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ef416fc2 | 1 | <!-- |
eac3a0a0 | 2 | PPD API introduction for CUPS. |
ef416fc2 | 3 | |
87cebdd2 | 4 | Copyright © 2007-2018 by Apple Inc. |
53f8d64f | 5 | Copyright © 1997-2006 by Easy Software Products, all rights reserved. |
ef416fc2 | 6 | |
53f8d64f MS |
7 | Licensed under Apache License v2.0. See the file "LICENSE" for more |
8 | information. | |
ef416fc2 | 9 | --> |
10 | ||
5a738aea | 11 | <h2 class='title'><a name='OVERVIEW'>Overview</a></h2> |
ef416fc2 | 12 | |
87cebdd2 | 13 | <blockquote>The PPD API is deprecated starting in CUPS 1.6/macOS 10.8. Please use the new Job Ticket APIs in the <a href="cupspm.html">CUPS API</a> documentation. These functions will be removed in a future release of CUPS.</blockquote> |
a2326b5b | 14 | |
5a738aea MS |
15 | <p>The CUPS PPD API provides read-only access the data in PostScript Printer |
16 | Description ("PPD") files which are used for all printers with a driver. With | |
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17 | it you can obtain the data necessary to display printer options to users, mark |
18 | option choices and check for conflicting choices, and output marked choices in | |
19 | PostScript output. The <a href="#ppd_file_t"><code>ppd_file_t</code></a> | |
20 | structure contains all of the information in a PPD file.</p> | |
21 | ||
22 | <blockquote><b>Note:</b> | |
23 | ||
24 | <p>The CUPS PPD API uses the terms "option" and "choice" instead of the Adobe | |
25 | terms "MainKeyword" and "OptionKeyword" to refer to specific printer options and | |
26 | features. CUPS also treats option ("MainKeyword") and choice ("OptionKeyword") | |
27 | values as case-insensitive strings, so option "InputSlot" and choice "Upper" | |
28 | are equivalent to "inputslot" and "upper", respectively.</p> | |
29 | </blockquote> | |
ef416fc2 | 30 | |
5a738aea | 31 | <h3><a name="LOADING">Loading a PPD File</a></h3> |
ef416fc2 | 32 | |
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33 | <p>The <a href="#ppdOpenFile"><code>ppdOpenFile</code></a> function "opens" a |
34 | PPD file and loads it into memory. For example, the following code opens the | |
35 | current printer's PPD file in a CUPS filter:</p> | |
ef416fc2 | 36 | |
5a738aea MS |
37 | <pre class="example"> |
38 | #include <cups/ppd.h> | |
ef416fc2 | 39 | |
5a738aea | 40 | <a href="#ppd_file_t">ppd_file_t</a> *ppd = <a href="#ppdOpenFile">ppdOpenFile</a>(getenv("PPD")); |
ef416fc2 | 41 | </pre> |
42 | ||
5a738aea MS |
43 | <p>The return value is a pointer to a new |
44 | <a href="#ppd_file_t"><code>ppd_file_t</code></a> structure or <code>NULL</code> | |
45 | if the PPD file does not exist or cannot be loaded. The | |
46 | <a href="#ppdClose"><code>ppdClose</code></a> function frees the memory used | |
47 | by the structure:</p> | |
ef416fc2 | 48 | |
5a738aea MS |
49 | <pre class="example"> |
50 | #include <cups/ppd.h> | |
51 | ||
52 | <a href="#ppd_file_t">ppd_file_t</a> *ppd; | |
53 | ||
54 | <a href="#ppdClose">ppdClose</a>(ppd); | |
55 | </pre> | |
56 | ||
79e1d494 MS |
57 | <p>Once closed, pointers to the <a href="#ppd_file_t"><code>ppd_file_t</code></a> |
58 | structure and any data in it will no longer be valid.</p> | |
59 | ||
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60 | <h3><a name="OPTIONS_AND_GROUPS">Options and Groups</a></h3> |
61 | ||
62 | <p>PPD files support multiple options, which are stored in arrays of | |
63 | <a href="#ppd_option_t"><code>ppd_option_t</code></a> and | |
64 | <a href="#ppd_choice_t"><code>ppd_choice_t</code></a> structures.</p> | |
65 | ||
66 | <p>Each option in turn is associated with a group stored in a | |
67 | <a href="#ppd_group_t"><code>ppd_group_t</code></a> structure. Groups can be | |
68 | specified in the PPD file; if an option is not associated with a group | |
69 | then it is put in an automatically-generated "General" group. Groups can also | |
70 | have sub-groups, however CUPS currently ignores sub-groups because of past | |
71 | abuses of this functionality.</p> | |
72 | ||
79e1d494 | 73 | <p>Option choices are selected by marking them using one of three functions. The |
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74 | first is <a href="#ppdMarkDefaults"><code>ppdMarkDefaults</code></a> which |
75 | selects all of the default options in the PPD file:</p> | |
76 | ||
77 | <pre class="example"> | |
78 | #include <cups/ppd.h> | |
79 | ||
80 | <a href="#ppd_file_t">ppd_file_t</a> *ppd; | |
81 | ||
82 | <a href="#ppdMarkDefaults">ppdMarkDefaults</a>(ppd); | |
83 | </pre> | |
84 | ||
85 | <p>The second is <a href="#ppdMarkOption"><code>ppdMarkOption</code></a> | |
86 | which selects a single option choice in the PPD file. For example, the following | |
79e1d494 | 87 | code selects the upper paper tray:</p> |
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88 | |
89 | <pre class="example"> | |
90 | #include <cups/ppd.h> | |
91 | ||
92 | <a href="#ppd_file_t">ppd_file_t</a> *ppd; | |
93 | ||
79e1d494 | 94 | <a href="#ppdMarkOption">ppdMarkOption</a>(ppd, "InputSlot", "Upper"); |
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95 | </pre> |
96 | ||
97 | <p>The last function is | |
98 | <a href="#cupsMarkOptions"><code>cupsMarkOptions</code></a> which selects | |
99 | multiple option choices in the PPD file from an array of CUPS options, mapping | |
100 | IPP attributes like "media" and "sides" to their corresponding PPD options. You | |
101 | typically use this function in a print filter with | |
102 | <code>cupsParseOptions</code> and | |
103 | <a href="#ppdMarkDefaults"><code>ppdMarkDefaults</code></a> to select all of | |
104 | the option choices needed for the job, for example:</p> | |
105 | ||
106 | <pre class="example"> | |
107 | #include <cups/ppd.h> | |
108 | ||
109 | <a href="#ppd_file_t">ppd_file_t</a> *ppd = <a href="#ppdOpenFile">ppdOpenFile</a>(getenv("PPD")); | |
110 | cups_option_t *options = NULL; | |
111 | int num_options = cupsParseOptions(argv[5], 0, &options); | |
112 | ||
113 | <a href="#ppdMarkDefaults">ppdMarkDefaults</a>(ppd); | |
114 | <a href="#cupsMarkOptions">cupsMarkOptions</a>(ppd, num_options, options); | |
79e1d494 | 115 | cupsFreeOptions(num_options, options); |
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116 | </pre> |
117 | ||
118 | <h3><a name="CONSTRAINTS">Constraints</a></h3> | |
119 | ||
120 | <p>PPD files support specification of conflict conditions, called | |
121 | constraints, between different options. Constraints are stored in an array of | |
122 | <a href="#ppd_const_t"><code>ppd_const_t</code></a> structures which specify | |
123 | the options and choices that conflict with each other. The | |
124 | <a href="#ppdConflicts"><code>ppdConflicts</code></a> function tells you | |
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125 | how many of the selected options are incompatible. Since constraints are |
126 | normally specified in pairs, the returned value is typically an even number.</p> | |
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127 | |
128 | <h3><a name="PAGE_SIZES">Page Sizes</a></h3> | |
129 | ||
130 | <p>Page sizes are special options which have physical dimensions and margins | |
131 | associated with them. The size information is stored in | |
132 | <a href="#ppd_size_t"><code>ppd_size_t</code></a> structures and is available | |
133 | by looking up the named size with the | |
134 | <a href="#ppdPageSize"><code>ppdPageSize</code></a> function. The page size and | |
135 | margins are returned in units called points; there are 72 points per inch. If | |
136 | you pass <code>NULL</code> for the size, the currently selected size is | |
137 | returned:</p> | |
138 | ||
139 | <pre class="example"> | |
140 | #include <cups/ppd.h> | |
141 | ||
142 | <a href="#ppd_file_t">ppd_file_t</a> *ppd; | |
143 | <a href="#ppd_size_t">ppd_size_t</a> *size = <a href="#ppdPageSize">ppdPageSize</a>(ppd, NULL); | |
144 | </pre> | |
145 | ||
146 | <p>Besides the standard page sizes listed in a PPD file, some printers | |
147 | support variable or custom page sizes. Custom page sizes are supported if the | |
148 | <code>variables_sizes</code> member of the | |
149 | <a href="#ppd_file_t"><code>ppd_file_t</code></a> structure is non-zero. | |
150 | The <code>custom_min</code>, <code>custom_max</code>, and | |
151 | <code>custom_margins</code> members of the | |
152 | <a href="#ppd_file_t"><code>ppd_file_t</code></a> structure define the limits | |
153 | of the printable area. To get the resulting media size, use a page size string | |
154 | of the form "Custom.<I>width</I>x<I>length</I>", where "width" and "length" are | |
155 | in points. Custom page size names can also be specified in inches | |
156 | ("Custom.<i>width</i>x<i>height</i>in"), centimeters | |
157 | ("Custom.<i>width</i>x<i>height</i>cm"), or millimeters | |
158 | ("Custom.<i>width</i>x<i>height</i>mm"):</p> | |
159 | ||
160 | <pre class="example"> | |
161 | #include <cups/ppd.h> | |
162 | ||
163 | <a href="#ppd_file_t">ppd_file_t</a> *ppd; | |
164 | ||
165 | /* Get an 576x720 point custom page size */ | |
166 | <a href="#ppd_size_t">ppd_size_t</a> *size = <a href="#ppdPageSize">ppdPageSize</a>(ppd, "Custom.576x720"); | |
167 | ||
168 | /* Get an 8x10 inch custom page size */ | |
169 | <a href="#ppd_size_t">ppd_size_t</a> *size = <a href="#ppdPageSize">ppdPageSize</a>(ppd, "Custom.8x10in"); | |
170 | ||
171 | /* Get a 100x200 millimeter custom page size */ | |
172 | <a href="#ppd_size_t">ppd_size_t</a> *size = <a href="#ppdPageSize">ppdPageSize</a>(ppd, "Custom.100x200mm"); | |
173 | ||
174 | /* Get a 12.7x34.5 centimeter custom page size */ | |
175 | <a href="#ppd_size_t">ppd_size_t</a> *size = <a href="#ppdPageSize">ppdPageSize</a>(ppd, "Custom.12.7x34.5cm"); | |
176 | </pre> | |
177 | ||
79e1d494 MS |
178 | <p>If the PPD does not support variable page sizes, the |
179 | <a href="#ppdPageSize"><code>ppdPageSize</code></a> function will return | |
180 | <code>NULL</code>.</p> | |
181 | ||
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182 | <h3><a name="ATTRIBUTES">Attributes</a></h3> |
183 | ||
184 | <p>Every PPD file is composed of one or more attributes. Most of these | |
185 | attributes are used to define groups, options, choices, and page sizes, | |
79e1d494 MS |
186 | however several informational attributes may be present which you can access |
187 | in your program or filter. Attributes normally look like one of the following | |
188 | examples in a PPD file:</p> | |
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189 | |
190 | <pre class="example"> | |
191 | *name: "value" | |
192 | *name spec: "value" | |
193 | *name spec/text: "value" | |
194 | </pre> | |
195 | ||
196 | <p>The <a href="#ppdFindAttr"><code>ppdFindAttr</code></a> and | |
197 | <a href="#ppdFindNextAttr"><code>ppdFindNextAttr</code></a> functions find the | |
198 | first and next instances, respectively, of the named attribute with the given | |
199 | "spec" string and return a <a href="#ppd_attr_t"><code>ppd_attr_t</code></a> | |
200 | structure. If you provide a NULL specifier string, all attributes with the | |
201 | given name will be returned. For example, the following code lists all of the | |
202 | <code>Product</code> attributes in a PPD file:</p> | |
203 | ||
204 | <pre class="example"> | |
205 | #include <cups/ppd.h> | |
206 | ||
207 | <a href="#ppd_file_t">ppd_file_t</a> *ppd; | |
208 | <a href="#ppd_attr_t">ppd_attr_t</a> *attr; | |
209 | ||
210 | for (attr = <a href="#ppdFindAttr">ppdFindAttr</a>(ppd, "Product", NULL); | |
211 | attr != NULL; | |
212 | attr = <a href="#ppdFindNextAttr">ppdFindNextAttr</a>(ppd, "Product", NULL)) | |
213 | puts(attr->value); | |
214 | </pre> |