how to resize windows taskbar programmatically?

Question

This autohotkey code works fine to resize the win 7 taskbar when it is on the left position

ResizeTaskbar(170)

ResizeTaskbar(size) {
    pAppBarData := Buffer(48), NumPut("uint", pAppBarData.Size, pAppBarData)
    DllCall("Shell32\SHAppBarMessage", "uint", 0x00000005, "ptr", pAppBarData)
        hTB := WinExist("ahk_class Shell_TrayWnd")
        NumPut("int", -A_ScreenWidth, pAppBarData, 24), NumPut("int", size, pAppBarData, 32)

        SendMessage(0x0214, 2, pAppBarData.Ptr + 24, , hTB), WinMove(0, 0)
}

I want to resize the taskbar when it is in bottom position so I changed the above code to:

ResizeTaskbar(170)

ResizeTaskbar(size) {
    pAppBarData := Buffer(48), NumPut("uint", pAppBarData.Size, pAppBarData)
    DllCall("Shell32\SHAppBarMessage", "uint", 0x00000005, "ptr", pAppBarData)
        hTB := WinExist("ahk_class Shell_TrayWnd")
        NumPut("int", -A_ScreenHeight, pAppBarData, 24), NumPut("int", size, pAppBarData, 32)

        ;https://learn.microsoft.com/en-us/windows/win32/winmsg/wm-sizing
        SendMessage(0x0214, 3, pAppBarData.Ptr + 24, , hTB), WinMove(0, 0)
}

but it does not work, where is the problem?

thank you

Answer 1

I could not make the autohotkey code to work, but i found a C code that worked after some editing, I posted the source and binary here if someone need it https://github.com/m417z/taskbar-resize/issues/3

// no need to compile 64, compile only 32 version it works fine with win7 64 
// i compile it with en_visual_studio_community_2013_with_update_5_x86_dvd_6816332.iso

#include <windows.h>
#include <shlwapi.h>

void main()
{
    int argc;
    WCHAR **argv = CommandLineToArgvW(GetCommandLine(), &argc);

    if(argv)
    {
        if(argc >= 3)
        {
            BOOL bBottom = lstrcmpi(argv[1], L"-b") == 0;
            BOOL bTop = lstrcmpi(argv[1], L"-t") == 0;
            BOOL bRight = lstrcmpi(argv[1], L"-r") == 0;
            BOOL bLeft = lstrcmpi(argv[1], L"-l") == 0;
            int nMySize = StrToInt(argv[2]);

            HWND hTaskbarWnd = FindWindow(L"Shell_TrayWnd", NULL);
            if(hTaskbarWnd)
            {
                RECT rc;
                GetWindowRect(hTaskbarWnd, &rc);

                if(bBottom) {
                    rc.top = rc.bottom - nMySize;
                    SendMessage(hTaskbarWnd, WM_SIZING, WMSZ_TOP, (LPARAM)&rc);
                    SetWindowPos(hTaskbarWnd, NULL, 0, 0, rc.right - rc.left, nMySize, SWP_NOMOVE | SWP_NOZORDER | SWP_NOACTIVATE);
                }
                else if(bTop) {
                    rc.bottom = rc.top + nMySize;
                    SendMessage(hTaskbarWnd, WM_SIZING, WMSZ_BOTTOM, (LPARAM)&rc);
                    SetWindowPos(hTaskbarWnd, NULL, 0, 0, rc.right - rc.left, nMySize, SWP_NOMOVE | SWP_NOZORDER | SWP_NOACTIVATE);
                }
                else if(bRight) {
                    rc.left = rc.right - nMySize;
                    SendMessage(hTaskbarWnd, WM_SIZING, WMSZ_LEFT, (LPARAM)&rc);
                    SetWindowPos(hTaskbarWnd, NULL, 0, 0, nMySize, rc.bottom - rc.top, SWP_NOMOVE | SWP_NOZORDER | SWP_NOACTIVATE);
                }
                else if(bLeft) {
                    rc.right = rc.left + nMySize;
                    SendMessage(hTaskbarWnd, WM_SIZING, WMSZ_LEFT, (LPARAM)&rc);
                    SetWindowPos(hTaskbarWnd, NULL, 0, 0, nMySize, rc.bottom - rc.top, SWP_NOMOVE | SWP_NOZORDER | SWP_NOACTIVATE);
                }
            }
        }

        LocalFree(argv);
    }

    ExitProcess(0);
}

Usage

taskbar_resize.exe (-l|-r|-b|-t) new_size

Description:

-l - The taskbar is on the left.

-r - The taskbar is on the right.

-b - The taskbar is on the bottom.

-t - The taskbar is on the top.

new_size - The new size of the taskbar, in pixels.

NB: for top and bottom positions, you cannot resize to 3 rows from 1 row you have to resize to 2 rows first then resize to 3 rows

the following numbers are based on the taskbar with small icons not the big ones

taskbar_resize.exe -b 60 ===> 1 row
taskbar_resize.exe -b 70 ===> 2 rows
taskbar_resize.exe -b 110 ===> 3 rows
taskbar_resize.exe -b 150 ===> 4 rows
taskbar_resize.exe -b 180 ===> 5 rows
taskbar_resize.exe -b 220 ===> 6 rows
taskbar_resize.exe -b 250 ===> 7 rows

update: I uploaded a compiled version for xp+ if someone need it, here: https://github.com/badrelmers/taskbar-resize/releases/tag/v1