public static Bitmap CleanUnecessaryPixel(this Bitmap image, CaptchaInfo info)
{
var colorList = info.Colors.Keys.ToList().Where(x => x != info.BackgroundColor).ToList();
int connections = 2;
for (int y = 0; y < image.Height; y++)
{
for (int x = 0; x < image.Width; x++)
{
Color pixel = image.GetPixel(x, y);
// Skip background pixel
if (pixel.Name == info.BackgroundColor)
{
continue;
}
if (colorList.Contains(pixel.Name))
{
bool connected = IsPixelWithinRadius(x, y, image, info, connections);
if (!connected)
{
image.SetPixel(x, y, ColorTranslator.FromHtml("#" + info.BackgroundColor));
}
}
}
}
return(image);
}
public static Bitmap GetCaptchaInfo(this Bitmap image, ref CaptchaInfo info)
{
for (int i = 0; i < image.Width; i++)
{
for (int j = 0; j < image.Height; j++)
{
Color pixel = image.GetPixel(i, j);
if (!info.Colors.ContainsKey(pixel.Name))
{
info.Colors[pixel.Name] = 1;
}
else
{
info.Colors[pixel.Name] = info.Colors[pixel.Name] + 1;
}
}
}
var list = info.Colors.Values.ToList();
list.Sort();
list.Reverse();
info.BackgroundColor = "";
info.CaptchaColor = "";
foreach (var item in info.Colors)
{
if (item.Value == list[0] && string.IsNullOrEmpty(info.BackgroundColor))
{
info.BackgroundColor = item.Key;
continue;
}
if (item.Value == list[1] && string.IsNullOrEmpty(info.CaptchaColor))
{
info.CaptchaColor = item.Key;
continue;
}
info.IrrelevantColor.Add(item.Key);
}
return(image);
}
private static bool IsPixelWithinRadius(int x, int y, Bitmap img, CaptchaInfo info, int connections = 3)
{
try
{
// Check left, right, bottomLeft, bottom, bottomRight, topLeft, top, topRight
Color color = img.GetPixel(x, y);
int count = 0;
//left
if (x - 1 >= 0)
{
color = img.GetPixel(x - 1, y);
if (info.CaptchaColor == color.Name)
{
count++;
}
}
//right
if (x + 1 < img.Width)
{
color = img.GetPixel(x + 1, y);
if (info.CaptchaColor == color.Name)
{
count++;
}
}
//top
if (y - 1 >= 0)
{
color = img.GetPixel(x, y - 1);
if (info.CaptchaColor == color.Name)
{
count++;
}
}
//top left
if (y - 1 >= 0 && x - 1 >= 0)
{
color = img.GetPixel(x - 1, y - 1);
if (info.CaptchaColor == color.Name)
{
count++;
}
}
//top right
if (y - 1 >= 0 && x + 1 >= 0)
{
color = img.GetPixel(x + 1, y - 1);
if (info.CaptchaColor == color.Name)
{
count++;
}
}
//bottomLeft
if (y + 1 < img.Height && x - 1 >= 0)
{
color = img.GetPixel(x - 1, y + 1);
if (info.CaptchaColor == color.Name)
{
count++;
}
}
//bottomRight
if (y + 1 < img.Height && x + 1 < img.Width)
{
color = img.GetPixel(x + 1, y + 1);
if (info.CaptchaColor == color.Name)
{
count++;
}
}
//bottom
if (y + 1 < img.Height)
{
color = img.GetPixel(x, y + 1);
if (info.CaptchaColor == color.Name)
{
count++;
}
}
return(count >= connections);
}
catch { }
return(true);
}