DDrawCompat/DDrawCompat/CompatGdiDc.cpp

#include <algorithm>
#include <unordered_map>

#include "CompatGdi.h"
#include "CompatGdiDc.h"
#include "CompatGdiDcCache.h"
#include "DDrawLog.h"
#include "Hook.h"
#include "ScopedCriticalSection.h"

namespace
{
	using CompatGdiDcCache::CachedDc;

	struct CompatDc : CachedDc
	{
		CompatDc(const CachedDc& cachedDc = {}) : CachedDc(cachedDc) {}
		DWORD refCount;
		HDC origDc;
		int savedState;
	};

	typedef std::unordered_map<HDC, CompatDc> CompatDcMap;
	CompatDcMap g_origDcToCompatDc;

	struct ExcludeClipRectsData
	{
		HDC compatDc;
		HWND rootWnd;
	};

	void copyDcAttributes(CompatDc& compatDc, HDC origDc, POINT& origin)
	{
		SelectObject(compatDc.dc, GetCurrentObject(origDc, OBJ_FONT));
		SelectObject(compatDc.dc, GetCurrentObject(origDc, OBJ_BRUSH));
		SelectObject(compatDc.dc, GetCurrentObject(origDc, OBJ_PEN));

		if (GM_ADVANCED == GetGraphicsMode(origDc))
		{
			SetGraphicsMode(compatDc.dc, GM_ADVANCED);
			XFORM transform = {};
			GetWorldTransform(origDc, &transform);
			SetWorldTransform(compatDc.dc, &transform);
		}

		SetMapMode(compatDc.dc, GetMapMode(origDc));

		POINT viewportOrg = {};
		GetViewportOrgEx(origDc, &viewportOrg);
		SetViewportOrgEx(compatDc.dc, viewportOrg.x + origin.x, viewportOrg.y + origin.y, nullptr);
		SIZE viewportExt = {};
		GetViewportExtEx(origDc, &viewportExt);
		SetViewportExtEx(compatDc.dc, viewportExt.cx, viewportExt.cy, nullptr);

		POINT windowOrg = {};
		GetWindowOrgEx(origDc, &windowOrg);
		SetWindowOrgEx(compatDc.dc, windowOrg.x, windowOrg.y, nullptr);
		SIZE windowExt = {};
		GetWindowExtEx(origDc, &windowExt);
		SetWindowExtEx(compatDc.dc, windowExt.cx, windowExt.cy, nullptr);

		SetArcDirection(compatDc.dc, GetArcDirection(origDc));
		SetBkColor(compatDc.dc, GetBkColor(origDc));
		SetBkMode(compatDc.dc, GetBkMode(origDc));
		SetDCBrushColor(compatDc.dc, GetDCBrushColor(origDc));
		SetDCPenColor(compatDc.dc, GetDCPenColor(origDc));
		SetLayout(compatDc.dc, GetLayout(origDc));
		SetPolyFillMode(compatDc.dc, GetPolyFillMode(origDc));
		SetROP2(compatDc.dc, GetROP2(origDc));
		SetStretchBltMode(compatDc.dc, GetStretchBltMode(origDc));
		SetTextAlign(compatDc.dc, GetTextAlign(origDc));
		SetTextCharacterExtra(compatDc.dc, GetTextCharacterExtra(origDc));
		SetTextColor(compatDc.dc, GetTextColor(origDc));

		POINT brushOrg = {};
		GetBrushOrgEx(origDc, &brushOrg);
		SetBrushOrgEx(compatDc.dc, brushOrg.x, brushOrg.y, nullptr);

		POINT currentPos = {};
		GetCurrentPositionEx(origDc, &currentPos);
		MoveToEx(compatDc.dc, currentPos.x, currentPos.y, nullptr);
	}

	BOOL CALLBACK excludeClipRectForOverlappingWindow(HWND hwnd, LPARAM lParam)
	{
		auto excludeClipRectsData = reinterpret_cast<ExcludeClipRectsData*>(lParam);
		if (hwnd == excludeClipRectsData->rootWnd)
		{
			return FALSE;
		}

		if (!IsWindowVisible(hwnd))
		{
			return TRUE;
		}

		RECT windowRect = {};
		GetWindowRect(hwnd, &windowRect);

		HRGN windowRgn = CreateRectRgnIndirect(&windowRect);
		ExtSelectClipRgn(excludeClipRectsData->compatDc, windowRgn, RGN_DIFF);
		DeleteObject(windowRgn);

		return TRUE;
	}

	void excludeClipRectsForOverlappingWindows(HWND hwnd, bool isMenuWindow, HDC compatDc)
	{
		ExcludeClipRectsData excludeClipRectsData = { compatDc, GetAncestor(hwnd, GA_ROOT) };
		if (!isMenuWindow)
		{
			EnumWindows(&excludeClipRectForOverlappingWindow,
				reinterpret_cast<LPARAM>(&excludeClipRectsData));
		}

		HWND menuWindow = FindWindow(reinterpret_cast<LPCSTR>(0x8000), nullptr);
		while (menuWindow && menuWindow != hwnd)
		{
			excludeClipRectForOverlappingWindow(
				menuWindow, reinterpret_cast<LPARAM>(&excludeClipRectsData));
			menuWindow = FindWindowEx(nullptr, menuWindow, reinterpret_cast<LPCSTR>(0x8000), nullptr);
		}
	}

	void setClippingRegion(HDC compatDc, HDC origDc, HWND hwnd, bool isMenuWindow, const POINT& origin)
	{
		HRGN clipRgn = CreateRectRgn(0, 0, 0, 0);
		if (1 == GetClipRgn(origDc, clipRgn))
		{
			OffsetRgn(clipRgn, origin.x, origin.y);
			SelectClipRgn(compatDc, clipRgn);
		}

		if (hwnd)
		{
			if (isMenuWindow || 1 != GetRandomRgn(origDc, clipRgn, SYSRGN))
			{
				RECT rect = {};
				GetWindowRect(hwnd, &rect);
				SetRectRgn(clipRgn, rect.left, rect.top, rect.right, rect.bottom);
			}

			excludeClipRectsForOverlappingWindows(hwnd, isMenuWindow, compatDc);
			ExtSelectClipRgn(compatDc, clipRgn, RGN_AND);
		}

		DeleteObject(clipRgn);
		SetMetaRgn(compatDc);
	}
}

namespace CompatGdiDc
{
	HDC getDc(HDC origDc, bool isMenuPaintDc)
	{
		if (!origDc || OBJ_DC != GetObjectType(origDc) || DT_RASDISPLAY != GetDeviceCaps(origDc, TECHNOLOGY))
		{
			return nullptr;
		}

		Compat::ScopedCriticalSection gdiLock(CompatGdi::g_gdiCriticalSection);

		auto it = g_origDcToCompatDc.find(origDc);
		if (it != g_origDcToCompatDc.end())
		{
			++it->second.refCount;
			return it->second.dc;
		}

		const HWND hwnd = WindowFromDC(origDc);
		const bool isMenuWindow = hwnd && 0x8000 == GetClassLongPtr(hwnd, GCW_ATOM);
		if (isMenuWindow && !isMenuPaintDc)
		{
			return nullptr;
		}

		CompatDc compatDc(CompatGdiDcCache::getDc());
		if (!compatDc.dc)
		{
			return nullptr;
		}

		POINT origin = {};
		GetDCOrgEx(origDc, &origin);

		compatDc.savedState = SaveDC(compatDc.dc);
		copyDcAttributes(compatDc, origDc, origin);
		setClippingRegion(compatDc.dc, origDc, hwnd, isMenuWindow, origin);

		compatDc.refCount = 1;
		compatDc.origDc = origDc;
		g_origDcToCompatDc.insert(CompatDcMap::value_type(origDc, compatDc));

		return compatDc.dc;
	}

	HDC getOrigDc(HDC dc)
	{
		const auto it = std::find_if(g_origDcToCompatDc.begin(), g_origDcToCompatDc.end(),
			[dc](const CompatDcMap::value_type& compatDc) { return compatDc.second.dc == dc; });
		return it != g_origDcToCompatDc.end() ? it->first : dc;
	}

	void releaseDc(HDC origDc)
	{
		Compat::ScopedCriticalSection gdiLock(CompatGdi::g_gdiCriticalSection);

		auto it = g_origDcToCompatDc.find(origDc);
		if (it == g_origDcToCompatDc.end())
		{
			return;
		}
		
		CompatDc& compatDc = it->second;
		--compatDc.refCount;
		if (0 == compatDc.refCount)
		{
			RestoreDC(compatDc.dc, compatDc.savedState);
			CompatGdiDcCache::releaseDc(compatDc);
			g_origDcToCompatDc.erase(origDc);
		}
	}
}