private System.Drawing.Region BuildRegionFromBitmap(BitmapSource bitmap, Point offset)
{
var region = new System.Drawing.Region();
region.MakeEmpty();
var rectangle = System.Drawing.Rectangle.Empty;
bool inImage = false;
for (int y = 0; y < bitmap.Height; y++)
{
for (int x = 0; x < bitmap.Width; x++)
{
var croppedPixel = new CroppedBitmap(bitmap, new Int32Rect(x, y, 1, 1));
byte[] pixel = new byte[bitmap.Format.BitsPerPixel / 8];
croppedPixel.CopyPixels(pixel, bitmap.Format.BitsPerPixel / 8, 0);
var pixelAlpha = pixel[0];
if (!inImage && pixelAlpha > 0)
{
inImage = true;
rectangle.X = x;
rectangle.Y = y;
rectangle.Height = 1;
}
else if (inImage && pixelAlpha == 0)
{
inImage = false;
rectangle.Width = x - rectangle.X;
rectangle.Offset((int)offset.X, (int)offset.Y);
region.Union(rectangle);
}
}
if (inImage)
{
inImage = false;
rectangle.Width = (int)bitmap.Width - rectangle.X;
rectangle.Offset((int)offset.X, (int)offset.Y);
region.Union(rectangle);
}
}
return(region);
}
public void Clip(IReadOnlyRegion2D region)
{
var clip = new System.Drawing.Region(System.Drawing.Rectangle.Empty);
foreach (var rect in region.Rects)
{
clip.Union(new System.Drawing.Rectangle(rect.X, rect.Y, rect.Width, rect.Height));
}
Graphics.SetClip(clip, System.Drawing.Drawing2D.CombineMode.Replace);
}
public void add(Area rhs)
{
if (rhs == null)
{
return;
}
if (rhs.region == null)
{
return;
}
if (region == null)
{
region = new System.Drawing.Region();
}
region.Union(rhs.region);
}
/// <summary>
/// 点在区域中是否可见（现已废弃，替代方法 PointInPolygon）
/// </summary>
/// <param name="point"></param>
/// <param name="pointColl"></param>
/// <returns></returns>
public static bool IsVisible_Region(Point point, List <Point> pointColl)
{
System.Drawing.Drawing2D.GraphicsPath path = new System.Drawing.Drawing2D.GraphicsPath();
System.Drawing.Region region = new System.Drawing.Region();
List <System.Drawing.Point> pathPoints = new List <System.Drawing.Point>();
foreach (var pathPoint in pointColl)
{
pathPoints.Add(new System.Drawing.Point((int)Math.Round(pathPoint.X), (int)Math.Round(pathPoint.Y)));
}
path.AddPolygon(pathPoints.ToArray());
path.CloseFigure();
region.MakeEmpty();
region.Union(path);
return(region.IsVisible(new System.Drawing.Point((int)Math.Round(point.X), (int)Math.Round(point.Y))));
}