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89 lines
3.4 KiB
C
89 lines
3.4 KiB
C
/**
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* Copyright (c) 2012-2016 Moodstocks SAS
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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#ifndef JPEC_H
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#define JPEC_H
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#include <stdint.h>
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/*************************************************
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* JPEG Encoder
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*************************************************/
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/* -------------------------------------------------
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* LIMITATIONS
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* -------------------------------------------------
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* - Grayscale *only* (monochrome JPEG file): no support for color
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* - Baseline DCT-based (SOF0), JFIF 1.01 (APP0) JPEG
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* - Block size of 8x8 pixels *only*
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* - Default quantization and Huffman tables *only*
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* - No border filling support: the input image *MUST* represent an integer
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* number of blocks, i.e. each dimension must be a multiple of 8
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*/
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/** Type of a JPEG encoder object */
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typedef struct jpec_enc_t_ jpec_enc_t;
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// Callback signatures
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typedef void (*jpec_init_callback_t)(jpec_enc_t *jpec);
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typedef void (*jpec_enc_callback_t)(int offset, uint8_t val);
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typedef void (*jpec_done_callback_t)(jpec_enc_t *jpec);
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/*
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* Create a JPEG encoder with default quality factor
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* `img' specifies the pointer to aligned image data.
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* `w' specifies the image width in pixels.
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* `h' specifies the image height in pixels.
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* Because the returned encoder is allocated by this function, it should be
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* released with the `jpec_enc_del' call when it is no longer useful.
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* Note: for efficiency the image data is *NOT* copied and the encoder just
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* retains a pointer to it. Thus the image data must not be deleted
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* nor change until the encoder object gets deleted.
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*/
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jpec_enc_t *jpec_enc_new(const uint8_t *img, uint16_t w, uint16_t h);
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/*
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* `q` specifies the JPEG quality factor in 0..100
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*/
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jpec_enc_t *jpec_enc_new2(const uint8_t *img, uint16_t w, uint16_t h, int q, jpec_enc_callback_t callback);
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/*
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* Release a JPEG encoder object
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* `e` specifies the encoder object
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*/
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void jpec_enc_del(jpec_enc_t *e);
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/*
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* Run the JPEG encoding
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* `e` specifies the encoder object
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* `len` specifies the pointer to the variable into which the length of the
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* JPEG blob is assigned
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* If successful, the return value is the pointer to the JPEG blob. `NULL` is
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* returned if an error occurred.
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* Note: the caller should take care to copy or save the JPEG blob before
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* calling `jpec_enc_del` since the blob will no longer be maintained after.
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*/
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const uint8_t *jpec_enc_run(jpec_enc_t *e);
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#endif |