Made controls transparent to tab backgrounds on Windows. It doesn't quite work right...

new/container_windows.c

@@ -1,6 +1,11 @@
 // 7 april 2015
 #include "uipriv_windows.h"
 
+// TODOs
+// - [12:24] <ZeroOne> There's flickering between tabs
+// - with CTLCOLOR handler: [12:24] <ZeroOne> And setting the button text blanked out the entire GUI until I ran my mouse over the elements / [12:25] <ZeroOne> https://dl.dropboxusercontent.com/u/15144168/GUI%20stuff.png
+// - without CTLCOLOR handler: [12:33] <ZeroOne> If I hide the stack, then show it, it looks like it's drawing duplicate buttons underneath
+
 /*
 all container windows (including the message-only window, hence this is not in container_windows.c) have to call the sharedWndProc() to ensure messages go in the right place and control colors are handled properly
 */
@@ -30,6 +35,42 @@ static LRESULT forwardNotify(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
 	return DefWindowProcW(hwnd, uMsg, wParam, lParam);
 }
 
+static void paintControlBackground(HWND hwnd, HDC dc)
+{
+	HWND parent;
+	RECT r;
+	POINT pOrig;
+	DWORD le;
+
+	parent = hwnd;
+	for (;;) {
+		parent = GetParent(parent);
+		if (parent == NULL)
+			logLastError("error getting parent control of control in paintControlBackground()");
+		// wine sends these messages early, yay...
+		if (parent == initialParent)
+			return;
+		// skip groupboxes; they're (supposed to be) transparent
+		if (windowClassOf(parent, L"button", NULL) != 0)
+			break;
+	}
+	if (GetWindowRect(hwnd, &r) == 0)
+		logLastError("error getting control's window rect in paintControlBackground()");
+	// the above is a window rect in screen coordinates; convert to client rect
+	SetLastError(0);
+	if (MapWindowRect(NULL, parent, &r) == 0) {
+		le = GetLastError();
+		SetLastError(le);		// just to be safe
+		if (le != 0)
+			logLastError("error getting client origin of control in paintControlBackground()");
+	}
+	if (SetWindowOrgEx(dc, r.left, r.top, &pOrig) == 0)
+		logLastError("error moving window origin in paintControlBackground()");
+	SendMessageW(parent, WM_PRINTCLIENT, (WPARAM) dc, PRF_CLIENT);
+	if (SetWindowOrgEx(dc, pOrig.x, pOrig.y, NULL) == 0)
+		logLastError("error resetting window origin in paintControlBackground()");
+}
+
 BOOL sharedWndProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam, LRESULT *lResult)
 {
 	switch (uMsg) {
@@ -39,19 +80,19 @@ BOOL sharedWndProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam, LRESULT *
 	case WM_NOTIFY:
 		*lResult = forwardNotify(hwnd, uMsg, wParam, lParam);
 		return TRUE;
-/*TODO	case WM_CTLCOLORSTATIC:
+	case WM_CTLCOLORSTATIC:
 	case WM_CTLCOLORBTN:
-		// read-only TextFields and Textboxes are exempt
+/*TODO		// read-only TextFields and Textboxes are exempt
 		// this is because read-only edit controls count under WM_CTLCOLORSTATIC
 		if (windowClassOf((HWND) lParam, L"edit", NULL) == 0)
 			if (textfieldReadOnly((HWND) lParam))
 				return FALSE;
-		if (SetBkMode((HDC) wParam, TRANSPARENT) == 0)
+*/		if (SetBkMode((HDC) wParam, TRANSPARENT) == 0)
-			xpanic("error setting transparent background mode to Labels", GetLastError());
+			logLastError("error setting transparent background mode to controls in sharedWndProc()");
 		paintControlBackground((HWND) lParam, (HDC) wParam);
 		*lResult = (LRESULT) hollowBrush;
 		return TRUE;
-*/	}
+	}
 	return FALSE;
 }
 

new/init_windows.c

@@ -6,6 +6,8 @@ int nCmdShow;
 
 HFONT hMessageFont;
 
+HBRUSH hollowBrush;
+
 struct uiInitError {
 	char *msg;
 	char failbuf[256];
@@ -97,6 +99,10 @@ const char *uiInit(uiInitOptions *o)
 	if (ce != NULL)
 		return loadLastError(ce);
 
+	hollowBrush = (HBRUSH) GetStockObject(HOLLOW_BRUSH);
+	if (hollowBrush == NULL)
+		return loadLastError("getting hollow brush");
+
 	return NULL;
 }
 

new/uipriv_windows.h

@@ -45,7 +45,10 @@ extern HRESULT logMemoryExhausted(const char *);
 extern HINSTANCE hInstance;
 extern int nCmdShow;
 extern HFONT hMessageFont;
-extern HWND initialParent;
+extern HBRUSH hollowBrush;
+
+// util_windows.c
+extern int windowClassOf(HWND, ...);
 
 // text_windows.c
 extern WCHAR *toUTF16(const char *);
@@ -66,4 +69,5 @@ extern const char *initCommonControls(void);
 extern ATOM registerWindowClass(HICON, HCURSOR);
 
 // initparent_windows.c
+extern HWND initialParent;
 extern const char *initInitialParent(HICON, HCURSOR);

new/util_windows.c

@@ -38,3 +38,36 @@ intmax_t uiWindowsWindowTextWidth(HWND hwnd)
 
 	return size.cx;
 }
+
+// this is a helper function that takes the logic of determining window classes and puts it all in one place
+// there are a number of places where we need to know what window class an arbitrary handle has
+// theoretically we could use the class atom to avoid a _wcsicmp()
+// however, raymond chen advises against this - http://blogs.msdn.com/b/oldnewthing/archive/2004/10/11/240744.aspx (and we're not in control of the Tab class, before you say anything)
+// usage: windowClassOf(hwnd, L"class 1", L"class 2", ..., NULL)
+int windowClassOf(HWND hwnd, ...)
+{
+// MSDN says 256 is the maximum length of a class name; add a few characters just to be safe (because it doesn't say whether this includes the terminating null character)
+#define maxClassName 260
+	WCHAR classname[maxClassName + 1];
+	va_list ap;
+	WCHAR *curname;
+	int i;
+
+	if (GetClassNameW(hwnd, classname, maxClassName) == 0)
+		logLastError("error getting name of window class in windowClassOf()");
+	va_start(ap, hwnd);
+	i = 0;
+	for (;;) {
+		curname = va_arg(ap, WCHAR *);
+		if (curname == NULL)
+			break;
+		if (_wcsicmp(classname, curname) == 0) {
+			va_end(ap);
+			return i;
+		}
+		i++;
+	}
+	// no match
+	va_end(ap);
+	return -1;
+}