c# 图像放大或缩小定位问题

ImageLayout属性成员Stretch和Zoom各有其优缺点
Stretch: 画像根据控件的尺寸伸缩表示
Zoom: 画像根据控件的尺寸伸缩表示。但和StretchImage不同，持有画像尺寸比率。表示位置在控件的中央
存在的问题:
          现在控件的尺寸已经固定了,如果使用Stretch,那么图片座标定位非常不精确,
    比如一幅800*600图片,压缩至300*200,如果只是通过比例来定位的话,基本上对应不上原图的点座标,
    误差不是一般的大
          如果使用Zoom,虽然定位很精确,但是由于控件的固定,使得有部分是空白,所以不能使用zoom
提出的问题:使用Stretch,能否精准定位座标(自己尝试了,不行)

 

这里参考了:http://topic.csdn.net/t/20060504/12/4729916.html

                http://tianyawulei.blog.163.com/blog/static/318855802007111605251660/

通过修改后,可以准确的对放大后的图片进行定位private void TestImgZoom() { string filePath = "F://vs2005//新建文件夹//0007//"; switch (this.cmbType.Text) { case "BMP": filePath += "L0002.bmp"; break; case "JPG": filePath += "test.jpg"; break; case "GIF": filePath += "test.gif"; break; } try { Image img = Image.FromFile(filePath); int destWidth = 0; int destHeight = 0; destWidth = pictureBox1.Width; destHeight = pictureBox1.Height; } System.Drawing.Imaging.ImageFormat format = img.RawFormat; Bitmap bmp = new Bitmap(destWidth, destHeight, img.PixelFormat); Graphics g = Graphics.FromImage(bmp); g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality; g.DrawImage(img, new Rectangle(0, 0, destWidth, destHeight), 0, 0, img.Width, img.Height, GraphicsUnit.Pixel); this.pictureBox1.Image = bmp; System.Drawing.ImageConverter imgConvert = new ImageConverter(); //申请位图对象 System.Drawing.Image MyImage = this.pictureBox1.Image; //申请画图对象 System.Drawing.Graphics h = System.Drawing.Graphics.FromImage(MyImage); //描一个点 //------------------1------------------- int posX1 = 18; int posY1 = 548; int uriPicWidth = 800; int uriPicHeight = 600; int width = this.pictureBox1.Width; int height = this.pictureBox1.Height; //int x1 = posX1 * width / uriPicWidth;// 800; int x1 = uriPicWidth-posX1 * width / uriPicWidth; int y1 = posY1 * height / uriPicHeight;// 600; int add = 12; Point p11 = new Point(x1 - add, y1); Point p21 = new Point(x1 + add, y1); Point p31 = new Point(x1, y1 - add); Point p41 = new Point(x1, y1 + add); h.DrawLine(new Pen(Color.Blue), p11, p21); h.DrawLine(new Pen(Color.Blue), p31, p41); //------------------1------------------- catch (Exception ex) { MessageBox.Show(ex.ToString()); } } private void button1_Click(object sender, EventArgs e) { TestImgZoom(); }

 

附加: C# pictureBox放大缩小功能代码

http://topic.csdn.net/u/20091023/08/d67935f1-9546-4bf5-8393-1c4b15b1a708.html

//对图片进行放大缩小操作 private void pictureBox1_MouseDown(object sender, MouseEventArgs e) { //string width = pictureBox1.Width.ToString(); if (e.Button == MouseButtons.Left) { if (pictureBox1.Width < 1360) { pictureBox1.Width = Convert.ToInt32(pictureBox1.Width * 1.2); pictureBox1.Height = Convert.ToInt32(pictureBox1.Height * 1.2); } } if (e.Button == MouseButtons.Right) { if (pictureBox1.Width > 635) { pictureBox1.Width = Convert.ToInt32(pictureBox1.Width / 1.2); pictureBox1.Height = Convert.ToInt32(pictureBox1.Height / 1.2); } } }