/// <summary>
/// Creates the captcha image.
/// </summary>
public byte[] DrawCaptcha(string message, string foreColor, float fontSize, string fontName)
{
return(useFont(fontName, fontSize, captchaFont =>
{
var fColor = ColorTranslator.FromHtml(foreColor);
message = message.Replace(",", string.Empty, StringComparison.Ordinal);
const int margin = 8;
var captchaSize = measureString(message, captchaFont);
var height = (int)captchaSize.Height + margin;
var width = (int)captchaSize.Width + margin;
using var pic = new Bitmap(width, height, PixelFormat.Format24bppRgb);
var data = pic.LockBits(new Rectangle(0, 0, pic.Width, pic.Height), ImageLockMode.WriteOnly, pic.PixelFormat);
var noise = new byte[data.Width * data.Height * 3];
_randomNumberProvider.NextBytes(noise);
Marshal.Copy(noise, 0, data.Scan0, noise.Length);
pic.UnlockBits(data);
using (var graphics = Graphics.FromImage(pic))
{
var stringFormat = new StringFormat
{
Alignment = StringAlignment.Center,
LineAlignment = StringAlignment.Center
};
graphics.DrawString(message, captchaFont, new SolidBrush(fColor), new RectangleF(0, 0, pic.Width, pic.Height), stringFormat);
for (var i = 0; i < 30; i++)
{
var x0 = _randomNumberProvider.NextNumber(0, width);
var y0 = _randomNumberProvider.NextNumber(0, height);
var x1 = _randomNumberProvider.NextNumber(0, width);
var y1 = _randomNumberProvider.NextNumber(0, height);
graphics.DrawLine(Pens.White, x0, y0, x1, y1);
}
}
using var stream = new MemoryStream();
distortImage(height, width, pic);
pic.Save(stream, ImageFormat.Png);
return stream.ToArray();
}));
}
