缩放比例:
// Draw the rectangle.
float zoomX = (float)original.Size.Width / pictureBox1.Width;
float zoomY = (float)original.Size.Height / pictureBox1.Height;
using (Graphics gr = Graphics.FromImage(bm))
{
gr.DrawRectangle(Pens.Red,
Math.Min(x0, x1) * zoomX, Math.Min(y0, y1) * zoomY,
Math.Abs(x0 - x1) * zoomX, Math.Abs(y0 - y1) * zoomY
);
}
在我的情况下,这可以修复红色矩形。 但是picturebox2中复制的部分仍然不正确...
这会将副本固定到第二个图片框:
// Copy the selected part of the image.
float zoomX = (float)original.Size.Width / pictureBox1.Width;
float zoomY = (float)original.Size.Height / pictureBox1.Height;
int wid = (int)(zoomX * Math.Abs(x0 - x1));
int hgt = (int)(zoomY * Math.Abs(y0 - y1));
if ((wid < 1) || (hgt < 1)) return;
Bitmap area = new Bitmap(wid, hgt);
using (Graphics gr = Graphics.FromImage(area))
{
Rectangle source_rectangle =
new Rectangle((int)(zoomX * Math.Min(x0, x1)), (int)(zoomY * Math.Min(y0, y1)),
wid, hgt);
Rectangle dest_rectangle =
new Rectangle(0, 0, wid, hgt);
gr.DrawImage(original, dest_rectangle,
source_rectangle, GraphicsUnit.Pixel);
}
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