| /* im_LabS2LabQ() |
| * |
| * 17/11/93 JC |
| * - adapted from im_LabQ2LabS() |
| * 16/11/94 JC |
| * - adapted to new im_wrap_oneonebuf() function |
| * 15/6/95 JC |
| * - oops! rounding was broken |
| * 6/6/95 JC |
| * - added round-to-nearest |
| * - somewhat slower ... |
| * 21/12/99 JC |
| * - a/b ==0 rounding was broken |
| * 2/11/09 |
| * - gtkdoc, cleanup |
| */ |
| |
| /* |
| |
| This file is part of VIPS. |
| |
| VIPS is free software; you can redistribute it and/or modify |
| it under the terms of the GNU Lesser General Public License as published by |
| the Free Software Foundation; either version 2 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public License |
| along with this program; if not, write to the Free Software |
| Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| |
| */ |
| |
| /* |
| |
| These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk |
| |
| */ |
| |
| #ifdef HAVE_CONFIG_H |
| #include <config.h> |
| #endif /*HAVE_CONFIG_H*/ |
| #include <vips/intl.h> |
| |
| #include <stdio.h> |
| |
| #include <vips/vips.h> |
| |
| #ifdef WITH_DMALLOC |
| #include <dmalloc.h> |
| #endif /*WITH_DMALLOC*/ |
| |
| /* Convert n pels from signed short to IM_CODING_LABQ. |
| */ |
| void |
| imb_LabS2LabQ( signed short *in, unsigned char *out, int n ) |
| { |
| int c; |
| signed short *p = in; |
| int l, a, b; |
| unsigned char *q = out; |
| unsigned char ext; |
| |
| for( c = 0; c < n; c++ ) { |
| /* Get LAB, rounding to 10, 11, 11. |
| */ |
| l = p[0] + 16; |
| if( l < 0 ) |
| l = 0; |
| else if( l > 32767 ) |
| l = 32767; |
| l >>= 5; |
| |
| /* Make sure we round -ves in the right direction! |
| */ |
| a = p[1]; |
| if( a >= 0 ) |
| a += 16; |
| else |
| a -= 16; |
| if( a < -32768 ) |
| a = -32768; |
| else if( a > 32767 ) |
| a = 32767; |
| a >>= 5; |
| |
| b = p[2]; |
| if( b >= 0 ) |
| b += 16; |
| else |
| b -= 16; |
| if( b < -32768 ) |
| b = -32768; |
| else if( b > 32767 ) |
| b = 32767; |
| b >>= 5; |
| |
| p += 3; |
| |
| /* Extract top 8 bits. |
| */ |
| q[0] = l >> 2; |
| q[1] = a >> 3; |
| q[2] = b >> 3; |
| |
| /* Form extension byte. |
| */ |
| ext = (l << 6) & 0xc0; |
| ext |= (a << 3) & 0x38; |
| ext |= b & 0x7; |
| q[3] = ext; |
| q += 4; |
| } |
| } |
| |
| /** |
| * im_LabS2LabQ: |
| * @in: input image |
| * @out: output image |
| * |
| * Convert a LabS three-band signed short image to LabQ |
| * |
| * See also: im_LabQ2LabS(). |
| * |
| * Returns: 0 on success, -1 on error. |
| */ |
| int |
| im_LabS2LabQ( IMAGE *in, IMAGE *out ) |
| { |
| IMAGE *t[1]; |
| |
| if( im_check_uncoded( "im_LabS2LabQ", in ) || |
| im_check_bands( "im_LabS2LabQ", in, 3 ) || |
| im_open_local_array( out, t, 1, "im_LabS2LabQ", "p" ) || |
| im_clip2fmt( in, t[0], IM_BANDFMT_SHORT ) ) |
| return( -1 ); |
| |
| /* Set up output image |
| */ |
| if( im_cp_desc( out, in ) ) |
| return( -1 ); |
| out->Bands = 4; |
| out->Type = IM_TYPE_LAB; |
| out->BandFmt = IM_BANDFMT_UCHAR; |
| out->Coding = IM_CODING_LABQ; |
| |
| if( im_wrapone( in, out, |
| (im_wrapone_fn) imb_LabS2LabQ, NULL, NULL ) ) |
| return( -1 ); |
| |
| return( 0 ); |
| } |