Prabhu Kumar

a tech twaddler..

Archive for February, 2010

Extracting Icon from an executable (name)

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Remember the Process Viewer that we worked on a few months back? I was wondering how to display the applications icons, the way task manager does. A small icon beside the application name gives it a pleasant look. So how do you extract the icon from an executable? Well, there’s an API for that (pun). ExtractIconEx() is the function we use to get a handle to the applications icon. It’s a simple API, just give it the full path to the executable and it returns an HICON (icon handle). So I went back to my Process Viewer and added a static label to display the icon. Here is the code:

HICON hIcon, hIc;
hIcon = ExtractIconEx(filename, 0, NULL, &hIc, 1);

if(!hIcon)
{
    hIcon = LoadIcon(g_hInst, MAKEINTRESOURCE(IDI_ICON1));
}

SendMessage(g_hStaticIcon, STM_SETIMAGE, IMAGE_ICON, (LPARAM)hIcon);
 

If the handle returned is NULL (for applications without user interface) then we display a default icon, the terminal. After getting the icon handle, we set it on the label using STM_SETIMAGE message.

Now to the interesting part. An application can contain quite many icons as resources, so how does the system know which icon to return? The answer is that the system chooses the icon whose resource identifier value is the smallest and returns it as the application icon. So if I have three icons in my application whose identifiers are defined as: (in Resourceppc.h)

#define IDI_ICON1                       103
#define IDI_ICON2                       104
#define IDI_ICON3                       105

then the resource IDI_ICON1 will be returned.

Here is another interesting bit, the static label (in the video below) was created using CreateWindow() as follows:

g_hStaticIcon = CreateWindowEx(0, L"STATIC", NULL, WS_CHILD | WS_VISIBLE | SS_ICON |
                          
SS_REALSIZEIMAGE, x, y, 16, 16, hWndParent, 0, g_hInst, NULL);
 

Now a static image label will expand itself if the image being displayed on it is bigger than the label size. This is what you wouldn’t want, imagine some application icons displayed in 16×16 pixels while others in 32×32. So to prevent this automatic scaling of the label we use the SS_REALSIZEIMAGE flag in the CreateWindow() call. But according to MSDN, SS_REALSIZEIMAGE is listed under "Unsupported static control styles".

If you have seen the video below already, then you’ll notice that the gwes.exe icon appears larger. There could be two reasons, either all other application’s icons are getting scaled down to 16×16 and gwes.exe’s isn’t (wonder why), or there is no scaling happening and all other applications are returning 16×16 icons while gwes is returning a larger 32×32 icon (unlikely). Now if I remove the SS_REALSIZEIMAGE flag while creating the label then all the icons are displayed big (32×32)! This means that scaling down is indeed happening and SS_REALSIZEIMAGE, although listed under ‘Unsupported static control styles‘, still works. I am a little confused as to why this is happening, if you got a clue then do let know.

Here’s the video:  

 

Displaying the icons like I did above is just the proof. Next step would be to display the icons right beside the application name (who needs serial number!), got to look at list views and images. And hopefully the image scaling problem should resolve itself with list_view images.

 

Written by Prabhu Kumar

February 25th, 2010 at 3:03 pm

Posted in Uncategorized

Fun with menus! update on Part I

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If you remember Fun with menus! Part I, then you’ll also remember that we were able to get two different popup menus on the left and the right softkeys. Morin Marco contacted me through the same post and via email, explaining that the code wasn’t working for him. We had a few mail exchanges and exchanges on the post too. It wasn’t clear why the same code wasn’t working for him, until he sent the screen shots of his problem. Turns out he was trying the code on the latest emulator, Windows Mobile 6.5.3. And when I installed the 6.5.3 emulator and ran the code, the result was the same. Here are a few screen shots of the same code running on different emulators:

On the 6.5 emulator

  
 

 On the 6.5.3 emulator

   

So from what we concluded, the functionality has been disabled by Microsoft on the latest emulator, which is a good thing because having popup menus on the left and the right softkeys wasn’t recommended by them in the first place. 

Update 1:
See this MSDN forum thread.

Written by Prabhu Kumar

February 21st, 2010 at 3:04 pm

Posted in Uncategorized