用AForge和Graphics.FromImage.DrawImage预防AForge

Question

我已经写了一个代码，允许用户从他们的网络摄像头启动和停止一个提要。我使用了AForge.NET的NewFrameEventArgs在每次更改新框架时使用新框架更新PictureBox。但是，无论何时启动提要，我的计算机上的内存使用量都会缓慢上升，直到出现OutOfMemoryException。

你能帮我弄清楚怎么清理或冲洗这个吗？当我得到异常时，它发生在ScaleImage代码的底部：

System.Drawing.Graphics.FromImage(newScaledImage).DrawImage(image, 0, 0, newWidth, newHeight);

到目前为止我的代码是：

using System;
using System.Windows.Forms;
using System.Drawing;
using System.Drawing.Imaging;
using AForge.Video;
using AForge.Video.DirectShow;

namespace WebCameraCapture
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private VideoCaptureDevice FinalFrame;
        System.Drawing.Bitmap fullResClone;

        void FinalFrame_NewFrame(object sender, NewFrameEventArgs eventArgs)
        {
            pictureBox1.Image = ScaleImage((Bitmap)eventArgs.Frame.Clone(), 640, 480);
        }

        private void btn_startCapture_Click(object sender, EventArgs e)
        {
            FinalFrame = new VideoCaptureDevice(CaptureDevice[comboBox1.SelectedIndex].MonikerString);//Specified web cam and its filter moniker string.
            FinalFrame.NewFrame += new NewFrameEventHandler(FinalFrame_NewFrame);
            FinalFrame.Start();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            CaptureDevice = new FilterInfoCollection(FilterCategory.VideoInputDevice);
            foreach (FilterInfo Device in CaptureDevice) { comboBox1.Items.Add(Device.Name); }

            comboBox1.SelectedIndex = 0; //Default index.
            FinalFrame = new VideoCaptureDevice();
        }

        //This ScaleImage is where the OutOfMemoryException occurs.
        public static System.Drawing.Image ScaleImage(System.Drawing.Image image, int maxWidth, int maxHeight) //Changes the height and width of the image to make sure it fits the PictureBox.
        {
            var ratioX = (double)maxWidth / image.Width;
            var ratioY = (double)maxHeight / image.Height;
            var ratio = Math.Min(ratioX, ratioY);

            var newWidth = (int)(image.Width * ratio);
            var newHeight = (int)(image.Height * ratio);

            var newScaledImage = new Bitmap(newWidth, newHeight);
            System.Drawing.Graphics.FromImage(newScaledImage).DrawImage(image, 0, 0, newWidth, newHeight); // <<<< RIGHT HERE
            return newScaledImage;
        }
    }
}

Answer 1

在添加新的缩放映像之前，您需要释放前一个映像(只要它不是空的)。

void FinalFrame_NewFrame(object sender, NewFrameEventArgs eventArgs)
{
    if (pictureBox1.Image != null) { pictureBox1.Image.Dispose(); }

    Bitmap tempBitmap = (Bitmap)eventArgs.Frame.Clone();
    pictureBox1.Image = ScaleImage(tempBitmap, 640, 480);
    tempBitmap.Dispose();
}

问:是否真的有必要创建输入映像的克隆？eventArgs.Frame究竟引用了什么？(我没有AForge。)