/* HALFTONE.C
Frosting: Master Theme Selector for Windows '95
Copyright (c) 1994-1999 Microsoft Corporation. All rights reserved.
*/
#include<windows.h>
#include<windowsx.h>
/*----------------------------------------------------------------------------
Division lookup tables. These tables compute 0-255 divided by 51 and
modulo 51. These tables could approximate gamma correction.
*/
char unsigned const aDividedBy51Rounded[256] =
{
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
};
char unsigned const aDividedBy51[256] =
{
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5,
};
char unsigned const aModulo51[256] =
{
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37,
38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 0, 1, 2, 3, 4, 5, 6,
7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43,
44, 45, 46, 47, 48, 49, 50, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30,
31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48,
49, 50, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,
18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35,
36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 0, 1, 2, 3,
4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,
23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 0,
};
/*----------------------------------------------------------------------------
Multiplication LUTs. These compute 0-5 times 6 and 36.
*/
char unsigned const aTimes6[6] =
{
0, 6, 12, 18, 24, 30
};
char unsigned const aTimes36[6] =
{
0, 36, 72, 108, 144, 180
};
/*----------------------------------------------------------------------------
Dither matrices for 8 bit to 2.6 bit halftones.
*/
char unsigned const aHalftone8x8[64] =
{
0, 38, 9, 47, 2, 40, 11, 50,
25, 12, 35, 22, 27, 15, 37, 24,
6, 44, 3, 41, 8, 47, 5, 43,
31, 19, 28, 15, 34, 21, 31, 18,
1, 39, 11, 49, 0, 39, 10, 48,
27, 14, 36, 23, 26, 13, 35, 23,
7, 46, 4, 43, 7, 45, 3, 42,
33, 20, 30, 17, 32, 19, 29, 16,
};
/*----------------------------------------------------------------------------
Buffer for brush bits.
*/
static BYTE aTranslate[216]; // map a 666 to a palette index
/*----------------------------------------------------------------------------
Dithering functions.
*/
__inline char unsigned DitherColor( char unsigned RedDiv51,
char unsigned RedMod51, char unsigned GreenDiv51, char unsigned GreenMod51,
char unsigned BlueDiv51, char unsigned BlueMod51, char unsigned Index )
{
// cbh! try out scoy's trick of adding without jumping
#pragma warning (disable:4135) // conversion between different integral types
char unsigned RedTemp = RedDiv51 + (RedMod51 > Index);
char unsigned GreenTemp = GreenDiv51 + (GreenMod51 > Index);
char unsigned BlueTemp = BlueDiv51 + (BlueMod51 > Index);
return aTranslate[RedTemp + aTimes6[GreenTemp] + aTimes36[BlueTemp]];
#pragma warning (default:4135) // conversion between different integral types
}
__inline BYTE DitherColorXY(COLORREF Color, int x, int y)
{
char unsigned RedDiv51 = aDividedBy51[GetRValue(Color)];
char unsigned RedMod51 = aModulo51[GetRValue(Color)];
char unsigned GreenDiv51 = aDividedBy51[GetGValue(Color)];
char unsigned GreenMod51 = aModulo51[GetGValue(Color)];
char unsigned BlueDiv51 = aDividedBy51[GetBValue(Color)];
char unsigned BlueMod51 = aModulo51[GetBValue(Color)];
return DitherColor(RedDiv51,RedMod51,GreenDiv51,
GreenMod51,BlueDiv51,BlueMod51,
aHalftone8x8[(x&7) + (y&7)*8]);
}
void InitHalftone(RGBQUAD FAR *pct)
{
int r,g,b,n,i;
DWORD FAR *pdw;
HPALETTE hpal;
if (hpal = CreateHalftonePalette(NULL))
{
pdw = (DWORD FAR *)pct;
n = GetPaletteEntries(hpal, 0, 256, (LPPALETTEENTRY)pdw);
//
// get the halftone palette colors
//
for (i=0; i<256; i++)
pdw[i] = RGB(GetBValue(pdw[i]),GetGValue(pdw[i]),GetRValue(pdw[i]));
pdw[8] = 0;
pdw[9] = 0;
pdw[246] = 0;
pdw[247] = 0;
//
// now build the 666->index translate,
//
for (i=b=0; b<6; b++)
for (g=0; g<6; g++)
for (r=0; r<6; r++)
aTranslate[i++] = (BYTE)(GetNearestPaletteIndex(hpal, RGB(r*51,g*51,b*51)));
DeleteObject(hpal);
}
}
BOOL HalftoneImage(HDC hdc, HBITMAP hbm, LPBITMAPINFOHEADER lpbi, LPBYTE lpBits)
{
int x, y;
BYTE r,g,b;
int dx, dy;
BITMAP bm;
LPBYTE pbSrc;
LPBYTE pbDst;
RGBQUAD ct[256];
if (lpbi->biBitCount != 24)
return FALSE;
InitHalftone(ct);
SetDIBColorTable(hdc, 0, 256, ct);
GetObject(hbm, sizeof(bm), &bm);
dx = lpbi->biWidth;
dy = lpbi->biHeight;
/* read line by line, quantize, and transfer */
for (y=0; y<dy; y++)
{
pbSrc = lpBits;
pbDst = bm.bmBits;
for (x=0; x<dx; x++)
{
b = *pbSrc++;
g = *pbSrc++;
r = *pbSrc++;
*pbDst++ = DitherColorXY(RGB(r,g,b),x,y);
}
(LPBYTE)lpBits += (lpbi->biWidth*3+3)&~3;
(LPBYTE)bm.bmBits += bm.bmWidthBytes;
}
return TRUE;
}