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[英]Getting correct coordinates from scaled picture box with Zoom SizeMode
[英]Draw Rectangle inside picture box SizeMode Zoom
我在 WindowsForms 项目中有一个图片框,其 SizeMode 为“缩放”。
我想在图像内绘制一个矩形并获取其相对于图像而不是图片框的坐标。
问题是矩形的坐标与在 Windows Paint Application 上选择的相同矩形不匹配。
这是使用的代码:
开始绘画:
/// <summary> /// Starts drawing. /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void pictureBox1_MouseDown(object sender, MouseEventArgs e) { backupImage = pictureBox1.Image; _once = true; RectStartPoint = e.Location; pictureBox1.Invalidate(); }
移动鼠标时:
/// <summary> /// While moving mouse event, paint rectangle /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void pictureBox1_MouseMove(object sender, MouseEventArgs e) { if (_once) //Only draw rectangle while drawing mode { Point tempEndPoint = e.Location; Rect.Location = new Point(Math.Min(RectStartPoint.X, tempEndPoint.X), Math.Min(RectStartPoint.Y, tempEndPoint.Y)); Rect = new Rectangle( Math.Min(tempEndPoint.X, Rect.Left), Math.Min(tempEndPoint.Y, Rect.Top), Math.Min(eX - RectStartPoint.X, pictureBox1.ClientRectangle.Width - RectStartPoint.X), Math.Min(eY - RectStartPoint.Y, pictureBox1.ClientRectangle.Height - RectStartPoint.Y)); pictureBox1.Refresh(); pictureBox1.CreateGraphics().DrawRectangle(cropPen, Rect); } }
2 单击时,完成绘制矩形:
/// <summary> /// When mouse click is released, write in texbox the rectangle's coordinates. /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void pictureBox1_MouseUp(object sender, MouseEventArgs e) { if (_once) { if (e.Button == System.Windows.Forms.MouseButtons.Left) { Point tempEndPoint = e.Location; _once = false; string sAux = string.Format("Left: {0}; Top: {1}; Width: {2}; Height: {3} \\r\\n", Math.Min(tempEndPoint.X, Rect.Left), Math.Min(tempEndPoint.Y, Rect.Top), Math.Min(eX - RectStartPoint.X, pictureBox1.ClientRectangle.Width - RectStartPoint.X), Math.Min(eY - RectStartPoint.Y, pictureBox1.ClientRectangle.Height - RectStartPoint.Y)); textBox1.Text += sAux; } } }
结果是:
正如您在两张图片中看到的,左、上、宽和高不匹配。
你能告诉我如何获得相同的结果吗?
这是一个帮助各种计算的函数:
void SetImageScale(PictureBox pbox, out RectangleF ImgArea, out float zoom)
{
SizeF sp = pbox.ClientSize;
SizeF si = pbox.Image.Size;
float rp = sp.Width / sp.Height; // calculate the ratios of
float ri = si.Width / si.Height; // pbox and image
if (rp > ri)
{
zoom = 1f * sp.Height / si.Height;
float width = si.Width * zoom;
float left = (sp.Width - width) / 2;
ImgArea = new RectangleF(left, 0, width, sp.Height);
}
else
{
zoom = 1f * sp.Width / si.Width;
float height = si.Height * zoom;
float top = (sp.Height - height) / 2;
ImgArea = new RectangleF(0, top, sp.Width, height);
}
}
给定一个根据鼠标坐标创建的Rectangle Rect
,您可以如何使用它:
float zoom = 1f;
RectangleF ImgArea = Rectangle.Empty;
SetImageScale(pictureBox1, out ImgArea, out zoom);
Point RLoc = Point.Round(new PointF( (Rect.X - ImgArea.X) / zoom,
(Rect.Y - ImgArea.Y) / zoom ));
Size RSz = Size.Round(new SizeF(Rect.Width / zoom, Rect.Height / zoom));
label1.Text = "Selection in mouse coordinates: " + Rect.ToString();
label2.Text = "Selection in image coordinates: " + new Rectangle(RLoc, RSz).ToString();
无论图像是横向还是纵向,或者哪个比例(如果有的话)更大,图像或图片框,这都应该有效。
请注意,在图像强烈缩放的情况下,很难进行像素完美选择。
该功能是在一个变种这个职位。
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