C# 实现图片为背景的不规则窗体

using System;

using System.Drawing;

using System.Drawing.Drawing2D;

using System.Windows.Forms;

namespace MYLOVE

{

    ///

    /// Summary description for BitmapRegion.

    ///

    public class BitmapRegion

    {

        public BitmapRegion()

        { }

        ///

        /// Create and apply the region on the supplied control

        /// 创建支持位图区域的控件（目前有button和form）

        ///

        /// The Control object to apply the region to控件

        /// The Bitmap object to create the region from位图

        public static void CreateControlRegion(Control control, Bitmap bitmap)

        {

            // Return if control and bitmap are null

            //判断是否存在控件和位图

            if (control == null || bitmap == null)

                return;

            // Set our control''s size to be the same as the bitmap

            //设置控件大小为位图大小

            control.Width = bitmap.Width;

            control.Height = bitmap.Height;

            // Check if we are dealing with Form here

            //当控件是form时

            if (control is System.Windows.Forms.Form)

            {

                // Cast to a Form object

                //强制转换为FORM

                Form form = (Form)control;

                // Set our form''s size to be a little larger that the bitmap just

                // in case the form''s border style is not set to none in the first place

                //当FORM的边界FormBorderStyle不为NONE时，应将FORM的大小设置成比位图大小稍大一点

                form.Width = control.Width;

                form.Height = control.Height;

                // No border

                //没有边界

                form.FormBorderStyle = FormBorderStyle.None;

                // Set bitmap as the background image

                //将位图设置成窗体背景图片

                form.BackgroundImage = bitmap;

                // Calculate the graphics path based on the bitmap supplied

                //计算位图中不透明部分的边界

                GraphicsPath graphicsPath = CalculateControlGraphicsPath(bitmap);

                // Apply new region

                //应用新的区域

                form.Region = new Region(graphicsPath);

            }

            // Check if we are dealing with Button here

            //当控件是button时

            else if (control is System.Windows.Forms.Button)

            {

                // Cast to a button object

                //强制转换为 button

                Button button = (Button)control;

                // Do not show button text

                //不显示button text

                button.Text = "";

                // Change cursor to hand when over button

                //改变 cursor的style

                button.Cursor = Cursors.Hand;

                // Set background image of button

                //设置button的背景图片

                button.BackgroundImage = bitmap;

                // Calculate the graphics path based on the bitmap supplied

                //计算位图中不透明部分的边界

                GraphicsPath graphicsPath = CalculateControlGraphicsPath(bitmap);

                // Apply new region

                //应用新的区域

                button.Region = new Region(graphicsPath);

            }

        }

        ///

        /// Calculate the graphics path that representing the figure in the bitmap

        /// excluding the transparent color which is the top left pixel.

        /// //计算位图中不透明部分的边界

        ///

        /// The Bitmap object to calculate our graphics path from

        /// Calculated graphics path

        private static GraphicsPath CalculateControlGraphicsPath(Bitmap bitmap)

        {

            // Create GraphicsPath for our bitmap calculation

            //创建 GraphicsPath

            GraphicsPath graphicsPath = new GraphicsPath();

            // Use the top left pixel as our transparent color

            //使用左上角的一点的颜色作为我们透明色

            Color colorTransparent = bitmap.GetPixel(0, 0);

            // This is to store the column value where an opaque pixel is first found.

            // This value will determine where we start scanning for trailing opaque pixels.

            //第一个找到点的X

            int colOpaquePixel = 0;

            // Go through all rows (Y axis)

            // 偏历所有行（Y方向）

            for (int row = 0; row < bitmap.Height; row++)

            {

                // Reset value

                //重设

                colOpaquePixel = 0;

                // Go through all columns (X axis)

                //偏历所有列（X方向）

                for (int col = 0; col < bitmap.Width; col++)

                {

                    // If this is an opaque pixel, mark it and search for anymore trailing behind

                    //如果是不需要透明处理的点则标记，然后继续偏历

                    if (bitmap.GetPixel(col, row) != colorTransparent)

                    {

                        // Opaque pixel found, mark current position

                        //记录当前

                        colOpaquePixel = col;

                        // Create another variable to set the current pixel position

                        //建立新变量来记录当前点

                        int colNext = col;

                        // Starting from current found opaque pixel, search for anymore opaque pixels

                        // trailing behind, until a transparent   pixel is found or minimum width is reached

                        ///从找到的不透明点开始，继续寻找不透明点,一直到找到或则达到图片宽度

                        for (colNext = colOpaquePixel; colNext < bitmap.Width; colNext++)

                            if (bitmap.GetPixel(colNext, row) == colorTransparent)

                                break;

                        // Form a rectangle for line of opaque   pixels found and add it to our graphics path

                        //将不透明点加到graphics path

                        graphicsPath.AddRectangle(new Rectangle(colOpaquePixel, row, colNext - colOpaquePixel, 1));

                        // No need to scan the line of opaque pixels just found

                        col = colNext;

                    }

                }

            }

            // Return calculated graphics path

            return graphicsPath;

        }

    }

}

调用方法：

//初始化调用不规则窗体生成代码

            BitmapRegion BitmapRegion = new BitmapRegion();//此为生成不规则窗体和控件的类

            BitmapRegion.CreateControlRegion(this, new Bitmap(Properties.Resources.Loveheart));