DDrawCompat/DDrawCompat/CompatGdiScrollBar.cpp

#include "CompatGdi.h"
#include "CompatGdiScrollBar.h"
#include "Hook.h"

namespace
{
	enum ScrollBarInfoIndex
	{
		SBII_SCROLLBAR = 0,
		SBII_TOP_RIGHT_ARROW = 1,
		SBII_PAGEUP_PAGERIGHT_REGION = 2,
		SBII_THUMB = 3,
		SBII_PAGEDOWN_PAGELEFT_REGION = 4,
		SBII_BOTTOM_LEFT_ARROW = 5
	};
}

namespace CompatGdi
{
	ScrollBar::ScrollBar(HWND hwnd, HDC compatDc) :
		m_hwnd(hwnd), m_compatDc(compatDc), m_windowRect(),
		m_isLeftMouseButtonDown(false), m_cursorPos(),
		m_horizontalSbi(), m_verticalSbi()
	{
		const LONG windowStyle = GetWindowLongPtr(hwnd, GWL_STYLE);

		m_horizontalSbi.isVisible = 0 != (windowStyle & WS_HSCROLL);
		m_verticalSbi.isVisible = 0 != (windowStyle & WS_VSCROLL);

		GetWindowRect(hwnd, &m_windowRect);

		if (m_horizontalSbi.isVisible || m_verticalSbi.isVisible)
		{
			m_isLeftMouseButtonDown =
				hwnd == GetCapture() &&
				GetAsyncKeyState(GetSystemMetrics(SM_SWAPBUTTON) ? VK_RBUTTON : VK_LBUTTON) < 0 &&
				GetCursorPos(&m_cursorPos);

			if (m_isLeftMouseButtonDown)
			{
				m_cursorPos.x -= m_windowRect.left;
				m_cursorPos.y -= m_windowRect.top;
			}

			if (m_horizontalSbi.isVisible)
			{
				m_horizontalSbi = getScrollBarInfo(OBJID_HSCROLL);
			}

			if (m_verticalSbi.isVisible)
			{
				m_verticalSbi = getScrollBarInfo(OBJID_VSCROLL);
			}
		}
	}

	void ScrollBar::drawAll() const
	{
		drawHorizArrows();
		drawVertArrows();
	}

	void ScrollBar::drawArrow(const ScrollBarChildInfo& sbci, UINT dfcState) const
	{
		UINT stateFlags = 0;
		if (sbci.state & STATE_SYSTEM_UNAVAILABLE)
		{
			stateFlags |= DFCS_INACTIVE;
		}
		else if (sbci.state & STATE_SYSTEM_PRESSED)
		{
			stateFlags |= DFCS_PUSHED;
		}

		RECT rect = sbci.rect;
		CALL_ORIG_FUNC(DrawFrameControl)(m_compatDc, &rect, DFC_SCROLL, dfcState | stateFlags);
	}

	void ScrollBar::drawHorizArrows() const
	{
		if (m_horizontalSbi.isVisible)
		{
			drawArrow(m_horizontalSbi.topLeftArrow, DFCS_SCROLLLEFT);
			drawArrow(m_horizontalSbi.bottomRightArrow, DFCS_SCROLLRIGHT);
		}
	}

	void ScrollBar::drawVertArrows() const
	{
		if (m_verticalSbi.isVisible)
		{
			drawArrow(m_verticalSbi.topLeftArrow, DFCS_SCROLLUP);
			drawArrow(m_verticalSbi.bottomRightArrow, DFCS_SCROLLDOWN);
		}
	}

	void ScrollBar::excludeFromClipRegion(const RECT& rect) const
	{
		ExcludeClipRect(m_compatDc, rect.left, rect.top, rect.right, rect.bottom);
	}

	void ScrollBar::excludeFromClipRegion(const ScrollBarInfo& sbi) const
	{
		if (sbi.isVisible)
		{
			excludeFromClipRegion(sbi.topLeftArrow.rect);
			excludeFromClipRegion(sbi.bottomRightArrow.rect);
		}
	}

	void ScrollBar::excludeFromClipRegion() const
	{
		excludeFromClipRegion(m_horizontalSbi);
		excludeFromClipRegion(m_verticalSbi);
	}

	ScrollBar::ScrollBarInfo ScrollBar::getScrollBarInfo(LONG objId) const
	{
		ScrollBarInfo scrollBarInfo = {};

		SCROLLBARINFO sbi = {};
		sbi.cbSize = sizeof(sbi);
		scrollBarInfo.isVisible = GetScrollBarInfo(m_hwnd, objId, &sbi) &&
			!(sbi.rgstate[SBII_SCROLLBAR] & (STATE_SYSTEM_INVISIBLE | STATE_SYSTEM_OFFSCREEN));

		if (!scrollBarInfo.isVisible)
		{
			return scrollBarInfo;
		}

		OffsetRect(&sbi.rcScrollBar, -m_windowRect.left, -m_windowRect.top);
		scrollBarInfo.topLeftArrow.rect = sbi.rcScrollBar;
		scrollBarInfo.bottomRightArrow.rect = sbi.rcScrollBar;

		if (OBJID_HSCROLL == objId)
		{
			const int w = GetSystemMetrics(SM_CXHSCROLL);

			scrollBarInfo.topLeftArrow.rect.right = scrollBarInfo.topLeftArrow.rect.left + w;
			scrollBarInfo.topLeftArrow.state = sbi.rgstate[SBII_BOTTOM_LEFT_ARROW];

			scrollBarInfo.bottomRightArrow.rect.left = scrollBarInfo.bottomRightArrow.rect.right - w;
			scrollBarInfo.bottomRightArrow.state = sbi.rgstate[SBII_TOP_RIGHT_ARROW];
		}
		else
		{
			const int h = GetSystemMetrics(SM_CYVSCROLL);

			scrollBarInfo.topLeftArrow.rect.bottom = scrollBarInfo.topLeftArrow.rect.top + h;
			scrollBarInfo.topLeftArrow.state = sbi.rgstate[SBII_TOP_RIGHT_ARROW];

			scrollBarInfo.bottomRightArrow.rect.top = scrollBarInfo.bottomRightArrow.rect.bottom - h;
			scrollBarInfo.bottomRightArrow.state = sbi.rgstate[SBII_BOTTOM_LEFT_ARROW];
		}

		if (m_isLeftMouseButtonDown)
		{
			setPressedState(scrollBarInfo.topLeftArrow);
			setPressedState(scrollBarInfo.bottomRightArrow);
		}

		return scrollBarInfo;
	}

	void ScrollBar::setPressedState(ScrollBarChildInfo& sbci) const
	{
		if (!(sbci.state & STATE_SYSTEM_UNAVAILABLE) && PtInRect(&sbci.rect, m_cursorPos))
		{
			sbci.state |= STATE_SYSTEM_PRESSED;
		}
	}
}