This program creates WC_EDIT control inside the main window. The main window resizes edit control whenever the window itself is resized. I am trying to set margins of edit control content by updating formatting rectange of WC_EDIT control whenever it is resized.
Main window responds to WM_SIZE message and resizes edit control, then edit control responds to its own WM_SIZE message and tries to update formatting rectangle using EM_SETRECT, but nothing happens.
#include <windows.h>
#include <commctrl.h>
LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
LRESULT CALLBACK EditWindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
HWND hwnd;
HWND editHwnd;
WNDPROC origEditProc;
int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE, LPSTR pCmdLine, int nCmdShow)
{
WNDCLASS wc = {};
wc.lpfnWndProc = WindowProc;
wc.hInstance = hInstance;
wc.lpszClassName = "Window Class";
RegisterClass(&wc);
hwnd = CreateWindow(
wc.lpszClassName,
"",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
NULL,
NULL,
hInstance,
NULL
);
editHwnd = CreateWindow(
WC_EDIT,
"Lorem ipsum",
WS_CHILD | WS_VISIBLE | WS_VSCROLL | ES_LEFT | ES_MULTILINE | ES_AUTOVSCROLL,
0,
0,
100,
100,
hwnd,
NULL,
hInstance,
NULL
);
origEditProc = (WNDPROC) GetWindowLongPtr(editHwnd, GWLP_WNDPROC);
SetWindowLongPtr(editHwnd, GWLP_WNDPROC, (LONG_PTR)EditWindowProc);
ShowWindow(hwnd, nCmdShow);
MSG msg = {};
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return 0;
}
LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch (uMsg)
{
case WM_DESTROY:
PostQuitMessage(0);
return 0;
return 0;
case WM_SIZE:
RECT clientRect;
GetClientRect(hwnd, &clientRect);
SetWindowPos(editHwnd, NULL, 0, 0, clientRect.right - clientRect.left, clientRect.bottom - clientRect.top,
SWP_NOMOVE | SWP_NOZORDER | SWP_NOOWNERZORDER | SWP_NOACTIVATE);
}
return DefWindowProc(hwnd, uMsg, wParam, lParam);
}
LRESULT CALLBACK EditWindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch (uMsg)
{
case WM_SIZE:
RECT rect;
GetClientRect(editHwnd, &rect);
rect.left += 50;
rect.top += 50;
rect.right -= 50;
rect.bottom -= 50;
SendMessage(editHwnd, EM_SETRECT, NULL, (LPARAM)&rect);
}
return CallWindowProc(origEditProc, hwnd, uMsg, wParam, lParam);
}
Original window procedure of the WC_EDIT control should be called before updating formatting rectangle:
LRESULT CALLBACK EditWindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
LRESULT result = CallWindowProc(origEditProc, hwnd, uMsg, wParam, lParam);
switch (uMsg)
{
case WM_SIZE:
RECT rect;
GetClientRect(editHwnd, &rect);
rect.left += 50;
rect.top += 50;
rect.right -= 50;
rect.bottom -= 50;
SendMessage(editHwnd, EM_SETRECT, NULL, (LPARAM)&rect);
}
return result;
}