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Diffstat (limited to 'render/thscreen.h')
| -rw-r--r-- | render/thscreen.h | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/render/thscreen.h b/render/thscreen.h new file mode 100644 index 0000000..d3ac9b1 --- /dev/null +++ b/render/thscreen.h @@ -0,0 +1,156 @@ + +#ifndef THSCREEN_H +#define THSCREEN_H + +/* + * render2d + * + * Threshold 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 + * All rights reserved. + * This material is licenced under the GNU AFFERO GENERAL PUBLIC LICENSE Version 3 :- + * see the License.txt file for licencing details. + * + */ + +/* Light Separation in screening flag */ +typedef enum { + scls_false = 0, /* Don't do light ink separation during screening. */ + scls_true = 0 /* Do light ink separation during screening. */ +} sc_lightsep; + +/* Input encoding */ +typedef enum { + scie_8 = 0, /* 8 bit per component */ + scie_16 = 1 /* 16 bit per component */ +} sc_iencoding; + +/* Output bit order within byte */ +typedef enum { + scoo_l = 0, /* Little endian */ + scoo_b = 1 /* Big endian */ +} sc_oorder; + + +/* ---------------------------- */ +/* Setup a set of screens */ + +struct _thscreens { + int np; /* Number of planes */ + struct _thscreen **sc; /* List of screens */ + + /* Screen a single color plane */ + 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 */ + + void (* del)( /* Destructor */ + struct _thscreens *t); /* Screening objects pointer */ + +}; typedef struct _thscreens thscreens; + + +/* Return a thscreens object */ +/* Screen data is used that best matches the requested parameters. */ +/* Return NULL on error */ +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 */ + 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 */ + int *oevalues, /* Optional output encoding values for each level */ + /* Must be oelev entries. Default is 0 .. oelev-1 */ + sc_oorder oo, /* Output bit ordering */ + double overlap, /* Overlap between levels, 0 - 1.0 */ + void **cntx, /* List of contexts for lookup table callback */ + double (**lutfunc)(void *cntx, double in) /* List of callback function, NULL if none */ +); + +/* ---------------------------- */ +/* Screen defintion information */ + +typedef struct { + int x; + int y; +} ccoord; + +typedef struct { + int size; /* General size */ + int width; /* width in pixels */ + int height; /* Height in pixels */ + double asp; /* Aspect ratio (== dpiX/dpiY) */ + int joint; /* na for joint screens */ + ccoord **list; /* Pointer to list of pointers to threshold coordinates */ +} thscdef; + +/* ------------------------ */ +/* Setup of a single screen */ + +struct _thscreen { + sc_iencoding ie; /* Input encoding */ + 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 */ + sc_oorder oo; /* Output bit ordering */ + double asp; /* Aspect ratio (== dpiX/dpiY) */ + double overlap; /* Overlap between levels, 0 - 1.0 */ + int *lut; /* Lookup table */ + unsigned char _tht[65536 * 3];/* Threshold table */ + unsigned char *tht; /* Pointer to base of threshold table */ + unsigned char **thp; /* Pointers to threshold table (offset int _tht) */ + int swidth; /* Given screen width */ + int sheight; /* Given screen height */ + int twidth; /* Rounded up screen table width & stride */ + int theight; /* Screen table height */ + + void (* screen)( /* Pointer to dither function */ + 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 */ + + void (* del)( /* Destructor */ + struct _thscreen *t); /* Screening object pointer */ + +}; typedef struct _thscreen thscreen; + +/* Create a new thscreen object */ +/* Return NULL on error */ +thscreen *new_thscreen( + int width, /* width in pixels */ + int height, /* Height in pixels */ + 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 */ + ccoord *thli, /* List of screen initialisation threshold coordinates */ + 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 */ + int *oevalues, /* Optional output encoding values for each level */ + /* Must be oelev entries. Default is 0 .. oelev-1 */ + sc_oorder oo, /* Output bit ordering */ + double olap, /* Overlap between levels, 0 - 1.0 */ + void *cntx, /* Context for LUT table callback */ + double (*lutfunc)(void *cntx, double in) /* Callback function, NULL if none */ +); + +#endif /* THSCREEN_H */ |