The Psychology of a WTL Project: Lowercase Cause (a typing program)

#include "StdAfx.h"
#include ".\texttypedctrl.h"

CTextTypedCtrl::CTextTypedCtrl(void)
{
}

LRESULT CTextTypedCtrl::OnPaint(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM /*lParam*/, BOOL& bHandled)
{
	CPaintDC dc(m_hWnd);	
	dc.SelectFont(settings::get_fixed_font());

	// find out how much of the text identical to the target text
	std::string good_text;
	for(int n = _current_text.size(); n >= 0; n--)
	{
		std::string search_text = _current_text.substr(0, n);
		if(_target_text.find(search_text) == 0)
		{
			good_text = search_text;
			break;
		}
	}
		
	CRect rect;
	GetClientRect(&rect);
	
	// paint our background
	// --------------------
	CPen pen;
	pen.CreatePen(PS_NULL, 1, RGB(0, 0, 0));

	CBrush brush;
	brush.CreateSolidBrush(_back_color);

	dc.SelectPen(pen);
	dc.SelectBrush(brush);
	dc.Rectangle(rect);


	// draw the text
	// -------------
	// adjust our rect for the text
	rect.InflateRect(-2, -2);

	dc.SetBkColor(_back_color);
		
	// determine if our color is within the red spectrum, if so
	// we want to use blue instead of red for errors
	if(GetRValue(_back_color) == 255 && GetGValue(_back_color) < 255)
		dc.SetTextColor(RGB(0, 0, 255));
	else
		dc.SetTextColor(RGB(255, 0, 0));

	// first pass draw all the text in the color which represents
	// incorrect
	dc.DrawText(_current_text.c_str(), _current_text.size(), &rect, 
		DT_NOPREFIX | DT_WORDBREAK | DT_EDITCONTROL | DT_EXPANDTABS);

	// now we overlay our text with the text that is good on top of it
	// turning the good black and the bad stays below which may become
	// uncovered if good_text is not _current_text
	dc.SetTextColor(RGB(0, 0, 0));
	dc.DrawText(good_text.c_str(), good_text.size(), &rect, 
		DT_NOPREFIX | DT_WORDBREAK | DT_EDITCONTROL | DT_EXPANDTABS);

	bHandled = TRUE;
	return 0;
}

LRESULT CTextTypedCtrl::OnEraseBkgnd(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM /*lParam*/, BOOL& /*bHandled*/)
{
	return 1;
}