Button positioning

Try this function inside WM_SIZE. Pass your button handle as the parameter.

Code:

/*
 *  Places a control at the bottom right of it's parent.
 */
void MakeBottomRight( HWND button )
{
  RECT rcClient, rcButton ;  
  HWND hwndParent ;
  int newButtonX, newButtonY ;
  
  if ( !IsWindow(button) )
    return ;
  
  hwndParent = GetParent(button);
  
  if ( !IsWindow(hwndParent) )
    return ;
  
  GetClientRect( hwndParent, &rcClient );  
  GetClientRect( button, &rcButton );  
  newButtonX = rcClient.right  - rcButton.right  ;
  newButtonY = rcClient.bottom - rcButton.bottom ;  
  SetWindowPos( button, NULL, newButtonX, newButtonY, 0, 0, 
                SWP_NOSIZE|SWP_NOZORDER );
}

Um... I can't get that code to work. I don't know how to pass a value to a windows procedure (I can pass values in C though).

Also it's telling me "missing ';' before 'type'" on the void MakeBottomRight line. The WM_SIZE worked fine before I added the function (!?)

mw

Put that piece of code at the top. Probably below your <windows.h>

Then in your WM_SIZE message, call it like this:

Code:

    case WM_SIZE:
      {
        MakeBottomRight( hwndButton );
        return 0 ;
      }

For reference, this is my complete code.

Code:

/*------------------------------------------------------------------------------
Demonstrates putting a button at the bottom right of a window.
  
Author: Dante Shamest
Date:   11th October 2005
------------------------------------------------------------------------------*/
#include <windows.h>

HWND hwndMain ;
HWND hwndButton ;

/*
 *  Places a control at the bottom right of it's parent.
 */
void MakeBottomRight( HWND button )
{
  RECT rcClient, rcButton ;  
  HWND hwndParent ;
  int newButtonX, newButtonY ;
  
  if ( !IsWindow(button) )
    return ;
  
  hwndParent = GetParent(button);
  
  if ( !IsWindow(hwndParent) )
    return ;
  
  GetClientRect( hwndParent, &rcClient );  
  GetClientRect( button, &rcButton );  
  newButtonX = rcClient.right  - rcButton.right  ;
  newButtonY = rcClient.bottom - rcButton.bottom ;  
  SetWindowPos( button, NULL, newButtonX, newButtonY, 0, 0, 
                SWP_NOSIZE|SWP_NOZORDER );
}

LRESULT CALLBACK WndProc( HWND hwnd,UINT msg,WPARAM wParam,LPARAM lParam )
{
  switch(msg)  
  {
    case WM_CREATE:
      {
        hwndButton = CreateWindow( "BUTTON", "My Button", WS_CHILD|WS_VISIBLE,
                                   10, 10, 200, 22, hwnd, 0, GetModuleHandle(0),
                                   0 );
                                   
        return 0;                                    
      }
      
    case WM_SIZE:
      {
        MakeBottomRight( hwndButton );
        return 0 ;
      }
    
    case WM_DESTROY:
      {
        PostQuitMessage(0);
        return 0;
      }
      
    default: return DefWindowProc(hwnd,msg,wParam,lParam);
  }
}

int WINAPI WinMain( HINSTANCE hInst, HINSTANCE hPrev, LPSTR args, int nShow )
{
  WNDCLASS wc = {0};
  MSG  msg ;    
  wc.lpszClassName = TEXT( "ButtonFun" );
  wc.hInstance     = hInst ;
  wc.hbrBackground = GetSysColorBrush(COLOR_3DFACE);
  wc.lpfnWndProc   = WndProc ;
  wc.hCursor       = LoadCursor(0,IDC_ARROW);
  
  RegisterClass(&wc);
  hwndMain = CreateWindow( wc.lpszClassName,TEXT("Button At Lower Right"),
                           WS_OVERLAPPEDWINDOW|WS_VISIBLE,
                           0,0,300,200,0,0,hInst,0);
  

  while( GetMessage(&msg,0,0,0) > 0 ) {
    TranslateMessage(&msg);
    DispatchMessage(&msg);
  }
  return (int)msg.wParam;
}

I'm still getting a bunch of errors/warnings, starting with "Illegal use of HWND" in the line that says "HWND hwndParent = GetParent(button);"

I'm sorry for being so much trouble man... :-(

I can probably print a button in the bottom right hand corner myself. Is that all you were wanting me to do? It probably won't print in the DISPLAYED bottom right hand corner though...

mw

Just want to check something. Are you using C, or C++?

And yes, basically my C++ function puts the button (or any control) at the bottom of its parent window.

I'm using C.

This is my button:

hwndButton = CreateWindow
(
TEXT ("button"),
TEXT ("New Game"),
WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON,
rect.right - btnWidth,
rect.bottom - btnHeight,
btnWidth,
btnHeight,
hwnd,
(HMENU) IDB_NEWGAMEBUTTON,
GetModuleHandle (NULL),
NULL
);

This is supposed to display the button as far to the right as it can and as far to the bottom as it can.

It displays the button approx 75% to the right and 75% to the bottom of the client area.

mw

Okay, I've changed my code to be C. It should work now.

Much better!

Ok, now it gives me the warning "hwndButton used without having been initialized". I added the CreateWindow command to my WM_CREATE just like you did and it still gives me this warning.

It doesn't print any button(s)...

mw

Have you assigned the button handle to hwndButton using the = operator?

Ok, two things:

1) I had defined HWND locally instead of globally like you did.

2) It works beautifully now and prints a non-clickable button in the very bottom right hand corner of the DISPLAYED client area with "My Button" text on it.

I guess this means I'm doing it wrong somehow...

Thanks for your patience, BTW!

What does this mean?

mw

Glad that there's finally some results.

I'm not sure what you're doing that's different, but instead of specifying the size in CreateWindow(Ex), calculate the position of the button in WM_SIZE, then use MoveWindow or SetWindowPos to change the button's position.

I think I figured out why I can't center my buttons properly:

When I declare my window class, I use CW_DEFAULT for the width/height settings. I create the buttons immediately after declaring the window. When I finally ShowWindow I specify it as maximized.

How do I change my window declaration to be maximized? You have to specify width/height instead of just saying "maximized" and Charles Petzold (of course) doesn't seem to have any information in his lousy book... :-(

mw

How do I change my window declaration to be maximized?

You mean in CreateWindow(Ex)? You'll have to calculate the size of the screen, and subtract the taskbar height.

Why not just do all your calculations in WM_SIZE? (e.g., in the code I posted above)

My boss wants the window full screen and unchangeable (ie: WS_OVERLAPPED instead of WS_OVERLAPPEDWINDOW). :-(

mw

My boss wants the window full screen and unchangeable

Fullscreen (and not just maximized)? Then that's easy. Use the following values as the width and height.

Code:

  int screenWidth  = GetSystemMetrics(SM_CXSCREEN) ;
  int screenHeight = GetSystemMetrics(SM_CYSCREEN) ;