OCR/TesseractScreenReader/TsrMainForm.cs

using System;
using System.Drawing;
using System.IO;
using System.Runtime.InteropServices;
using System.Windows.Forms;
using Tesseract;

namespace TesseractScreenReader
{
    public partial class TsrMainForm : Form
    {
        private readonly string _origWindowTitle;

        private DateTime _lastClipboard = DateTime.Now;

        private string AppendTitle
        {
            set => Text = $"{_origWindowTitle} - {value}";
        }

        public TsrMainForm()
        {
            InitializeComponent();
            _origWindowTitle = Text;
            AppendTitle = "就绪";
        }

        private void ReadClipBoardPicture_Click(object sender, EventArgs e)
        {
            using var img = Clipboard.GetImage();
            OcrImage(img);
        }

        private void TopMostCheckBox_CheckedChanged(object sender, EventArgs e) => TopMost = TopMostCheckBox.Checked;

        private void ClearButton_Click(object sender, EventArgs e) => OutputRichTextBox.Clear();

        private void OcrImage(Image img)
        {

            AppendTitle = "正在处理…";
            try
            {
                if (null == img) throw new InvalidOperationException("无图片");
                if (false == File.Exists("chi_sim.traineddata")) throw new FileNotFoundException("缺少数据文件，请前 https://github.com/tesseract-ocr/tessdata/blob/master/chi_sim.traineddata 往下载，然后放到exe旁", "chi_sim.traineddata");

                using var upscale = new Bitmap(img, img.Width * 2, img.Height * 2);
                using (var tess = new TesseractEngine(@".", "chi_sim"))
                {
                    tess.SetVariable("preserve_interword_spaces", SpaceCheckBox.Checked ? 1 : 0);
                    var result = tess.Process((Bitmap)upscale, PageSegMode.Auto);
                    OutputRichTextBox.Text =
                        "========== " + DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.ff") + " =========="
                        + Environment.NewLine + result.GetText().Trim()
                        + Environment.NewLine + OutputRichTextBox.Text
                        ;
                }
            }
            catch (Exception exception)
            {
                OutputRichTextBox.Text =
                    "========== " + DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.ff") + " =========="
                    + Environment.NewLine + "错误：" + exception.Message
                    + Environment.NewLine + OutputRichTextBox.Text
                    ;
            }
            finally
            {
                AppendTitle = "就绪";
            }
        }

        private void WatchingClipBoard_CheckedChanged(object sender, EventArgs e)
        {
            if (WatchingClipBoard.Checked) AddClipboardFormatListener(Handle);
            else RemoveClipboardFormatListener(Handle);
        }

        protected override void WndProc(ref Message m)
        {
            base.WndProc(ref m);

            if (m.Msg == WM_CLIPBOARDUPDATE && (DateTime.Now - _lastClipboard).TotalSeconds >= 1)
            {

                OcrImage(Clipboard.GetImage());
                _lastClipboard = DateTime.Now;
            }
        }

        [DllImport("user32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        private static extern bool AddClipboardFormatListener(IntPtr hwnd);

        [DllImport("user32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        private static extern bool RemoveClipboardFormatListener(IntPtr hwnd);

        private const int WM_CLIPBOARDUPDATE = 0x031D;
    }
}