110,538
社区成员
发帖
与我相关
我的任务
分享
using System;
using System.Drawing;
public static class Captcha {
private static double[] addVector (double[] a, double[] b) {
return new double[] { a[0] + b[0], a[1] + b[1], a[2] + b[2] };
}
private static double[] scalarProduct (double[] vector, double scalar) {
return new double[] { vector[0] * scalar, vector[1] * scalar, vector[2] * scalar };
}
private static double dotProduct (double[] a, double[] b) {
return a[0] * b[0] + a[1] * b[1] + a[2] * b[2];
}
private static double norm (double[] vector) {
return Math.Sqrt(dotProduct(vector, vector));
}
private static double[] normalize (double[] vector) {
return scalarProduct(vector, 1.0 / norm(vector));
}
private static double[] crossProduct (double[] a, double[] b) {
return new double[]
{
(a[1] * b[2] - a[2] * b[1]),
(a[2] * b[0] - a[0] * b[2]),
(a[0] * b[1] - a[1] * b[0])
};
}
private static double[] vectorProductIndexed (double[] v, double[] m, int i) {
return new double[]
{
v[i + 0] * m[0] + v[i + 1] * m[4] + v[i + 2] * m[8] + v[i + 3] * m[12],
v[i + 0] * m[1] + v[i + 1] * m[5] + v[i + 2] * m[9] + v[i + 3] * m[13],
v[i + 0] * m[2] + v[i + 1] * m[6] + v[i + 2] * m[10]+ v[i + 3] * m[14],
v[i + 0] * m[3] + v[i + 1] * m[7] + v[i + 2] * m[11]+ v[i + 3] * m[15]
};
}
private static double[] vectorProduct (double[] v, double[] m) {
return vectorProductIndexed(v, m, 0);
}
private static double[] matrixProduct (double[] a, double[] b) {
double[] o1 = vectorProductIndexed(a, b, 0);
double[] o2 = vectorProductIndexed(a, b, 4);
double[] o3 = vectorProductIndexed(a, b, 8);
double[] o4 = vectorProductIndexed(a, b, 12);
return new double[]
{
o1[0], o1[1], o1[2], o1[3],
o2[0], o2[1], o2[2], o2[3],
o3[0], o3[1], o3[2], o3[3],
o4[0], o4[1], o4[2], o4[3]
};
}
private static double[] cameraTransform (double[] C, double[] A) {
double[] w = normalize(addVector(C, scalarProduct(A, -1)));
double[] y = new double[] { 0, 1, 0 };
double[] u = normalize(crossProduct(y, w));
double[] v = crossProduct(w, u);
double[] t = scalarProduct(C, -1);
return new double[]
{
u[0], v[0], w[0], 0,
u[1], v[1], w[1], 0,
u[2], v[2], w[2], 0,
dotProduct(u, t), dotProduct(v, t), dotProduct(w, t), 1
};
}
private static double[] viewingTransform (double fov, double n, double f) {
fov *= (Math.PI / 180);
double cot = 1.0 / Math.Tan(fov / 2);
return new double[] { cot, 0, 0, 0, 0, cot, 0, 0, 0, 0, (f + n) / (f - n), -1, 0, 0, 2 * f * n / (f - n), 0 };
}
public static Image Generate (string captchaText) {
int fontsize = 24;
Font font = new Font("Arial", fontsize);
SizeF sizeF;
using (Graphics g = Graphics.FromImage(new Bitmap(1, 1))) {
sizeF = g.MeasureString(captchaText, font, 0, StringFormat.GenericDefault);
}
int image2d_x = (int)sizeF.Width;
int image2d_y = (int)(fontsize * 1.3);
Bitmap image2d = new Bitmap(image2d_x, image2d_y);
Color black = Color.Black;
Color white = Color.White;
using (Graphics g = Graphics.FromImage(image2d)) {
g.Clear(black);
g.DrawString(captchaText, font, Brushes.White, 0, 0);
}
Random rnd = new Random();
double[] T = cameraTransform(new double[] { rnd.Next(-90, 90), -200, rnd.Next(150, 250) }, new double[] { 0, 0, 0 });
T = matrixProduct(T, viewingTransform(60, 300, 3000));
double[][] coord = new double[image2d_x * image2d_y][];
int count = 0;
for (int y = 0; y < image2d_y; y += 2) {
for (int x = 0; x < image2d_x; x++) {
int xc = x - image2d_x / 2;
int zc = y - image2d_y / 2;
double yc = -(double)(image2d.GetPixel(x, y).ToArgb() & 0xff) / 256 * 4;
double[] xyz = new double[] { xc, yc, zc, 1 };
xyz = vectorProduct(xyz, T);
coord[count] = xyz;
count++;
}
}
int image3d_x = 256;
int image3d_y = image3d_x * 9 / 16;
Bitmap image3d = new Bitmap(image3d_x, image3d_y);
Color fgcolor = Color.White;
Color bgcolor = Color.Black;
using (Graphics g = Graphics.FromImage(image3d)) {
g.Clear(bgcolor);
count = 0;
double scale = 1.75 - (double)image2d_x / 400;
for (int y = 0; y < image2d_y; y += 2) {
for (int x = 0; x < image2d_x; x++) {
if (x > 0) {
double x0 = coord[count - 1][0] * scale + image3d_x / 2;
double y0 = coord[count - 1][1] * scale + image3d_y / 2;
double x1 = coord[count][0] * scale + image3d_x / 2;
double y1 = coord[count][1] * scale + image3d_y / 2;
g.DrawLine(new Pen(fgcolor), (float)x0, (float)y0, (float)x1, (float)y1);
}
count++;
}
}
}
return image3d;
}
}
Image image = Captcha.Generate("12345");
System.IO.MemoryStream ms = new System.IO.MemoryStream();
image.Save(ms, System.Drawing.Imaging.ImageFormat.Png);
Response.ClearContent();//Response.ClearContent();
Response.ContentType = "image/Jpeg";
Response.BinaryWrite(ms.ToArray());
image.Dispose();