如何填写封闭区域中的位图对象与颜色 [英] How to fill enclosed area in the Bitmap object with a color
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问题描述
给区域内点用颜色来填充该区域,类似于在涂料桶的功能的图。结果,
的。 NET Framework中,没有直接等同的。结果
但我希望用C#这样做。结果
这可能吗?
Give point within the region with a color to fill the region, similar to the "drawing" in the paint bucket function.
The. NET Framework, there is no direct equivalent.
but i hope use C# to do it.
is it possible?
推荐答案
这里是一个应该让你开始一个很天真的洪水填充算法
Here's a very naive flood fill algorithm that should get you started
void Form1_Paint(object sender, PaintEventArgs e)
{
using (Bitmap bitmap = new Bitmap(500, 500))
{
using (Graphics g = Graphics.FromImage(bitmap))
{
g.Clear(Color.White);
List<Point> points = new List<Point>();
for (double i = 0; i < 10; i++)
{
double dist = (i % 2 == 0) ? 100 : 50;
double x = 200 + Math.Cos(i / 10d * Math.PI * 2d) * dist;
double y = 200 + Math.Sin(i / 10d * Math.PI * 2d) * dist;
points.Add(new Point((int)x, (int)y));
}
g.DrawPolygon(Pens.Black, points.ToArray());
}
FloodFill(bitmap, 200, 200, Color.Red);
e.Graphics.DrawImage(bitmap, 0, 0);
}
}
void FloodFill(Bitmap bitmap, int x, int y, Color color)
{
BitmapData data = bitmap.LockBits(
new Rectangle(0, 0, bitmap.Width, bitmap.Height),
ImageLockMode.ReadWrite, PixelFormat.Format32bppArgb);
int[] bits = new int[data.Stride / 4 * data.Height];
Marshal.Copy(data.Scan0, bits, 0, bits.Length);
LinkedList<Point> check = new LinkedList<Point>();
int floodTo = color.ToArgb();
int floodFrom = bits[x + y * data.Stride / 4];
bits[x + y * data.Stride / 4] = floodTo;
if (floodFrom != floodTo)
{
check.AddLast(new Point(x, y));
while (check.Count > 0)
{
Point cur = check.First.Value;
check.RemoveFirst();
foreach (Point off in new Point[] {
new Point(0, -1), new Point(0, 1),
new Point(-1, 0), new Point(1, 0)})
{
Point next = new Point(cur.X + off.X, cur.Y + off.Y);
if (next.X >= 0 && next.Y >= 0 &&
next.X < data.Width &&
next.Y < data.Height)
{
if (bits[next.X + next.Y * data.Stride / 4] == floodFrom)
{
check.AddLast(next);
bits[next.X + next.Y * data.Stride / 4] = floodTo;
}
}
}
}
}
Marshal.Copy(bits, 0, data.Scan0, bits.Length);
bitmap.UnlockBits(data);
}
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