228 lines
10 KiB
C#
228 lines
10 KiB
C#
using System.Collections.Generic;
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using System.Text;
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using UnityEngine;
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/// <summary>
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/// 图形验证码生成器：运行时动态生成验证码图片（Texture2D → Sprite），不依赖任何外部图片资源。
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/// 用法：var sprite = CaptchaGenerator.Generate(width, height, out string code);
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/// </summary>
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public static class CaptchaGenerator
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{
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// 验证码字符集（去除易混淆字符 0/O/1/I/l）
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private const string CharSet = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ";
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// 干扰线颜色池
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private static readonly Color[] NoiseColors =
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{
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new Color(0.6f, 0.6f, 0.6f),
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new Color(0.4f, 0.4f, 0.8f),
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new Color(0.8f, 0.4f, 0.4f),
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new Color(0.4f, 0.8f, 0.4f),
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new Color(0.8f, 0.8f, 0.2f),
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};
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// 字符颜色池
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private static readonly Color[] TextColors =
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{
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new Color(0.1f, 0.1f, 0.6f),
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new Color(0.6f, 0.1f, 0.1f),
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new Color(0.1f, 0.5f, 0.1f),
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new Color(0.5f, 0.2f, 0.5f),
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new Color(0.2f, 0.2f, 0.2f),
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new Color(0.6f, 0.3f, 0.1f),
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};
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/// <summary>
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/// 生成验证码图片并转换为 Sprite。
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/// </summary>
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/// <param name="width">图片宽度</param>
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/// <param name="height">图片高度</param>
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/// <param name="code">输出的验证码文本</param>
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/// <param name="length">验证码字符数（默认4）</param>
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/// <returns>验证码 Sprite（可直接赋给 Image）</returns>
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public static Sprite Generate(int width, int height, out string code, int length = 4)
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{
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code = RandomCode(length);
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var tex = DrawCaptcha(code, width, height);
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return Sprite.Create(tex, new Rect(0, 0, width, height), new Vector2(0.5f, 0.5f));
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}
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/// <summary>
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/// 生成验证码图片并转换为 Sprite（无 out 参数的便捷重载）。
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/// </summary>
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public static Sprite Generate(int width, int height, int length = 4)
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{
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return Generate(width, height, out _, length);
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}
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/// <summary>生成随机验证码文本</summary>
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private static string RandomCode(int length)
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{
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var sb = new StringBuilder(length);
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for (int i = 0; i < length; i++)
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sb.Append(CharSet[Random.Range(0, CharSet.Length)]);
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return sb.ToString();
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}
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/// <summary>把验证码画到 Texture2D 上</summary>
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private static Texture2D DrawCaptcha(string code, int width, int height)
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{
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// 半透明背景，方便看清楚字符
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var bg = new Color(0.95f, 0.95f, 0.95f, 1f);
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var tex = new Texture2D(width, height, TextureFormat.RGBA32, false);
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tex.filterMode = FilterMode.Point;
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var pixels = new Color32[width * height];
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// 填充背景
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for (int i = 0; i < pixels.Length; i++)
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pixels[i] = bg;
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tex.SetPixels32(pixels);
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// 画干扰线
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int lineCount = 3 + Random.Range(0, 3); // 3~5 条
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for (int i = 0; i < lineCount; i++)
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{
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var c = NoiseColors[Random.Range(0, NoiseColors.Length)];
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int x0 = Random.Range(0, width);
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int y0 = Random.Range(0, height);
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int x1 = Random.Range(0, width);
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int y1 = Random.Range(0, height);
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DrawLine(tex, x0, y0, x1, y1, c);
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}
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// 画干扰点
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int dotCount = 30 + Random.Range(0, 30); // 30~59 个
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for (int i = 0; i < dotCount; i++)
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{
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var c = NoiseColors[Random.Range(0, NoiseColors.Length)];
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int x = Random.Range(0, width);
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int y = Random.Range(0, height);
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tex.SetPixel(x, y, c);
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}
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// 逐个字符绘制（使用内置 8x8 像素字体）
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int charPixelSize = Mathf.Min(height * 2 / 3, width / (code.Length + 1)); // 字符像素大小
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int startX = (width - code.Length * charPixelSize) / 2;
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int startY = (height - charPixelSize) / 2;
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for (int i = 0; i < code.Length; i++)
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{
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var c = TextColors[Random.Range(0, TextColors.Length)];
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int x = startX + i * charPixelSize;
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// 每个字符的 y 做轻微随机偏移
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int y = startY + Random.Range(-charPixelSize / 6, charPixelSize / 6);
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DrawChar(tex, code[i], x, y, charPixelSize, c);
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}
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tex.Apply();
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return tex;
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}
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/// <summary>绘制单条直线（Bresenham）</summary>
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private static void DrawLine(Texture2D tex, int x0, int y0, int x1, int y1, Color c)
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{
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int dx = Mathf.Abs(x1 - x0), sx = x0 < x1 ? 1 : -1;
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int dy = -Mathf.Abs(y1 - y0), sy = y0 < y1 ? 1 : -1;
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int err = dx + dy;
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while (true)
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{
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if (x0 >= 0 && x0 < tex.width && y0 >= 0 && y0 < tex.height)
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tex.SetPixel(x0, y0, c);
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if (x0 == x1 && y0 == y1) break;
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int e2 = 2 * err;
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if (e2 >= dy) { err += dy; x0 += sx; }
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if (e2 <= dx) { err += dx; y0 += sy; }
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}
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}
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/// <summary>用 8x8 像素位图绘制单个字符，可缩放到任意像素大小</summary>
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private static void DrawChar(Texture2D tex, char ch, int x, int y, int size, Color c)
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{
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// 5x7 像素位图（行宽5，行高7）的简单 ASCII 字库
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bool[,] pattern = GetCharPattern(ch);
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if (pattern == null) return;
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int pw = pattern.GetLength(0); // 5
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int ph = pattern.GetLength(1); // 7
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float sx = size / (float)pw;
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float sy = size / (float)ph;
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for (int py = 0; py < ph; py++)
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{
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for (int px = 0; px < pw; px++)
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{
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if (!pattern[px, py]) continue;
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// 把位图的一个像素映射到 size×size 区域（从下往上画，因为 Texture2D 原点在左下）
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int xStart = Mathf.RoundToInt(x + px * sx);
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int xEnd = Mathf.RoundToInt(x + (px + 1) * sx);
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int yStart = Mathf.RoundToInt(y + (ph - 1 - py) * sy);
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int yEnd = Mathf.RoundToInt(y + (ph - py) * sy);
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for (int yy = yStart; yy < yEnd; yy++)
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{
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for (int xx = xStart; xx < xEnd; xx++)
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{
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if (xx >= 0 && xx < tex.width && yy >= 0 && yy < tex.height)
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tex.SetPixel(xx, yy, c);
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}
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}
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}
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}
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}
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/// <summary>
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/// 简单的 5x7 像素字库（支持 0-9 A-Z，去掉易混淆字符）。
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/// 返回 bool[x, y]，x=0..4（列），y=0..6（行，从上到下）。
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/// </summary>
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private static bool[,] GetCharPattern(char ch)
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{
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// 每个字符 7 行，每行 5 个像素（从上到下）
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// '1' = 亮，'0' = 暗
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string[] rows;
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switch (ch)
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{
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case '2': rows = new[] { "01110", "10001", "00001", "00010", "00100", "01000", "11111" }; break;
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case '3': rows = new[] { "01110", "10001", "00001", "00110", "00001", "10001", "01110" }; break;
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case '4': rows = new[] { "00010", "00110", "01010", "10010", "11111", "00010", "00010" }; break;
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case '5': rows = new[] { "11111", "10000", "11110", "00001", "00001", "10001", "01110" }; break;
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case '6': rows = new[] { "00110", "01000", "10000", "11110", "10001", "10001", "01110" }; break;
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case '7': rows = new[] { "11111", "00001", "00010", "00100", "01000", "01000", "01000" }; break;
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case '8': rows = new[] { "01110", "10001", "10001", "01110", "10001", "10001", "01110" }; break;
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case '9': rows = new[] { "01110", "10001", "10001", "01111", "00001", "00010", "01100" }; break;
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case 'A': rows = new[] { "01110", "10001", "10001", "11111", "10001", "10001", "10001" }; break;
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case 'B': rows = new[] { "11110", "10001", "10001", "11110", "10001", "10001", "11110" }; break;
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case 'C': rows = new[] { "01110", "10001", "10000", "10000", "10000", "10001", "01110" }; break;
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case 'D': rows = new[] { "11110", "10001", "10001", "10001", "10001", "10001", "11110" }; break;
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case 'E': rows = new[] { "11111", "10000", "10000", "11110", "10000", "10000", "11111" }; break;
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case 'F': rows = new[] { "11111", "10000", "10000", "11110", "10000", "10000", "10000" }; break;
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case 'G': rows = new[] { "01110", "10001", "10000", "10111", "10001", "10001", "01110" }; break;
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case 'H': rows = new[] { "10001", "10001", "10001", "11111", "10001", "10001", "10001" }; break;
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case 'J': rows = new[] { "00111", "00010", "00010", "00010", "00010", "10010", "01100" }; break;
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case 'K': rows = new[] { "10001", "10010", "10100", "11000", "10100", "10010", "10001" }; break;
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case 'L': rows = new[] { "10000", "10000", "10000", "10000", "10000", "10000", "11111" }; break;
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case 'M': rows = new[] { "10001", "11011", "10101", "10101", "10001", "10001", "10001" }; break;
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case 'N': rows = new[] { "10001", "11001", "10101", "10011", "10001", "10001", "10001" }; break;
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case 'P': rows = new[] { "11110", "10001", "10001", "11110", "10000", "10000", "10000" }; break;
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case 'Q': rows = new[] { "01110", "10001", "10001", "10001", "10101", "10010", "01101" }; break;
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case 'R': rows = new[] { "11110", "10001", "10001", "11110", "10100", "10010", "10001" }; break;
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case 'S': rows = new[] { "01111", "10000", "10000", "01110", "00001", "10001", "11110" }; break;
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case 'T': rows = new[] { "11111", "00100", "00100", "00100", "00100", "00100", "00100" }; break;
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case 'U': rows = new[] { "10001", "10001", "10001", "10001", "10001", "10001", "01110" }; break;
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case 'V': rows = new[] { "10001", "10001", "10001", "10001", "10001", "01010", "00100" }; break;
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case 'W': rows = new[] { "10001", "10001", "10001", "10101", "10101", "11011", "10001" }; break;
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case 'X': rows = new[] { "10001", "10001", "01010", "00100", "01010", "10001", "10001" }; break;
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case 'Y': rows = new[] { "10001", "10001", "01010", "00100", "00100", "00100", "00100" }; break;
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case 'Z': rows = new[] { "11111", "00001", "00010", "00100", "01000", "10000", "11111" }; break;
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default: return null;
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}
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var pattern = new bool[5, 7];
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for (int y = 0; y < 7; y++)
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for (int x = 0; x < 5; x++)
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pattern[x, y] = rows[y][x] == '1';
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return pattern;
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}
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}
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