Custom Captions (Including Multi-line Captions)

////////////////////////////////////////////////////////////////
//
// class CMultiLineCaption
//
// Multi-line auto-wrap caption painter. 
//
// To use:
// - call Install from your frame's OnCreate function. 
// - Set a custom CaptionBackground if desired
// - Set custom TextAttributes if required
//
//   If you are drawing custom caption buttons, you must handle WM_NCLBUTTONDOWN & co.
//   yourself. CMultiLineCaption does not handle the mouse for custom caption buttons. 
//
//	Author: Dave Lorde	(dlorde@cix.compulink.co.uk)
//
//          Copyright 1999
//
////////////////////////////////////////////////////////////////
//

#include "StdAfx.h"
#include "MultiLineCaption.h"
#include "CaptionBackground.h"
#include "CaptionTextAttributes.h"
#include "SuppressStyle.h"
#include "AutoSelector.h"
#include <algorithm>

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

using std::_cpp_max;
using std::_cpp_min;

IMPLEMENT_DYNAMIC(CMultiLineCaption, CCaption); 	  

namespace
{
const int TextFormat			= DT_CENTER|DT_WORDBREAK;
const int SingleLineTextFormat	= DT_LEFT|DT_END_ELLIPSIS;
const int DrawTextFudgeFactor	= 2;
const int TextLowerBorder		= 2;
const UINT RestoreFromMinimized	= 0x8124;		  // WindowPosChanged flags
const CString ellipsis("...");
}

///////////////
// Constructor
//
CMultiLineCaption::CMultiLineCaption(int maxLines)
	:m_MaxLines(maxLines > 0 ? maxLines : 1), 
	m_InitialShow(true), 
	m_ActiveSysColor(GetSysColor(COLOR_ACTIVECAPTION)),
	m_InactiveSysColor(GetSysColor(COLOR_INACTIVECAPTION))
{
}

//////////
// Adjust maximum lines for title wrapping, and refresh
//
void CMultiLineCaption::SetMaxLines(int maxLines)
{
	m_MaxLines = maxLines > 0 ? maxLines : 1;

	AdjustHeight();
	Repaint();								// Redraw caption
}

////////////////
// Return maximum permitted lines for title
//
int CMultiLineCaption::GetMaxLines() const
{
	return m_MaxLines;
}

//////////////////
// Message handler handles caption size-related messages
//
LRESULT CMultiLineCaption::WindowProc(UINT msg, WPARAM wp, LPARAM lp)
{
	switch (msg) 
	{
	case WM_NCACTIVATE:
		return OnNcActivate(wp);

		///////////
		// 	Adjust height of client area according to text wrapping
		//
	case WM_SETTEXT:
		OnSetText((LPCTSTR)lp);
		return 0;

		///////////
		// Change colours if using system colours and SysColorChange
	case WM_NCPAINT:
		OnNcPaint(HRGN(wp));
		return 0;
		
		///////////
		// Adjust height of client area according to required caption height
		//
	case WM_NCCALCSIZE:
		return OnNcCalcSize((BOOL)wp, (LPNCCALCSIZE_PARAMS)lp);

		////////////
		// Ensure caption repaints smoothly when sized
		//
	case WM_SIZE:
		OnSize( (UINT)wp, LOWORD(lp), HIWORD(lp) );
		return 0;

		///////////
		// Prevent multi-line caption being overdrawn by client area
		//
	case WM_GETMINMAXINFO:
		OnGetMinMaxInfo((LPMINMAXINFO)lp);
		return 0;

		///////////
		// Refresh when activated or inactivated
		//
	case WM_MDIACTIVATE:
		OnMDIActivate();
		return 0;

		///////////
		// Refresh when sizing stopped
		// 
	case WM_EXITSIZEMOVE:
		OnExitSizeMove();
		return 0;

		///////////
		// Refresh caption when window is tiled 
		//
	case WM_WINDOWPOSCHANGED:
		OnWindowPosChanged( (WINDOWPOS*) lp);
		return 0;
	}
	////////////
	// We don't handle it: pass to base class
	//
	return CCaption::WindowProc(msg, wp, lp);
}

//////////////////
// Handle WM_NCACTIVATE for main window
//
BOOL CMultiLineCaption::OnNcActivate(BOOL bActive)
{
	BOOL result = CCaption::OnNcActivate(bActive);

	Repaint();								// Redraw caption

	return result;
}

void CMultiLineCaption::OnSetText(LPCTSTR lpStr)
{
	CCaption::OnSetText(lpStr);
	
	AdjustHeight();
	Repaint();								// Redraw caption
}

void CMultiLineCaption::OnNcPaint(HRGN hRgn)
{
	if (GetBackground()->IsUsingSystemColors())
	{
		if (m_ActiveSysColor != GetSysColor(COLOR_ACTIVECAPTION) ||
			m_InactiveSysColor != GetSysColor(COLOR_INACTIVECAPTION))
		{
			m_ActiveSysColor = GetSysColor(COLOR_ACTIVECAPTION);
			m_InactiveSysColor = GetSysColor(COLOR_INACTIVECAPTION);
			Repaint();
		}
	}
	CCaption::OnNcPaint(hRgn);	
}

void CMultiLineCaption::OnSize( UINT nType, int cx, int cy )
{
	Default();
	Refresh();
}

void CMultiLineCaption::OnExitSizeMove()
{
	Default();
	Refresh();
}

/////////////
// Paint wrapped header text in rectangle
//
void CMultiLineCaption::PaintText(CDC* pDC)
{
	ASSERT(m_pWndHooked);
	ASSERT(m_pWndHooked);
	CWnd& wnd = *m_pWndHooked;

	// For minimised windows, forget all the multi-line stuff
	if (wnd.IsIconic())
	{
		CCaption::PaintText(pDC);
		return;
	}

	pDC->SetBkMode(TRANSPARENT);						// draw on top of our background

	// Get window text to paint
	//
	CString text;
	wnd.GetWindowText(text);

	// Set text color into device context
	//
	COLORREF textColor = GetTextColor(m_bActive);
	pDC->SetTextColor(textColor);

	// Get the rect to paint the text in
	//
	CRect paintRect(CalcTextRect(m_MaxLines > 1 ? TextFormat : SingleLineTextFormat));

	// Get caption font	and select into DC	 
	//
	AutoSelector a(pDC, GetFont(m_bActive));

	// Paint text into rectangle
	//
	if (m_MaxLines > 1)
	{
		int height = pDC->DrawText(text, paintRect, TextFormat|DT_TOP);

		// Unfortunately, DT_END_ELLIPSIS doesn't work with DT_WORDBREAK, so we must handle
		// ellipsis manually...	 (unless you know better)
		//
		if (height > paintRect.Height())		// Text won't fit, so output truncation ellipsis
		{
			int lenEllipsis = pDC->GetTextExtent(ellipsis).cx;
			paintRect.left = paintRect.right;
			paintRect.right += lenEllipsis;
			paintRect.top = paintRect.bottom - (GetLineHeight(pDC) + 2);

			pDC->DrawText(ellipsis, paintRect, DT_SINGLELINE|DT_LEFT); 
		}
	}
	else // m_MaxLines == 1
	{
		pDC->DrawText(text, paintRect, SingleLineTextFormat);
	}
}

//////////////
// Refresh caption when window is tiled
//
void CMultiLineCaption::OnWindowPosChanged( WINDOWPOS* lpwndpos )
{
	Default();						// Let Windows handle it

	// These flags together seem unique to windows being tiled
	//
	UINT tileFlags = SWP_NOZORDER | SWP_NOACTIVATE | SWP_NOCOPYBITS;
	
	if ((lpwndpos->flags & tileFlags) == tileFlags)
	{
		Refresh();
	}
}

void CMultiLineCaption::OnGetMinMaxInfo( MINMAXINFO FAR* lpMMI )
{
	Default();							// Let Windows handle it

	// Ensure min height is correct - we mustn't allow a height less 
	// than the caption height
	//
	lpMMI->ptMinTrackSize.y = 
		max(lpMMI->ptMinTrackSize.y, GetCaptionHeight() + GetFrameSize().cy);
}

////////////////
// Refresh on activate/deactivate for windows with different font
// sizes for active and inactive caption
//
void CMultiLineCaption::OnMDIActivate()
{
	AdjustHeight();
	Repaint();							// Redraw caption

	Default();							// Let Windows handle it
}

// Call Windows to do WM_NCCALCSIZE then set the top of the new client area to allow for 
// multi-line caption
//
LRESULT CMultiLineCaption::OnNcCalcSize( BOOL bCalcValidRects, LPNCCALCSIZE_PARAMS lpncsp )
{
	LRESULT res = Default();							// Let Windows handle it

	CString text;
	ASSERT(m_pWndHooked);
	CWnd& wnd = *m_pWndHooked;
	wnd.GetWindowText(text);

	// When restoring from minimised (old client area left and right are both zero), CalcTextRect()
	// won't calculate the new client area correctly because the current client area is not valid.
	// In this case, skip it and let OnSize() trigger this function when the client area is valid.
	//
	BOOL wasIconic = lpncsp->rgrc[2].left == lpncsp->rgrc[2].right;
	BOOL isZoomed = wnd.IsZoomed();

	if (text.GetLength() > 0 && !isZoomed && !wasIconic)
	{
		// LPNCCALCSIZE_PARAMS are relative to parent client area (or screen origin if no parent),
		// so add vertical offset of child frame into parent client area 
		//
		lpncsp->rgrc[0].top =  GetChildOffset() + GetCaptionHeight();
	}
	return res;
} 

///////////////
// Return the rectangle occupied by caption text with the specified DrawText() format
//
CRect CMultiLineCaption::CalcTextRect(int textFormat)
{
	CString text;
	ASSERT(m_pWndHooked);
	m_pWndHooked->GetWindowText(text);

	// Get caption font	and select into window DC
	//
	CWindowDC dc(m_pWndHooked);
	AutoSelector a(&dc, GetFont(m_bActive));

	// Size caption to exclude buttons & icon
	//
	CRect textRect = GetCaptionRect();

	textRect.left  += GetIconWidth();				// start text after icon
	textRect.right -= GetButtonsWidth() + 4;		// end text before buttons

	// Use DrawText to calculate the height necessary to contain the text
	//
	int width = textRect.Width();
	int height = dc.DrawText(text, textRect, textFormat | DT_CALCRECT | DT_EXTERNALLEADING);

	// Restrict to specified maximun height
	//
	int maxHeight = GetLineHeight(&dc) * m_MaxLines;
	if (height > maxHeight)
		textRect.bottom = textRect.top + maxHeight;

	// Restrict to minimum height
	//
	int minTextHeight = GetSystemMetrics(SM_CYCAPTION) - 6; 
	if (textRect.Height() < minTextHeight)
		textRect.bottom = textRect.top + minTextHeight;

	// I'll work out why I need this when I get more time... :-)
 	textRect.top -=	DrawTextFudgeFactor;

	// DrawText word-wrap fails to clip for very narrow rects, so ignore if necessary
	//
	if (textRect.Width() > width)
		textRect.right = textRect.left + width;

	return textRect;
}

///////////
// Returns the height of a line of text in the specified device context
//
LONG CMultiLineCaption::GetLineHeight(CDC* pDC)
{
    TEXTMETRIC textMetric;
    pDC->GetOutputTextMetrics(&textMetric);
    return textMetric.tmHeight;
}

///////////
// Returns the total caption height needed to contain the text
//
int CMultiLineCaption::GetCaptionHeight()
{
	return GetFrameSize().cy + 
		CalcTextRect(m_MaxLines > 1 ? TextFormat : SingleLineTextFormat).bottom + 
		TextLowerBorder;
}

///////////
// Return vertical offset of child frame into parent client area (for OnNcCalcSize).
//
int CMultiLineCaption::GetChildOffset()
{
	CRect parentRect(0,0,0,0);		
	ASSERT(m_pWndHooked);
	CWnd& wnd = *m_pWndHooked;

	CWnd* pParent = wnd.GetParent();
	if (pParent)
	{
		pParent->GetClientRect(parentRect );
		pParent->ClientToScreen(parentRect);
	}
	CRect hookedRect;
	wnd.GetWindowRect( &hookedRect );
	return hookedRect.top - parentRect.top;
}

/////////////
// Override of base class function:
// Return caption drawing rectangle, the lower edge abutting the
// client area (as adjusted in OnNcCalcSize())
//
CRect CMultiLineCaption::GetCaptionRect()
{
	ASSERT(m_pWndHooked);
	CWnd& wnd = *m_pWndHooked;

	// When minimised, draw normal size caption
	if (wnd.IsIconic())
		return CCaption::GetCaptionRect();

	// Get client rect in screen co-ordinates
	//
	CRect captionRect;
	wnd.GetClientRect(captionRect);
	wnd.ClientToScreen(captionRect);

	// Convert client rect to window co-ordinates
	//
	CRect windowRect;
	wnd.GetWindowRect(windowRect);
	captionRect -= windowRect.TopLeft();

	// Set top and botton for caption
	//
	captionRect.bottom = captionRect.top;	// bottom of caption is top of client window
	captionRect.top = GetFrameSize().cy;	// top of caption is window rect top + frame thickness

	return captionRect;
}

///////////
// Ensure caption size is recalculated by triggering an OnNcCalcSize()
//
void CMultiLineCaption::Repaint()
{
	ASSERT(m_pWndHooked);
	CWnd& wnd = *m_pWndHooked;

	// Trigger an OnNcCalcSize() to resize caption
	//
	Invalidate();
	wnd.SetWindowPos(&CWnd::wndTopMost, 0,0,0,0, 
		SWP_FRAMECHANGED|SWP_NOACTIVATE|SWP_NOZORDER|SWP_NOSIZE|SWP_NOMOVE);
}

///////////
// Redraw caption and client area, sizing window as required
void CMultiLineCaption::Refresh()
{
	AdjustHeight();							 
	Repaint();								// Redraw caption

	ASSERT(m_pWndHooked);
	CWnd& wnd = *m_pWndHooked;
	wnd.Invalidate();						// paint client area
	UpdateWindow(wnd.GetSafeHwnd());		
}


void CMultiLineCaption::AdjustHeight()
{
	// Size window to caption if caption is taller
	//
	ASSERT(m_pWndHooked);
	CWnd& wnd = *m_pWndHooked;
	CRect wndRect;
	wnd.GetWindowRect(wndRect);
	if (wndRect.Height() < GetCaptionHeight() + GetFrameSize().cy)
	{
		wnd.SetWindowPos(&CWnd::wndTopMost, 0,0,wndRect.Width(),
		                 GetCaptionHeight() + GetFrameSize().cy, 
						 SWP_FRAMECHANGED|SWP_NOACTIVATE|SWP_NOZORDER|SWP_NOMOVE);
	}
}