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669 lines
18 KiB
669 lines
18 KiB
#include "stdafx.h"
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#include "imgutil.h"
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#include "cdithtbl.h"
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CDitherTable::CDitherTable() :
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m_nColors( 0 ),
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m_nRefCount( 0 ),
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m_pnDistanceBuffer( NULL )
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{
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}
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CDitherTable::~CDitherTable()
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{
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}
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BOOL CDitherTable::Match( ULONG nColors, const RGBQUAD* prgbColors )
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{
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if( m_nColors != nColors )
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{
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return( FALSE );
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}
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if( memcmp( m_argbColors, prgbColors, m_nColors*sizeof( RGBQUAD ) ) != 0 )
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{
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return( FALSE );
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}
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return( TRUE );
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}
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HRESULT CDitherTable::SetColors( ULONG nColors, const RGBQUAD* prgbColors )
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{
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HRESULT hResult;
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m_nColors = nColors;
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memcpy( m_argbColors, prgbColors, m_nColors*sizeof( RGBQUAD ) );
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hResult = BuildInverseMap();
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if( FAILED( hResult ) )
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{
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return( hResult );
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}
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return( S_OK );
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}
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/*
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void CDitherTable::BuildInverseMap()
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{
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ULONG r;
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ULONG g;
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ULONG b;
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ULONG iColor;
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ULONG iMapEntry;
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int nMinDistance;
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int nDistance;
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int nRedDistance;
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int nBlueDistance;
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int nGreenDistance;
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iMapEntry = 0;
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for( r = 0; r < 32; r++ )
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{
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for( g = 0; g < 32; g++ )
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{
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for( b = 0; b < 32; b++ )
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{
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nMinDistance = 1000000;
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for( iColor = 0; iColor < m_nColors; iColor++ )
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{
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nRedDistance = m_argbColors[iColor].rgbRed-((r<<3)+(r>>2));
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nGreenDistance = m_argbColors[iColor].rgbGreen-((g<<3)+(g>>2));
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nBlueDistance = m_argbColors[iColor].rgbBlue-((b<<3)+(b>>2));
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nDistance = (nRedDistance*nRedDistance)+(nGreenDistance*
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nGreenDistance)+(nBlueDistance*nBlueDistance);
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if( nDistance < nMinDistance )
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{
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nMinDistance = nDistance;
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m_abInverseMap[iMapEntry] = BYTE( iColor );
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}
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}
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iMapEntry++;
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}
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}
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}
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}
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*/
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HRESULT CDitherTable::BuildInverseMap()
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{
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_ASSERTE( m_pnDistanceBuffer == NULL );
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m_pnDistanceBuffer = new ULONG[32768];
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if( m_pnDistanceBuffer == NULL )
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{
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return( E_OUTOFMEMORY );
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}
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inv_cmap( m_nColors, m_argbColors, 5, m_pnDistanceBuffer, m_abInverseMap );
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delete m_pnDistanceBuffer;
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m_pnDistanceBuffer = NULL;
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return( S_OK );
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}
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/*****************************************************************
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* TAG( inv_cmap )
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*
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* Compute an inverse colormap efficiently.
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* Inputs:
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* colors: Number of colors in the forward colormap.
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* colormap: The forward colormap.
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* bits: Number of quantization bits. The inverse
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* colormap will have (2^bits)^3 entries.
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* dist_buf: An array of (2^bits)^3 long integers to be
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* used as scratch space.
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* Outputs:
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* rgbmap: The output inverse colormap. The entry
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* rgbmap[(r<<(2*bits)) + (g<<bits) + b]
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* is the colormap entry that is closest to the
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* (quantized) color (r,g,b).
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* Assumptions:
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* Quantization is performed by right shift (low order bits are
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* truncated). Thus, the distance to a quantized color is
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* actually measured to the color at the center of the cell
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* (i.e., to r+.5, g+.5, b+.5, if (r,g,b) is a quantized color).
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* Algorithm:
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* Uses a "distance buffer" algorithm:
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* The distance from each representative in the forward color map
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* to each point in the rgb space is computed. If it is less
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* than the distance currently stored in dist_buf, then the
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* corresponding entry in rgbmap is replaced with the current
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* representative (and the dist_buf entry is replaced with the
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* new distance).
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*
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* The distance computation uses an efficient incremental formulation.
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*
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* Distances are computed "outward" from each color. If the
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* colors are evenly distributed in color space, the expected
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* number of cells visited for color I is N^3/I.
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* Thus, the complexity of the algorithm is O(log(K) N^3),
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* where K = colors, and N = 2^bits.
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*/
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/*
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* Here's the idea: scan from the "center" of each cell "out"
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* until we hit the "edge" of the cell -- that is, the point
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* at which some other color is closer -- and stop. In 1-D,
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* this is simple:
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* for i := here to max do
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* if closer then buffer[i] = this color
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* else break
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* repeat above loop with i := here-1 to min by -1
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*
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* In 2-D, it's trickier, because along a "scan-line", the
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* region might start "after" the "center" point. A picture
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* might clarify:
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* | ...
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* | ... .
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* ... .
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* ... | .
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* . + .
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* . .
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* . .
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* .........
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*
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* The + marks the "center" of the above region. On the top 2
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* lines, the region "begins" to the right of the "center".
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*
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* Thus, we need a loop like this:
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* detect := false
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* for i := here to max do
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* if closer then
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* buffer[..., i] := this color
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* if !detect then
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* here = i
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* detect = true
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* else
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* if detect then
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* break
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*
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* Repeat the above loop with i := here-1 to min by -1. Note that
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* the "detect" value should not be reinitialized. If it was
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* "true", and center is not inside the cell, then none of the
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* cell lies to the left and this loop should exit
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* immediately.
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*
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* The outer loops are similar, except that the "closer" test
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* is replaced by a call to the "next in" loop; its "detect"
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* value serves as the test. (No assignment to the buffer is
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* done, either.)
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*
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* Each time an outer loop starts, the "here", "min", and
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* "max" values of the next inner loop should be
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* re-initialized to the center of the cell, 0, and cube size,
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* respectively. Otherwise, these values will carry over from
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* one "call" to the inner loop to the next. This tracks the
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* edges of the cell and minimizes the number of
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* "unproductive" comparisons that must be made.
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*
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* Finally, the inner-most loop can have the "if !detect"
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* optimized out of it by splitting it into two loops: one
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* that finds the first color value on the scan line that is
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* in this cell, and a second that fills the cell until
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* another one is closer:
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* if !detect then {needed for "down" loop}
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* for i := here to max do
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* if closer then
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* buffer[..., i] := this color
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* detect := true
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* break
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* for i := i+1 to max do
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* if closer then
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* buffer[..., i] := this color
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* else
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* break
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*
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* In this implementation, each level will require the
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* following variables. Variables labelled (l) are local to each
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* procedure. The ? should be replaced with r, g, or b:
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* cdist: The distance at the starting point.
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* ?center: The value of this component of the color
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* c?inc: The initial increment at the ?center position.
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* ?stride: The amount to add to the buffer
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* pointers (dp and rgbp) to get to the
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* "next row".
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* min(l): The "low edge" of the cell, init to 0
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* max(l): The "high edge" of the cell, init to
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* colormax-1
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* detect(l): True if this row has changed some
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* buffer entries.
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* i(l): The index for this row.
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* ?xx: The accumulated increment value.
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*
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* here(l): The starting index for this color. The
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* following variables are associated with here,
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* in the sense that they must be updated if here
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* is changed.
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* ?dist: The current distance for this level. The
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* value of dist from the previous level (g or r,
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* for level b or g) initializes dist on this
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* level. Thus gdist is associated with here(b)).
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* ?inc: The initial increment for the row.
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*
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* ?dp: Pointer into the distance buffer. The value
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* from the previous level initializes this level.
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* ?rgbp: Pointer into the rgb buffer. The value
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* from the previous level initializes this level.
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*
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* The blue and green levels modify 'here-associated' variables (dp,
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* rgbp, dist) on the green and red levels, respectively, when here is
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* changed.
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*/
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/* Track minimum and maximum. */
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#define MINMAX_TRACK
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void CDitherTable::inv_cmap(int colors, RGBQUAD *colormap, int bits,
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ULONG* dist_buf, BYTE* rgbmap )
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{
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int nbits = 8 - bits;
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colormax = 1 << bits;
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x = 1 << nbits;
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xsqr = 1 << (2 * nbits);
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/* Compute "strides" for accessing the arrays. */
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gstride = (int) colormax;
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rstride = (int) (colormax * colormax);
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maxfill( dist_buf, colormax );
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for ( cindex = 0; cindex < colors; cindex++ )
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{
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/* The caller can force certain colors in the output space to be
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* omitted by setting a nonzero value for the color's 'x' component.
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* This will produce a map that never refers to those colors.
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* -francish, 2/16/96
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*/
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if (!colormap[cindex].rgbReserved)
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{
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/*
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* Distance formula is
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* (red - map[0])^2 + (green - map[1])^2 + (blue - map[2])^2
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*
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* Because of quantization, we will measure from the center of
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* each quantized "cube", so blue distance is
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* (blue + x/2 - map[2])^2,
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* where x = 2^(8 - bits).
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* The step size is x, so the blue increment is
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* 2*x*blue - 2*x*map[2] + 2*x^2
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*
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* Now, b in the code below is actually blue/x, so our
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* increment will be 2*(b*x^2 + x^2 - x*map[2]). For
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* efficiency, we will maintain this quantity in a separate variable
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* that will be updated incrementally by adding 2*x^2 each time.
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*/
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/* The initial position is the cell containing the colormap
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* entry. We get this by quantizing the colormap values.
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*/
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rcenter = colormap[cindex].rgbRed >> nbits;
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gcenter = colormap[cindex].rgbGreen >> nbits;
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bcenter = colormap[cindex].rgbBlue >> nbits;
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rdist = colormap[cindex].rgbRed - (rcenter * x + x/2);
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gdist = colormap[cindex].rgbGreen - (gcenter * x + x/2);
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cdist = colormap[cindex].rgbBlue - (bcenter * x + x/2);
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cdist = rdist*rdist + gdist*gdist + cdist*cdist;
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crinc = 2 * ((rcenter + 1) * xsqr - (colormap[cindex].rgbRed*x));
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cginc = 2 * ((gcenter + 1) * xsqr - (colormap[cindex].rgbGreen*x));
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cbinc = 2 * ((bcenter + 1) * xsqr - (colormap[cindex].rgbBlue*x));
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/* Array starting points. */
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cdp = dist_buf + rcenter * rstride + gcenter * gstride + bcenter;
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crgbp = rgbmap + rcenter * rstride + gcenter * gstride + bcenter;
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(void)redloop();
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}
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}
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}
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/* redloop -- loop up and down from red center. */
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int CDitherTable::redloop()
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{
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int detect;
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int r;
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int first;
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long txsqr = xsqr + xsqr;
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detect = 0;
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/* Basic loop up. */
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for ( r = rcenter, rdist = cdist, rxx = crinc,
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rdp = cdp, rrgbp = crgbp, first = 1;
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r < (int) colormax;
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r++, rdp += rstride, rrgbp += rstride,
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rdist += rxx, rxx += txsqr, first = 0 )
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{
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if ( greenloop( first ) )
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detect = 1;
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else if ( detect )
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break;
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}
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/* Basic loop down. */
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for ( r = rcenter - 1, rxx = crinc - txsqr, rdist = cdist - rxx,
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rdp = cdp - rstride, rrgbp = crgbp - rstride, first = 1;
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r >= 0;
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r--, rdp -= rstride, rrgbp -= rstride,
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rxx -= txsqr, rdist -= rxx, first = 0 )
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{
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if ( greenloop( first ) )
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detect = 1;
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else if ( detect )
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break;
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}
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return detect;
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}
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#undef min
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#undef max
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#define here greenloop_here
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#define min greenloop_min
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#define max greenloop_max
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#define prevmin greenloop_prevmin
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#define prevmax greenloop_prevmax
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/* greenloop -- loop up and down from green center. */
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int CDitherTable::greenloop( int restart )
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{
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int detect;
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int g;
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int first;
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long txsqr = xsqr + xsqr;
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#ifdef MINMAX_TRACK
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int thismax, thismin;
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#endif
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if ( restart )
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{
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here = gcenter;
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min = 0;
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max = (int) colormax - 1;
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ginc = cginc;
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#ifdef MINMAX_TRACK
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prevmax = 0;
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prevmin = (int) colormax;
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#endif
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}
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#ifdef MINMAX_TRACK
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thismin = min;
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thismax = max;
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#endif
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detect = 0;
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/* Basic loop up. */
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for ( g = here, gcdist = gdist = rdist, gxx = ginc,
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gcdp = gdp = rdp, gcrgbp = grgbp = rrgbp, first = 1;
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g <= max;
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g++, gdp += gstride, gcdp += gstride, grgbp += gstride, gcrgbp += gstride,
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gdist += gxx, gcdist += gxx, gxx += txsqr, first = 0 )
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{
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if ( blueloop( first ) )
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{
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if ( !detect )
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{
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/* Remember here and associated data! */
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if ( g > here )
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{
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here = g;
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rdp = gcdp;
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rrgbp = gcrgbp;
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rdist = gcdist;
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ginc = gxx;
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#ifdef MINMAX_TRACK
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thismin = here;
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#endif
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}
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detect = 1;
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}
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}
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else if ( detect )
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{
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#ifdef MINMAX_TRACK
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thismax = g - 1;
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#endif
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break;
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}
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}
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/* Basic loop down. */
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for ( g = here - 1, gxx = ginc - txsqr, gcdist = gdist = rdist - gxx,
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gcdp = gdp = rdp - gstride, gcrgbp = grgbp = rrgbp - gstride,
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first = 1;
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g >= min;
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g--, gdp -= gstride, gcdp -= gstride, grgbp -= gstride, gcrgbp -= gstride,
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gxx -= txsqr, gdist -= gxx, gcdist -= gxx, first = 0 )
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{
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if ( blueloop( first ) )
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{
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if ( !detect )
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{
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/* Remember here! */
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here = g;
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rdp = gcdp;
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rrgbp = gcrgbp;
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rdist = gcdist;
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ginc = gxx;
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#ifdef MINMAX_TRACK
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thismax = here;
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#endif
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detect = 1;
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}
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}
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else if ( detect )
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{
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#ifdef MINMAX_TRACK
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thismin = g + 1;
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#endif
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break;
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}
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}
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#ifdef MINMAX_TRACK
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/* If we saw something, update the edge trackers. For now, only
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* tracks edges that are "shrinking" (min increasing, max
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* decreasing.
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*/
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if ( detect )
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{
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if ( thismax < prevmax )
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max = thismax;
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prevmax = thismax;
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if ( thismin > prevmin )
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min = thismin;
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prevmin = thismin;
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}
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#endif
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return detect;
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}
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#undef min
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#undef max
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#undef here
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#undef prevmin
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#undef prevmax
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#define here blueloop_here
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#define min blueloop_min
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#define max blueloop_max
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#define prevmin blueloop_prevmin
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#define prevmax blueloop_prevmax
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|
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/* blueloop -- loop up and down from blue center. */
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int CDitherTable::blueloop( int restart )
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{
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int detect;
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register ULONG* dp;
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register BYTE* rgbp;
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register long bdist, bxx;
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register int b, i = cindex;
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register long txsqr = xsqr + xsqr;
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register int lim;
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#ifdef MINMAX_TRACK
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int thismin, thismax;
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#endif /* MINMAX_TRACK */
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|
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if ( restart )
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{
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here = bcenter;
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min = 0;
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max = (int) colormax - 1;
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binc = cbinc;
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#ifdef MINMAX_TRACK
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prevmin = (int) colormax;
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prevmax = 0;
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#endif /* MINMAX_TRACK */
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}
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detect = 0;
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#ifdef MINMAX_TRACK
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thismin = min;
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thismax = max;
|
|
#endif
|
|
|
|
/* Basic loop up. */
|
|
/* First loop just finds first applicable cell. */
|
|
for ( b = here, bdist = gdist, bxx = binc, dp = gdp, rgbp = grgbp, lim = max;
|
|
b <= lim;
|
|
b++, dp++, rgbp++,
|
|
bdist += bxx, bxx += txsqr )
|
|
{
|
|
if ( *dp > (DWORD)bdist )
|
|
{
|
|
/* Remember new 'here' and associated data! */
|
|
if ( b > here )
|
|
{
|
|
here = b;
|
|
gdp = dp;
|
|
grgbp = rgbp;
|
|
gdist = bdist;
|
|
binc = bxx;
|
|
#ifdef MINMAX_TRACK
|
|
thismin = here;
|
|
#endif
|
|
}
|
|
detect = 1;
|
|
break;
|
|
}
|
|
}
|
|
/* Second loop fills in a run of closer cells. */
|
|
for ( ;
|
|
b <= lim;
|
|
b++, dp++, rgbp++,
|
|
bdist += bxx, bxx += txsqr )
|
|
{
|
|
if ( *dp > (DWORD)bdist )
|
|
{
|
|
*dp = bdist;
|
|
*rgbp = (BYTE) i;
|
|
}
|
|
else
|
|
{
|
|
#ifdef MINMAX_TRACK
|
|
thismax = b - 1;
|
|
#endif
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Basic loop down. */
|
|
/* Do initializations here, since the 'find' loop might not get
|
|
* executed.
|
|
*/
|
|
lim = min;
|
|
b = here - 1;
|
|
bxx = binc - txsqr;
|
|
bdist = gdist - bxx;
|
|
dp = gdp - 1;
|
|
rgbp = grgbp - 1;
|
|
/* The 'find' loop is executed only if we didn't already find
|
|
* something.
|
|
*/
|
|
if ( !detect )
|
|
for ( ;
|
|
b >= lim;
|
|
b--, dp--, rgbp--,
|
|
bxx -= txsqr, bdist -= bxx )
|
|
{
|
|
if ( *dp > (DWORD)bdist )
|
|
{
|
|
/* Remember here! */
|
|
/* No test for b against here necessary because b <
|
|
* here by definition.
|
|
*/
|
|
here = b;
|
|
gdp = dp;
|
|
grgbp = rgbp;
|
|
gdist = bdist;
|
|
binc = bxx;
|
|
#ifdef MINMAX_TRACK
|
|
thismax = here;
|
|
#endif
|
|
detect = 1;
|
|
break;
|
|
}
|
|
}
|
|
/* The 'update' loop. */
|
|
for ( ;
|
|
b >= lim;
|
|
b--, dp--, rgbp--,
|
|
bxx -= txsqr, bdist -= bxx )
|
|
{
|
|
if ( *dp > (DWORD)bdist )
|
|
{
|
|
*dp = bdist;
|
|
*rgbp = (BYTE) i;
|
|
}
|
|
else
|
|
{
|
|
#ifdef MINMAX_TRACK
|
|
thismin = b + 1;
|
|
#endif
|
|
break;
|
|
}
|
|
}
|
|
|
|
|
|
/* If we saw something, update the edge trackers. */
|
|
#ifdef MINMAX_TRACK
|
|
if ( detect )
|
|
{
|
|
/* Only tracks edges that are "shrinking" (min increasing, max
|
|
* decreasing.
|
|
*/
|
|
if ( thismax < prevmax )
|
|
max = thismax;
|
|
|
|
if ( thismin > prevmin )
|
|
min = thismin;
|
|
|
|
/* Remember the min and max values. */
|
|
prevmax = thismax;
|
|
prevmin = thismin;
|
|
}
|
|
#endif /* MINMAX_TRACK */
|
|
|
|
return detect;
|
|
}
|
|
|
|
void CDitherTable::maxfill( ULONG* buffer, long side)
|
|
{
|
|
register unsigned long maxv = (unsigned long)~0L;
|
|
register long i;
|
|
register ULONG* bp;
|
|
|
|
(void)side;
|
|
|
|
for ( i = colormax * colormax * colormax, bp = buffer;
|
|
i > 0;
|
|
i--, bp++ )
|
|
*bp = maxv;
|
|
}
|