1 files changed, 73 insertions, 0 deletions
diff --git a/new/windows/util.c b/new/windows/util.c
new file mode 100644
index 0000000..93b32d8
--- /dev/null
+++ b/new/windows/util.c
@@ -0,0 +1,73 @@
+// 6 april 2015
+#include "uipriv_windows.h"
+
+intmax_t uiWindowsWindowTextWidth(HWND hwnd)
+{
+	LRESULT len;
+	WCHAR *text;
+	HDC dc;
+	HFONT prevfont;
+	SIZE size;
+
+	size.cx = 0;
+	size.cy = 0;
+
+	// first we need the window text
+	len = SendMessageW(hwnd, WM_GETTEXTLENGTH, 0, 0);
+	if (len == 0)		// no text; nothing to do
+		return 0;
+	text = (WCHAR *) uiAlloc((len + 1) * sizeof (WCHAR), "WCHAR[]");
+	// note the comparison: the size includes the null terminator, but the return does not
+	if (GetWindowText(hwnd, text, len + 1) != len)
+		logLastError("error getting window text in uiWindowsWindowTextWidth()");
+
+	// now we can do the calculations
+	dc = GetDC(hwnd);
+	if (dc == NULL)
+		logLastError("error getting DC in uiWindowsWindowTextWidth()");
+	prevfont = (HFONT) SelectObject(dc, hMessageFont);
+	if (prevfont == NULL)
+		logLastError("error loading control font into device context in uiWindowsWindowTextWidth()");
+	if (GetTextExtentPoint32W(dc, text, len, &size) == 0)
+		logLastError("error getting text extent point in uiWindowsWindowTextWidth()");
+	if (SelectObject(dc, prevfont) != hMessageFont)
+		logLastError("error restoring previous font into device context in uiWindowsWindowTextWidth()");
+	if (ReleaseDC(hwnd, dc) == 0)
+		logLastError("error releasing DC in uiWindowsWindowTextWidth()");
+	uiFree(text);
+
+	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;
+}