public Task <string> GenerateImageBase64Async(string codeText, PainterOption option)
{
using Image <Rgba32> img = CreateImage(codeText, option);
string base64Text = img.ToBase64String(JpegFormat.Instance);
return(Task.FromResult(base64Text));
}
public async Task <byte[]> GenerateImageAsync(string codeText, PainterOption option)
{
using Image <Rgba32> img = CreateImage(codeText, option);
using var ms = new MemoryStream();
await img.SaveAsJpegAsync(ms);
return(ms.ToArray());
}
public CaptchaController(
IOptions <PainterOption> painterOpt,
ICodeTextGenerator codeTextGenerator,
IPainter painter)
{
_painterOption = painterOpt.Value;
_codeTextGenerator = codeTextGenerator;
_painter = painter;
}
private Image <Rgba32> CreateImage(string codeText, PainterOption option)
{
Image <Rgba32> img = new(option.Width, option.Height);
img.Mutate(Operate);
return(img);
void Operate(IImageProcessingContext ctx)
{
var random = RandomHelper.CurrentRandom;
float fontSize = RandomFontSize(option.Width, option.Height, codeText.Length);
ctx.BackgroundColor(option.UseBlackWhiteOnly ? Color.White : _colorRandomer.RandomLight());
//.Glow(_colorRandomer.RandomLight())
// Draw Points
if (option.PointCount > 0)
{
for (int i = 0; i < option.PointCount; i++)
{
ctx.Draw(color: option.UseBlackWhiteOnly ? Color.Black : _colorRandomer.RandomDark(),
thickness: DefaultPointSize,
shape: new RectangleF(
x: random.Next(DefaultPointSize, option.Width - DefaultPointSize),
y: random.Next(DefaultPointSize, option.Height - DefaultPointSize),
width: DefaultPointSize,
height: DefaultPointSize)
);
}
}
// Draw Bubbles
if (option.BubbleCount > 0)
{
int rad = random.Next(5, 11);
for (int i = 0; i < option.BubbleCount; i++)
{
var ep = new EllipsePolygon(x: random.Next(rad + 1, option.Width - rad - 1),
y: random.Next(rad + 1, option.Height - rad - 1),
radius: rad);
ctx.Draw(option.UseBlackWhiteOnly ? Color.Black : _colorRandomer.RandomDark(), 0.2f, ep.Clip());
}
}
// Draw Chars for interference
if (option.InterferCharCount > 0)
{
float interferCharSize = fontSize * 0.36f;
for (int i = 0; i < option.InterferCharCount; i++)
{
ctx.DrawText(text: RandomChar().ToString(),
font: _fontRandomer.Random(interferCharSize, FontStyle.Regular),
color: option.UseBlackWhiteOnly ? Color.Black : _colorRandomer.RandomDark(),
location: new(random.Next(1, (int)(option.Width - interferCharSize)), random.Next(0, (int)(option.Height - interferCharSize))));
}
}
// Draw CodeText
var fontLocations = RandomFontLocations(option.Width, option.Height, codeText.Length);
for (int i = 0; i < codeText.Length; i++)
{
ctx.DrawText(text: codeText[i].ToString(),
font: _fontRandomer.Random(fontSize, FontStyle.Regular),
color: option.UseBlackWhiteOnly ? Color.Black : _colorRandomer.RandomDark(),
location: fontLocations[i]);
}
//Draw Lines
if (option.LineCount > 0)
{
if (option.LineCount > 1)
{
for (int i = 1; i < option.LineCount; i++)
{
ctx.DrawLines(color: option.UseBlackWhiteOnly ? Color.Black : _colorRandomer.RandomDark(),
thickness: DefaultLineThickness,
new PointF(random.Next(0, option.Width / 2), random.Next(1, option.Height)),
new PointF(random.Next(option.Width / 2 + 1, option.Width), random.Next(1, option.Height))
);
}
}
ctx.DrawBeziers(color: option.UseBlackWhiteOnly ? Color.Black : _colorRandomer.RandomDark(),
thickness: DefaultLineThickness,
new PointF(random.Next(0, option.Width / 4), random.Next(1, option.Height)),
new PointF(random.Next(option.Width / 4 + 1, option.Width / 2), random.Next(1, option.Height)),
new PointF(random.Next(option.Width / 2 + 1, option.Width * 3 / 4), random.Next(1, option.Height)),
new PointF(random.Next(option.Width * 3 / 4 + 1, option.Width), random.Next(1, option.Height))
);
}
//ctx.GaussianBlur(0.4f);
char RandomChar()
{
int ascii = random.Next(48, 110);
if (ascii >= 84)// a - z
{
return((char)(ascii + 13));
}
if (ascii >= 58)// A - Z
{
return((char)(ascii + 7));
}
return((char)ascii);// 0 - 9
}
float RandomFontSize(int width, int height, int length)
{
return(Math.Min(width / (length + 1f), height * 0.8f) * random.Next(90, 100) * 0.01f);
}
PointF[] RandomFontLocations(int width, int height, int length)
{
int sideOffset = random.Next(0, (int)(width * 0.1f)) + 1;
int interval = (width - 2 * sideOffset) / length;
var result = new PointF[length];
for (int i = 0; i < length; i++)
{
double x = sideOffset + interval * (i + 0.5d * random.NextDouble());
double y = height * 0.1d * random.NextDouble();
result[i] = new PointF((float)x, (float)y);
}
return(result);
}
}
}
