GDI+常用操作、入门解析

以下这些是常用的基本操作，属于比较基础的入门知识，如果要往深了学这些仅仅是皮毛。希望对初学、和入门者有些帮助，同时也算是自我学习的一个总结。

先上个图：主界面：



第一：绘制带箭头线段

Pen p;
Graphics g1;
//绘制带箭头的直线
private void button1_Click(object sender, EventArgs e)
{
g1 = this.CreateGraphics();
g1.Clear(Color.White);
p = new Pen(Color.YellowGreen, 8);
p.StartCap = LineCap.Round;
p.EndCap = LineCap.ArrowAnchor;
g1.DrawLine(p, 150, 150, 500, 200);

}

效果图：



第二：绘制艺术框

/// <summary>
/// 绘制艺术相框，主用用到了阴影画刷HatchBrush
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button2_Click(object sender, EventArgs e)
{
g1 = this.CreateGraphics();
g1.Clear(Color.White);
g1.FillRectangle(Brushes.LightBlue, this.ClientRectangle);//画板颜色
HatchBrush hb = new HatchBrush(HatchStyle.WideDownwardDiagonal, Color.White, Color.Black);
p = new Pen(hb, 10);
g1.DrawRectangle(p, 300, 30, 80, 80);
}

效果图：



第三：绘制特殊艺术图像

/// <summary> /// 绘制特殊的渐变图形，主要用到GraphicsPath类的AddLines()方法 /// PathGradientBrush路径渐变画刷，PathGradientBrush的CenterColor属性 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void button3_Click(object sender, EventArgs e) { g1 = this.CreateGraphics(); g1.Clear(Color.White); Point[] points ={ new Point(175,0),new Point(200,150), new Point(250,0),new Point(200,175), new Point(250,250),new Point(165,200), new Point(0,250),new Point(135,175), new Point(0,150),new Point(150,150), new Point(175,0) }; GraphicsPath gPath = new GraphicsPath();//创建路径 gPath.AddLines(points); //在路径中添加直线 PathGradientBrush pGradientBrush = new PathGradientBrush(gPath);//路径渐变画刷 pGradientBrush.CenterColor = Color.Red;//设置中心点色彩 Color[] colors = new Color[] { Color.Aqua,Color.Green, Color.Blue,Color.White, Color.Beige,Color.Green, Color.Blue,Color.White, Color.Black,Color.Green }; pGradientBrush.SurroundColors = colors;//设置路径渐变画刷边缘色 g1.FillPath(pGradientBrush, gPath); //填充路径

}

效果图：



　　

第四：绘制渐变图行

/// <summary>
/// 绘制渐变图形主要使用渐变画刷LinearGradientBrush类
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button4_Click(object sender, EventArgs e)
{
g1 = this.CreateGraphics();
g1.Clear(Color.White);
p = new Pen(Color.YellowGreen, 2);
//LinearGradientBrush渐变画刷，可以实现简单线性渐变效果
LinearGradientBrush linGrBrush1 = new LinearGradientBrush(new Rectangle(0, 0, 80, 40), Color.Red, Color.Yellow, 30.0f);
g1.FillRectangle(linGrBrush1, new Rectangle(150, 20, 120, 120)); //填充指定矩形内部
g1.DrawRectangle(p, new Rectangle(150, 20, 120, 120));
}

效果图：

第五：绘制数学曲线


/// <summary>
/// 绘制数学曲线Graphic.DrawBezier()数学曲线
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button5_Click(object sender, EventArgs e)
{
g1 = this.CreateGraphics();
g1.Clear(Color.White);
p = new Pen(Color.Black, 2);
//绘制曲线
g1.DrawBezier(p, new Point(20, 30), new Point(60, 0), new Point(200, 180), new Point(300, 200));

}

效果图：



第六：图形缩放：

/// <summary>
/// 缩放图形 Graphics.ScaleTransform()缩放
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button6_Click(object sender, EventArgs e)
{
Bitmap bmp1 = new Bitmap(pictureBox1.Image); //创建图形对象
Bitmap bmp2 = new Bitmap(pictureBox1.Image);
g1 = pictureBox2.CreateGraphics(); //创建画板
g1.Clear(pictureBox2.BackColor); //清空画板
float s = Convert.ToSingle(0.5); //缩放倍数
g1.ScaleTransform(s, s); //缩放 ，图形缩放方法
//重绘图形
g1.DrawImage(bmp1, this.pictureBox2.ClientRectangle, 0, 0, bmp2.Width, bmp2.Height, GraphicsUnit.Pixel);
}

效果图：



第七：图形旋转

/// <summary>
/// 图形的旋转Graphics.RotateTransform()函数
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button7_Click(object sender, EventArgs e)
{
Bitmap bmp1 = new Bitmap(pictureBox1.Image);
Bitmap bmp2 = new Bitmap(pictureBox1.Image);
g1 = pictureBox2.CreateGraphics();
g1.Clear(pictureBox2.BackColor);
g1.RotateTransform(30); //旋转，使图形按照一定角度旋转
g1.DrawImage(bmp1, this.pictureBox2.ClientRectangle, 0, 0, bmp2.Width, bmp2.Height, GraphicsUnit.Pixel);
}

效果图：



第八：图形移动

/// <summary>
/// 图形平移
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button8_Click(object sender, EventArgs e)
{
Bitmap bmp1 = new Bitmap(pictureBox1.Image);
Bitmap bmp2 = new Bitmap(pictureBox1.Image);
g1 = pictureBox2.CreateGraphics();
g1.Clear(pictureBox2.BackColor);
float sx = Convert.ToSingle(20);
float sy = Convert.ToSingle(20);
g1.TranslateTransform(sx, sy);
g1.DrawImage(bmp1, this.pictureBox2.ClientRectangle, 0, 0, bmp2.Width, bmp2.Height, GraphicsUnit.Pixel);
}

效果图：



第九：图形动画
/// 通过绘制线条，绘制动画
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button9_Click(object sender, EventArgs e)
{
g1 = pictureBox2.CreateGraphics();
g1.Clear(pictureBox2.BackColor);
Pen p1 = new Pen(Color.Blue);
p = new Pen(Color.Red);
int y = 256;
for (int x = 0; x < 256; x += 5)
{
g1.DrawLine(p1, 0, y, x, 0);
g1.DrawLine(p, 256, x, y, 256);
y -= 5;
Thread.Sleep(20); //线程延迟20毫秒
}
for(y=0;y<256;y+=5)
{
Pen p2=new Pen (Color.FromArgb(y,Color.Yellow));
g1.DrawLine(p2,0,y,256,y);
Thread.Sleep(20);
}

效果图：

第十：图像缩放


/// <summary>
/// 图像放缩
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button10_Click(object sender, EventArgs e)
{
g1 = pictureBox2.CreateGraphics();

g1.DrawImage(pictureBox1.Image, 80, 30, 150, 150); //通过绘图方法实现图片的放缩
}

效果图：



第十一：图像旋转

/// <summary>
/// 图像旋转Bitmap.RotateFlip()图像旋转方法
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button11_Click(object sender, EventArgs e)
{
Bitmap bmp = new Bitmap(pictureBox1.Image);
bmp.RotateFlip(RotateFlipType.RotateNoneFlipX);//旋转,图像本身的旋转
pictureBox2.Image=bmp;
}

效果图：