Clock Screen Saver

// RotatingTextSprite.cpp : implementation file
//

#include "stdafx.h"
#include "RotatingTextSprite.h"
#include "AlternatingGlyph.h"

#include <cmath>

extern double pi;

// CRotatingTextSprite

CRotatingTextSprite::CRotatingTextSprite(const double height, const double width, COLORREF color) :	
											CCircularSprite( height, width, color ),					
											m_ForceLeftToRight( false )											
{
}

CRotatingTextSprite::~CRotatingTextSprite()
{
}


// CRotatingTextSprite member functions

void CRotatingTextSprite::SetText( CString strText )
{
	ASSERT( m_paGlyphs );

	CString str;
	CString str2;

	CString reversedText( strText );
	reversedText.MakeReverse();

	//add each character to the array as a glyph
	for ( int i = 0, l = strText.GetLength(); i < l; i++ ) 
	{
		str = strText.GetAt(i);
		str2 = reversedText.GetAt(i);

		m_paGlyphs->Add( new CAlternatingGlyph( i, str, str2 ) );
	}

	if ( GetGlyphCount() > 0 )
		m_rSplit = 360.0 / GetGlyphCount();
}

void CRotatingTextSprite::SetForceLeftToRight( bool value )
{
	m_ForceLeftToRight = value;
}

double CRotatingTextSprite::GetTickX()
{
	return ::GetTickCount() * m_rRotateSpeed;
}

double CRotatingTextSprite::GetTickY()
{
	return ::GetTickCount() * m_rRotateSpeed;
}

void CRotatingTextSprite::TrackPoint(const CPoint* ppoint, const double trackingSpeed)
{
	m_Point = *ppoint;
	CSprite::TrackPoint( ppoint, trackingSpeed );
}

void CRotatingTextSprite::ReDraw(CDC* pDC)
{	
 	if ( m_ForceLeftToRight )
	{
		COLORREF oldColor = pDC->SetTextColor( m_Color );

		CAlternatingGlyph* glyph;

		for ( int i=0, l=m_paGlyphs->GetCount(); i < l; i++ )
		{
			glyph = (CAlternatingGlyph*)((*m_paGlyphs)[i]);
			
			//set the glyph to its final location by
			//calling CalcX and CalcY which returns the custom 
			//animation's relative location from the derived class
			glyph->SetPoint( glyph->x + CalcX( glyph ), glyph->y + CalcY( glyph ) );

			DrawGlpyh( pDC, glyph );
		}

		pDC->SetTextColor( oldColor );
	}
	else
	{
		CSprite::ReDraw( pDC );
	}
}

void CRotatingTextSprite::DrawGlpyh( CDC* pDC, CAlternatingGlyph* pGlyph )
{
	const double FADE_ANGLE = 23.0;

	// get the polar angle of the glyph
	double theta = ::atan2( (double)(pGlyph->y - m_Point.y), (double)(pGlyph->x - m_Point.x) ) * ( 180 / pi );

	COLORREF color = m_Color;

	// if the glyph is approaching 180 or 0 degrees fade its color
	// as a function of its distance from those values
	if ( abs( theta ) < FADE_ANGLE )
		color = Darken( color, ::abs( theta ) / FADE_ANGLE );
	else if ( 180.0 - ::abs( theta ) < FADE_ANGLE )
		color = Darken( color, ( 180.0 - ::abs( theta ) ) / FADE_ANGLE );

	pDC->SetTextColor( color );

	if ( theta > 0.0 && theta < 180.0 )
		pGlyph->DrawAlternate( pDC );
	else
		pGlyph->Draw( pDC );
}

COLORREF CRotatingTextSprite::Darken( COLORREF color, double pct )
{
	return RGB( GetRValue( color ) * pct, GetGValue( color ) * pct, GetBValue( color ) * pct );
}