Question

在C#的Graphic绘图，坐标问题

如果我想改变坐标度量单位，改为厘米，而不是像素点，再进行画直线或者圆之类的，那么该这样改变写坐标变换代码，比如Graphics g = CreateGraphics();
g.DrawLine(new Pen(Color.Black,02),0,0,5,5);如果不改变的话，基本看不到画出的线

Answer 1

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace testGDIScale
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            Graphics g = pictureBox1.CreateGraphics();
            //画出来后用尺子量，1cm
            g.DrawRectangle(new Pen(Brushes.Red), Xmm2pixels(g, 0), Ymm2pixels(g, 0), Xmm2pixels(g, 10), Ymm2pixels(g, 10));
        }
        public float Xmm2pixels(Graphics g, float mmx)
        {
            double r;
            r = mmx / 25.4 * g.DpiX;
            return (float)r;
        }
        public float Ymm2pixels(Graphics g, float mmy)
        {
            double r;
            r = mmy / 25.4 * g.DpiY;
            return (float)r;
        }
    }
}

Answer 2

可以通过Graphics类的PageUnit属性，改变坐标的单位