《.net开发技术》之 实验7：GDI+编程

【实验目的】

1．理解Graphics对象概念，并熟悉Graphics对象的创建方法。

2．掌握利用Graphics对象绘制线条和形状方法。

3．掌握利用Graphics对象的DrawString()呈现文本方法。

4．掌握利用Graphics对象DrawImage()显示图像方法。

【实验内容】

1、编写一个Windows应用程序，实现窗体自上而下，由白色到绿色渐变的背景。

代码：

using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;

namespace shiyan7
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            this.Text = "渐变的背景";
        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            Graphics g = e.Graphics;
            LinearGradientBrush brush = new LinearGradientBrush(this.ClientRectangle, Color.White, Color.Green, LinearGradientMode.Vertical);
            g.FillRectangle(brush, this.ClientRectangle);
            g.Dispose();
        }
    }
}

2、编写一个Windows应用程序。当窗体加载后，呈现一个半径为100像素的蓝色圆。该圆在窗体范围内左右移动，并在圆内显示圆心相对于窗体的坐标。

 

代码：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace shiyan7
{
    public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();
            this.Text = "移动圆";
        }

        private void Form2_Paint(object sender, PaintEventArgs e)
        {

            Graphics graphics = e.Graphics;
            Pen pen = new Pen(Color.Gray, 1);
            Point point = new Point(160, 110);
            int r = 100;
            Random rd = new Random();
            int X = rd.Next(0, this.ClientSize.Width - 2 * r);
            graphics.DrawEllipse(pen, X, point.Y - r, 2 * r, 2 * r);//画圆,矩形左上角坐标决定矩形位置
            SolidBrush sb = new SolidBrush(Color.Blue);
            graphics.FillEllipse(sb, X, point.Y - r, 2 * r, 2 * r);
            label1.Location = new Point(X + r, point.Y);
            label1.Text = "X=" + (X) + ",Y=" + (point.Y-r);
        }
        private void Form2_Load(object sender, EventArgs e)
        {
            label1.BackColor = Color.Blue;
            label1.ForeColor = Color.Yellow;
        }
    }
}

 

3．编写一个Windows应用程序。利用Graphics对象的DrawString方法在窗体上绘制文字“烟台大学”，要求文字用一幅图片填充。给出图片名称p1.jpg，大家也可以自行寻找其它图片。

代码：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace shiyan7
{
    public partial class Form3 : Form
    {
        public Form3()
        {
            InitializeComponent();
            this.Text = "绘制文字";
        }

        private void Form3_Paint(object sender, PaintEventArgs e)
        {
            Graphics graphics = e.Graphics;
            Image image = Image.FromFile(Application.StartupPath + @"\p1.jpg");
            TextureBrush textureBrush = new TextureBrush(image);
            Font font = new Font("黑体", 100, FontStyle.Underline ^ FontStyle.Bold);
            graphics.DrawString("烟台大学", font, textureBrush, new Point(10, 10));
            graphics.Dispose();
        }
    }
}

 

 

4．画线实验。创建一个窗体，在窗体上添加一个按钮（按钮标题为“选择画笔颜色”）。窗体界面如下图所示。单击“选择画笔颜色”按钮，能够打开一个颜色对话框，选择颜色，进而更改画笔颜色。使用画笔可以在窗体上画任意的曲线。

代码：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace shiyan7
{
    public partial class Form4 : Form
    {
        Pen pen = new Pen(Color.White);
        Graphics graphics;
        Point x, y;
        public Form4()
        {
            InitializeComponent();
            this.Text = "手绘曲线";
        }

        private void button1_Click(object sender, EventArgs e)
        {
            ColorDialog colorDialog = new ColorDialog();
            colorDialog.ShowDialog();
            pen.Color = colorDialog.Color;
        }

        private void Form4_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
                y = e.Location;
        }

        private void Form4_MouseMove(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                x = y;
                y = e.Location;
                graphics.DrawLine(pen, x,y);
            }
        }

        private void Form4_Paint(object sender, PaintEventArgs e)
        {
            graphics = this.CreateGraphics();
        }

        private void Form4_Load(object sender, EventArgs e)
        {
            this.button1.Text = "选择画笔颜色";
        }

    }
}