How to get coordinates of first displayed line in windows relatively to DATA-BUFFER ?

[schlebe]

Description of the new feature

where DATA-BUFFER contains all rows displayed and all rows that has been displayed before and that are currently only visible in scrolling console vertically.

My question with more explanation can be found on StackOverflow on https://stackoverflow.com/questions/79725603/on-windows-terminal-in-visual-c-how-can-i-overwrite-previous-lines

Proposed technical implementation details

No response

[DHowett]

I see that you are combining the Windows Console APIs with the use of Virtual Terminal sequences.

I wonder if you would be able to use the Virtual Terminal sequences for cursor positioning, rather than trying to move the cursor directly in the coordinate system.

You can move the cursor up one line relative to the current position (X stays the same, Y decrements) with \x1b[1A.

CSI Ps A Cursor Up Ps Times (default = 1) (CUU).

You can move the cursor to the beginning of the previous line (X = 0, Y decrements) with \x1b[1F

CSI Ps F Cursor Preceding Line Ps Times (default = 1) (CPL).

Does that help?

[schlebe]

No !
Using proposed Virtual Terminal sequences don't help me.

Why ?

Because some times length of filename is greater than 1 row !
CSI Ps A or CSI Ps F don't move the cursor 1 line as written in documentation but only 1 row !

I think that there exists some confusion in documentation that use "Line" word to describe "Row" objects !
For me, a line is a string of character terminated by "\n" or "\r\n".

I have also tested using Save/Restore ANSI and not ANSI cursor position but this doesn't work correclty.

Here is a part of my test code

    COORD oCurrentCoord;
    HANDLE hStdout = GetStdHandle(STD_OUTPUT_HANDLE);
    int iPreviousLineLen; 
    
    // clear screen
    wprintf(L"\x1b[2J");
    // set cursor on first line
    wprintf(L"\x1b[0;0H");

    PrintToConsole("// BS2EDT.Sources");
    PrintToConsole("//   Commands");
    PrintToConsole("//     LineCommands");

    oCurrentCoord = GetConsoleCursorPositionx();
    PrintToConsole("++ CmdDeleteLine.cpp");

    SetConsoleCursorPositionx(oCurrentCoord);
    PrintToConsole("++ CmdSplitLine.cpp");

    oCurrentCoord = GetConsoleCursorPositionx();
    oCurrentCoord.Y -= 1;
    SetConsoleCursorPositionx(oCurrentCoord);
    PrintToConsole("++ CmdSwitchLine.cpp");

    // print one line upper
    wprintf(L"\x1b[1F");
    // save cursor position for next file
    wprintf(L"\x1b7");
    PrintToConsole("++ CmdWriteFile.cpp");

    // save cursor position
    wprintf(L"\x1b8");
    PrintToConsole("++ CmdWriteText.cpp");

    PrintToConsole("");
    PrintToConsole("// BS2EDT.Sources");
    PrintToConsole("//   Commands");
    PrintToConsole("//     LineCommands");

    oCurrentCoord = GetConsoleCursorPositionx();
    PrintToConsole("++ CmdDeleteLine.Very-Long-File-Name.Very-Long-File-Name.Very-Long-File-Name.Very-Long-FileName.Very-Long-FileName.Very-Long-FileName.cpp");

    SetConsoleCursorPositionx(oCurrentCoord);
    PrintToConsole("++ CmdSplitLine.Very-Long-File-Name.Very-Long-File-Name.Very-Long-File-Name.Very-Long-FileName.Very-Long-FileName.Very-Long-FileName.cpp");

    oCurrentCoord = GetConsoleCursorPositionx();
    oCurrentCoord.Y -= 1;
    SetConsoleCursorPositionx(oCurrentCoord);
    PrintToConsole("++ CmdSwitchLine.Very-Long-File-Name.Very-Long-File-Name.Very-Long-File-Name.Very-Long-FileName.Very-Long-FileName.Very-Long-FileName.cpp");

    // print one line upper
    wprintf(L"\x1b[1F");
    // save cursor position for next file
    //wprintf(L"\x1b7");
    wprintf(L"\x1b[s");
    PrintToConsole("++ CmdWriteLine.Very-Long-File-Name.Very-Long-File-Name.Very-Long-File-Name.Very-Long-FileName.Very-Long-FileName.Very-Long-FileName.cpp");

    // save cursor position
    //wprintf(L"\x1b8");
    wprintf(L"\x1b[u");
    PrintToConsole("++ CmdWriteText.Very-Long-File-Name.Very-Long-File-Name.Very-Long-File-Name.Very-Long-FileName.Very-Long-FileName.Very-Long-FileName.cpp");

    // set cursor on last line
    wprintf(L"\x1b[28;0H");

    PrintToConsole("// BS2EDT.Sources");
    PrintToConsole("//   Commands");
    PrintToConsole("//     LineCommands");

    oCurrentCoord = GetConsoleCursorPositionx();
    PrintToConsole("++ CmdDeleteLine.cpp");

    SetConsoleCursorPositionx(oCurrentCoord);
    PrintToConsole("++ CmdSplitLine.cpp");

    oCurrentCoord = GetConsoleCursorPositionx();
    oCurrentCoord.Y -= 1;
    SetConsoleCursorPositionx(oCurrentCoord);
    PrintToConsole("++ CmdSwitchLine.cpp");

    // print one line upper
    wprintf(L"\x1b[1F");
    // save cursor position for next file
    //wprintf(L"\x1b7");
    wprintf(L"\x1b[s");
    PrintToConsole("++ CmdWriteFile.cpp");

    // save cursor position
    //wprintf(L"\x1b8");
    wprintf(L"\x1b[u");
    PrintToConsole("++ CmdWriteText.cpp");

and the result

The code of functions used in my test is following

int PrintToConsole(const char* szLine)
    {
    //Clear line completetly before overwriting it with new line
    wprintf(L"\x1b[100K");
    cout << szLine << endl;
    return strlen(szLine);
    }

COORD GetConsoleCursorPositionx()
    {
    HANDLE hStdout = GetStdHandle(STD_OUTPUT_HANDLE);
    CONSOLE_SCREEN_BUFFER_INFO infoConsole;

    GetConsoleScreenBufferInfo(
        hStdout,
        &infoConsole);

    return infoConsole.dwCursorPosition;
    }

void SetConsoleCursorPositionx(COORD dwCursorPosition)
    {
    HANDLE hStdout = GetStdHandle(STD_OUTPUT_HANDLE);

    SetConsoleCursorPosition(hStdout, dwCursorPosition);
    }

[schlebe]

I want to add a little remark.

Today, 5 minutes ago, I have tested my code above using ANSI code

    wprintf(L"\x1b[s"); // save cursor position
    wprintf(L"\x1b[u"); // restore cursor position

... and this work correctly for the 3 cases ...
Displaying "CmdWriteLine" is always overwritten by "CmdWriteText".

This is not the case when I use

   wprintf(L"\x1b7");
   wprintf(L"\x1b8");

I can use your technic with success but the next step in my program is to overwrite "folder" line when no file in folder matchs the searching text !

In this new situation, I find API solution easier that API command sequence !

The problem is that API solution doesn't allow to correct previous recorded cursor position when cursor is at bottom of screen !!!

[schlebe]

I continued to work with your proposed solution but as written before, this solution doesn't work correctly when I try to delete previous line representing a directory.

Here is my new code

    Write     ("// 0. BS2EDT.Documentation");
    ClearPreviousLine(); // delete 0. foler name
    Write     ("// 1. BS2EDT.Sources");
    Write     ("//   2. Commands");
    Write     ("//     3. LineCommands");

    Write     ("++ CmdDeleteLineInArea.cpp");
    OverWrite ("++ CmdSplitLine.cpp");
    OverWrite ("++ CmdWriteLine.Very-Long-File-Name.Very-Long-File-Name.Very-Long-File-Name.Very-Long-FileName.Very-Long-FileName.Very-Long-FileName.cpp");
    OverWrite ("++ CmdSwitchLine.cpp");
    OverWrite ("++ CmdWriteFile.cpp");
    OverWrite ("++ CmdWriteText.cpp");

    ClearPreviousLine(); // delete last .CPP filename displayed 
    ClearPreviousLine(); // delete 3. folder name -> NOK
    ClearPreviousLine(); // delete 2. folder name -> NOK

where

void Write(const char* szLine)
    {
   // save cursor position and write line
    wprintf(L"\x1b[s");
    cout << szLine << endl;
    }

void ClearPreviousLine()
    {
    // restore cursor position  
    wprintf(L"\x1b[u");
    // clear all character from cursor position on 10 lines to be sure to delete long filename  
    wprintf(L"\x1b[10M");
    }

void OverWrite(const char* szLine)
    {
    ClearPreviousLine()
    Write(szLine);
    }

and the result

The 2 last statements doesn't work.

I think that that SAVE sequence can only use 1 time. It seems impossible to have stack S sequence.
You can have SUSUSUSU sequence but not SSUU !
I think that second S delete first one so that first one is lost !

Can you confirm my analyse ?

But that is not written in documentation !!!

I don't have this problem using API !
I have another problem but not this one ;-)

PS: to delete all character from restored cursor to be certain to delete previous name I use now L"\x1b[10M"
Before I used L"\x1b[100K" but 100 is not a correct value for integer.
I tried to use L"\x1b[2K" but it doesn't work when line is greater that 1 row !
I searched then a sequence to delete all screen from cursor position but I don't find it !
But this is another issue/question that I can post on StackOverflow.