michael@0: /*
michael@0:  * jccolext.c
michael@0:  *
michael@0:  * This file was part of the Independent JPEG Group's software:
michael@0:  * Copyright (C) 1991-1996, Thomas G. Lane.
michael@0:  * libjpeg-turbo Modifications:
michael@0:  * Copyright (C) 2009-2012, D. R. Commander.
michael@0:  * For conditions of distribution and use, see the accompanying README file.
michael@0:  *
michael@0:  * This file contains input colorspace conversion routines.
michael@0:  */
michael@0: 
michael@0: 
michael@0: /* This file is included by jccolor.c */
michael@0: 
michael@0: 
michael@0: /*
michael@0:  * Convert some rows of samples to the JPEG colorspace.
michael@0:  *
michael@0:  * Note that we change from the application's interleaved-pixel format
michael@0:  * to our internal noninterleaved, one-plane-per-component format.
michael@0:  * The input buffer is therefore three times as wide as the output buffer.
michael@0:  *
michael@0:  * A starting row offset is provided only for the output buffer.  The caller
michael@0:  * can easily adjust the passed input_buf value to accommodate any row
michael@0:  * offset required on that side.
michael@0:  */
michael@0: 
michael@0: INLINE
michael@0: LOCAL(void)
michael@0: rgb_ycc_convert_internal (j_compress_ptr cinfo,
michael@0:                           JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
michael@0:                           JDIMENSION output_row, int num_rows)
michael@0: {
michael@0:   my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
michael@0:   register int r, g, b;
michael@0:   register INT32 * ctab = cconvert->rgb_ycc_tab;
michael@0:   register JSAMPROW inptr;
michael@0:   register JSAMPROW outptr0, outptr1, outptr2;
michael@0:   register JDIMENSION col;
michael@0:   JDIMENSION num_cols = cinfo->image_width;
michael@0: 
michael@0:   while (--num_rows >= 0) {
michael@0:     inptr = *input_buf++;
michael@0:     outptr0 = output_buf[0][output_row];
michael@0:     outptr1 = output_buf[1][output_row];
michael@0:     outptr2 = output_buf[2][output_row];
michael@0:     output_row++;
michael@0:     for (col = 0; col < num_cols; col++) {
michael@0:       r = GETJSAMPLE(inptr[RGB_RED]);
michael@0:       g = GETJSAMPLE(inptr[RGB_GREEN]);
michael@0:       b = GETJSAMPLE(inptr[RGB_BLUE]);
michael@0:       inptr += RGB_PIXELSIZE;
michael@0:       /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations
michael@0:        * must be too; we do not need an explicit range-limiting operation.
michael@0:        * Hence the value being shifted is never negative, and we don't
michael@0:        * need the general RIGHT_SHIFT macro.
michael@0:        */
michael@0:       /* Y */
michael@0:       outptr0[col] = (JSAMPLE)
michael@0: 		((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
michael@0: 		 >> SCALEBITS);
michael@0:       /* Cb */
michael@0:       outptr1[col] = (JSAMPLE)
michael@0: 		((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF])
michael@0: 		 >> SCALEBITS);
michael@0:       /* Cr */
michael@0:       outptr2[col] = (JSAMPLE)
michael@0: 		((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF])
michael@0: 		 >> SCALEBITS);
michael@0:     }
michael@0:   }
michael@0: }
michael@0: 
michael@0: 
michael@0: /**************** Cases other than RGB -> YCbCr **************/
michael@0: 
michael@0: 
michael@0: /*
michael@0:  * Convert some rows of samples to the JPEG colorspace.
michael@0:  * This version handles RGB->grayscale conversion, which is the same
michael@0:  * as the RGB->Y portion of RGB->YCbCr.
michael@0:  * We assume rgb_ycc_start has been called (we only use the Y tables).
michael@0:  */
michael@0: 
michael@0: INLINE
michael@0: LOCAL(void)
michael@0: rgb_gray_convert_internal (j_compress_ptr cinfo,
michael@0:                            JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
michael@0:                            JDIMENSION output_row, int num_rows)
michael@0: {
michael@0:   my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
michael@0:   register int r, g, b;
michael@0:   register INT32 * ctab = cconvert->rgb_ycc_tab;
michael@0:   register JSAMPROW inptr;
michael@0:   register JSAMPROW outptr;
michael@0:   register JDIMENSION col;
michael@0:   JDIMENSION num_cols = cinfo->image_width;
michael@0: 
michael@0:   while (--num_rows >= 0) {
michael@0:     inptr = *input_buf++;
michael@0:     outptr = output_buf[0][output_row];
michael@0:     output_row++;
michael@0:     for (col = 0; col < num_cols; col++) {
michael@0:       r = GETJSAMPLE(inptr[RGB_RED]);
michael@0:       g = GETJSAMPLE(inptr[RGB_GREEN]);
michael@0:       b = GETJSAMPLE(inptr[RGB_BLUE]);
michael@0:       inptr += RGB_PIXELSIZE;
michael@0:       /* Y */
michael@0:       outptr[col] = (JSAMPLE)
michael@0: 		((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
michael@0: 		 >> SCALEBITS);
michael@0:     }
michael@0:   }
michael@0: }
michael@0: 
michael@0: 
michael@0: /*
michael@0:  * Convert some rows of samples to the JPEG colorspace.
michael@0:  * This version handles extended RGB->plain RGB conversion
michael@0:  */
michael@0: 
michael@0: INLINE
michael@0: LOCAL(void)
michael@0: rgb_rgb_convert_internal (j_compress_ptr cinfo,
michael@0:                           JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
michael@0:                           JDIMENSION output_row, int num_rows)
michael@0: {
michael@0:   register JSAMPROW inptr;
michael@0:   register JSAMPROW outptr0, outptr1, outptr2;
michael@0:   register JDIMENSION col;
michael@0:   JDIMENSION num_cols = cinfo->image_width;
michael@0: 
michael@0:   while (--num_rows >= 0) {
michael@0:     inptr = *input_buf++;
michael@0:     outptr0 = output_buf[0][output_row];
michael@0:     outptr1 = output_buf[1][output_row];
michael@0:     outptr2 = output_buf[2][output_row];
michael@0:     output_row++;
michael@0:     for (col = 0; col < num_cols; col++) {
michael@0:       outptr0[col] = GETJSAMPLE(inptr[RGB_RED]);
michael@0:       outptr1[col] = GETJSAMPLE(inptr[RGB_GREEN]);
michael@0:       outptr2[col] = GETJSAMPLE(inptr[RGB_BLUE]);
michael@0:       inptr += RGB_PIXELSIZE;
michael@0:     }
michael@0:   }
michael@0: }