【发布时间】：2014-10-11 09:22:55
【问题描述】：
我目前在主窗体上有一个图像 (1280px,1024px)，用户可以单击一个选项在图像周围绘制一个框。当他们单击此选项时，会打开一个新表单，其中包含大小为 526,302 的图片框内的图像并填充图片框（我使用了缩放，但这会使图像无法填充框，使用 Stretch 会这样做但不会保持纵横比。
我想要的是，当用户开始制作方形框时，他们点击的地方将保持 1280,1024px 的比例，此刻，如果我点击图像的右下角，mouse.x 和 mouse .y 出现在 400,500 左右，而不是 1200、1000 左右的预期值。
谁能明白为什么会这样？
这是我的代码。
namespace Valo.CustomDraw
{
/// <summary>
/// Class which controls what happens when the user selected to create a custom view to focus on
/// with the camera. It creates a form which the user draws a rectabnge on. It's height, width and
/// starting mouse point are calcualted and sent the main window class to be processed appropriately.
/// </summary>
public partial class bitmap_Square : Form
{
#region instance variabls
public Point p1; //starting point of rectangle.
public Point p2; //ending point of rectangle.
MainForm mainApp; //reference to the MainForm which called this form.
Bitmap bmp; //bitmap of the camera imag (1280px, 1024px)
int [] rectDim = new int [2]; //dimentions of the rectangle (width, height).
#endregion
/// <summary>
/// Constuctor that starts the application.
/// It creates the form with bitmap image in and applies the mouse listeners
/// and pain functionality to the picture box as well as controlling the response
/// from the 'apply button'.
/// </summary>
public bitmap_Square(Bitmap b, MainForm ma)
{
//initialses the form object.
InitializeComponent();
//assigns the passed in MainForm paramater to the local instance.
mainApp = ma;
DoubleBuffered = true;
//assigns the passed in bitmap from the MainForm to a local instance.
this.bmp = b;
MessageBox.Show("" + bmp.Width);
MessageBox.Show("" + bmp.Height);
//pb_bitmapImage.Image = scaledBMP;
pb_bitmapImage.Image = bmp;
pb_bitmapImage.SizeMode = PictureBoxSizeMode.Zoom;
//invalidates the picture box so it can be drawn on.
pb_bitmapImage.Invalidate();
MessageBox.Show("" + bmp.Width);
MessageBox.Show("" + bmp.Height);
//adding the MouseEventHandler and PaintEventHandler.
pb_bitmapImage.Paint += new System.Windows.Forms.PaintEventHandler(this.Bitmap_Square_Paint);
pb_bitmapImage.MouseDown += new System.Windows.Forms.MouseEventHandler(this.Bitmap_Square_MouseDown);
pb_bitmapImage.MouseMove += new System.Windows.Forms.MouseEventHandler(this.Bitmap_Square_MouseMove);
pb_bitmapImage.MouseUp += new System.Windows.Forms.MouseEventHandler(this.Bitmap_Square_MouseUp);
}
/// <summary>
/// Mouse_Down event handler which deals with what happens when the mouse is pressed down
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void Bitmap_Square_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == System.Windows.Forms.MouseButtons.Left)
p1 = e.Location;
}
/// <summary>
/// Mouse_Down event handler which deals with what happens when the mouse is moved
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void Bitmap_Square_MouseMove(object sender, MouseEventArgs e)
{
if (e.Button == System.Windows.Forms.MouseButtons.Left)
{
p2 = e.Location;
pb_bitmapImage.Invalidate();
}
}
/// <summary>
/// Mouse_Down event handler which deals with what happens when the mouse is released
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void Bitmap_Square_MouseUp(object sender, MouseEventArgs e)
{
if (e.Button == System.Windows.Forms.MouseButtons.Left)
{
p2 = e.Location;
pb_bitmapImage.Invalidate();
}
}
/// <summary>
/// Manages the paint method when the mouse is moved and ensures the lines are drawn
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void Bitmap_Square_Paint(object sender, PaintEventArgs e)
{
Graphics g = e.Graphics;
//calcuates what lines to draw when tou move your mouse accross the screen and
//draws them onto the bitmap inside the picture box.
if (p1.X > 0 && p1.Y > 0 && p2.X > 0 && p2.Y > 0)
g.DrawRectangle(Pens.Red, new Rectangle(p1.X, p1.Y, p2.X - p1.X, p2.Y - p1.Y));
}
/// <summary>
/// When pressed, it then calls the method from the MainForm which sets the Custom View and changes
/// labels etc in on the main form to refect this as well as the calculation to focus the camera.
/// It works out the width and heigh before calling this method as these values are part of the
/// parameter list.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btn_rectApply_Click(object sender, EventArgs e)
{
//Rectangle Height
rectDim[0] = (p2.X - p1.X);
//Rectangle Width
rectDim[1] = (p2.Y - p1.Y);
MessageBox.Show("" + p1.X);
MessageBox.Show("" + p1.Y);
MessageBox.Show("" + p2.X);
MessageBox.Show("" + p2.Y);
MessageBox.Show("" + rectDim[0]);
MessageBox.Show("" + rectDim[1]);
//method call from the MainForm to initiate the changes to the Form to reflect the newly
//selected area.);
mainApp.ApplyScreenSelection("Current View: Custom", p1.X, p1.Y, rectDim[0], rectDim[1]);
this.Close();
}
}
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标签： c# forms graphics aspect-ratio