Subclassed button not producing animation on every repeated click - c++

Question

I have a custom subclassed button created in the WM_CREATE message of my WindowProc callback. Here are the creation and subclassing instructions, along with a structure used to control the button state:
static button_state btnstateBtnInstall;
hBtnInstall = CreateWindow(WC_BUTTON, L"Button", WS_CHILD | WS_VISIBLE, (window_width / 2) - (btn_install_width / 2), window_height - (window_height / 6) - (btn_install_height / 2), btn_install_width, btn_install_height, hwnd, (HMENU)HMENU_btn_install, NULL, NULL);
SetWindowSubclass(hBtnInstall, BtnInstallProc, 0, (DWORD_PTR)&btnstateBtnInstall);
The struct is defined as follows:
struct button_state
{
bool pushed;
button_state() { pushed = false; }
};
The subclassed procedure is coded as follows:
LRESULT CALLBACK BtnInstallProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam, UINT_PTR uIdSubClass, DWORD_PTR dwRefData)
{
button_state* state = (button_state*)dwRefData;
// Omitted part where I create brushes and font to be used for painting
switch (msg)
{
case WM_PAINT:
{
PAINTSTRUCT ps;
HDC hdc = BeginPaint(hwnd, &ps);
RECT rc = ps.rcPaint;
POINT pt;
GetCursorPos(&pt);
ScreenToClient(hwnd, &pt);
BOOL hover = PtInRect(&rc, pt);
if (state->pushed)
{
// Pushed
FillRect(hdc, &rc, hBrPushed);
}
else if (hover)
{
// Mouse over
FillRect(hdc, &rc, hBrHover);
}
else
{
// Normal
FillRect(hdc, &rc, hBrNormal);
}
SetBkMode(hdc, TRANSPARENT);
SetTextColor(hdc, RGB(255, 255, 255));
SelectFont(hdc, SegoeUI);
static LPCWSTR InstallBtnTxt = L"Install";
static int InstallBtnTxtLen = static_cast<int>(wcslen(InstallBtnTxt)); // Should be a safe cast, for small arrays like this one
DrawText(hdc, InstallBtnTxt, InstallBtnTxtLen, &rc, DT_SINGLELINE | DT_CENTER | DT_VCENTER);
EndPaint(hwnd, &ps);
return 0;
}
case WM_LBUTTONDOWN:
{
state->pushed = true;
break;
}
case WM_LBUTTONUP:
{
state->pushed = false;
break;
}
// Omitted part where I handle WM_DESTROY to do cleanup
}
return DefSubclassProc(hwnd, msg, wParam, lParam);
}
To compare the behaviour of my button with a standard one, I created another button without subclassing and using only the standard BUTTON class and WS_VISIBLE | WS_CHILD attributes.
As you can see from the attached gif, when I repeatedly click on a standard class button, every click produces the animation while when hitting multiple times the button I created with this code it seems like it isn't catching every click but (as you can see) something like 50% of them.
What am I missing? Why isn't my button as responsive as the one that comes with the standard class?
TL;DR: when clicking slowly on my subclassed button, the painting is correct. As you can see from my attached image, the difference between mine and a standard button is big when repeating clicks on them. How can I make my control be as responsive as the standard one?

Answer 1

When you are clicking fast some WM_LBUTTONDOWN messages are substituted by the WM_LBUTTONDBLCLK (default double click handling). You need to handle it just like you are handling the WM_LBUTTONDOWN message.
case WM_LBUTTONDOWN:
case WM_LBUTTONDBLCLK: // <-- Added
{
state->pushed = true;
break;
}