Transparent Console

[bradszy]

Righty-o, so ive been using VB6 for a break from c++ for a while...
And now im back to the basics.
And stuck.
.
.
I'm using this:

#include <iostream>
#define _WIN32_WINNT 0x0500
#include <windows.h>
using namespace std;
int main()
{
    HWND hWnd = GetConsoleWindow();
    SetConsoleTitle("Test");
    SetWindowLong(hWnd, GWL_EXSTYLE,
    GetWindowLong(hWnd, GWL_EXSTYLE) | WS_EX_LAYERED);
    SetLayeredWindowAttributes(hWnd, 0, 50, LWA_ALPHA);
    system("PAUSE");
    return 0;
}

To try and make the console window translucent, but failing miserably.
Any idea's guys?

Thanks guys.

[matsp]

Check the return value from each function, and show the GetLastError() if zero.

--
Mats

[bradszy]

Sorry for this... But, English?
I'm just starting from the basics again, .
VB6 dumbed me down.
Thankyou, matsp.

[matsp]

Something like this (not in English, I think what I wrote classifies as English - but an example is probably better):

void error()
{
    cout << "Error: " << GetLastError() << endl;
    system("PAUSE");
    exit(1);   // Naughty, but otherwise we would need a lot of nested if or goto's. 
 }

int main()
{
    HWND hWnd = GetConsoleWindow();
    if (!hwnd)
        error();
    if (!SetConsoleTitle("Test"))
       error();
    if (!SetWindowLong(hWnd, GWL_EXSTYLE,
                                     GetWindowLong(hWnd, GWL_EXSTYLE) | WS_EX_LAYERED))
        error();
    if(!SetLayeredWindowAttributes(hWnd, 0, 50, LWA_ALPHA))
       error();
    system("PAUSE");
    return 0;
}

Then look up the error code you get (I'm 99% sure that you will) on:
http://msdn2.microsoft.com/en-us/lib...81(VS.85).aspx

--
Mats

[Elysia]

In other words:

#include <iostream>
#define _WIN32_WINNT 0x0500
#include <windows.h>
using namespace std;
int main()
{
    LONG lRet;
    HWND hWnd = GetConsoleWindow();
    SetConsoleTitle("Test");
    lRet = SetWindowLong(hWnd, GWL_EXSTYLE,
        GetWindowLong(hWnd, GWL_EXSTYLE) | WS_EX_LAYERED);
    // What is lRet equal to?
    lRet = SetLayeredWindowAttributes(hWnd, 0, 50, LWA_ALPHA);
    // What is lRet equal to?
    system("PAUSE");
    return 0;
}

Also note that it's very important that if you break a long line into several, add indentation to the rest of the lines, starting from line 2, like I did and marked with red.
I didn't even see it was two lines until I started transforming the code because you hadn't done that.

[bradszy]

Woah, thankyou soo very much.
Error: 5.
Be right back, looking it up.

EDIT: Access is denied. What.The.Hell? Vista error?

[Elysia]

May be. I'd look at the functions (documented at MSDN) and any reasons they might fail. Try running your app as administator, as well.

[matsp]

It may of course help to add a string to the arguments of error() and tell us WHICH one of the functions returned that error - I expect it may be that the console window doesn't accept the alpha value, but that's just a guess... [And the driver could also block this sort of setting, I expect].

--
Mats

[bradszy]

Running as admin, same result.
Hm...

[matsp]

Running as admin, same result.
Hm...

Yes, I expected that to be irrelevant - you should be able to set YOUR own window to transparent if you like, whether you are a regular user or administrator - but it may be that console windows can't be set to transparent, for example. Which of the functions are failing?

--
Mats

[bradszy]

I checked, and

if (!SetWindowLong(hWnd, GWL_EXSTYLE,
GetWindowLong(hWnd, GWL_EXSTYLE) | WS_EX_LAYERED))

And

if(!SetLayeredWindowAttributes(hWnd, 0, 50, LWA_ALPHA))

Seem to be failing.

[matsp]

I tried on my XP machine, and I get error 5 from SetWindowLong(), and then (probably as a consequence) error 87 (Invalid parameter) from the SetLayeredWindowsAttributes()).

As I just saw your update, I expect this is similar to your experience.

--
Mats

[bradszy]

Any work around or fix?
Now that we're on the same page, what do you think is the cause?

EDIT: I used

#include <iostream>
#define _WIN32_WINNT 0x0500
#include <windows.h>
using namespace std;

int main()
{
int ERRORNUMB = 0;
HWND hWnd = GetConsoleWindow();
if (!hWnd)
ERRORNUMB = 1;
cout<<ERRORNUMB;
if (!SetConsoleTitle("Test"))
ERRORNUMB = 2;
cout<<ERRORNUMB;
if (!SetWindowLong(hWnd, GWL_EXSTYLE,
GetWindowLong(hWnd, GWL_EXSTYLE) | WS_EX_LAYERED))
ERRORNUMB = 3;
cout<<ERRORNUMB;
if(!SetLayeredWindowAttributes(hWnd, 0, 50, LWA_ALPHA))
ERRORNUMB = 4;
cout<<ERRORNUMB;
system("PAUSE");
return 0;
}

To get the errors... Correct?

[matsp]

I did this

#include <stdio.h>
#define _WIN32_WINNT 0x0500
#include <windows.h>

#define CHECK_ERROR(x) if (!x) error(__FILE__, __LINE__, GetLastError())


void error(const char *file, int line, int err)
{
  printf("&#37;s:%d: Error %d\n", file, line, err);
}

int main()
{
    LONG lRet;
    HWND hWnd = GetConsoleWindow();
    CHECK_ERROR(hWnd);
    SetConsoleTitle("Test");
    lRet = SetWindowLong(hWnd, GWL_EXSTYLE,
        GetWindowLong(hWnd, GWL_EXSTYLE) | WS_EX_LAYERED);
    CHECK_ERROR(lRet);
    lRet = SetLayeredWindowAttributes(hWnd, 0, 50, LWA_ALPHA);
    CHECK_ERROR(lRet);
	
    system("PAUSE");
    return 0;
}

It would help to do something like:

#include <stdio.h>
#define _WIN32_WINNT 0x0500
#include <windows.h>

#define CHECK_ERROR(x, name) if (!x) error(__FILE__, __LINE__, name, GetLastError())


void error(const char *file, int line, const char *name, int err)
{
  printf("%s:%d: Error on %s: %d\n", file, line, name, err);
}

int main()
{
    LONG lRet;
    HWND hWnd = GetConsoleWindow();
    CHECK_ERROR(hWnd, "GetConsoleWindow");
...

--
Mats

[bradszy]

K:\Computers\C++ stuff\C++ Projects\Untitled1.cpp:21: Error 5
K:\Computers\C++ stuff\C++ Projects\Untitled1.cpp:23: Error 87

I tried your error checking code, and seems to be alot more efficient .