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ef416fc2 | 1 | <!-- |
eac3a0a0 | 2 | PPD API introduction for CUPS. |
ef416fc2 | 3 | |
73721e3e | 4 | Copyright © 2007-2019 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 | |
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13 | <blockquote><b>Note:</b> |
14 | ||
15 | <p>The PPD API was deprecated in CUPS 1.6/macOS 10.8. Please use the new Job Ticket APIs in the <a href="cupspm.html">CUPS Programming Manual</a> documentation. These functions will be removed in a future release of CUPS.</p> | |
16 | </blockquote> | |
a2326b5b | 17 | |
5a738aea MS |
18 | <p>The CUPS PPD API provides read-only access the data in PostScript Printer |
19 | Description ("PPD") files which are used for all printers with a driver. With | |
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20 | it you can obtain the data necessary to display printer options to users, mark |
21 | option choices and check for conflicting choices, and output marked choices in | |
22 | PostScript output. The <a href="#ppd_file_t"><code>ppd_file_t</code></a> | |
23 | structure contains all of the information in a PPD file.</p> | |
24 | ||
25 | <blockquote><b>Note:</b> | |
26 | ||
27 | <p>The CUPS PPD API uses the terms "option" and "choice" instead of the Adobe | |
28 | terms "MainKeyword" and "OptionKeyword" to refer to specific printer options and | |
29 | features. CUPS also treats option ("MainKeyword") and choice ("OptionKeyword") | |
30 | values as case-insensitive strings, so option "InputSlot" and choice "Upper" | |
31 | are equivalent to "inputslot" and "upper", respectively.</p> | |
32 | </blockquote> | |
ef416fc2 | 33 | |
73721e3e | 34 | |
5a738aea | 35 | <h3><a name="LOADING">Loading a PPD File</a></h3> |
ef416fc2 | 36 | |
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37 | <p>The <a href="#ppdOpenFile"><code>ppdOpenFile</code></a> function "opens" a |
38 | PPD file and loads it into memory. For example, the following code opens the | |
39 | current printer's PPD file in a CUPS filter:</p> | |
ef416fc2 | 40 | |
5a738aea MS |
41 | <pre class="example"> |
42 | #include <cups/ppd.h> | |
ef416fc2 | 43 | |
5a738aea | 44 | <a href="#ppd_file_t">ppd_file_t</a> *ppd = <a href="#ppdOpenFile">ppdOpenFile</a>(getenv("PPD")); |
ef416fc2 | 45 | </pre> |
46 | ||
5a738aea MS |
47 | <p>The return value is a pointer to a new |
48 | <a href="#ppd_file_t"><code>ppd_file_t</code></a> structure or <code>NULL</code> | |
49 | if the PPD file does not exist or cannot be loaded. The | |
50 | <a href="#ppdClose"><code>ppdClose</code></a> function frees the memory used | |
51 | by the structure:</p> | |
ef416fc2 | 52 | |
5a738aea MS |
53 | <pre class="example"> |
54 | #include <cups/ppd.h> | |
55 | ||
56 | <a href="#ppd_file_t">ppd_file_t</a> *ppd; | |
57 | ||
58 | <a href="#ppdClose">ppdClose</a>(ppd); | |
59 | </pre> | |
60 | ||
79e1d494 MS |
61 | <p>Once closed, pointers to the <a href="#ppd_file_t"><code>ppd_file_t</code></a> |
62 | structure and any data in it will no longer be valid.</p> | |
63 | ||
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64 | <h3><a name="OPTIONS_AND_GROUPS">Options and Groups</a></h3> |
65 | ||
66 | <p>PPD files support multiple options, which are stored in arrays of | |
67 | <a href="#ppd_option_t"><code>ppd_option_t</code></a> and | |
68 | <a href="#ppd_choice_t"><code>ppd_choice_t</code></a> structures.</p> | |
69 | ||
70 | <p>Each option in turn is associated with a group stored in a | |
71 | <a href="#ppd_group_t"><code>ppd_group_t</code></a> structure. Groups can be | |
72 | specified in the PPD file; if an option is not associated with a group | |
73 | then it is put in an automatically-generated "General" group. Groups can also | |
74 | have sub-groups, however CUPS currently ignores sub-groups because of past | |
75 | abuses of this functionality.</p> | |
76 | ||
79e1d494 | 77 | <p>Option choices are selected by marking them using one of three functions. The |
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78 | first is <a href="#ppdMarkDefaults"><code>ppdMarkDefaults</code></a> which |
79 | selects all of the default options in the PPD file:</p> | |
80 | ||
81 | <pre class="example"> | |
82 | #include <cups/ppd.h> | |
83 | ||
84 | <a href="#ppd_file_t">ppd_file_t</a> *ppd; | |
85 | ||
86 | <a href="#ppdMarkDefaults">ppdMarkDefaults</a>(ppd); | |
87 | </pre> | |
88 | ||
89 | <p>The second is <a href="#ppdMarkOption"><code>ppdMarkOption</code></a> | |
90 | which selects a single option choice in the PPD file. For example, the following | |
79e1d494 | 91 | code selects the upper paper tray:</p> |
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92 | |
93 | <pre class="example"> | |
94 | #include <cups/ppd.h> | |
95 | ||
96 | <a href="#ppd_file_t">ppd_file_t</a> *ppd; | |
97 | ||
79e1d494 | 98 | <a href="#ppdMarkOption">ppdMarkOption</a>(ppd, "InputSlot", "Upper"); |
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99 | </pre> |
100 | ||
101 | <p>The last function is | |
102 | <a href="#cupsMarkOptions"><code>cupsMarkOptions</code></a> which selects | |
103 | multiple option choices in the PPD file from an array of CUPS options, mapping | |
104 | IPP attributes like "media" and "sides" to their corresponding PPD options. You | |
105 | typically use this function in a print filter with | |
106 | <code>cupsParseOptions</code> and | |
107 | <a href="#ppdMarkDefaults"><code>ppdMarkDefaults</code></a> to select all of | |
108 | the option choices needed for the job, for example:</p> | |
109 | ||
110 | <pre class="example"> | |
111 | #include <cups/ppd.h> | |
112 | ||
113 | <a href="#ppd_file_t">ppd_file_t</a> *ppd = <a href="#ppdOpenFile">ppdOpenFile</a>(getenv("PPD")); | |
114 | cups_option_t *options = NULL; | |
115 | int num_options = cupsParseOptions(argv[5], 0, &options); | |
116 | ||
117 | <a href="#ppdMarkDefaults">ppdMarkDefaults</a>(ppd); | |
118 | <a href="#cupsMarkOptions">cupsMarkOptions</a>(ppd, num_options, options); | |
79e1d494 | 119 | cupsFreeOptions(num_options, options); |
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120 | </pre> |
121 | ||
73721e3e | 122 | |
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123 | <h3><a name="CONSTRAINTS">Constraints</a></h3> |
124 | ||
125 | <p>PPD files support specification of conflict conditions, called | |
126 | constraints, between different options. Constraints are stored in an array of | |
127 | <a href="#ppd_const_t"><code>ppd_const_t</code></a> structures which specify | |
128 | the options and choices that conflict with each other. The | |
129 | <a href="#ppdConflicts"><code>ppdConflicts</code></a> function tells you | |
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130 | how many of the selected options are incompatible. Since constraints are |
131 | normally specified in pairs, the returned value is typically an even number.</p> | |
5a738aea | 132 | |
73721e3e | 133 | |
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134 | <h3><a name="PAGE_SIZES">Page Sizes</a></h3> |
135 | ||
136 | <p>Page sizes are special options which have physical dimensions and margins | |
137 | associated with them. The size information is stored in | |
138 | <a href="#ppd_size_t"><code>ppd_size_t</code></a> structures and is available | |
139 | by looking up the named size with the | |
140 | <a href="#ppdPageSize"><code>ppdPageSize</code></a> function. The page size and | |
141 | margins are returned in units called points; there are 72 points per inch. If | |
142 | you pass <code>NULL</code> for the size, the currently selected size is | |
143 | returned:</p> | |
144 | ||
145 | <pre class="example"> | |
146 | #include <cups/ppd.h> | |
147 | ||
148 | <a href="#ppd_file_t">ppd_file_t</a> *ppd; | |
149 | <a href="#ppd_size_t">ppd_size_t</a> *size = <a href="#ppdPageSize">ppdPageSize</a>(ppd, NULL); | |
150 | </pre> | |
151 | ||
152 | <p>Besides the standard page sizes listed in a PPD file, some printers | |
153 | support variable or custom page sizes. Custom page sizes are supported if the | |
154 | <code>variables_sizes</code> member of the | |
155 | <a href="#ppd_file_t"><code>ppd_file_t</code></a> structure is non-zero. | |
156 | The <code>custom_min</code>, <code>custom_max</code>, and | |
157 | <code>custom_margins</code> members of the | |
158 | <a href="#ppd_file_t"><code>ppd_file_t</code></a> structure define the limits | |
159 | of the printable area. To get the resulting media size, use a page size string | |
160 | of the form "Custom.<I>width</I>x<I>length</I>", where "width" and "length" are | |
161 | in points. Custom page size names can also be specified in inches | |
162 | ("Custom.<i>width</i>x<i>height</i>in"), centimeters | |
163 | ("Custom.<i>width</i>x<i>height</i>cm"), or millimeters | |
164 | ("Custom.<i>width</i>x<i>height</i>mm"):</p> | |
165 | ||
166 | <pre class="example"> | |
167 | #include <cups/ppd.h> | |
168 | ||
169 | <a href="#ppd_file_t">ppd_file_t</a> *ppd; | |
170 | ||
171 | /* Get an 576x720 point custom page size */ | |
172 | <a href="#ppd_size_t">ppd_size_t</a> *size = <a href="#ppdPageSize">ppdPageSize</a>(ppd, "Custom.576x720"); | |
173 | ||
174 | /* Get an 8x10 inch custom page size */ | |
175 | <a href="#ppd_size_t">ppd_size_t</a> *size = <a href="#ppdPageSize">ppdPageSize</a>(ppd, "Custom.8x10in"); | |
176 | ||
177 | /* Get a 100x200 millimeter custom page size */ | |
178 | <a href="#ppd_size_t">ppd_size_t</a> *size = <a href="#ppdPageSize">ppdPageSize</a>(ppd, "Custom.100x200mm"); | |
179 | ||
180 | /* Get a 12.7x34.5 centimeter custom page size */ | |
181 | <a href="#ppd_size_t">ppd_size_t</a> *size = <a href="#ppdPageSize">ppdPageSize</a>(ppd, "Custom.12.7x34.5cm"); | |
182 | </pre> | |
183 | ||
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184 | <p>If the PPD does not support variable page sizes, the |
185 | <a href="#ppdPageSize"><code>ppdPageSize</code></a> function will return | |
186 | <code>NULL</code>.</p> | |
187 | ||
73721e3e | 188 | |
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189 | <h3><a name="ATTRIBUTES">Attributes</a></h3> |
190 | ||
191 | <p>Every PPD file is composed of one or more attributes. Most of these | |
192 | attributes are used to define groups, options, choices, and page sizes, | |
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193 | however several informational attributes may be present which you can access |
194 | in your program or filter. Attributes normally look like one of the following | |
195 | examples in a PPD file:</p> | |
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196 | |
197 | <pre class="example"> | |
198 | *name: "value" | |
199 | *name spec: "value" | |
200 | *name spec/text: "value" | |
201 | </pre> | |
202 | ||
203 | <p>The <a href="#ppdFindAttr"><code>ppdFindAttr</code></a> and | |
204 | <a href="#ppdFindNextAttr"><code>ppdFindNextAttr</code></a> functions find the | |
205 | first and next instances, respectively, of the named attribute with the given | |
206 | "spec" string and return a <a href="#ppd_attr_t"><code>ppd_attr_t</code></a> | |
207 | structure. If you provide a NULL specifier string, all attributes with the | |
208 | given name will be returned. For example, the following code lists all of the | |
209 | <code>Product</code> attributes in a PPD file:</p> | |
210 | ||
211 | <pre class="example"> | |
212 | #include <cups/ppd.h> | |
213 | ||
214 | <a href="#ppd_file_t">ppd_file_t</a> *ppd; | |
215 | <a href="#ppd_attr_t">ppd_attr_t</a> *attr; | |
216 | ||
217 | for (attr = <a href="#ppdFindAttr">ppdFindAttr</a>(ppd, "Product", NULL); | |
218 | attr != NULL; | |
219 | attr = <a href="#ppdFindNextAttr">ppdFindNextAttr</a>(ppd, "Product", NULL)) | |
220 | puts(attr->value); | |
221 | </pre> |