359 lines
12 KiB
C#
359 lines
12 KiB
C#
using System.Text;
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using DotNext;
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using SixLabors.ImageSharp;
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using SixLabors.ImageSharp.Formats.Jpeg;
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using SixLabors.ImageSharp.PixelFormats;
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namespace Common;
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/// <summary>
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/// 图像处理工具
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/// </summary>
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public class Image
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{
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/// <summary>
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/// 将 RGB565 格式转换为 RGB24 格式
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/// RGB565: 5位红色 + 6位绿色 + 5位蓝色 = 16位 (2字节)
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/// RGB24: 8位红色 + 8位绿色 + 8位蓝色 = 24位 (3字节)
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/// </summary>
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/// <param name="rgb565Data">RGB565格式的原始数据</param>
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/// <param name="width">图像宽度</param>
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/// <param name="height">图像高度</param>
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/// <param name="isLittleEndian">是否为小端序（默认为true）</param>
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/// <returns>RGB24格式的转换后数据</returns>
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public static Result<byte[]> ConvertRGB565ToRGB24(byte[] rgb565Data, int width, int height, bool isLittleEndian = true)
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{
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if (rgb565Data == null)
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return new(new ArgumentNullException(nameof(rgb565Data)));
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if (width <= 0 || height <= 0)
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return new(new ArgumentException("Width and height must be positive"));
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// 计算像素数量
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var expectedPixelCount = width * height;
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var actualPixelCount = rgb565Data.Length / 2;
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if (actualPixelCount < expectedPixelCount)
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{
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return new(new ArgumentException(
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$"RGB565 data length insufficient. Expected: {expectedPixelCount * 2} bytes, Actual: {rgb565Data.Length} bytes"));
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}
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try
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{
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var pixelCount = Math.Min(actualPixelCount, expectedPixelCount);
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var rgb24Data = new byte[pixelCount * 3];
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for (int i = 0; i < pixelCount; i++)
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{
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// 读取 RGB565 数据
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var rgb565Index = i * 2;
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if (rgb565Index + 1 >= rgb565Data.Length) break;
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// 组合成16位值
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UInt16 rgb565;
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if (isLittleEndian)
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{
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rgb565 = (UInt16)(rgb565Data[rgb565Index] | (rgb565Data[rgb565Index + 1] << 8));
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}
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else
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{
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rgb565 = (UInt16)((rgb565Data[rgb565Index] << 8) | rgb565Data[rgb565Index + 1]);
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}
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// 提取各颜色分量
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var r5 = (rgb565 >> 11) & 0x1F; // 高5位为红色
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var g6 = (rgb565 >> 5) & 0x3F; // 中间6位为绿色
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var b5 = rgb565 & 0x1F; // 低5位为蓝色
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// 转换为8位颜色值
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var r8 = (byte)((r5 * 255) / 31); // 5位扩展到8位
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var g8 = (byte)((g6 * 255) / 63); // 6位扩展到8位
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var b8 = (byte)((b5 * 255) / 31); // 5位扩展到8位
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// 存储到 RGB24 数组
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var rgb24Index = i * 3;
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rgb24Data[rgb24Index] = r8; // R
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rgb24Data[rgb24Index + 1] = g8; // G
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rgb24Data[rgb24Index + 2] = b8; // B
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}
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return rgb24Data;
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}
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catch (Exception ex)
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{
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return new(ex);
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}
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}
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/// <summary>
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/// 将 RGB24 格式转换为 RGB565 格式
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/// RGB24: 8位红色 + 8位绿色 + 8位蓝色 = 24位 (3字节)
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/// RGB565: 5位红色 + 6位绿色 + 5位蓝色 = 16位 (2字节)
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/// </summary>
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/// <param name="rgb24Data">RGB24格式的原始数据</param>
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/// <param name="width">图像宽度</param>
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/// <param name="height">图像高度</param>
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/// <param name="isLittleEndian">是否为小端序（默认为true）</param>
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/// <returns>RGB565格式的转换后数据</returns>
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public static Result<byte[]> ConvertRGB24ToRGB565(byte[] rgb24Data, int width, int height, bool isLittleEndian = true)
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{
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if (rgb24Data == null)
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return new(new ArgumentNullException(nameof(rgb24Data)));
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if (width <= 0 || height <= 0)
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return new(new ArgumentException("Width and height must be positive"));
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var expectedPixelCount = width * height;
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var actualPixelCount = rgb24Data.Length / 3;
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if (actualPixelCount < expectedPixelCount)
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{
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return new(new ArgumentException(
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$"RGB24 data length insufficient. Expected: {expectedPixelCount * 3} bytes, Actual: {rgb24Data.Length} bytes"));
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}
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try
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{
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var pixelCount = Math.Min(actualPixelCount, expectedPixelCount);
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var rgb565Data = new byte[pixelCount * 2];
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for (int i = 0; i < pixelCount; i++)
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{
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var rgb24Index = i * 3;
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if (rgb24Index + 2 >= rgb24Data.Length) break;
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// 读取 RGB24 数据
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var r8 = rgb24Data[rgb24Index];
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var g8 = rgb24Data[rgb24Index + 1];
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var b8 = rgb24Data[rgb24Index + 2];
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// 转换为5位、6位、5位
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var r5 = (UInt16)((r8 * 31) / 255);
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var g6 = (UInt16)((g8 * 63) / 255);
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var b5 = (UInt16)((b8 * 31) / 255);
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// 组合成16位值
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var rgb565 = (UInt16)((r5 << 11) | (g6 << 5) | b5);
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// 存储到 RGB565 数组
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var rgb565Index = i * 2;
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if (isLittleEndian)
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{
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rgb565Data[rgb565Index] = (byte)(rgb565 & 0xFF);
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rgb565Data[rgb565Index + 1] = (byte)(rgb565 >> 8);
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}
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else
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{
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rgb565Data[rgb565Index] = (byte)(rgb565 >> 8);
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rgb565Data[rgb565Index + 1] = (byte)(rgb565 & 0xFF);
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}
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}
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return rgb565Data;
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}
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catch (Exception ex)
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{
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return new(ex);
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}
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}
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/// <summary>
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/// 将 RGB24 数据转换为 JPEG 格式
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/// </summary>
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/// <param name="rgb24Data">RGB24格式的图像数据</param>
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/// <param name="width">图像宽度</param>
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/// <param name="height">图像高度</param>
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/// <param name="quality">JPEG质量（1-100，默认80）</param>
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/// <returns>JPEG格式的字节数组</returns>
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public static Result<byte[]> ConvertRGB24ToJpeg(byte[] rgb24Data, int width, int height, int quality = 80)
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{
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if (rgb24Data == null)
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return new(new ArgumentNullException(nameof(rgb24Data)));
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if (width <= 0 || height <= 0)
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return new(new ArgumentException("Width and height must be positive"));
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if (quality < 1 || quality > 100)
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return new(new ArgumentException("Quality must be between 1 and 100"));
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var expectedDataLength = width * height * 3;
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if (rgb24Data.Length < expectedDataLength)
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{
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return new(new ArgumentException(
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$"RGB24 data length insufficient. Expected: {expectedDataLength} bytes, Actual: {rgb24Data.Length} bytes"));
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}
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try
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{
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using var image = new SixLabors.ImageSharp.Image<Rgb24>(width, height);
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// 将 RGB 数据复制到 ImageSharp 图像
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for (int y = 0; y < height; y++)
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{
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for (int x = 0; x < width; x++)
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{
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int index = (y * width + x) * 3;
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if (index + 2 < rgb24Data.Length)
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{
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var pixel = new Rgb24(rgb24Data[index], rgb24Data[index + 1], rgb24Data[index + 2]);
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image[x, y] = pixel;
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}
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}
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}
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using var stream = new MemoryStream();
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image.SaveAsJpeg(stream, new JpegEncoder { Quality = quality });
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return stream.ToArray();
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}
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catch (Exception ex)
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{
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return new(ex);
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}
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}
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/// <summary>
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/// 将 RGB565 数据直接转换为 JPEG 格式
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/// </summary>
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/// <param name="rgb565Data">RGB565格式的图像数据</param>
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/// <param name="width">图像宽度</param>
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/// <param name="height">图像高度</param>
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/// <param name="quality">JPEG质量（1-100，默认80）</param>
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/// <param name="isLittleEndian">是否为小端序（默认为true）</param>
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/// <returns>JPEG格式的字节数组</returns>
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public static Result<byte[]> ConvertRGB565ToJpeg(byte[] rgb565Data, int width, int height, int quality = 80, bool isLittleEndian = true)
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{
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// 先转换为RGB24
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var rgb24Result = ConvertRGB565ToRGB24(rgb565Data, width, height, isLittleEndian);
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if (!rgb24Result.IsSuccessful)
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{
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return new(rgb24Result.Error);
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}
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// 再转换为JPEG
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return ConvertRGB24ToJpeg(rgb24Result.Value, width, height, quality);
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}
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/// <summary>
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/// 创建 MJPEG 帧头部
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/// </summary>
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/// <param name="frameDataLength">帧数据长度</param>
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/// <param name="boundary">边界字符串（默认为"--boundary"）</param>
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/// <returns>MJPEG帧头部字节数组</returns>
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public static byte[] CreateMjpegFrameHeader(int frameDataLength, string boundary = "--boundary")
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{
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var header = $"{boundary}\r\nContent-Type: image/jpeg\r\nContent-Length: {frameDataLength}\r\n\r\n";
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return Encoding.ASCII.GetBytes(header);
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}
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/// <summary>
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/// 创建 MJPEG 帧尾部
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/// </summary>
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/// <returns>MJPEG帧尾部字节数组</returns>
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public static byte[] CreateMjpegFrameFooter()
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{
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return Encoding.ASCII.GetBytes("\r\n");
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}
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/// <summary>
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/// 创建完整的 MJPEG 帧数据
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/// </summary>
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/// <param name="jpegData">JPEG数据</param>
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/// <param name="boundary">边界字符串（默认为"--boundary"）</param>
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/// <returns>完整的MJPEG帧数据</returns>
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public static Result<byte[]> CreateMjpegFrame(byte[] jpegData, string boundary = "--boundary")
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{
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if (jpegData == null)
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return new(new ArgumentNullException(nameof(jpegData)));
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try
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{
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var header = CreateMjpegFrameHeader(jpegData.Length, boundary);
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var footer = CreateMjpegFrameFooter();
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var totalLength = header.Length + jpegData.Length + footer.Length;
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var frameData = new byte[totalLength];
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var offset = 0;
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Array.Copy(header, 0, frameData, offset, header.Length);
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offset += header.Length;
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Array.Copy(jpegData, 0, frameData, offset, jpegData.Length);
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offset += jpegData.Length;
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Array.Copy(footer, 0, frameData, offset, footer.Length);
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return frameData;
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}
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catch (Exception ex)
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{
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return new(ex);
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}
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}
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/// <summary>
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/// 验证图像数据长度是否正确
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/// </summary>
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/// <param name="data">图像数据</param>
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/// <param name="width">图像宽度</param>
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/// <param name="height">图像高度</param>
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/// <param name="bytesPerPixel">每像素字节数</param>
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/// <returns>验证结果</returns>
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public static bool ValidateImageDataLength(byte[] data, int width, int height, int bytesPerPixel)
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{
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if (data == null || width <= 0 || height <= 0 || bytesPerPixel <= 0)
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return false;
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var expectedLength = width * height * bytesPerPixel;
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return data.Length >= expectedLength;
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}
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/// <summary>
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/// 获取图像格式信息
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/// </summary>
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/// <param name="format">图像格式枚举</param>
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/// <returns>格式信息</returns>
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public static ImageFormatInfo GetImageFormatInfo(ImageFormat format)
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{
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return format switch
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{
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ImageFormat.RGB565 => new ImageFormatInfo("RGB565", 2, "16-bit RGB format (5R+6G+5B)"),
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ImageFormat.RGB24 => new ImageFormatInfo("RGB24", 3, "24-bit RGB format (8R+8G+8B)"),
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ImageFormat.RGBA32 => new ImageFormatInfo("RGBA32", 4, "32-bit RGBA format (8R+8G+8B+8A)"),
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ImageFormat.Grayscale8 => new ImageFormatInfo("Grayscale8", 1, "8-bit grayscale format"),
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_ => new ImageFormatInfo("Unknown", 0, "Unknown image format")
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};
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}
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}
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/// <summary>
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/// 图像格式枚举
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/// </summary>
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public enum ImageFormat
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{
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/// <summary>
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/// RGB565
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/// </summary>
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RGB565,
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/// <summary>
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/// RGB888 / RGB24
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/// </summary>
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RGB24,
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/// <summary>
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/// RGBA8888 / RGBA32
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/// </summary>
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RGBA32,
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/// <summary>
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/// 灰度图
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/// </summary>
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Grayscale8
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}
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/// <summary>
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/// 图像格式信息
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/// </summary>
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public record ImageFormatInfo(string Name, int BytesPerPixel, string Description);
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