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/*
=head1 NAME
convert.c - image conversions
=head1 SYNOPSIS
i_convert(outimage, srcimage, coeff, outchans, inchans)
=head1 DESCRIPTION
Converts images from one format to another, typically in this case for
converting from RGBA to greyscale and back.
=over
=cut
*/
#include "imager.h"
/*
=item i_convert(src, coeff, outchan, inchan)
Converts the image src into another image.
coeff contains the co-efficients of an outchan x inchan matrix, for
each output pixel:
coeff[0], coeff[1] ...
im[x,y] = [ coeff[inchan], coeff[inchan+1]... ] * [ src[x,y], 1]
... coeff[inchan*outchan-1]
If im has the wrong number of channels or is the wrong size then
i_convert() will re-create it.
Now handles images with more than 8-bits/sample.
=cut
*/
i_img *
i_convert(i_img *src, const float *coeff, int outchan, int inchan) {
int x, y;
int i, j;
int ilimit;
double work[MAXCHANNELS];
i_img *im = NULL;
mm_log((1,"i_convert(src %p, coeff %p,outchan %d, inchan %d)\n",im,src, coeff,outchan, inchan));
i_clear_error();
ilimit = inchan;
if (ilimit > src->channels)
ilimit = src->channels;
if (outchan > MAXCHANNELS) {
i_push_error(0, "cannot have outchan > MAXCHANNELS");
return 0;
}
if (src->type == i_direct_type) {
im = i_sametype_chans(src, src->xsize, src->ysize, outchan);
if (src->bits == i_8_bits) {
i_color *vals;
/* we can always allocate a single scanline of i_color */
vals = mymalloc(sizeof(i_color) * src->xsize); /* checked 04Jul05 tonyc */
for (y = 0; y < src->ysize; ++y) {
i_glin(src, 0, src->xsize, y, vals);
for (x = 0; x < src->xsize; ++x) {
for (j = 0; j < outchan; ++j) {
work[j] = 0;
for (i = 0; i < ilimit; ++i) {
work[j] += coeff[i+inchan*j] * vals[x].channel[i];
}
if (i < inchan) {
work[j] += coeff[i+inchan*j] * 255.9;
}
}
for (j = 0; j < outchan; ++j) {
if (work[j] < 0)
vals[x].channel[j] = 0;
else if (work[j] >= 256)
vals[x].channel[j] = 255;
else
vals[x].channel[j] = work[j];
}
}
i_plin(im, 0, src->xsize, y, vals);
}
myfree(vals);
}
else {
i_fcolor *vals;
/* we can always allocate a single scanline of i_fcolor
for a >8 image */
vals = mymalloc(sizeof(i_fcolor) * src->xsize); /* checked 4Jul05 tonyc */
for (y = 0; y < src->ysize; ++y) {
i_glinf(src, 0, src->xsize, y, vals);
for (x = 0; x < src->xsize; ++x) {
for (j = 0; j < outchan; ++j) {
work[j] = 0;
for (i = 0; i < ilimit; ++i) {
work[j] += coeff[i+inchan*j] * vals[x].channel[i];
}
if (i < inchan) {
work[j] += coeff[i+inchan*j];
}
}
for (j = 0; j < outchan; ++j) {
if (work[j] < 0)
vals[x].channel[j] = 0;
else if (work[j] >= 1)
vals[x].channel[j] = 1;
else
vals[x].channel[j] = work[j];
}
}
i_plinf(im, 0, src->xsize, y, vals);
}
myfree(vals);
}
}
else {
int count;
int outcount;
int index;
i_color *colors;
i_palidx *vals;
im = i_img_pal_new(src->xsize, src->ysize, outchan,
i_maxcolors(src));
/* just translate the color table */
count = i_colorcount(src);
outcount = i_colorcount(im);
/* color table allocated for image, so it must fit */
colors = mymalloc(count * sizeof(i_color)); /* check 04Jul05 tonyc */
i_getcolors(src, 0, colors, count);
for (index = 0; index < count; ++index) {
for (j = 0; j < outchan; ++j) {
work[j] = 0;
for (i = 0; i < ilimit; ++i) {
work[j] += coeff[i+inchan*j] * colors[index].channel[i];
}
if (i < inchan) {
work[j] += coeff[i+inchan*j] * 255.9;
}
}
for (j = 0; j < outchan; ++j) {
if (work[j] < 0)
colors[index].channel[j] = 0;
else if (work[j] >= 255)
colors[index].channel[j] = 255;
else
colors[index].channel[j] = work[j];
}
}
if (count < outcount) {
i_setcolors(im, 0, colors, count);
}
else {
i_setcolors(im, 0, colors, outcount);
i_addcolors(im, colors, count-outcount);
}
/* and copy the indicies */
/* i_palidx is always unsigned char and will never be bigger than short
and since a line of 4-byte i_colors can fit then a line of i_palidx
will fit */
vals = mymalloc(sizeof(i_palidx) * im->xsize); /* checked 4jul05 tonyc */
for (y = 0; y < im->ysize; ++y) {
i_gpal(src, 0, im->xsize, y, vals);
i_ppal(im, 0, im->xsize, y, vals);
}
myfree(vals);
myfree(colors);
}
return im;
}
/*
=back
=head1 SEE ALSO
Imager(3)
=head1 AUTHOR
Tony Cook <tony@develop-help.com>
=cut
*/
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