Having a problem with function: openfiledialog iam using c++ win GUI, opencv

Question

Having a problem with function: openfiledialog iam using c++ win GUI, opencv

Hesham AbdMalek Ramadan 1

need that "path:"

private: System::Void open_Click(System::Object^ sender, System::EventArgs^ e)
{
openFileDialog1->Filter = "Images Files | *.JPG; *.PNG";
if (openFileDialog1->ShowDialog() == System::Windows::Forms::DialogResult::OK)
{
MessageBox::Show(openFileDialog1->FileName, "Path:");

}
}

to use it at:

Mat src = imread("path:", 0);
namedWindow("show", 0);
imshow("show", src);

to call the image and don't know-how.

tried to save it as a string did not work
help, please

thanks

David Lowndes 4,726 Reputation points

2021-12-13T09:28:58.283+00:00

Rather than having us try and guess what you've tried, why don't you show us a brief real example of what you've tried that "did not work"?

1 answer

Your answer

David Lowndes 4,726 Reputation points

2021-12-13T09:28:58.283+00:00

Rather than having us try and guess what you've tried, why don't you show us a brief real example of what you've tried that "did not work"?

Answer 1

Viorel 125.8K

According to https://learn.microsoft.com/en-us/cpp/dotnet/how-to-convert-system-string-to-standard-string, try something like this:

if (openFileDialog1->ShowDialog() == System::Windows::Forms::DialogResult::OK)  
{  
    MessageBox::Show( openFileDialog1->FileName, "Path:");  

    IntPtr p = Runtime::InteropServices::Marshal::StringToHGlobalAnsi( openFileDialog1->FileName);  
    const char* path = (const char*)p.ToPointer( );  
  
    Mat src = imread( path, 0);  
    . . .  
    Marshal::FreeHGlobal( p);  
}

See also:

Hesham AbdMalek Ramadan 1 Reputation point

2021-12-13T10:32:46.867+00:00
thanks bro i did this:

private: System::Void open_Click(System::Object^ sender, System::EventArgs^ e)
{
openFileDialog1->Filter = "Images Files | *.JPG; .PNG";
if (openFileDialog1->ShowDialog() == System::Windows::Forms::DialogResult::OK)
{
MessageBox::Show(openFileDialog1->FileName, "Path:");
IntPtr p = Runtime::InteropServices::Marshal::StringToHGlobalAnsi(openFileDialog1->FileName);
const char path = (const char*)p.ToPointer();

Mat src = imread(path, 0); namedWindow("show", 0); imshow("show", src); } }

put I need to use it globally for other functions like this fun

private: System::Void button1_Click(System::Object^ sender, System::EventArgs^ e)
{
Mat equ_image;

float hist[256] = { 0 }; for (int g = 0; g < 256; g++) { for (int r = 0; r < src.rows; r++) { for (int c = 0; c < src.cols; c++) { if (src.at<uchar>(r, c) == g) hist[g] = hist[g] + 1; } } if (hist[g] != 0) cout << "hist[" << g << "]= " << hist[g] << endl; } equalizeHist(src, equ_image); namedWindow("show", 0); imshow("show", equ_image); }

how to do that

thanks for your help
Viorel 125.8K Reputation points

2021-12-13T10:53:34.887+00:00
If you need src in different places, then use a member of your form, for example:

. . . Mat src; private: System::Void open_Click(System::Object^ sender, System::EventArgs^ e) { . . . src = imread(path, 0); . . . }

Then you can use it in button1_Click.
Hesham AbdMalek Ramadan 1 Reputation point

2021-12-13T11:29:56.987+00:00

tried it it says
Viorel 125.8K Reputation points

2021-12-13T11:41:55.227+00:00

It seems that the original problem is solved and you can focus on OpenCV issues and even start new questions. Maybe you should use another type instead of <uchar>,

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Having a problem with function: openfiledialog iam using c++ win GUI, opencv

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