Bir Windows API programında, bir Edit kontrolunun arka plan ve metin renklerini kontrolun içinde bulunduğu pencerenin mesaj fonksiyonunda WM_CTLCOLOREDIT mesajına işlem yaparak, dış çerçeve rengini ise subclassing işlemi için oluşturulan fonksiyonda WM_NCPAINT ve WM_NCCALCSIZE mesajlarına işlem yaparak değiştirebiliriz.
Programda yer alacak main.c dosya içeriği aşağıdaki şekilde olacaktır:
main.c
#if defined(UNICODE) && !defined(_UNICODE)
#define _UNICODE
#elif defined(_UNICODE) && !defined(UNICODE)
#define UNICODE
#endif
#define _WIN32_WINNT 0x0501
#define _WIN32_IE 0x0501
#include <tchar.h>
#include <windows.h>
#include <commctrl.h>
#define IDC_EDIT 1001
/* Declare Windows procedure */
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);
/* Subclassing fonksiyon bildirimi */
LRESULT CALLBACK ControlBorderProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam, UINT_PTR uIdSubclass, DWORD_PTR dwRefData);
/* Make the class name into a global variable */
TCHAR szClassName[ ] = _T("CodeBlocksWindowsApp");
HWND hwndEdit;
int WINAPI WinMain (HINSTANCE hThisInstance,
HINSTANCE hPrevInstance,
LPSTR lpszArgument,
int nCmdShow)
{
HWND hwnd; /* This is the handle for our window */
MSG messages; /* Here messages to the application are saved */
WNDCLASSEX wincl; /* Data structure for the windowclass */
/* The Window structure */
wincl.hInstance = hThisInstance;
wincl.lpszClassName = szClassName;
wincl.lpfnWndProc = WindowProcedure; /* This function is called by windows */
wincl.style = CS_DBLCLKS; /* Catch double-clicks */
wincl.cbSize = sizeof (WNDCLASSEX);
/* Use default icon and mouse-pointer */
wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
wincl.lpszMenuName = NULL; /* No menu */
wincl.cbClsExtra = 0; /* No extra bytes after the window class */
wincl.cbWndExtra = 0; /* structure or the window instance */
/* Use Windows's default colour as the background of the window */
wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;
/* Register the window class, and if it fails quit the program */
if (!RegisterClassEx (&wincl))
return 0;
/* The class is registered, let's create the program*/
hwnd = CreateWindowEx (
0, /* Extended possibilites for variation */
szClassName, /* Classname */
_T("Edit (Renkleri değişebilen)"), /* Title Text */
WS_OVERLAPPEDWINDOW, /* default window */
CW_USEDEFAULT, /* Windows decides the position */
CW_USEDEFAULT, /* where the window ends up on the screen */
400, /* The programs width */
300, /* and height in pixels */
HWND_DESKTOP, /* The window is a child-window to desktop */
NULL, /* No menu */
hThisInstance, /* Program Instance handler */
NULL /* No Window Creation data */
);
/* Make the window visible on the screen */
ShowWindow (hwnd, nCmdShow);
/* Run the message loop. It will run until GetMessage() returns 0 */
while (GetMessage (&messages, NULL, 0, 0))
{
/* Translate virtual-key messages into character messages */
TranslateMessage(&messages);
/* Send message to WindowProcedure */
DispatchMessage(&messages);
}
/* The program return-value is 0 - The value that PostQuitMessage() gave */
return messages.wParam;
}
/* This function is called by the Windows function DispatchMessage() */
LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message) /* handle the messages */
{
case WM_CREATE:
{
// Sadece rakam girilebilen Edit kontrolu
hwndEdit = CreateWindowEx(0, "EDIT", "",
WS_CHILD | WS_VISIBLE, 20, 20, 200, 20,
hwnd, (HMENU) IDC_EDIT, NULL, NULL);
SetWindowSubclass(hwndEdit, ControlBorderProc, 0, 0);
SetWindowPos(hwndEdit, NULL, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | SWP_FRAMECHANGED);
}
break;
case WM_CTLCOLOREDIT:
{
if (lParam==(LPARAM)hwndEdit) {
HDC hdcStatic = (HDC) wParam;
SetTextColor(hdcStatic, RGB(250, 250, 250));
SetBkColor(hdcStatic, RGB(255, 200, 0));
return (INT_PTR)CreateSolidBrush(RGB(255, 200, 0));
}
}
break;
case WM_DESTROY:
PostQuitMessage (0); /* send a WM_QUIT to the message queue */
break;
default: /* for messages that we don't deal with */
return DefWindowProc (hwnd, message, wParam, lParam);
}
return 0;
}
// Subclassing fonksiyonu
LRESULT CALLBACK ControlBorderProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam, UINT_PTR uIdSubclass, DWORD_PTR dwRefData)
{
switch (message) {
case WM_NCPAINT:
{
RECT rect;
HDC hdc;
hdc = GetWindowDC(hwnd);
GetWindowRect(hwnd, &rect);
OffsetRect(&rect, -rect.left, -rect.top);
FrameRect(hdc, &rect, CreateSolidBrush(RGB(210, 0, 160)));
ReleaseDC(hwnd, hdc);
return 0;
break;
}
case WM_NCCALCSIZE:
if(lParam) {
NCCALCSIZE_PARAMS* sz = (NCCALCSIZE_PARAMS*)lParam;
InflateRect(&sz->rgrc[0], -1, -1);
return 0;
}
break;
break;
}
return DefSubclassProc(hwnd, message, wParam, lParam);
}
Program derleyip çalıştırdığımızda aşağıdakine benzer bir ekran görüntüsü karşımıza gelecektir: