drawellipse

问题 I am trying to plot rings of trees and calculate their areas. However, I have noticed that in reality not all rings have symmetric radii like a circle. I have data measurements of 4 radii, and I would like to plot rings (or any similar shape) following each point of every radio like this example (this figure was done manually with vectors in PowerPoint): the problem is that in R I found only the possibility to plot these rings with the circles option from the symbols() function, and I got

问题 I am trying to draw some ellipse in a picturebox that contains a PNG on a formload in c#. When I execute the code down below, I see my ellipses for half of a second, then I don't see them no more. When I click on my picturebox, I am able to draw an ellipse however, when I minimize the form, they don't appear no more. I've read that you shouldn't put your drawing code in the formload but rather in the OnPaint method, which is what I did. I don't know what to try anymore. thank you. (Be aware

问题 I want to draw a circle with DrawEllipse on a specified Bitmap , with the same size of the Bitmap, but the result is that the circle appears clipped at the edges. Why this problem? Bitmap layer = new Bitmap(80, 80); using (Graphics g = Graphics.FromImage(layer)) { using (Pen p = new Pen(Color.Black, 4)) { g.DrawEllipse(p, new Rectangle(0, 0, layer.Width, layer.Height)); } } pictureBox3.Size = new Size(100, 100); pictureBox3.Image = layer; 回答1: By default a Pen has a PenAlignment.Center. This

问题 As suggested by @TaW on this previous question, I setted PenAlignment.Inset to draw the circle inside the Bitmap, but this caused another problem. I want to draw a circle on a specified Bitmap with antialiasing. SmoothingMode.AntiAlias The problem is that, when I use PenAlignment.Inset , the antialiasing doesn't work correctly! Instead, with PenAlignment.Center , it works correctly... Any suggestion to resolve this problem? Bitmap layer = new Bitmap(80, 80); using (Graphics g = Graphics