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|
/*
/--------------------------------------------------------------------
|
| $Id: shadow.cpp,v 1.6 2002/03/31 13:36:42 uzadow Exp $
| Shadow Graphic item class
|
| A shadowed region on a canvas. The item is basically a
| partially transparent region. Transparency is defined by an
| alpha DIB and a global transparency value. Most of the code
| was just copied from CDIBGrItem & changed a bit.
|
| Copyright (c) 1996-2002 Ulrich von Zadow
|
\--------------------------------------------------------------------
*/
#include "stdafx.h"
#include "shadow.h"
#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char BASED_CODE THIS_FILE[] = __FILE__;
#endif
IMPLEMENT_DYNAMIC (CShadowItem, CGrItem);
CShadowItem::CShadowItem
( int x, // Position on the canvas
int y,
int w, // Width
int h, // Height
int z, // Position in z-Order
PLBYTE Opacity, // Opacity of the object. 255 is completely
// opaque, 0 is completely transparent.
PLPixel32 * pColor, // Shadow color.
PLBmp * pAlphaBmp // Alpha channel (must be 8 bpp). Can be NULL.
)
: CGrItem (x, y, w, h, z, Opacity)
{
m_Color = *pColor;
m_pAlphaBmp = pAlphaBmp;
if (m_pAlphaBmp)
m_pLineArray = m_pAlphaBmp->GetLineArray();
else
m_pLineArray = NULL;
}
CShadowItem::~CShadowItem
()
{
}
void CShadowItem::Draw
( PLBmp * pCanvas,
CRect * pUpdateRect
)
// Responsible for drawing the object on the canvas.
{
// ASSERT_VALID (pCanvas);
ASSERT (pCanvas->GetBitsPerPixel() == 32);
// Perform clipping.
CRect ClipRect (pUpdateRect);
clip (pCanvas, &ClipRect);
// Draw
if (m_pAlphaBmp)
{
if (m_w == m_pAlphaBmp->GetWidth() &&
m_h == m_pAlphaBmp->GetHeight())
drawClippedNoScale (pCanvas, &ClipRect);
else
drawClipped (pCanvas, &ClipRect);
}
else
drawClippedNoScale (pCanvas, &ClipRect);
// If this fails, the procedure destroyed something.
// ASSERT_VALID (pCanvas);
}
void CShadowItem::drawClippedNoScale
( PLBmp * pCanvas,
CRect * pRect
)
// Draws the object. pRect must have been clipped already.
// Assumes that no scaling is nessesary.
{
PLBYTE * pDest;
PLBYTE * pAlpha;
PLBYTE ** pDestLineArray = pCanvas->GetLineArray();
// Set up loop invariants.
int SrcXOfs = (pRect->left-m_x);
for (int sy = pRect->top; sy<pRect->bottom; sy++)
{ // For each line
pDest = pDestLineArray[sy] + pRect->left*4;
if (m_pAlphaBmp)
{
pAlpha = m_pLineArray[sy-m_y] + SrcXOfs;
drawAlphaLine (pDest, pAlpha, pRect);
}
else
drawFadeLine (pDest, pRect);
}
}
inline void CShadowItem::drawAlphaLine
( PLBYTE * pDest,
PLBYTE * pAlpha,
CRect * pRect
)
{
int alpha;
int negalpha;
PLBYTE * pColor = (PLBYTE *)(&m_Color); // Well...
for (int sx = pRect->left; sx<pRect->right; sx++)
{ // For each pixel
alpha = ((*pAlpha) * m_Opacity)>>8;
negalpha = 255-alpha;
pDest[PL_RGBA_RED] = (pDest[PL_RGBA_RED]*negalpha +
*(pColor+PL_RGBA_RED)*alpha)>>8;
pDest[PL_RGBA_GREEN] = (pDest[PL_RGBA_GREEN]*negalpha +
*(pColor+PL_RGBA_GREEN)*alpha)>>8;
pDest[PL_RGBA_BLUE] = (pDest[PL_RGBA_BLUE]*negalpha +
*(pColor+PL_RGBA_BLUE)*alpha)>>8;
pDest += 4;
pAlpha++;
}
}
inline void CShadowItem::drawFadeLine
( PLBYTE * pDest,
CRect * pRect
)
// Draws one line. No scaling. Assumes alpha channel doesn't
// exist.
{
int negalpha;
PLBYTE * pColor = (PLBYTE *)(&m_Color); // Well...
PLBYTE Color[4];
Color[PL_RGBA_BLUE] = *(pColor+PL_RGBA_BLUE)*m_Opacity>>8;
Color[PL_RGBA_GREEN] = *(pColor+PL_RGBA_GREEN)*m_Opacity>>8;
Color[PL_RGBA_RED] = *(pColor+PL_RGBA_RED)*m_Opacity>>8;
negalpha = 255-m_Opacity;
for (int sx = pRect->left; sx<pRect->right; sx++)
{ // For each pixel
pDest[PL_RGBA_BLUE] = (pDest[PL_RGBA_BLUE]*negalpha>>8)+Color[PL_RGBA_BLUE];
pDest[PL_RGBA_GREEN] = (pDest[PL_RGBA_GREEN]*negalpha>>8)+Color[PL_RGBA_GREEN];
pDest[PL_RGBA_RED] = (pDest[PL_RGBA_RED]*negalpha>>8)+Color[PL_RGBA_RED];
pDest += 4;
}
}
void CShadowItem::drawClipped
( PLBmp * pCanvas,
CRect * pRect
)
// Draws the object. pRect must have been clipped already.
{
PLBYTE * pDest;
PLBYTE * pAlpha = NULL;
int SrcLineNum;
PLBYTE ** pDestLineArray = pCanvas->GetLineArray();
double YScale = (double)(m_pAlphaBmp->GetHeight())/m_h;
for (int sy = pRect->top; sy<pRect->bottom; sy++)
{ // For each line
pDest = pDestLineArray[sy] + pRect->left*4;
SrcLineNum = (int)((sy-m_y)*YScale);
pAlpha = m_pLineArray [SrcLineNum];
drawScaleLine (pDest, pAlpha, pRect);
}
}
inline void CShadowItem::drawScaleLine
( PLBYTE * pDest,
PLBYTE * pAlpha,
CRect * pRect
)
{
int alpha;
int negalpha;
int SrcOfs;
double XScale = (double)(m_pAlphaBmp->GetWidth())/m_w;
int xs = (int)(XScale*65536);
PLBYTE * pColor = (PLBYTE *)(&m_Color); // Well...
for (int sx = pRect->left-m_x; sx<pRect->right-m_x; sx++)
{ // For each pixel
SrcOfs = (sx*xs)>>16;
if (pAlpha)
alpha = ((*(pAlpha+SrcOfs)) * m_Opacity)>>8;
else
alpha = m_Opacity;
negalpha = 255-alpha;
pDest[PL_RGBA_BLUE] = (pDest[PL_RGBA_BLUE]*negalpha +
pColor[PL_RGBA_BLUE]*alpha)>>8;
pDest[PL_RGBA_GREEN] = (pDest[PL_RGBA_GREEN]*negalpha +
pColor[PL_RGBA_GREEN]*alpha)>>8;
pDest[PL_RGBA_RED] = (pDest[PL_RGBA_RED]*negalpha +
pColor[PL_RGBA_RED]*alpha)>>8;
pDest += 4;
}
}
/*
/--------------------------------------------------------------------
|
| $Log: shadow.cpp,v $
| Revision 1.6 2002/03/31 13:36:42 uzadow
| Updated copyright.
|
| Revision 1.5 2001/09/16 19:03:23 uzadow
| Added global name prefix PL, changed most filenames.
|
|
--------------------------------------------------------------------
*/
|
