twapi::find_windows -pids [pid] -visible 1 -toplevel 1

// TkAero.cpp - The one-and-only code file for TkAero.dll
// Written by jdp 2009
// This program is licensed under a Tcl-style BSD license.

// This will create one command, dwm::extendglass.
// It takes 5 arguments: hwnd, left, right, top, & bottom, in that order.
// hwnd is the window handle. You will probably want to use twapi to find this.
// left, right, top, & bottom are the number of pixels to extend the glass on those sides.
// Setting them all to -1 will make the whole window glass.
// Note that ONLY areas that are black will become glassified.
// Also note that drawing regular widgets onto this glass frame has some (spectacularly) ugly results.

// Macros defining things that are boring to type out

// Arguments for a proc defining a command
#define TCL_CMD_ARGS ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj * CONST objv[]

// Command to get an int from the args (with error checking)
#define TCL_GET_INT(n, p) if (Tcl_GetIntFromObj(interp, objv[n + 1], p) != TCL_OK) return TCL_ERROR;

// Check for the right number of args
#define TCL_WNA(n, m) if (objc != n + 1) {Tcl_WrongNumArgs(interp, 1, objv, m); return TCL_ERROR;}

// Create a command from a proc
#define TCL_CREATE_CMD(n, c) Tcl_CreateObjCommand(interp, n, c, NULL, NULL)

#define USE_TCL_STUBS 1

#include <tcl.h>

// This is the header file for the DWM API. You'll also want to have a reference to dwmapi.lib.
// Both files are in the Windows SDK. It is recommended that you delay-load dwmapi.dll.
#include <dwmapi.h>

extern "C"
{
        __declspec(dllexport) int Tkaero_Init(Tcl_Interp* interp);
}

// The command to extend glass.
// Note that you will have to do all your own version checking, etc. before calling this.
// If you are on Windows < Vista, you will get a nasty error when you call this.
// (Unless you didn't compile with delay-loading for dwmapi.dll, in which case the whole program will
// crash upon loading this extension.)
static int extendGlassCmd(TCL_CMD_ARGS)
{
        // Make sure we have the correct number of arguments
        TCL_WNA(5, "hwnd left right top bottom");

        // extract ints from our arguments
        int hwnd, left, right, top, bottom;
        TCL_GET_INT(0, &hwnd);
        TCL_GET_INT(1, &left);
        TCL_GET_INT(2, &right);
        TCL_GET_INT(3, &top);
        TCL_GET_INT(4, &bottom);

        // The DWM stuff.

        // Create the margins struct
        MARGINS mar = {top, bottom, left, right};

        // Extend the frame into the client area
        DwmExtendFrameIntoClientArea((HWND)hwnd, &mar);

        return TCL_OK;
}

int Tkaero_Init(Tcl_Interp *interp) {
        if (Tcl_InitStubs(interp, "8.1", 0) == NULL) {
                return TCL_ERROR;
        }
        TCL_CREATE_CMD("dwm::extendglass", extendGlassCmd);
        return TCL_OK;
}