diff options
Diffstat (limited to 'render/thscreen.h')
| -rw-r--r-- | render/thscreen.h | 52 |
1 files changed, 37 insertions, 15 deletions
diff --git a/render/thscreen.h b/render/thscreen.h index d3ac9b1..9a504bc 100644 --- a/render/thscreen.h +++ b/render/thscreen.h @@ -5,20 +5,22 @@ /* * render2d * - * Threshold screen pixel processing object. + * Threshold or Error diffusion screen pixel processing object. * (Simplified from DPS code) * * Author: Graeme W. Gill * Date: 11/7/2005 * Version: 1.00 * - * Copyright 2005, 2012 Graeme W. Gill + * Copyright 2005, 2012, 2014 Graeme W. Gill * All rights reserved. * This material is licenced under the GNU AFFERO GENERAL PUBLIC LICENSE Version 3 :- * see the License.txt file for licencing details. * */ +#define THMXCH2D 8 /* Maximum color channels */ + /* Light Separation in screening flag */ typedef enum { scls_false = 0, /* Don't do light ink separation during screening. */ @@ -45,15 +47,31 @@ struct _thscreens { int np; /* Number of planes */ struct _thscreen **sc; /* List of screens */ - /* Screen a single color plane */ + int oebpc; /* Output encoding bits per component, 1,2,4 or 8 */ + int oelev; /* Output encoding levels. Must be <= 2 ^ oebpc */ + int oevalues[256]; /* Output encoding values for each level */ + + int edif; /* nz if using error diffusion */ + int **luts; /* Lookup tables */ + int mxwidth; /* max width in pixels of raster to be screened */ + int lastyoff; /* Last y offset */ + float **ebuf; /* Error buffer for each plane */ + /* ebuf[][-1] is used for next pixel error */ + + void (*quant)(void *qcntx, double *out, double *in); /* optional quantization func. for edif */ + void *qcntx; /* Context for quant */ + + sobol *so; /* Random number generator for error diffusion */ + + /* Screen pixel values */ void (* screen)( /* Pointer to dither function */ struct _thscreens *t, /* Screening object pointer */ int width, int height, /* Width and height to screen in pixels */ int xoff, int yoff, /* Offset into screening pattern */ - unsigned char *in, /* Input pixel buffer */ - unsigned long ipitch, /* Increment between input lines */ unsigned char *out, /* Output pixel buffer */ - unsigned long opitch); /* Increment between output lines */ + unsigned long opitch, /* Increment between output lines in components */ + unsigned char *in, /* Input pixel buffer */ + unsigned long ipitch); /* Increment between input lines in components */ void (* del)( /* Destructor */ struct _thscreens *t); /* Screening objects pointer */ @@ -68,7 +86,7 @@ thscreens *new_thscreens( int exact, /* Return only exact matches */ int nplanes, /* Number of planes to screen */ double asp, /* Target aspect ratio (== dpiX/dpiY) */ - int size, /* Target size */ + int size, /* Target screen size */ sc_iencoding ie, /* Input encoding - must be scie_16 */ int oebpc, /* Output encoding bits per component - must be 8 */ int oelev, /* Output encoding levels. Must be <= 2 ^ oebpc */ @@ -76,8 +94,12 @@ thscreens *new_thscreens( /* Must be oelev entries. Default is 0 .. oelev-1 */ sc_oorder oo, /* Output bit ordering */ double overlap, /* Overlap between levels, 0 - 1.0 */ + int mxwidth, /* max width in pixels of raster to be screened */ void **cntx, /* List of contexts for lookup table callback */ - double (**lutfunc)(void *cntx, double in) /* List of callback function, NULL if none */ + double (**lutfunc)(void *cntx, double in), /* List of callback function, NULL if none */ + int edif, /* nz if using error diffusion */ + void (*quant)(void *qcntx, double *out, double *in), /* optional quantization func. for edif */ + void *qcntx ); /* ---------------------------- */ @@ -121,12 +143,12 @@ struct _thscreen { struct _thscreen *t, /* Screening object pointer */ int width, int height, /* Width and height to screen in pixels */ int xoff, int yoff, /* Offset into screening pattern */ - unsigned char *in, /* Input pixel buffer */ - unsigned long ipinc, /* Increment between input pixels */ - unsigned long ipitch, /* Increment between input lines */ unsigned char *out, /* Output pixel buffer */ - unsigned long opinc, /* Increment between output pixels */ - unsigned long opitch); /* Increment between output lines */ + unsigned long opinc, /* Increment between output pixels in components */ + unsigned long opitch, /* Increment between output lines in components */ + unsigned char *in, /* Input pixel buffer */ + unsigned long ipinc, /* Increment between input pixels in components */ + unsigned long ipitch); /* Increment between input lines in components */ void (* del)( /* Destructor */ struct _thscreen *t); /* Screening object pointer */ @@ -136,8 +158,8 @@ struct _thscreen { /* Create a new thscreen object */ /* Return NULL on error */ thscreen *new_thscreen( - int width, /* width in pixels */ - int height, /* Height in pixels */ + int width, /* width in pixels of screen */ + int height, /* Height in pixels of screen */ int xoff, int yoff, /* Pattern offsets into width & height (must be +ve) */ double asp, /* Aspect ratio (== dpiX/dpiY) */ int swap, /* Swap X & Y to invert aspect ratio */ |