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      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 
     25 unsigned 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 
     34 bool 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 
     46 bool 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 
     56 void etc1_pkm_format_header(unsigned char* pHeader, unsigned int width, unsigned int height);
     57 
     58 // Check if a PKM header is correctly formatted.
     59 
     60 bool etc1_pkm_is_valid(const unsigned char* pHeader);
     61 
     62 // Read the image width from a PKM header
     63 
     64 unsigned int etc1_pkm_get_width(const unsigned char* pHeader);
     65 
     66 // Read the image height from a PKM header
     67 
     68 unsigned int etc1_pkm_get_height(const unsigned char* pHeader);
     69 
     70 #endif // THIRD_PARTY_ANDROID_OPENGL_ETC1_ETC1_H_
     71