1 /*
2 * Copyright 2013 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8 #include "src/pdf/SkPDFResourceDict.h"
9
10 #include "include/core/SkStream.h"
11 #include "include/core/SkString.h"
12 #include "include/private/base/SkAssert.h"
13 #include "src/pdf/SkPDFTypes.h"
14
15 #include <cstddef>
16 #include <utility>
17
18 // Verify that the values of enum ResourceType correspond to the expected values
19 // as defined in the arrays below.
20 // If these are failing, you may need to update the kResourceTypePrefixes
21 // and kResourceTypeNames arrays below.
22 static_assert(0 == (int)SkPDFResourceType::kExtGState, "resource_type_mismatch");
23 static_assert(1 == (int)SkPDFResourceType::kPattern, "resource_type_mismatch");
24 static_assert(2 == (int)SkPDFResourceType::kXObject, "resource_type_mismatch");
25 static_assert(3 == (int)SkPDFResourceType::kFont, "resource_type_mismatch");
26
27 // One extra character for the Prefix.
28 constexpr size_t kMaxResourceNameLength = 1 + kSkStrAppendS32_MaxSize;
29
30 // returns pointer just past end of what's written into `dst`.
get_resource_name(char dst[kMaxResourceNameLength],SkPDFResourceType type,int key)31 static char* get_resource_name(char dst[kMaxResourceNameLength], SkPDFResourceType type, int key) {
32 static const char kResourceTypePrefixes[] = {
33 'G', // kExtGState
34 'P', // kPattern
35 'X', // kXObject
36 'F' // kFont
37 };
38 SkASSERT((unsigned)type < std::size(kResourceTypePrefixes));
39 dst[0] = kResourceTypePrefixes[(unsigned)type];
40 return SkStrAppendS32(dst + 1, key);
41 }
42
SkPDFWriteResourceName(SkWStream * dst,SkPDFResourceType type,int key)43 void SkPDFWriteResourceName(SkWStream* dst, SkPDFResourceType type, int key) {
44 // One extra character for the leading '/'.
45 char buffer[1 + kMaxResourceNameLength];
46 buffer[0] = '/';
47 char* end = get_resource_name(buffer + 1, type, key);
48 dst->write(buffer, (size_t)(end - buffer));
49 }
50
resource_name(SkPDFResourceType type)51 static const char* resource_name(SkPDFResourceType type) {
52 static const char* kResourceTypeNames[] = {
53 "ExtGState",
54 "Pattern",
55 "XObject",
56 "Font"
57 };
58 SkASSERT((unsigned)type < std::size(kResourceTypeNames));
59 return kResourceTypeNames[(unsigned)type];
60 }
61
resource(SkPDFResourceType type,int index)62 static SkString resource(SkPDFResourceType type, int index) {
63 char buffer[kMaxResourceNameLength];
64 char* end = get_resource_name(buffer, type, index);
65 return SkString(buffer, (size_t)(end - buffer));
66 }
67
add_subdict(const std::vector<SkPDFIndirectReference> & resourceList,SkPDFResourceType type,SkPDFDict * dst)68 static void add_subdict(const std::vector<SkPDFIndirectReference>& resourceList,
69 SkPDFResourceType type,
70 SkPDFDict* dst) {
71 if (!resourceList.empty()) {
72 auto resources = SkPDFMakeDict();
73 for (SkPDFIndirectReference ref : resourceList) {
74 resources->insertRef(resource(type, ref.fValue), ref);
75 }
76 dst->insertObject(resource_name(type), std::move(resources));
77 }
78 }
79
make_proc_set()80 static std::unique_ptr<SkPDFArray> make_proc_set() {
81 auto procSets = SkPDFMakeArray();
82 static const char kProcs[][7] = { "PDF", "Text", "ImageB", "ImageC", "ImageI"};
83 procSets->reserve(std::size(kProcs));
84 for (const char* proc : kProcs) {
85 procSets->appendName(proc);
86 }
87 return procSets;
88 }
89
SkPDFMakeResourceDict(const std::vector<SkPDFIndirectReference> & graphicStateResources,const std::vector<SkPDFIndirectReference> & shaderResources,const std::vector<SkPDFIndirectReference> & xObjectResources,const std::vector<SkPDFIndirectReference> & fontResources)90 std::unique_ptr<SkPDFDict> SkPDFMakeResourceDict(
91 const std::vector<SkPDFIndirectReference>& graphicStateResources,
92 const std::vector<SkPDFIndirectReference>& shaderResources,
93 const std::vector<SkPDFIndirectReference>& xObjectResources,
94 const std::vector<SkPDFIndirectReference>& fontResources) {
95 auto dict = SkPDFMakeDict();
96 dict->insertObject("ProcSet", make_proc_set());
97 add_subdict(graphicStateResources, SkPDFResourceType::kExtGState, dict.get());
98 add_subdict(shaderResources, SkPDFResourceType::kPattern, dict.get());
99 add_subdict(xObjectResources, SkPDFResourceType::kXObject, dict.get());
100 add_subdict(fontResources, SkPDFResourceType::kFont, dict.get());
101 return dict;
102 }
103