缩放Picturebox根本不会更改图像 [英] Scaling Picturebox does not change image at all

问题描述

我正在使用图片框创建我的truss类实例的视觉效果.我通过在paint事件中直接绘制到图片框上来创建视觉效果.方法看起来像这样

I'm using a picturebox to create a visual of an instance of my truss class. I'm creating the visual by drawing directly onto the picture box in the paint event. The method looks like this

private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
    if (isDraw)
    {
        //Preparing to draw
        Graphics g = e.Graphics;
        g.SmoothingMode = SmoothingMode.AntiAlias;
        g.InterpolationMode = InterpolationMode.Bicubic;
        RunEntry entry = this.passedHistory.SelectedItem as RunEntry;
        AnsFile objToDraw = entry.FileRead;
        Pen pen = new Pen(Color.Black);

        //Getting size of bitmap
        int maxWidth = 0, maxHeight = 0;
        foreach (AnsJoint joint in objToDraw.AnsJoints)
        {
            if (joint.Location.X.Length > maxWidth)
            {
                maxWidth = (int)joint.Location.X.Length;
            }
            if (joint.Location.Y.Length > maxHeight)
            {
                maxHeight = (int)joint.Location.Y.Length;
            }
        }

        //Drawing joints
        foreach (AnsJoint joint in objToDraw.AnsJoints)
        {
            PointF jointPoint = this.ToCartesian(new PointF((float)joint.Location.X.Length - 4f, (float)joint.Location.Y.Length + 10f), maxHeight);
            e.Graphics.DrawString(joint.JointID.ToString(), new Font(FontFamily.GenericMonospace, 6f, FontStyle.Regular, GraphicsUnit.Point, 1, false), Brushes.Black, jointPoint);
        }

        //Draw the panels and links
        foreach (AnsMember member in objToDraw.AnsMembers)
        {
            List<AnsPanel> panels = member.Panels; //Drawing the panels

            foreach (AnsPanel pan in panels)
            {
                pen.Color = Color.Red;
                PointF p1 = this.ToCartesian(new PointF((float)pan.I.Location.X.Length, (float)pan.I.Location.Y.Length), maxHeight);
                PointF p2 = this.ToCartesian(new PointF((float)pan.J.Location.X.Length, (float)pan.J.Location.Y.Length), maxHeight);

                g.DrawEllipse(pen, p1.X - 2.5f, p1.Y - 2.5f, 5, 5);
                g.DrawEllipse(pen, p2.X - 2.5f, p2.Y - 2.5f, 5, 5);

                g.DrawEllipse(pen, p1.X - 3, p1.Y - 3.3f, 5, 5);
                g.DrawEllipse(pen, p2.X - 3, p2.Y - 3.3f, 5, 5);
                pen.Color = Color.Black;
                g.DrawLine(pen, p1, p2);
            }
            List<AnsLink> links = member.Links; //Drawing the links
            foreach (AnsLink link in links)
            {
                PointF p1 = this.ToCartesian(new PointF((float)link.I.Location.X.Length, (float)link.I.Location.Y.Length), maxHeight);
                PointF p2 = this.ToCartesian(new PointF((float)link.J.Location.X.Length, (float)link.J.Location.Y.Length), maxHeight);
                g.FillEllipse(Brushes.Green, p1.X - 1.5f, p1.Y - 1.5f, 3, 3);
                g.FillEllipse(Brushes.Green, p2.X - 1.5f, p2.Y - 1.5f, 3, 3);
                g.DrawLine(pen, p1, p2);
            }
        }
        g.ScaleTransform(.5f, .5f);
        pictureBox1.Tag = entry.FileName;
    }
}

产生我期望的结果

，除了我希望桁架图像能够缩放以更多地填充图片框.我将ScaleTransform调用添加到paint事件方法的末尾，但这似乎没有任何影响，因为无论调用与否，图片的大小都是相同的.如何将我在画框上绘制的内容缩放为画框的大小?

except that I want the truss image to scale to fill the picturebox more. I added the ScaleTransform call to the end of the paint event method but that doesn't seem to have any impact as the picture is the same size with or without the call. How can I scale what I draw on the picturebox to the size of the picturebox?

推荐答案

在绘制图形之前，请先调用ScaleTransform.您可以像这样计算所需的比例因子:

Call ScaleTransform before you do your drawing. You can calculate the desired scale factor like this:

// place this code after the calculation of maxWidth and maxHeight
// but before the drawing code
PictureBox p = (PictureBox)sender;
float scaleFactor = Math.Min(
    ((float)p.Width) / maxWidth,
    ((float)p.Height) / maxHeight
);

g.ScaleTransform(scaleFactor, scaleFactor);

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