/// <returns>Calculated graphics path</returns>
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