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22e8b6df19
- switch to canvas for print screen functionality - implement jpg encoder for print screen
82 lines
3.0 KiB
C
82 lines
3.0 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_STREAM_H
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#define JPEC_STREAM_H
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#include <stdint.h>
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#include "buf.h"
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// header-----
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typedef struct jpec_enc_t_ jpec_enc_t;
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jpec_enc_t *jpec_enc_new(const uint8_t *img, uint16_t w, uint16_t h);
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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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void jpec_enc_del(jpec_enc_t *e);
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const uint8_t *jpec_enc_run(jpec_enc_t *e, int *len);
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// header-----
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/** Structure used to hold and process an image 8x8 block */
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typedef struct jpec_block_t_ {
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float dct[64]; /* DCT coefficients */
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int quant[64]; /* Quantization coefficients */
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int zz[64]; /* Zig-Zag coefficients */
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int len; /* Length of Zig-Zag coefficients */
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} jpec_block_t;
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/** Skeleton for an Huffman entropy coder */
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typedef struct jpec_huff_skel_t_ {
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void *opq;
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void (*del)(void *opq);
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void (*encode_block)(void *opq, jpec_block_t *block, jpec_buffer_t *buf);
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} jpec_huff_skel_t;
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/** JPEG encoder */
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struct jpec_enc_t_ {
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/** Input image data */
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const uint8_t *img; /* image buffer */
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uint16_t w; /* image width */
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uint16_t h; /* image height */
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uint16_t w8; /* w rounded to upper multiple of 8 */
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/** JPEG extensible byte buffer */
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jpec_buffer_t *buf;
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/** Compression parameters */
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int qual; /* JPEG quality factor */
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int dqt[64]; /* scaled quantization matrix */
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/** Current 8x8 block */
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int bmax; /* maximum number of blocks (N) */
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int bnum; /* block number in 0..N-1 */
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uint16_t bx; /* block start X */
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uint16_t by; /* block start Y */
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jpec_block_t block; /* block data */
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/** Huffman entropy coder */
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jpec_huff_skel_t *hskel;
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};
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#endif
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