1/*
2 * "$Id: image.h,v 1.2 2005/10/18 02:08:16 rlk Exp $"
3 *
4 *   libgimpprint image functions.
5 *
6 *   Copyright 1997-2000 Michael Sweet (mike@easysw.com) and
7 *	Robert Krawitz (rlk@alum.mit.edu)
8 *
9 *   This program is free software; you can redistribute it and/or modify it
10 *   under the terms of the GNU General Public License as published by the Free
11 *   Software Foundation; either version 2 of the License, or (at your option)
12 *   any later version.
13 *
14 *   This program is distributed in the hope that it will be useful, but
15 *   WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16 *   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
17 *   for more details.
18 *
19 *   You should have received a copy of the GNU General Public License
20 *   along with this program; if not, write to the Free Software
21 *   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
22 */
23
24/**
25 * @file gutenprint/image.h
26 * @brief Image functions.
27 */
28
29#ifndef GUTENPRINT_IMAGE_H
30#define GUTENPRINT_IMAGE_H
31
32#ifdef __cplusplus
33extern "C" {
34#endif
35
36/**
37 * The image type is an abstract data type for interfacing with the
38 * image creation program.
39 *
40 * @defgroup image image
41 * @{
42 */
43
44/*
45 * Constants...
46 */
47
48/*! The maximum number of channels. */
49#define STP_CHANNEL_LIMIT	(32)
50
51
52/** Image status. */
53typedef enum
54{
55  STP_IMAGE_STATUS_OK,   /*!< Everything is OK. */
56  STP_IMAGE_STATUS_ABORT /*!< An error occured, or the job was aborted. */
57} stp_image_status_t;
58
59/**
60 * The image type is an abstract data type for interfacing with the
61 * image creation program.  It provides callbacks to functions defined
62 * within the client application which are called while printing the
63 * image.
64 */
65typedef struct stp_image
66{
67  /**
68   * This callback is used to perform any initialization required by
69   * the image layer for the image.  It will be called once per image.
70   * @param image the image in use.
71   */
72  void (*init)(struct stp_image *image);
73  /**
74   * This callback is called to reset the image to the beginning.  It
75   * may (in principle) be called multiple times if a page is being
76   * printed more than once.
77   * @warning The reset() call may be removed in the future.
78   * @param image the image in use.
79   */
80  void (*reset)(struct stp_image *image);
81  /**
82   * This callback returns the width of the image in pixels.
83   * @param image the image in use.
84   */
85  int  (*width)(struct stp_image *image);
86  /**
87   * This callback returns the height of the image in pixels.
88   * @param image the image in use.
89   */
90  int  (*height)(struct stp_image *image);
91  /**
92   * This callback transfers the data from the image to the gimp-print
93   * library.  It is called from the driver layer.  It should copy
94   * WIDTH (as returned by the width() member) pixels of data into the
95   * data buffer.  It normally returns STP_IMAGE_STATUS_OK; if
96   * something goes wrong, or the application wishes to stop producing
97   * any further output (e. g. because the user cancelled the print
98   * job), it should return STP_IMAGE_STATUS_ABORT.  This will cause
99   * the driver to flush any remaining data to the output.  It will
100   * always request rows in monotonically ascending order, but it may
101   * skip rows (if, for example, the resolution of the input is higher
102   * than the resolution of the output).
103   * @param image the image in use.
104   * @param data a pointer to width() bytes of pixel data.
105   * @param byte_limit (image width * number of channels).
106   * @param row (unused).
107   */
108  stp_image_status_t (*get_row)(struct stp_image *image, unsigned char *data,
109                                size_t byte_limit, int row);
110
111  /**
112   * This callback returns the name of the application.  This is
113   * embedded in the output by some drivers.
114   */
115  const char *(*get_appname)(struct stp_image *image);
116  /**
117   * This callback is called at the end of each page.
118   */
119  void (*conclude)(struct stp_image *image);
120  /**
121   * A pointer to an application-specific state information that might
122   * need to be associated with the image object.
123   */
124  void *rep;
125} stp_image_t;
126
127extern void stp_image_init(stp_image_t *image);
128extern void stp_image_reset(stp_image_t *image);
129extern int stp_image_width(stp_image_t *image);
130extern int stp_image_height(stp_image_t *image);
131extern stp_image_status_t stp_image_get_row(stp_image_t *image,
132					    unsigned char *data,
133					    size_t limit, int row);
134extern const char *stp_image_get_appname(stp_image_t *image);
135extern void stp_image_conclude(stp_image_t *image);
136
137  /** @} */
138
139#ifdef __cplusplus
140  }
141#endif
142
143#endif /* GUTENPRINT_IMAGE_H */
144/*
145 * End of "$Id: image.h,v 1.2 2005/10/18 02:08:16 rlk Exp $".
146 */
147