C#截屏及图片处理

截屏返回Bitmap

截图方法返回Bitmap可以方便后面对图片进行处理

截屏并绘制鼠标坐在位置

代码语言：javascript复制

private const PixelFormat FORMAT = PixelFormat.Format24bppRgb;

public static Bitmap GetScreen()
{
    Bitmap screenshot = new Bitmap(
        Screen.PrimaryScreen.Bounds.Width,
        Screen.PrimaryScreen.Bounds.Height,
        FORMAT
    );
    using (Graphics gfx = Graphics.FromImage(screenshot))
    {
        gfx.CopyFromScreen(
            Screen.PrimaryScreen.Bounds.X,
            Screen.PrimaryScreen.Bounds.Y,
            0,
            0,
            Screen.PrimaryScreen.Bounds.Size,
            CopyPixelOperation.SourceCopy
        );

        // 绘制光标图标
        // 创建一个红色的画刷
        Brush brush = new SolidBrush(Color.LimeGreen);
        gfx.FillEllipse(
            brush,
            Cursor.Position.X - 10,
            Cursor.Position.Y - 10,
            20,
            20
        );
        return screenshot;
    }
}

缩放

代码语言：javascript复制

public static Bitmap ScalePic
(
    Bitmap sourrce,
    int width,
    int height
)
{
    Bitmap result = new Bitmap(
        width,
        height,
        FORMAT
    );
    using (Graphics g = Graphics.FromImage(result))
    {
        g.InterpolationMode = InterpolationMode.HighQualityBicubic;
        g.DrawImage(
            sourrce,
            0,
            0,
            width,
            height
        );
        return result;
    }
}

图片保存

使用默认方式

代码语言：javascript复制

public static byte[] GetPicByte(Bitmap sourrce)
{
    using (MemoryStream ms = new MemoryStream())
    {
        sourrce.Save(
            ms,
            ImageFormat.Jpeg
        );
        return ms.ToArray();
    }
}

自定义压缩率

代码语言：javascript复制

public static byte[] GetPicByte
(
    Bitmap sourrce,
    int quality
)
{
    using (MemoryStream ms = new MemoryStream())
    {
        ImageCodecInfo jpegCodec = GetEncoderInfo("image/jpeg");
        var encoderParameters = GetEncoderParameters(quality);
        sourrce.Save(
            ms,
            jpegCodec,
            encoderParameters
        );
        return ms.ToArray();
    }
}

public static EncoderParameters GetEncoderParameters(int quality = 90)
{
    Encoder qualityEncoder = Encoder.Quality;
    EncoderParameters encoderParams = new EncoderParameters(1);
    encoderParams.Param[0] = new EncoderParameter(
        qualityEncoder,
        quality
    );
    return encoderParams;
}

/// <summary>
/// 获取解码器
/// </summary>
/// <param name="mimeType">
/// </param>
/// <returns>
/// </returns>
private static ImageCodecInfo GetEncoderInfo(string mimeType)
{
    int j;
    var encoders = ImageCodecInfo.GetImageEncoders();
    for (j = 0; j < encoders.Length;   j)
    {
        if (encoders[j].MimeType == mimeType)
        {
            return encoders[j];
        }
    }
    return null;
}

保存到文件

代码语言：javascript复制

bmp.Save(savePath, ImageFormat.Jpeg);

截屏并获取Byte

代码语言：javascript复制

/// <summary>
/// 获取屏幕的Byte[]
/// </summary>
/// <param name="maxHeight"></param>
/// <returns></returns>
public static byte[] GetScreenshot(int maxHeight = 720)
{
    var screen = GetScreen();
    Bitmap targetPic;
    int width = screen.Width;
    int height = screen.Height;
    if (screen.Height > maxHeight)
    {
        double rate = 1.0d * screen.Height / maxHeight;
        height = (int)(height / rate);
        width = (int)(width / rate);
        targetPic = ScalePic(
            screen,
            width,
            height
        );
        screen.Dispose();
    }
    else
    {
        targetPic = screen;
    }
    var picByte = GetPicByte(
        targetPic,
        40
    );
    targetPic.Dispose();
    return picByte;
}

Bitmap转BGR格式

在做视频编码的时候，我们需要的是原始的BGR数据。

代码语言：javascript复制

public static byte[] Bitmap2Bgr(Bitmap bitmap)
{
    BitmapData data = bitmap.LockBits(
        new Rectangle(
            0,
            0,
            bitmap.Width,
            bitmap.Height
        ),
        ImageLockMode.ReadWrite,
        PixelFormat.Format24bppRgb
    );
    bitmap.UnlockBits(data);
    int dstBytes = data.Stride * data.Height;
    byte[] dstValues = new byte[dstBytes];
    System.IntPtr srcPtr = data.Scan0;
    Marshal.Copy(
        srcPtr,
        dstValues,
        0,
        dstBytes
    );
    return dstValues;
}

获取屏幕并转为Bgr格式

代码语言：javascript复制

/// <summary>
/// 获取屏幕并转为Bgr格式
/// </summary>
/// <param name="targetWidth"></param>
/// <param name="targetHeight"></param>
/// <returns></returns>
public static byte[] CaptureScreen
(
    int targetWidth,
    int targetHeight
)
{
    var screen = GetScreen();
    var targetPic = ScalePic(
        screen,
        targetWidth,
        targetHeight
    );
    screen.Dispose();
    byte[] bgrByte = Bitmap2Bgr(targetPic);
    targetPic.Dispose();
    return bgrByte;
}

c# 图片处理 bitmap int screen

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