Error on creating TesseractEngine

[Vernizze]

Hi!

I'm starting with Tesseract and have this code, that runs very well on Windows:

using (var engine = new TesseractEngine("tessdata", "por"))
{            
    var image = Pix.LoadFromFile(filePath);

    var page = engine.Process(image);

    text = page.GetText();
}

But I need run this one on Linux, most specifically on Mint distribution, and I use in this form:

using (var engine = new TesseractEngine("./tessdata", "por"))
{            
    var image = Pix.LoadFromFile(filePath);

    var page = engine.Process(image);

    text = page.GetText();
}

And I receive this error in the 'new TesseractEngine' line:

Unhandled exception. System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
---> System.ArgumentNullException: Value cannot be null. (Parameter 'path1')
at System.ArgumentNullException.Throw(String paramName)
at System.IO.Path.Combine(String path1, String path2)
at InteropDotNet.LibraryLoader.InternalLoadLibrary(String baseDirectory, String platformName, String fileName)
at InteropDotNet.LibraryLoader.CheckExecutingAssemblyDomain(String fileName, String platformName)
at InteropDotNet.LibraryLoader.LoadLibrary(String fileName, String platformName)
at InteropRuntimeImplementer.LeptonicaApiSignaturesInstance.LeptonicaApiSignaturesImplementation..ctor(LibraryLoader loader)
at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor)
at System.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span1 copyOfArgs, BindingFlags invokeAttr) --- End of inner exception stack trace --- at System.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span1 copyOfArgs, BindingFlags invokeAttr)
at System.Reflection.MethodBaseInvoker.InvokeWithOneArg(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture)
at InteropDotNet.InteropRuntimeImplementer.CreateInstanceT
at Tesseract.Interop.LeptonicaApi.Initialize()
at Tesseract.Interop.TessApi.Initialize()
at Tesseract.Interop.TessApi.get_Native()
at Tesseract.TesseractEngine..ctor(String datapath, String language, EngineMode engineMode, IEnumerable1 configFiles, IDictionary2 initialOptions, Boolean setOnlyNonDebugVariables)
at Tesseract.TesseractEngine..ctor(String datapath, String language)
at TesteConversaoPdfParaImagem.Program.ReadImage(String prefix, String filePath, String resultFileName, Boolean isSingleblock) in C:\Users\carlo\source\repos\TesteConversaoPdfParaImagem\TesteConversaoPdfParaImagem\Program.cs:line 127
at TesteConversaoPdfParaImagem.Program.Main(String[] args) in C:\Users\carlo\source\repos\TesteConversaoPdfParaImagem\TesteConversaoPdfParaImagem\Program.cs:line 53

Do you help me with this, please?

Thanks a lot, guys! :)

[Yanik39]

System.ArgumentNullException: Value cannot be null. (Parameter 'path1')
at System.ArgumentNullException.Throw(String paramName)
at System.IO.Path.Combine(String path1, String path2)

I am not expert but, its definitely about your path :D.
I would Console.WriteLine(filePath); to see what is result of your Path.Combine. Probably you have null there.

[mitchuhl]

Yesterday I discovered the same error on the project that I just started. When I debug from Visual Studio there is no issue. When I publish and run it somewhere else, I get the same error message.

I discovered that I get the error when I enable the checkbox "Produce single file". When it's enabled I get the error. When it's disabled, I don't get the error.

In both situations the tessdata folder is on the same location (on the same level as my console executable). Also in both situations I confirmed my code was pointing to the right location by adding a console message:

string tesseractDataPath = Path.Combine(AppContext.BaseDirectory, "tessdata");
Console.WriteLine($"Tesseract data folder: {tesseractDataPath}");
using var ocrEngine = new TesseractEngine(tesseractDataPath, "nld+eng", EngineMode.Default);

[Vernizze]

Hi guys!

I found the error. It's happen on the class 'InteropDotNet.LibraryLoader', at the line 86:

var baseDirectory = Path.GetDirectoryName(executingAssembly.Location);

The code executingAssembly.Location return null and it's the cause of the crash. I created a handler class called 'EnvironmentUtils.cs' in 'Tesseract.Internal' with this code:

` using System;
using System.IO;
using System.Reflection;

namespace Tesseract.Internal
{
internal static class EnvironmentUtils
{
public static string AppPath(Assembly assembly)
{
string appPath = Path.GetDirectoryName(Path.GetDirectoryName(assembly?.Location));

        if (!string.IsNullOrWhiteSpace(appPath))
            return appPath;

        return AppPath();
    }

    public static string AppPath() 
    {
        string appPath;

        appPath = Directory.GetCurrentDirectory();

        if (!string.IsNullOrWhiteSpace(appPath))
            return appPath;

        appPath = Environment.CurrentDirectory;

        if (!string.IsNullOrWhiteSpace(appPath))
            return appPath;

        appPath = Path.Combine(AppContext.BaseDirectory, "tessdata");

        if (!string.IsNullOrWhiteSpace(appPath))
            return appPath;

        appPath = Path.GetDirectoryName(Path.GetDirectoryName(Assembly.GetEntryAssembly()?.Location));

        if (!string.IsNullOrWhiteSpace(appPath))
            return appPath;

        appPath = AppDomain.CurrentDomain.BaseDirectory;

        if (!string.IsNullOrWhiteSpace(appPath))
            return appPath;

        throw new ArgumentNullException("Application path not found");
    }
}

} `

And the problem has solved. But after this, the error change to this:

Unhandled exception. System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.DllNotFoundException: Failed to find library "libleptonica-1.82.0.so" for platform x64. at InteropDotNet.LibraryLoader.LoadLibrary(String fileName, String platformName) in D:\git\tesseract\src\Tesseract\Internal\InteropDotNet\LibraryLoader.cs:line 57 at InteropRuntimeImplementer.LeptonicaApiSignaturesInstance.LeptonicaApiSignaturesImplementation..ctor(LibraryLoader loader) at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor) at System.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span1 copyOfArgs, BindingFlags invokeAttr)
--- End of inner exception stack trace ---
at System.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span1 copyOfArgs, BindingFlags invokeAttr) at System.Reflection.MethodBaseInvoker.InvokeWithOneArg(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) at System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture) at InteropDotNet.InteropRuntimeImplementer.CreateInstance[T]() in D:\git\tesseract\src\Tesseract\Internal\InteropDotNet\InteropRuntimeImplementer.cs:line 45 at Tesseract.Interop.LeptonicaApi.Initialize() in D:\git\tesseract\src\Tesseract\Interop\LeptonicaApi.cs:line 563 at Tesseract.Interop.TessApi.Initialize() in D:\git\tesseract\src\Tesseract\Interop\BaseApi.cs:line 583 at Tesseract.Interop.TessApi.get_Native() in D:\git\tesseract\src\Tesseract\Interop\BaseApi.cs:line 372 at Tesseract.TesseractEngine..ctor(String datapath, String language, EngineMode engineMode, IEnumerable1 configFiles, IDictionary2 initialOptions, Boolean setOnlyNonDebugVariables) in D:\git\tesseract\src\Tesseract\TesseractEngine.cs:line 181 at Tesseract.TesseractEngine..ctor(String datapath, String language) in D:\git\tesseract\src\Tesseract\TesseractEngine.cs:line 37 at TesteConversaoPdfParaImagem.Program.ReadImage(String prefix, String filePath, String resultFileName, Boolean isSingleblock) in C:\Users\carlo\source\repos\TesteConversaoPdfParaImagem\TesteConversaoPdfParaImagem\Program.cs:line 147 at TesteConversaoPdfParaImagem.Program.Extract(String pdfName, String readedFilePath) in C:\Users\carlo\source\repos\TesteConversaoPdfParaImagem\TesteConversaoPdfParaImagem\Program.cs:line 68 at TesteConversaoPdfParaImagem.Program.Main(String[] args) in C:\Users\carlo\source\repos\TesteConversaoPdfParaImagem\TesteConversaoPdfParaImagem\Program.cs:line 14

In the next week I expect return to see this new problem.

Thank's for your help :)

[charlesw]

Thanks, I'll see if I can find some time this evening to put in a fix. If I don't, feel free to create a push request with fix and I'll merge it in. Sorry haven't been all that active lately, pretty much all my free time is taken up with home Reno's/repairs.

…

On Sun, 30 June 2024, 4:53 am Carlos Felippe Vernizze, < ***@***.***> wrote: Hi guys! I found the error. It's happen on the class 'InteropDotNet.LibraryLoader', at the line 86: var baseDirectory = Path.GetDirectoryName(executingAssembly.Location); The code executingAssembly.Location return null and it's the cause of the crash. I created a handler class called 'EnvironmentUtils.cs' in 'Tesseract.Internal' with this code: ` using System; using System.IO; using System.Reflection; namespace Tesseract.Internal { internal static class EnvironmentUtils { public static string AppPath(Assembly assembly) { string appPath = Path.GetDirectoryName(Path.GetDirectoryName(assembly?.Location)); if (!string.IsNullOrWhiteSpace(appPath)) return appPath; return AppPath(); } public static string AppPath() { string appPath; appPath = Directory.GetCurrentDirectory(); if (!string.IsNullOrWhiteSpace(appPath)) return appPath; appPath = Environment.CurrentDirectory; if (!string.IsNullOrWhiteSpace(appPath)) return appPath; appPath = Path.Combine(AppContext.BaseDirectory, "tessdata"); if (!string.IsNullOrWhiteSpace(appPath)) return appPath; appPath = Path.GetDirectoryName(Path.GetDirectoryName(Assembly.GetEntryAssembly()?.Location)); if (!string.IsNullOrWhiteSpace(appPath)) return appPath; appPath = AppDomain.CurrentDomain.BaseDirectory; if (!string.IsNullOrWhiteSpace(appPath)) return appPath; throw new ArgumentNullException("Application path not found"); } } } ` And the problem has solved. But after this, the error change to this: Unhandled exception. System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.DllNotFoundException: Failed to find library " libleptonica-1.82.0.so" for platform x64. at InteropDotNet.LibraryLoader.LoadLibrary(String fileName, String platformName) in D:\git\tesseract\src\Tesseract\Internal\InteropDotNet\LibraryLoader.cs:line 57 at InteropRuntimeImplementer.LeptonicaApiSignaturesInstance.LeptonicaApiSignaturesImplementation..ctor(LibraryLoader loader) at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor) at System.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span1 copyOfArgs, BindingFlags invokeAttr) --- End of inner exception stack trace --- at System.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span1 copyOfArgs, BindingFlags invokeAttr) at System.Reflection.MethodBaseInvoker.InvokeWithOneArg(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) at System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture) at InteropDotNet.InteropRuntimeImplementer.CreateInstance[T]() in D:\git\tesseract\src\Tesseract\Internal\InteropDotNet\InteropRuntimeImplementer.cs:line 45 at Tesseract.Interop.LeptonicaApi.Initialize() in D:\git\tesseract\src\Tesseract\Interop\LeptonicaApi.cs:line 563 at Tesseract.Interop.TessApi.Initialize() in D:\git\tesseract\src\Tesseract\Interop\BaseApi.cs:line 583 at Tesseract.Interop.TessApi.get_Native() in D:\git\tesseract\src\Tesseract\Interop\BaseApi.cs:line 372 at Tesseract.TesseractEngine..ctor(String datapath, String language, EngineMode engineMode, IEnumerable1 configFiles, IDictionary2 initialOptions, Boolean setOnlyNonDebugVariables) in D:\git\tesseract\src\Tesseract\TesseractEngine.cs:line 181 at Tesseract.TesseractEngine..ctor(String datapath, String language) in D:\git\tesseract\src\Tesseract\TesseractEngine.cs:line 37 at TesteConversaoPdfParaImagem.Program.ReadImage(String prefix, String filePath, String resultFileName, Boolean isSingleblock) in C:\Users\carlo\source\repos\TesteConversaoPdfParaImagem\TesteConversaoPdfParaImagem\Program.cs:line 147 at TesteConversaoPdfParaImagem.Program.Extract(String pdfName, String readedFilePath) in C:\Users\carlo\source\repos\TesteConversaoPdfParaImagem\TesteConversaoPdfParaImagem\Program.cs:line 68 at TesteConversaoPdfParaImagem.Program.Main(String[] args) in C:\Users\carlo\source\repos\TesteConversaoPdfParaImagem\TesteConversaoPdfParaImagem\Program.cs:line 14 In the next week I expect return to see this new problem. Thank's for your help :) — Reply to this email directly, view it on GitHub <#673 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAB7HSCU24LUJLZFIBIQMADZJ37CFAVCNFSM6AAAAABJ6R2EHKVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDCOJYGMYDAOJWG4> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>