1 files changed, 166 insertions, 0 deletions
diff --git a/src/libui_sdl/libui/windows/d2dscratch.cpp b/src/libui_sdl/libui/windows/d2dscratch.cpp
new file mode 100644
index 0000000..6dc2ba5
--- /dev/null
+++ b/src/libui_sdl/libui/windows/d2dscratch.cpp
@@ -0,0 +1,166 @@
+// 17 april 2016
+#include "uipriv_windows.hpp"
+
+// The Direct2D scratch window is a utility for libui internal use to do quick things with Direct2D.
+// To use, call newD2DScratch() passing in a subclass procedure. This subclass procedure should handle the msgD2DScratchPaint message, which has the following usage:
+// - wParam - 0
+// - lParam - ID2D1RenderTarget *
+// - lResult - 0
+// You can optionally also handle msgD2DScratchLButtonDown, which is sent when the left mouse button is either pressed for the first time or held while the mouse is moving.
+// - wParam - position in DIPs, as D2D1_POINT_2F *
+// - lParam - size of render target in DIPs, as D2D1_SIZE_F *
+// - lResult - 0
+// Other messages can also be handled here.
+
+// TODO allow resize
+
+#define d2dScratchClass L"libui_d2dScratchClass"
+
+// TODO clip rect
+static HRESULT d2dScratchDoPaint(HWND hwnd, ID2D1RenderTarget *rt)
+{
+	COLORREF bgcolorref;
+	D2D1_COLOR_F bgcolor;
+
+	rt->BeginDraw();
+
+	// TODO only clear the clip area
+	// TODO clear with actual background brush
+	bgcolorref = GetSysColor(COLOR_BTNFACE);
+	bgcolor.r = ((float) GetRValue(bgcolorref)) / 255.0;
+	// due to utter apathy on Microsoft's part, GetGValue() does not work with MSVC's Run-Time Error Checks
+	// it has not worked since 2008 and they have *never* fixed it
+	// TODO now that -RTCc has just been deprecated entirely, should we switch back?
+	bgcolor.g = ((float) ((BYTE) ((bgcolorref & 0xFF00) >> 8))) / 255.0;
+	bgcolor.b = ((float) GetBValue(bgcolorref)) / 255.0;
+	bgcolor.a = 1.0;
+	rt->Clear(&bgcolor);
+
+	SendMessageW(hwnd, msgD2DScratchPaint, 0, (LPARAM) rt);
+
+	return rt->EndDraw(NULL, NULL);
+}
+
+static void d2dScratchDoLButtonDown(HWND hwnd, ID2D1RenderTarget *rt, LPARAM lParam)
+{
+	double xpix, ypix;
+	FLOAT dpix, dpiy;
+	D2D1_POINT_2F pos;
+	D2D1_SIZE_F size;
+
+	xpix = (double) GET_X_LPARAM(lParam);
+	ypix = (double) GET_Y_LPARAM(lParam);
+	// these are in pixels; we need points
+	// TODO separate the function from areautil.cpp?
+	rt->GetDpi(&dpix, &dpiy);
+	pos.x = (xpix * 96) / dpix;
+	pos.y = (ypix * 96) / dpiy;
+
+	size = realGetSize(rt);
+
+	SendMessageW(hwnd, msgD2DScratchLButtonDown, (WPARAM) (&pos), (LPARAM) (&size));
+}
+
+static LRESULT CALLBACK d2dScratchWndProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
+{
+	LONG_PTR init;
+	ID2D1HwndRenderTarget *rt;
+	ID2D1DCRenderTarget *dcrt;
+	RECT client;
+	HRESULT hr;
+
+	init = GetWindowLongPtrW(hwnd, 0);
+	if (!init) {
+		if (uMsg == WM_CREATE)
+			SetWindowLongPtrW(hwnd, 0, (LONG_PTR) TRUE);
+		return DefWindowProcW(hwnd, uMsg, wParam, lParam);
+	}
+
+	rt = (ID2D1HwndRenderTarget *) GetWindowLongPtrW(hwnd, GWLP_USERDATA);
+	if (rt == NULL) {
+		rt = makeHWNDRenderTarget(hwnd);
+		SetWindowLongPtrW(hwnd, GWLP_USERDATA, (LONG_PTR) rt);
+	}
+
+	switch (uMsg) {
+	case WM_DESTROY:
+		rt->Release();
+		SetWindowLongPtrW(hwnd, 0, (LONG_PTR) FALSE);
+		break;
+	case WM_PAINT:
+		hr = d2dScratchDoPaint(hwnd, rt);
+		switch (hr) {
+		case S_OK:
+			if (ValidateRect(hwnd, NULL) == 0)
+				logLastError(L"error validating D2D scratch control rect");
+			break;
+		case D2DERR_RECREATE_TARGET:
+			// DON'T validate the rect
+			// instead, simply drop the render target
+			// we'll get another WM_PAINT and make the render target again
+			// TODO would this require us to invalidate the entire client area?
+			rt->Release();
+			SetWindowLongPtrW(hwnd, GWLP_USERDATA, (LONG_PTR) NULL);
+			break;
+		default:
+			logHRESULT(L"error drawing D2D scratch window", hr);
+		}
+		return 0;
+	case WM_PRINTCLIENT:
+		uiWindowsEnsureGetClientRect(hwnd, &client);
+		dcrt = makeHDCRenderTarget((HDC) wParam, &client);
+		hr = d2dScratchDoPaint(hwnd, dcrt);
+		if (hr != S_OK)
+			logHRESULT(L"error printing D2D scratch window client area", hr);
+		dcrt->Release();
+		return 0;
+	case WM_LBUTTONDOWN:
+		d2dScratchDoLButtonDown(hwnd, rt, lParam);
+		return 0;
+	case WM_MOUSEMOVE:
+		// also send LButtonDowns when dragging
+		if ((wParam & MK_LBUTTON) != 0)
+			d2dScratchDoLButtonDown(hwnd, rt, lParam);
+		return 0;
+	}
+	return DefWindowProcW(hwnd, uMsg, wParam, lParam);
+}
+
+ATOM registerD2DScratchClass(HICON hDefaultIcon, HCURSOR hDefaultCursor)
+{
+	WNDCLASSW wc;
+
+	ZeroMemory(&wc, sizeof (WNDCLASSW));
+	wc.lpszClassName = d2dScratchClass;
+	wc.lpfnWndProc = d2dScratchWndProc;
+	wc.hInstance = hInstance;
+	wc.hIcon = hDefaultIcon;
+	wc.hCursor = hDefaultCursor;
+	wc.hbrBackground = (HBRUSH) (COLOR_BTNFACE + 1);
+	wc.cbWndExtra = sizeof (LONG_PTR);			// for the init status
+	return RegisterClassW(&wc);
+}
+
+void unregisterD2DScratchClass(void)
+{
+	if (UnregisterClassW(d2dScratchClass, hInstance) == 0)
+		logLastError(L"error unregistering D2D scratch window class");
+}
+
+HWND newD2DScratch(HWND parent, RECT *rect, HMENU controlID, SUBCLASSPROC subclass, DWORD_PTR subclassData)
+{
+	HWND hwnd;
+
+	hwnd = CreateWindowExW(0,
+		d2dScratchClass, L"",
+		WS_CHILD | WS_VISIBLE,
+		rect->left, rect->top,
+		rect->right - rect->left, rect->bottom - rect->top,
+		parent, controlID, hInstance, NULL);
+	if (hwnd == NULL)
+		// TODO return decoy window
+		logLastError(L"error creating D2D scratch window");
+	if (SetWindowSubclass(hwnd, subclass, 0, subclassData) == FALSE)
+		logLastError(L"error subclassing D2D scratch window");
+	return hwnd;
+}