有 Windows 控制台 API 报告 Window 调整大小

Question

In the windows console API, you can collect input for when the BUFFER is resized (Via window resize), but you cannot collect input for when the WINDOW is resized. To illustrate this issue, here is a small program:

#include <Windows.h>
#include <stdio.h>

#define STR_BUF_SIZE 128
#define ENABLE_WINDOW_INPUT

int main() {
    HANDLE screenBufferHandle = CreateConsoleScreenBuffer(
        GENERIC_READ | GENERIC_WRITE,
        0,
        NULL,
        CONSOLE_TEXTMODE_BUFFER,
        NULL
    );
    SetConsoleActiveScreenBuffer(screenBufferHandle);
    HANDLE in = GetStdHandle(STD_INPUT_HANDLE);

    CONSOLE_SCREEN_BUFFER_INFO info;
    INPUT_RECORD recordBuffer[32];

    char strBuf[STR_BUF_SIZE];

    while (1) {

        // Collect the input
        int inputLeft, inputToProcess;
        do {
            GetNumberOfConsoleInputEvents(in, &inputLeft);
            if (!inputLeft) {
                break;
            }
            inputLeft -= 32;
            ReadConsoleInput(
                in,
                recordBuffer,
                32,
                &inputToProcess
            );
            int i = 0;
            while (i < inputToProcess) {
                if (recordBuffer[i].EventType == WINDOW_BUFFER_SIZE_EVENT) {
                    COORD size = recordBuffer[i].Event.WindowBufferSizeEvent.dwSize;
                    sprintf_s(strBuf, STR_BUF_SIZE, "Event recorded, %dx%d\n", size.X, size.Y);
                    OutputDebugString(strBuf);
                }
                i++;
            }
        } while (inputLeft > 0);

        GetConsoleScreenBufferInfo(screenBufferHandle, &info);
    }

}

This will report (To debug) when the buffer is resized. Here is when this becomes a problem: The buffer is not resized if :

• The buffer is already taller than the window (Vertical scrollbars appear) AND

• The resize event only affects the Y axis

In this case, the buffer is not resized, the window shrinks, and the handle on the scrollbar does too. However, I want windows to report this event because :

I would like to keep the buffer exactly the same size as the window, to hide the scrollbars.

Answer 1

I had the same challenge, and so I wrote this function to deal with it. Called from the right place in your program, the window resize event can be captured within millisecs of the event itself. Best wishes to all.

#include <windows.h>

/*------------------------------------------------------------------------------------

check_console_window_resize_event()

2022.10.05 - Created by Greg Spears and placed in the public domain.
           - Tested -- use at your own risk.

Params: none
Returns: TRUE if the console window has changed size.  FALSE if not.

USAGE: Best practice is to call the function repeatedly from your main application 
loop.   Preferably a place where the function can be called several times per second 
throughout the program's run time.

*--------------------------------------------------------------------------------**/

int check_console_window_resize_event(void) {

/* variables declared static hold their value between function calls.*/
static int old_screen_w=0, old_screen_h=0;
static HANDLE hConOut=NULL;
int current_screen_w, current_screen_h;
int window_resized = FALSE;
CONSOLE_SCREEN_BUFFER_INFO csbi;
SECURITY_ATTRIBUTES sa;

if(!hConOut)
{
    /* First call -- get the window handle one time and save it*/
    sa.nLength = sizeof(sa);
    sa.lpSecurityDescriptor = NULL;
    sa.bInheritHandle = TRUE;
    /* Using CreateFile we get the true console handle, avoiding any redirection.*/
    hConOut = CreateFile( TEXT("CONOUT$"),
         GENERIC_READ | GENERIC_WRITE,
         FILE_SHARE_READ | FILE_SHARE_WRITE,
         &sa, OPEN_EXISTING, (DWORD)0, (HANDLE)0 );
}
if(!hConOut) /* actually, this is a bad error, let your app handle the error as needed*/
    return FALSE;

GetConsoleScreenBufferInfo( hConOut, &csbi );
current_screen_w  = csbi.srWindow.Right - csbi.srWindow.Left + 1;
current_screen_h  = csbi.srWindow.Bottom - csbi.srWindow.Top + 1;

if(!old_screen_w && !old_screen_h)
{
    /* Execution comes here if this is first time this function is called.  
    ** Initialize the static variables and bail...*/
    old_screen_w = current_screen_w;
    old_screen_h = current_screen_h;
    return FALSE;
}

/* At last the real work of this function can be realized...*/
if(current_screen_w != old_screen_w || current_screen_h != old_screen_h)
{
    old_screen_w = current_screen_w;
    old_screen_h = current_screen_h;
    window_resized = TRUE;
}
return window_resized;

}