1 /* Copyright (C) 1995, 1996 Aladdin Enterprises. All rights reserved. 2 3 This file is part of AFPL Ghostscript. 4 5 AFPL Ghostscript is distributed with NO WARRANTY OF ANY KIND. No author or 6 distributor accepts any responsibility for the consequences of using it, or 7 for whether it serves any particular purpose or works at all, unless he or 8 she says so in writing. Refer to the Aladdin Free Public License (the 9 "License") for full details. 10 11 Every copy of AFPL Ghostscript must include a copy of the License, normally 12 in a plain ASCII text file named PUBLIC. The License grants you the right 13 to copy, modify and redistribute AFPL Ghostscript, but only under certain 14 conditions described in the License. Among other things, the License 15 requires that the copyright notice and this notice be preserved on all 16 copies. 17 */ 18 19 /*$Id: gdevstc1.c,v 1.2 2000/09/19 19:00:22 lpd Exp $*/ 20 /* Epson Stylus-Color Printer-Driver */ 21 22 /*** 23 This file holds the sample-implementation of a monochrome-algorithm for 24 the stcolor-driver. It is available via 25 26 gs -sDEVICE=stcolor -sDithering=gsmono ... 27 28 Actually this is no dithering-algorithm, it lets ghostscript do the job. 29 This achieved, by requesting BYTE-Values between 0 and 1 to be delivered, 30 which causes a depth of 1-Bit by default. 31 32 ***/ 33 34 /* 35 * gdevstc.h holds all the includes and the driver-specific definitions, so 36 * it is the only include you need. To add a new algorthim, STC_MODI in 37 * gdevstc.h should be extended. (see the instructions there) 38 */ 39 40 #include "gdevstc.h" 41 42 /* 43 * the routine required. 44 */ 45 46 /*ARGSUSED*/ 47 int 48 stc_gsmono(stcolor_device *sdev,int npixel,byte *in,byte *buf,byte *out) 49 { 50 51 /* 52 * There are basically 3 Types of calls: 53 * npixel < 0 => initialize buf, if this is required 54 * (happens only if requested) 55 * npixel > 0 => process next scanline, if the flag STC_WHITE is set, then 56 * in == NULL signals, that the basic-driver has decided 57 * that this scanline is white. (Useful for really dithering 58 * drivers) 59 */ 60 61 /* ============================================================= */ 62 if(npixel > 0) { /* npixel > 0 -> scanline-processing */ 63 /* ============================================================= */ 64 65 /* -----------------------------------------------*/ 66 if(in != NULL) { /* normal processing */ 67 /* -----------------------------------------------*/ 68 69 memcpy(out,in,npixel); /* really simple algorithm */ 70 71 /* -----------------------------------------------*/ 72 } else { /* skip-notification */ 73 /* -----------------------------------------------*/ 74 75 /* An algorithm may use the output-line as a buffer. 76 So it might need to be cleared on white-lines. 77 */ 78 79 memset(out,0,npixel); 80 81 /* -----------------------------------------------*/ 82 } /* normal / skip */ 83 /* -----------------------------------------------*/ 84 85 /* ============================================================= */ 86 } else { /* npixel <= 0 -> initialisation */ 87 /* ============================================================= */ 88 /* 89 * the optional buffer is already allocated by the basic-driver, here 90 * you just need to fill it, for instance, set it all to zeros: 91 */ 92 int buf_size; 93 94 /* 95 * compute the size of the buffer, according to the requested values 96 * the buffer consists of a constant part, e.g. related to the number 97 * of color-components, and a number of arrays, which are multiples of 98 * the size of a scanline times the number of components. 99 * additionally, the size of the scanlines may be expanded by one to the 100 * right and to the left. 101 */ 102 buf_size = 103 sdev->stc.dither->bufadd /* scanline-independend size */ 104 + (-npixel) /* pixels */ 105 * (sdev->stc.dither->flags/STC_SCAN) /* * scanlines */ 106 * sdev->color_info.num_components; /* * comp */ 107 108 if(buf_size > 0) { /* we obviously have a buffer */ 109 memset(buf,0,buf_size * sdev->stc.alg_item); 110 } /* we obviously have a buffer */ 111 112 /* 113 * Usually one should check parameters upon initializaon 114 */ 115 if(sdev->color_info.num_components != 1) return -1; 116 117 if((sdev->stc.dither->flags & STC_TYPE) != STC_BYTE) return -2; 118 119 /* 120 * must neither have STC_DIRECT nor STC_WHITE 121 */ 122 if((sdev->stc.dither->flags & STC_DIRECT) != 0) return -3; 123 124 } /* scanline-processing or initialisation */ 125 126 return 0; /* negative values are error-codes, that abort printing */ 127 } 128