71 lines
2.9 KiB
C++
71 lines
2.9 KiB
C++
/******************************************************************************
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*
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* imglib.h
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*
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* SPDX-License-Identifier: MIT
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*****************************************************************************/
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#ifndef _IMGLIB_H_
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#define _IMGLIB_H_ 1
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// extract bytes from an unsigned word
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#define LOBYTE(x) ((x)&0xff)
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#define HIBYTE(x) (((x) >> 8) & 0xff)
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// GIF encoding constants
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#define DESCRIPTOR_INTRODUCER 0x2c
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#define TERMINATOR_INTRODUCER 0x3b
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#define LZ_MAX_CODE 4095 // Biggest code possible in 12 bits
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#define LZ_BITS 12
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#define FLUSH_OUTPUT 4096 // Impossible code, to signal flush
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#define FIRST_CODE 4097 // Impossible code, to signal first
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#define NO_SUCH_CODE 4098 // Impossible code, to signal empty
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// magfic constants and declarations for GIF LZW
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#define HT_SIZE 8192 /* 12bits = 4096 or twice as big! */
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#define HT_KEY_MASK 0x1FFF /* 13bits keys */
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#define HT_KEY_NUM_BITS 13 /* 13bits keys */
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#define HT_MAX_KEY 8191 /* 13bits - 1, maximal code possible */
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#define HT_MAX_CODE 4095 /* Biggest code possible in 12 bits. */
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/* The 32 bits of the long are divided into two parts for the key & code: */
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/* 1. The code is 12 bits as our compression algorithm is limited to 12bits */
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/* 2. The key is 12 bits Prefix code + 8 bit new char or 20 bits. */
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/* The key is the upper 20 bits. The code is the lower 12. */
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#define HT_GET_KEY(l) (l >> 12)
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#define HT_GET_CODE(l) (l & 0x0FFF)
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#define HT_PUT_KEY(l) (l << 12)
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#define HT_PUT_CODE(l) (l & 0x0FFF)
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typedef unsigned char GifPixelType;
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typedef unsigned char GifByteType;
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typedef struct GifHashTableType {
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uint32_t HTable[HT_SIZE];
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} GifHashTableType;
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typedef struct GifFilePrivateType {
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uint8_t BitsPerPixel; // Bits per pixel (Codes uses at least this + 1)
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uint16_t ClearCode; // The CLEAR LZ code
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uint16_t EOFCode; // The EOF LZ code
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uint16_t RunningCode; // The next code algorithm can generate
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uint16_t RunningBits; // The number of bits required to represent RunningCode
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uint16_t MaxCode1; // 1 bigger than max. possible code, in RunningBits bits
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uint16_t LastCode; // The code before the current code.
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uint16_t CrntCode; // Current algorithm code
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uint16_t CrntShiftState; // Number of bits in CrntShiftDWord
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uint32_t CrntShiftDWord; // For bytes decomposition into codes
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uint32_t PixelCount; // Number of pixels in image
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GifByteType Buf[256]; // Compressed input is buffered here
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GifHashTableType *HashTable;
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} GifFilePrivateType;
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bool createGIF(uint8_t *framebuffer, std::vector<uint8_t>* imageBuffer, uint16_t width, uint16_t height);
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bool createBMP(uint8_t *framebuffer, std::vector<uint8_t>* imageBuffer, uint16_t width, uint16_t height);
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bool createPBM(uint8_t *framebuffer, std::vector<uint8_t>* gifBuffer, uint16_t width, uint16_t height);
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#endif /* _IMGLIB_H */
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