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fix im_invertlut()

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didn't work for 1 high input matrices
didn't work for file output
This commit is contained in:
John Cupitt 2013-05-23 22:07:05 +01:00
parent b0c5a9340e
commit 964c415925
1 changed files with 41 additions and 23 deletions
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64
libvips/histograms_lut/im_invertlut.c
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@ -7,6 +7,9 @@
* - generate image rather than doublemask (arrg)
* 23/3/10
* - gtkdoc
* 23/5/13
* - fix 1 high input matrices
* - fix file output
*/
/*
@ -59,6 +62,7 @@ typedef struct {
int lut_size; /* Number of output elements to generate */
double **data; /* Rows of unpacked matrix */
double *buf; /* Output buffer */
} State;
/* Use this to sort our input rows by the first column.
@ -110,6 +114,9 @@ build_state( State *state, DOUBLEMASK *input, IMAGE *output, int lut_size )
state->lut_size = lut_size;
state->data = NULL;
if( !(state->buf = im_malloc( NULL, IM_IMAGE_SIZEOF_LINE( output ) )) )
return( -1 );
if( !(state->data = IM_ARRAY( NULL, input->ysize, double * )) )
return( -1 );
for( y = 0; y < input->ysize; y++ )
@ -129,8 +136,10 @@ build_state( State *state, DOUBLEMASK *input, IMAGE *output, int lut_size )
for( x = 0; x < input->xsize; x++ )
if( state->data[y][x] > 1.0 ||
state->data[y][x] < 0.0 ) {
im_error( "im_invertlut", "%s",
_( "element out of range [0,1]" ) );
im_error( "im_invertlut",
_( "element (%d, %d) is %g, "
"outside range [0,1]" ),
x, y, state->data[y][x] );
return( -1 );
}
@ -159,40 +168,48 @@ invertlut( State *state )
DOUBLEMASK *input = state->input;
int ysize = input->ysize;
int xsize = input->xsize;
IMAGE *output = state->output;
double *odata = (double *) output->data;
double *buf = state->buf;
int bands = xsize - 1;
double **data = state->data;
int lut_size = state->lut_size;
int i;
int b;
/* Do each output channel separately.
*/
for( i = 0; i < bands; i++ ) {
for( b = 0; b < bands; b++ ) {
/* The first and last lut positions we know real values for.
*/
int first = data[0][i + 1] * (lut_size - 1);
int last = data[ysize - 1][i + 1] * (lut_size - 1);
int first = data[0][b + 1] * (lut_size - 1);
int last = data[ysize - 1][b + 1] * (lut_size - 1);
int k;
double fac;
/* Extrapolate bottom and top segments to (0,0) and (1,1).
*/
fac = data[0][0] / first;
for( k = 0; k < first; k++ )
odata[i + k * bands] = k * fac;
for( k = 0; k < first; k++ ) {
/* Have this inside the loop to avoid /0 errors if
* first == 0.
*/
double fac = data[0][0] / first;
fac = (1 - data[ysize - 1][0]) / ((lut_size - 1) - last);
for( k = last + 1; k < lut_size; k++ )
odata[i + k * bands] =
buf[b + k * bands] = k * fac;
}
for( k = last; k < lut_size; k++ ) {
/* Inside the loop to avoid /0 errors for last ==
* (lut_size - 1).
*/
double fac = (1 - data[ysize - 1][0]) /
((lut_size - 1) - last);
buf[b + k * bands] =
data[ysize - 1][0] + (k - last) * fac;
}
/* Interpolate the data setions.
/* Interpolate the data sections.
*/
for( k = first; k <= last; k++ ) {
for( k = first; k < last; k++ ) {
/* Where we're at in the [0,1] range.
*/
double ki = (double) k / (lut_size - 1);
@ -204,7 +221,7 @@ invertlut( State *state )
* not be one: if not, just use 0. Tiny error.
*/
for( j = ysize - 1; j >= 0; j-- )
if( data[j][i + 1] < ki )
if( data[j][b + 1] < ki )
break;
if( j == -1 )
j = 0;
@ -212,11 +229,11 @@ invertlut( State *state )
/* Interpolate k as being between row data[j] and row
* data[j + 1].
*/
irange = data[j + 1][i + 1] - data[j][i + 1];
irange = data[j + 1][b + 1] - data[j][b + 1];
orange = data[j + 1][0] - data[j][0];
odata[i + k * bands] = data[j][0] +
orange * ((ki - data[j][i + 1]) / irange);
buf[b + k * bands] = data[j][0] +
orange * ((ki - data[j][b + 1]) / irange);
}
}
@ -302,7 +319,8 @@ im_invertlut( DOUBLEMASK *input, IMAGE *output, int lut_size )
return( -1 );
if( build_state( &state, input, output, lut_size ) ||
invertlut( &state ) ) {
invertlut( &state ) ||
im_writeline( 0, output, (VipsPel *) state.buf ) ) {
free_state( &state );
return( -1 );
}