1 /*
2  * Copyright (C) 2015 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef AAPT_PNG_H
18 #define AAPT_PNG_H
19 
20 #include <iostream>
21 #include <string>
22 
23 #include "android-base/macros.h"
24 
25 #include "Diagnostics.h"
26 #include "Source.h"
27 #include "compile/Image.h"
28 #include "io/Io.h"
29 #include "process/IResourceTableConsumer.h"
30 #include "util/BigBuffer.h"
31 
32 namespace aapt {
33 
34 // Size in bytes of the PNG signature.
35 constexpr size_t kPngSignatureSize = 8u;
36 
37 struct PngOptions {
38   int grayscale_tolerance = 0;
39 };
40 
41 /**
42  * Deprecated. Removing once new PNG crunching code is proved to be correct.
43  */
44 class Png {
45  public:
Png(IDiagnostics * diag)46   explicit Png(IDiagnostics* diag) : mDiag(diag) {}
47 
48   bool process(const Source& source, std::istream* input, BigBuffer* outBuffer,
49                const PngOptions& options);
50 
51  private:
52   DISALLOW_COPY_AND_ASSIGN(Png);
53 
54   IDiagnostics* mDiag;
55 };
56 
57 /**
58  * An InputStream that filters out unimportant PNG chunks.
59  */
60 class PngChunkFilter : public io::InputStream {
61  public:
62   explicit PngChunkFilter(const android::StringPiece& data);
63   virtual ~PngChunkFilter() = default;
64 
65   bool Next(const void** buffer, size_t* len) override;
66   void BackUp(size_t count) override;
67 
CanRewind()68   bool CanRewind() const override { return true; }
69   bool Rewind() override;
ByteCount()70   size_t ByteCount() const override { return window_start_; }
71 
HadError()72   bool HadError() const override {
73     return !error_msg_.empty();
74   }
GetError()75   std::string GetError() const override {
76     return error_msg_;
77   }
78 
79  private:
80   DISALLOW_COPY_AND_ASSIGN(PngChunkFilter);
81 
82   bool ConsumeWindow(const void** buffer, size_t* len);
83 
84   android::StringPiece data_;
85   size_t window_start_ = 0;
86   size_t window_end_ = 0;
87   std::string error_msg_;
88 };
89 
90 /**
91  * Reads a PNG from the InputStream into memory as an RGBA Image.
92  */
93 std::unique_ptr<Image> ReadPng(IAaptContext* context, const Source& source, io::InputStream* in);
94 
95 /**
96  * Writes the RGBA Image, with optional 9-patch meta-data, into the OutputStream
97  * as a PNG.
98  */
99 bool WritePng(IAaptContext* context, const Image* image,
100               const NinePatch* nine_patch, io::OutputStream* out,
101               const PngOptions& options);
102 
103 }  // namespace aapt
104 
105 #endif  // AAPT_PNG_H
106