template<class T> int
GDALComputeMedianCutPCTInternal(
GDALRasterBandH hRed,
GDALRasterBandH hGreen,
GDALRasterBandH hBlue,
GByte* pabyRedBand,
GByte* pabyGreenBand,
GByte* pabyBlueBand,
int (*pfnIncludePixel)(int, int, void*),
int nColors,
int nBits,
T* panHistogram, // NULL, or >= size (1<<nBits)^3 * sizeof(T) bytes.
GDALColorTableH hColorTable,
GDALProgressFunc pfnProgress,
void * pProgressArg )
{
VALIDATE_POINTER1( hRed, "GDALComputeMedianCutPCT", CE_Failure );
VALIDATE_POINTER1( hGreen, "GDALComputeMedianCutPCT", CE_Failure );
VALIDATE_POINTER1( hBlue, "GDALComputeMedianCutPCT", CE_Failure );
CPLErr err = CE_None;
/* -------------------------------------------------------------------- */
/* Validate parameters. */
/* -------------------------------------------------------------------- */
const int nXSize = GDALGetRasterBandXSize( hRed );
const int nYSize = GDALGetRasterBandYSize( hRed );
if( GDALGetRasterBandXSize( hGreen ) != nXSize
|| GDALGetRasterBandYSize( hGreen ) != nYSize
|| GDALGetRasterBandXSize( hBlue ) != nXSize
|| GDALGetRasterBandYSize( hBlue ) != nYSize )
{
CPLError(CE_Failure, CPLE_IllegalArg,
"Green or blue band doesn't match size of red band.");
return CE_Failure;
}
if( pfnIncludePixel != NULL )
{
CPLError(CE_Failure, CPLE_IllegalArg,
"GDALComputeMedianCutPCT() doesn't currently support "
"pfnIncludePixel function.");
return CE_Failure;
}
if( nColors <= 0 )
{
CPLError(CE_Failure, CPLE_IllegalArg,
"GDALComputeMedianCutPCT(): "
"nColors must be strictly greater than 1.");
return CE_Failure;
}
if( nColors > 256 )
{
CPLError(CE_Failure, CPLE_IllegalArg,
"GDALComputeMedianCutPCT(): "
"nColors must be lesser than or equal to 256.");
return CE_Failure;
}
if( pfnProgress == NULL )
pfnProgress = GDALDummyProgress;
/* ==================================================================== */
/* STEP 1: create empty boxes. */
/* ==================================================================== */
if( static_cast<GUInt32>(nXSize) >
std::numeric_limits<T>::max() / static_cast<GUInt32>(nYSize) )
{
CPLError(CE_Warning, CPLE_AppDefined,
"GDALComputeMedianCutPCTInternal() not called "
"with large enough type");
}
T nPixels = 0;
if( nBits == 8 && pabyRedBand != NULL && pabyGreenBand != NULL &&
pabyBlueBand != NULL &&
static_cast<GUInt32>(nXSize) <=
std::numeric_limits<T>::max() / static_cast<GUInt32>(nYSize) )
{
nPixels = static_cast<T>(nXSize) * static_cast<T>(nYSize);
}
const int nCLevels = 1 << nBits;
T* histogram = NULL;
HashHistogram* psHashHistogram = NULL;
if( panHistogram )
{
if( nBits == 8 && static_cast<GUIntBig>(nXSize) * nYSize <= 65536 )
{
// If the image is small enough, then the number of colors
// will be limited and using a hashmap, rather than a full table
// will be more efficient.
histogram = NULL;
psHashHistogram = (HashHistogram*)panHistogram;
memset(psHashHistogram,
0xFF,
sizeof(HashHistogram) * PRIME_FOR_65536);
}
else
{
histogram = panHistogram;
memset(histogram, 0, nCLevels*nCLevels*nCLevels * sizeof(T));
}
}
else
{
histogram = static_cast<T*>(
VSI_CALLOC_VERBOSE(nCLevels * nCLevels * nCLevels, sizeof(T)));
if( histogram == NULL )
{
return CE_Failure;
}
}
Colorbox *box_list =
static_cast<Colorbox *>(CPLMalloc(nColors*sizeof (Colorbox)));
Colorbox *freeboxes = box_list;
freeboxes[0].next = &freeboxes[1];
freeboxes[0].prev = NULL;
for( int i = 1; i < nColors-1; ++i )
{
freeboxes[i].next = &freeboxes[i+1];
freeboxes[i].prev = &freeboxes[i-1];
}
freeboxes[nColors-1].next = NULL;
freeboxes[nColors-1].prev = &freeboxes[nColors-2];
/* ==================================================================== */
/* Build histogram. */
/* ==================================================================== */
/* -------------------------------------------------------------------- */
/* Initialize the box datastructures. */
/* -------------------------------------------------------------------- */
Colorbox *ptr = freeboxes;
freeboxes = ptr->next;
if( freeboxes )
freeboxes->prev = NULL;
Colorbox *usedboxes = NULL; // TODO(schwehr): What?
ptr->next = usedboxes;
usedboxes = ptr;
if( ptr->next )
ptr->next->prev = ptr;
ptr->rmin = 999;
ptr->gmin = 999;
ptr->bmin = 999;
ptr->rmax = -1;
ptr->gmax = -1;
ptr->bmax = -1;
ptr->total = static_cast<GUIntBig>(nXSize) * static_cast<GUIntBig>(nYSize);
/* -------------------------------------------------------------------- */
/* Collect histogram. */
/* -------------------------------------------------------------------- */
// TODO(schwehr): Move these closer to usage after removing gotos.
const int nColorShift = 8 - nBits;
int nColorCounter = 0;
GByte anRed[256] = {};
GByte anGreen[256] = {};
GByte anBlue[256] = {};
GByte *pabyRedLine = static_cast<GByte *>(VSI_MALLOC_VERBOSE(nXSize));
GByte *pabyGreenLine = static_cast<GByte *>(VSI_MALLOC_VERBOSE(nXSize));
GByte *pabyBlueLine = static_cast<GByte *>(VSI_MALLOC_VERBOSE(nXSize));
if( pabyRedLine == NULL ||
pabyGreenLine == NULL ||
pabyBlueLine == NULL )
{
err = CE_Failure;
goto end_and_cleanup;
}
for( int iLine = 0; iLine < nYSize; iLine++ )
{
if( !pfnProgress( iLine / static_cast<double>(nYSize),
"Generating Histogram", pProgressArg ) )
{
CPLError( CE_Failure, CPLE_UserInterrupt, "User Terminated" );
err = CE_Failure;
goto end_and_cleanup;
}
err = GDALRasterIO( hRed, GF_Read, 0, iLine, nXSize, 1,
pabyRedLine, nXSize, 1, GDT_Byte, 0, 0 );
if( err == CE_None )
err = GDALRasterIO( hGreen, GF_Read, 0, iLine, nXSize, 1,
pabyGreenLine, nXSize, 1, GDT_Byte, 0, 0 );
if( err == CE_None )
err = GDALRasterIO( hBlue, GF_Read, 0, iLine, nXSize, 1,
pabyBlueLine, nXSize, 1, GDT_Byte, 0, 0 );
if( err != CE_None )
goto end_and_cleanup;
for( int iPixel = 0; iPixel < nXSize; iPixel++ )
{
const int nRed = pabyRedLine[iPixel] >> nColorShift;
const int nGreen = pabyGreenLine[iPixel] >> nColorShift;
const int nBlue = pabyBlueLine[iPixel] >> nColorShift;
ptr->rmin = std::min(ptr->rmin, nRed);
ptr->gmin = std::min(ptr->gmin, nGreen);
ptr->bmin = std::min(ptr->bmin, nBlue);
ptr->rmax = std::max(ptr->rmax, nRed);
ptr->gmax = std::max(ptr->gmax, nGreen);
ptr->bmax = std::max(ptr->bmax, nBlue);
bool bFirstOccurrence;
if( psHashHistogram )
{
int* pnColor = FindAndInsertColorCount(psHashHistogram,
MAKE_COLOR_CODE(nRed, nGreen, nBlue));
bFirstOccurrence = ( *pnColor == 0 );
(*pnColor)++;
}
else
{
T* pnColor =
HISTOGRAM(histogram, nCLevels, nRed, nGreen, nBlue);
bFirstOccurrence = ( *pnColor == 0 );
(*pnColor)++;
}
if( bFirstOccurrence)
{
if( nColorShift == 0 && nColorCounter < nColors )
{
anRed[nColorCounter] = static_cast<GByte>(nRed);
anGreen[nColorCounter] = static_cast<GByte>(nGreen);
anBlue[nColorCounter] = static_cast<GByte>(nBlue);
}
nColorCounter++;
}
}
}
if( !pfnProgress( 1.0, "Generating Histogram", pProgressArg ) )
{
CPLError( CE_Failure, CPLE_UserInterrupt, "User Terminated" );
err = CE_Failure;
goto end_and_cleanup;
}
if( nColorShift == 0 && nColorCounter <= nColors )
{
#if DEBUG_VERBOSE
CPLDebug("MEDIAN_CUT", "%d colors found <= %d", nColorCounter, nColors);
#endif
for( int iColor = 0; iColor < nColorCounter; iColor++ )
{
const GDALColorEntry sEntry =
{
static_cast<GByte>(anRed[iColor]),
static_cast<GByte>(anGreen[iColor]),
static_cast<GByte>(anBlue[iColor]),
255
};
GDALSetColorEntry( hColorTable, iColor, &sEntry );
}
goto end_and_cleanup;
}
/* ==================================================================== */
/* STEP 3: continually subdivide boxes until no more free */
/* boxes remain or until all colors assigned. */
/* ==================================================================== */
while( freeboxes != NULL )
{
ptr = largest_box(usedboxes);
if( ptr != NULL )
splitbox(ptr, histogram, psHashHistogram, nCLevels,
&freeboxes, &usedboxes,
pabyRedBand, pabyGreenBand, pabyBlueBand, nPixels);
else
freeboxes = NULL;
}
/* ==================================================================== */
/* STEP 4: assign colors to all boxes */
/* ==================================================================== */
ptr = usedboxes;
for( int i = 0; ptr != NULL; ++i, ptr = ptr->next )
{
const GDALColorEntry sEntry = {
static_cast<GByte>(((ptr->rmin + ptr->rmax) << nColorShift) / 2),
static_cast<GByte>(((ptr->gmin + ptr->gmax) << nColorShift) / 2),
static_cast<GByte>(((ptr->bmin + ptr->bmax) << nColorShift) / 2),
255
};
GDALSetColorEntry( hColorTable, i, &sEntry );
}
end_and_cleanup:
CPLFree( pabyRedLine );
CPLFree( pabyGreenLine );
CPLFree( pabyBlueLine );
// We're done with the boxes now.
CPLFree(box_list);
freeboxes = NULL;
usedboxes = NULL;
if( panHistogram == NULL )
CPLFree( histogram );
return err;
}
int
GDALComputeMedianCutPCTInternal( GDALRasterBandH hRed,
GDALRasterBandH hGreen,
GDALRasterBandH hBlue,
GByte* pabyRedBand,
GByte* pabyGreenBand,
GByte* pabyBlueBand,
int (*pfnIncludePixel)(int,int,void*),
int nColors,
int nBits,
int* panHistogram, /* NULL, or at least of size (1<<nBits)^3 * sizeof(int) bytes */
GDALColorTableH hColorTable,
GDALProgressFunc pfnProgress,
void * pProgressArg )
{
VALIDATE_POINTER1( hRed, "GDALComputeMedianCutPCT", CE_Failure );
VALIDATE_POINTER1( hGreen, "GDALComputeMedianCutPCT", CE_Failure );
VALIDATE_POINTER1( hBlue, "GDALComputeMedianCutPCT", CE_Failure );
int nXSize, nYSize;
CPLErr err = CE_None;
/* -------------------------------------------------------------------- */
/* Validate parameters. */
/* -------------------------------------------------------------------- */
nXSize = GDALGetRasterBandXSize( hRed );
nYSize = GDALGetRasterBandYSize( hRed );
if( GDALGetRasterBandXSize( hGreen ) != nXSize
|| GDALGetRasterBandYSize( hGreen ) != nYSize
|| GDALGetRasterBandXSize( hBlue ) != nXSize
|| GDALGetRasterBandYSize( hBlue ) != nYSize )
{
CPLError( CE_Failure, CPLE_IllegalArg,
"Green or blue band doesn't match size of red band.\n" );
return CE_Failure;
}
if( pfnIncludePixel != NULL )
{
CPLError( CE_Failure, CPLE_IllegalArg,
"GDALComputeMedianCutPCT() doesn't currently support "
" pfnIncludePixel function." );
return CE_Failure;
}
if ( nColors <= 0 )
{
CPLError( CE_Failure, CPLE_IllegalArg,
"GDALComputeMedianCutPCT() : nColors must be strictly greater than 1." );
return CE_Failure;
}
if ( nColors > 256 )
{
CPLError( CE_Failure, CPLE_IllegalArg,
"GDALComputeMedianCutPCT() : nColors must be lesser than or equal to 256." );
return CE_Failure;
}
if( pfnProgress == NULL )
pfnProgress = GDALDummyProgress;
/* ==================================================================== */
/* STEP 1: create empty boxes. */
/* ==================================================================== */
int i;
Colorbox *box_list, *ptr;
int* histogram;
Colorbox *freeboxes;
Colorbox *usedboxes;
int nCLevels = 1 << nBits;
int nColorShift = 8 - nBits;
int nColorCounter = 0;
GByte anRed[256], anGreen[256], anBlue[256];
int nPixels = 0;
HashHistogram* psHashHistogram = NULL;
if( nBits == 8 && pabyRedBand != NULL && pabyGreenBand != NULL &&
pabyBlueBand != NULL && nXSize < INT_MAX / nYSize )
{
nPixels = nXSize * nYSize;
}
if( panHistogram )
{
if( nBits == 8 && (GIntBig)nXSize * nYSize <= 65536 )
{
/* If the image is small enough, then the number of colors */
/* will be limited and using a hashmap, rather than a full table */
/* will be more efficient */
histogram = NULL;
psHashHistogram = (HashHistogram*)panHistogram;
memset(psHashHistogram, 0xFF, sizeof(HashHistogram) * PRIME_FOR_65536);
}
else
{
histogram = panHistogram;
memset(histogram, 0, nCLevels*nCLevels*nCLevels * sizeof(int));
}
}
else
{
histogram = (int*) VSICalloc(nCLevels*nCLevels*nCLevels,sizeof(int));
if( histogram == NULL )
{
CPLError( CE_Failure, CPLE_OutOfMemory,
"VSICalloc(): Out of memory in GDALComputeMedianCutPCT" );
return CE_Failure;
}
}
usedboxes = NULL;
box_list = freeboxes = (Colorbox *)CPLMalloc(nColors*sizeof (Colorbox));
freeboxes[0].next = &freeboxes[1];
freeboxes[0].prev = NULL;
for (i = 1; i < nColors-1; ++i) {
freeboxes[i].next = &freeboxes[i+1];
freeboxes[i].prev = &freeboxes[i-1];
}
freeboxes[nColors-1].next = NULL;
freeboxes[nColors-1].prev = &freeboxes[nColors-2];
/* ==================================================================== */
/* Build histogram. */
/* ==================================================================== */
GByte *pabyRedLine, *pabyGreenLine, *pabyBlueLine;
int iLine, iPixel;
/* -------------------------------------------------------------------- */
/* Initialize the box datastructures. */
/* -------------------------------------------------------------------- */
ptr = freeboxes;
freeboxes = ptr->next;
if (freeboxes)
freeboxes->prev = NULL;
ptr->next = usedboxes;
usedboxes = ptr;
if (ptr->next)
ptr->next->prev = ptr;
ptr->rmin = ptr->gmin = ptr->bmin = 999;
ptr->rmax = ptr->gmax = ptr->bmax = -1;
ptr->total = nXSize * nYSize;
/* -------------------------------------------------------------------- */
/* Collect histogram. */
/* -------------------------------------------------------------------- */
pabyRedLine = (GByte *) VSIMalloc(nXSize);
pabyGreenLine = (GByte *) VSIMalloc(nXSize);
pabyBlueLine = (GByte *) VSIMalloc(nXSize);
if (pabyRedLine == NULL ||
pabyGreenLine == NULL ||
pabyBlueLine == NULL)
{
CPLError( CE_Failure, CPLE_OutOfMemory,
"VSIMalloc(): Out of memory in GDALComputeMedianCutPCT" );
err = CE_Failure;
goto end_and_cleanup;
}
for( iLine = 0; iLine < nYSize; iLine++ )
{
if( !pfnProgress( iLine / (double) nYSize,
"Generating Histogram", pProgressArg ) )
{
CPLError( CE_Failure, CPLE_UserInterrupt, "User Terminated" );
err = CE_Failure;
goto end_and_cleanup;
}
GDALRasterIO( hRed, GF_Read, 0, iLine, nXSize, 1,
pabyRedLine, nXSize, 1, GDT_Byte, 0, 0 );
GDALRasterIO( hGreen, GF_Read, 0, iLine, nXSize, 1,
pabyGreenLine, nXSize, 1, GDT_Byte, 0, 0 );
GDALRasterIO( hBlue, GF_Read, 0, iLine, nXSize, 1,
pabyBlueLine, nXSize, 1, GDT_Byte, 0, 0 );
for( iPixel = 0; iPixel < nXSize; iPixel++ )
{
int nRed, nGreen, nBlue;
nRed = pabyRedLine[iPixel] >> nColorShift;
nGreen = pabyGreenLine[iPixel] >> nColorShift;
nBlue = pabyBlueLine[iPixel] >> nColorShift;
ptr->rmin = MIN(ptr->rmin, nRed);
ptr->gmin = MIN(ptr->gmin, nGreen);
ptr->bmin = MIN(ptr->bmin, nBlue);
ptr->rmax = MAX(ptr->rmax, nRed);
ptr->gmax = MAX(ptr->gmax, nGreen);
ptr->bmax = MAX(ptr->bmax, nBlue);
int* pnColor;
if( psHashHistogram )
{
pnColor = FindAndInsertColorCount(psHashHistogram,
MAKE_COLOR_CODE(nRed, nGreen, nBlue));
}
else
{
pnColor = &HISTOGRAM(histogram, nCLevels, nRed, nGreen, nBlue);
}
if( *pnColor == 0 )
{
if( nColorShift == 0 && nColorCounter < nColors )
{
anRed[nColorCounter] = nRed;
anGreen[nColorCounter] = nGreen;
anBlue[nColorCounter] = nBlue;
}
nColorCounter++;
}
(*pnColor) ++;
}
}
if( !pfnProgress( 1.0, "Generating Histogram", pProgressArg ) )
{
CPLError( CE_Failure, CPLE_UserInterrupt, "User Terminated" );
err = CE_Failure;
goto end_and_cleanup;
}
if( nColorShift == 0 && nColorCounter <= nColors )
{
//CPLDebug("MEDIAN_CUT", "%d colors found <= %d", nColorCounter, nColors);
for(int iColor = 0; iColor<nColorCounter; iColor++)
{
GDALColorEntry sEntry;
sEntry.c1 = (GByte) anRed[iColor];
sEntry.c2 = (GByte) anGreen[iColor];
sEntry.c3 = (GByte) anBlue[iColor];
sEntry.c4 = 255;
GDALSetColorEntry( hColorTable, iColor, &sEntry );
}
goto end_and_cleanup;
}
/* ==================================================================== */
/* STEP 3: continually subdivide boxes until no more free */
/* boxes remain or until all colors assigned. */
/* ==================================================================== */
while (freeboxes != NULL) {
ptr = largest_box(usedboxes);
if (ptr != NULL)
splitbox(ptr, histogram, psHashHistogram, nCLevels, &freeboxes, &usedboxes,
pabyRedBand, pabyGreenBand, pabyBlueBand, nPixels);
else
freeboxes = NULL;
}
/* ==================================================================== */
/* STEP 4: assign colors to all boxes */
/* ==================================================================== */
for (i = 0, ptr = usedboxes; ptr != NULL; ++i, ptr = ptr->next)
{
GDALColorEntry sEntry;
sEntry.c1 = (GByte) (((ptr->rmin + ptr->rmax) << nColorShift) / 2);
sEntry.c2 = (GByte) (((ptr->gmin + ptr->gmax) << nColorShift) / 2);
sEntry.c3 = (GByte) (((ptr->bmin + ptr->bmax) << nColorShift) / 2);
sEntry.c4 = 255;
GDALSetColorEntry( hColorTable, i, &sEntry );
}
end_and_cleanup:
CPLFree( pabyRedLine );
CPLFree( pabyGreenLine );
CPLFree( pabyBlueLine );
/* We're done with the boxes now */
CPLFree(box_list);
freeboxes = usedboxes = NULL;
if( panHistogram == NULL )
CPLFree( histogram );
return err;
}
extern "C" int CPL_STDCALL
GDALComputeMedianCutPCT( GDALRasterBandH hRed,
GDALRasterBandH hGreen,
GDALRasterBandH hBlue,
int (*pfnIncludePixel)(int,int,void*),
int nColors,
GDALColorTableH hColorTable,
GDALProgressFunc pfnProgress,
void * pProgressArg )
{
VALIDATE_POINTER1( hRed, "GDALComputeMedianCutPCT", CE_Failure );
VALIDATE_POINTER1( hGreen, "GDALComputeMedianCutPCT", CE_Failure );
VALIDATE_POINTER1( hBlue, "GDALComputeMedianCutPCT", CE_Failure );
int nXSize, nYSize;
CPLErr err = CE_None;
/* -------------------------------------------------------------------- */
/* Validate parameters. */
/* -------------------------------------------------------------------- */
nXSize = GDALGetRasterBandXSize( hRed );
nYSize = GDALGetRasterBandYSize( hRed );
if( GDALGetRasterBandXSize( hGreen ) != nXSize
|| GDALGetRasterBandYSize( hGreen ) != nYSize
|| GDALGetRasterBandXSize( hBlue ) != nXSize
|| GDALGetRasterBandYSize( hBlue ) != nYSize )
{
CPLError( CE_Failure, CPLE_IllegalArg,
"Green or blue band doesn't match size of red band.\n" );
return CE_Failure;
}
if( pfnIncludePixel != NULL )
{
CPLError( CE_Failure, CPLE_IllegalArg,
"GDALComputeMedianCutPCT() doesn't currently support "
" pfnIncludePixel function." );
return CE_Failure;
}
if ( nColors <= 0 )
{
CPLError( CE_Failure, CPLE_IllegalArg,
"GDALComputeMedianCutPCT() : nColors must be strictly greater than 1." );
return CE_Failure;
}
if ( nColors > 256 )
{
CPLError( CE_Failure, CPLE_IllegalArg,
"GDALComputeMedianCutPCT() : nColors must be lesser than or equal to 256." );
return CE_Failure;
}
if( pfnProgress == NULL )
pfnProgress = GDALDummyProgress;
/* ==================================================================== */
/* STEP 1: crate empty boxes. */
/* ==================================================================== */
int i;
Colorbox *box_list, *ptr;
int (*histogram)[GMC_B_LEN][GMC_B_LEN];
Colorbox *freeboxes;
Colorbox *usedboxes;
histogram = (int (*)[GMC_B_LEN][GMC_B_LEN])
CPLCalloc(GMC_B_LEN * GMC_B_LEN * GMC_B_LEN,sizeof(int));
usedboxes = NULL;
box_list = freeboxes = (Colorbox *)CPLMalloc(nColors*sizeof (Colorbox));
freeboxes[0].next = &freeboxes[1];
freeboxes[0].prev = NULL;
for (i = 1; i < nColors-1; ++i) {
freeboxes[i].next = &freeboxes[i+1];
freeboxes[i].prev = &freeboxes[i-1];
}
freeboxes[nColors-1].next = NULL;
freeboxes[nColors-1].prev = &freeboxes[nColors-2];
/* ==================================================================== */
/* Build histogram. */
/* ==================================================================== */
GByte *pabyRedLine, *pabyGreenLine, *pabyBlueLine;
int iLine, iPixel;
/* -------------------------------------------------------------------- */
/* Initialize the box datastructures. */
/* -------------------------------------------------------------------- */
ptr = freeboxes;
freeboxes = ptr->next;
if (freeboxes)
freeboxes->prev = NULL;
ptr->next = usedboxes;
usedboxes = ptr;
if (ptr->next)
ptr->next->prev = ptr;
ptr->rmin = ptr->gmin = ptr->bmin = 999;
ptr->rmax = ptr->gmax = ptr->bmax = -1;
ptr->total = nXSize * nYSize;
/* -------------------------------------------------------------------- */
/* Collect histogram. */
/* -------------------------------------------------------------------- */
pabyRedLine = (GByte *) VSIMalloc(nXSize);
pabyGreenLine = (GByte *) VSIMalloc(nXSize);
pabyBlueLine = (GByte *) VSIMalloc(nXSize);
if (pabyRedLine == NULL ||
pabyGreenLine == NULL ||
pabyBlueLine == NULL)
{
CPLError( CE_Failure, CPLE_OutOfMemory,
"VSIMalloc(): Out of memory in GDALComputeMedianCutPCT" );
err = CE_Failure;
goto end_and_cleanup;
}
for( iLine = 0; iLine < nYSize; iLine++ )
{
if( !pfnProgress( iLine / (double) nYSize,
"Generating Histogram", pProgressArg ) )
{
CPLError( CE_Failure, CPLE_UserInterrupt, "User Terminated" );
err = CE_Failure;
goto end_and_cleanup;
}
GDALRasterIO( hRed, GF_Read, 0, iLine, nXSize, 1,
pabyRedLine, nXSize, 1, GDT_Byte, 0, 0 );
GDALRasterIO( hGreen, GF_Read, 0, iLine, nXSize, 1,
pabyGreenLine, nXSize, 1, GDT_Byte, 0, 0 );
GDALRasterIO( hBlue, GF_Read, 0, iLine, nXSize, 1,
pabyBlueLine, nXSize, 1, GDT_Byte, 0, 0 );
for( iPixel = 0; iPixel < nXSize; iPixel++ )
{
int nRed, nGreen, nBlue;
nRed = pabyRedLine[iPixel] >> COLOR_SHIFT;
nGreen = pabyGreenLine[iPixel] >> COLOR_SHIFT;
nBlue = pabyBlueLine[iPixel] >> COLOR_SHIFT;
ptr->rmin = MIN(ptr->rmin, nRed);
ptr->gmin = MIN(ptr->gmin, nGreen);
ptr->bmin = MIN(ptr->bmin, nBlue);
ptr->rmax = MAX(ptr->rmax, nRed);
ptr->gmax = MAX(ptr->gmax, nGreen);
ptr->bmax = MAX(ptr->bmax, nBlue);
histogram[nRed][nGreen][nBlue]++;
}
}
if( !pfnProgress( 1.0, "Generating Histogram", pProgressArg ) )
{
CPLError( CE_Failure, CPLE_UserInterrupt, "User Terminated" );
err = CE_Failure;
goto end_and_cleanup;
}
/* ==================================================================== */
/* STEP 3: continually subdivide boxes until no more free */
/* boxes remain or until all colors assigned. */
/* ==================================================================== */
while (freeboxes != NULL) {
ptr = largest_box(usedboxes);
if (ptr != NULL)
splitbox(ptr, histogram, &freeboxes, &usedboxes);
else
freeboxes = NULL;
}
/* ==================================================================== */
/* STEP 4: assign colors to all boxes */
/* ==================================================================== */
for (i = 0, ptr = usedboxes; ptr != NULL; ++i, ptr = ptr->next)
{
GDALColorEntry sEntry;
sEntry.c1 = (GByte) (((ptr->rmin + ptr->rmax) << COLOR_SHIFT) / 2);
sEntry.c2 = (GByte) (((ptr->gmin + ptr->gmax) << COLOR_SHIFT) / 2);
sEntry.c3 = (GByte) (((ptr->bmin + ptr->bmax) << COLOR_SHIFT) / 2);
sEntry.c4 = 255;
GDALSetColorEntry( hColorTable, i, &sEntry );
}
end_and_cleanup:
CPLFree( pabyRedLine );
CPLFree( pabyGreenLine );
CPLFree( pabyBlueLine );
/* We're done with the boxes now */
CPLFree(box_list);
freeboxes = usedboxes = NULL;
CPLFree( histogram );
return err;
}
