1// Copyright 2009 Google Inc.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15// This is branched from AOSP's frameworks/base/opengl/include/ETC1/etc1.h
16//
17// It has been modified to implement Chromium's ETC1 API.  The decoding path
18// has been removed as we do not require it.
19
20#ifndef THIRD_PARTY_ANDROID_OPENGL_ETC1_ETC1_H_
21#define THIRD_PARTY_ANDROID_OPENGL_ETC1_ETC1_H_
22
23// Return the size of the encoded image data.
24
25unsigned int etc1_get_encoded_data_size(unsigned int width, unsigned int height);
26
27// Encode an entire image.
28// pIn - pointer to the image data. Formatted such that
29//       pixel (x,y) is at pIn + pixelSize * x + stride * y;
30// pOut - pointer to encoded data. Must be large enough to store entire encoded image.
31// pixelSize can be 2 or 3. 2 is an GL_UNSIGNED_SHORT_5_6_5 image, 3 is a GL_BYTE RGB image.
32// returns non-zero if there is an error.
33
34bool etc1_encode_image(const unsigned char* pIn, unsigned int width, unsigned int height,
35         unsigned int pixelSize, unsigned int stride, unsigned char* pOut, unsigned int outWidth,
36         unsigned int outHeight);
37
38// Decode an entire image.
39// pIn - pointer to encoded data.
40// pOut - pointer to the image data. Will be written such that
41//        pixel (x,y) is at pIn + pixelSize * x + stride * y. Must be
42//        large enough to store entire image.
43// pixelSize can be 2 or 3. 2 is an GL_UNSIGNED_SHORT_5_6_5 image, 3 is a GL_BYTE RGB image.
44// returns false if there is an error.
45
46bool etc1_decode_image(const unsigned char* pIn, unsigned char* pOut,
47        unsigned int width, unsigned int height,
48        unsigned int pixelSize, unsigned int stride);
49
50// Size of a PKM header, in bytes.
51
52#define ETC_PKM_HEADER_SIZE 16
53
54// Format a PKM header
55
56void etc1_pkm_format_header(unsigned char* pHeader, unsigned int width, unsigned int height);
57
58// Check if a PKM header is correctly formatted.
59
60bool etc1_pkm_is_valid(const unsigned char* pHeader);
61
62// Read the image width from a PKM header
63
64unsigned int etc1_pkm_get_width(const unsigned char* pHeader);
65
66// Read the image height from a PKM header
67
68unsigned int etc1_pkm_get_height(const unsigned char* pHeader);
69
70#endif // THIRD_PARTY_ANDROID_OPENGL_ETC1_ETC1_H_
71