/******************************************************************************

gif_lib.h - service library for decoding and encoding GIF images

SPDX-License-Identifier: MIT

*****************************************************************************/

#ifndef _GIF_LIB_H_
#define _GIF_LIB_H_ 1

#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */

#define GIFLIB_MAJOR 6
#define GIFLIB_MINOR 1
#define GIFLIB_RELEASE 3

#define GIF_ERROR 0
#define GIF_OK 1

#include <stdbool.h>
#include <stddef.h>

#define GIF_STAMP "GIFVER" /* First chars in file - GIF stamp.  */
#define GIF_STAMP_LEN sizeof(GIF_STAMP) - 1
#define GIF_VERSION_POS 3    /* Version first character in stamp. */
#define GIF87_STAMP "GIF87a" /* First chars in file - GIF stamp.  */
#define GIF89_STAMP "GIF89a" /* First chars in file - GIF stamp.  */

typedef unsigned char GifPixelType;
typedef unsigned char *GifRowType;
typedef unsigned char GifByteType;
typedef unsigned int GifPrefixType;
typedef int GifWord;

typedef struct GifColorType {
	GifByteType Red, Green, Blue;
} GifColorType;

typedef struct ColorMapObject {
	int ColorCount;
	int BitsPerPixel;
	bool SortFlag;
	GifColorType *Colors; /* on malloc(3) heap */
} ColorMapObject;

typedef struct GifImageDesc {
	GifWord Left, Top, Width, Height; /* Current image dimensions. */
	bool Interlace;                   /* Sequential/Interlaced lines. */
	ColorMapObject *ColorMap;         /* The local color map */
} GifImageDesc;

typedef struct ExtensionBlock {
	int ByteCount;
	GifByteType *Bytes;            /* on malloc(3) heap */
	int Function;                  /* The block function code */
#define CONTINUE_EXT_FUNC_CODE 0x00    /* continuation subblock */
#define COMMENT_EXT_FUNC_CODE 0xfe     /* comment */
#define GRAPHICS_EXT_FUNC_CODE 0xf9    /* graphics control (GIF89) */
#define PLAINTEXT_EXT_FUNC_CODE 0x01   /* plaintext */
#define APPLICATION_EXT_FUNC_CODE 0xff /* application block (GIF89) */
} ExtensionBlock;

typedef struct SavedImage {
	GifImageDesc ImageDesc;
	GifByteType *RasterBits;         /* on malloc(3) heap */
	int ExtensionBlockCount;         /* Count of extensions before image */
	ExtensionBlock *ExtensionBlocks; /* Extensions before image */
} SavedImage;

typedef struct GifFileType {
	GifWord SWidth, SHeight;   /* Size of virtual canvas */
	GifWord SColorResolution;  /* How many colors can we generate? */
	GifWord SBackGroundColor;  /* Background color for virtual canvas */
	GifByteType AspectByte;    /* Used to compute pixel aspect ratio */
	ColorMapObject *SColorMap; /* Global colormap, NULL if nonexistent. */
	int ImageCount;            /* Number of current image (both APIs) */
	GifImageDesc Image;        /* Current image (low-level API) */
	SavedImage *SavedImages;   /* Image sequence (high-level API) */
	int ExtensionBlockCount;   /* Count extensions past last image */
	ExtensionBlock *ExtensionBlocks; /* Extensions past last image */
	int Error;                       /* Last error condition reported */
	void *UserData;                  /* hook to attach user data (TVT) */
	void *Private;                   /* Don't mess with this! */
} GifFileType;

#define GIF_ASPECT_RATIO(n) ((n) + 15.0 / 64.0)

typedef enum {
	UNDEFINED_RECORD_TYPE,
	SCREEN_DESC_RECORD_TYPE,
	IMAGE_DESC_RECORD_TYPE, /* Begin with ',' */
	EXTENSION_RECORD_TYPE,  /* Begin with '!' */
	TERMINATE_RECORD_TYPE   /* Begin with ';' */
} GifRecordType;

/* func type to read gif data from arbitrary sources (TVT) */
typedef int (*InputFunc)(GifFileType *, GifByteType *, int);

/* func type to write gif data to arbitrary targets.
 * Returns count of bytes written. (MRB)
 */
typedef int (*OutputFunc)(GifFileType *, const GifByteType *, int);

/******************************************************************************
 GIF89 structures
******************************************************************************/

typedef struct GraphicsControlBlock {
	int DisposalMode;
#define DISPOSAL_UNSPECIFIED 0 /* No disposal specified. */
#define DISPOSE_DO_NOT 1       /* Leave image in place */
#define DISPOSE_BACKGROUND 2   /* Set area too background color */
#define DISPOSE_PREVIOUS 3     /* Restore to previous content */
	bool UserInputFlag;    /* User confirmation required before disposal */
	int DelayTime;         /* pre-display delay in 0.01sec units */
	int TransparentColor;  /* Palette index for transparency, -1 if none */
#define NO_TRANSPARENT_COLOR -1
} GraphicsControlBlock;

/******************************************************************************
 GIF encoding routines
******************************************************************************/

/* Main entry points */
GifFileType *EGifOpenFileName(const char *GifFileName,
                              const bool GifTestExistence, int *Error);
GifFileType *EGifOpenFileHandle(const int GifFileHandle, int *Error);
GifFileType *EGifOpen(void *userPtr, OutputFunc writeFunc, int *Error);
int EGifSpew(GifFileType *GifFile, int *ErrorCode);
const char *EGifGetGifVersion(GifFileType *GifFile); /* new in 5.x */
int EGifCloseFile(GifFileType *GifFile, int *ErrorCode);

#define E_GIF_SUCCEEDED 0
#define E_GIF_ERR_OPEN_FAILED 201 /* And EGif possible errors. */
#define E_GIF_ERR_WRITE_FAILED 202
#define E_GIF_ERR_HAS_SCRN_DSCR 203
#define E_GIF_ERR_HAS_IMAG_DSCR 204
#define E_GIF_ERR_NO_COLOR_MAP 205
#define E_GIF_ERR_DATA_TOO_BIG 206
#define E_GIF_ERR_NOT_ENOUGH_MEM 207
#define E_GIF_ERR_DISK_IS_FULL 208
#define E_GIF_ERR_CLOSE_FAILED 209
#define E_GIF_ERR_NOT_WRITEABLE 210

/* These are legacy.  You probably do not want to call them directly */
int EGifPutScreenDesc(GifFileType *GifFile, const int GifWidth,
                      const int GifHeight, const int GifColorRes,
                      const int GifBackGround,
                      const ColorMapObject *GifColorMap);
int EGifPutImageDesc(GifFileType *GifFile, const int GifLeft, const int GifTop,
                     const int GifWidth, const int GifHeight,
                     const bool GifInterlace,
                     const ColorMapObject *GifColorMap);
void EGifSetGifVersion(GifFileType *GifFile, const bool gif89);
int EGifPutLine(GifFileType *GifFile, GifPixelType *GifLine, int GifLineLen);
int EGifPutPixel(GifFileType *GifFile, const GifPixelType GifPixel);
int EGifPutComment(GifFileType *GifFile, const char *GifComment);
int EGifPutExtensionLeader(GifFileType *GifFile, const int GifExtCode);
int EGifPutExtensionBlock(GifFileType *GifFile, const int GifExtLen,
                          const void *GifExtension);
int EGifPutExtensionTrailer(GifFileType *GifFile);
int EGifPutExtension(GifFileType *GifFile, const int GifExtCode,
                     const int GifExtLen, const void *GifExtension);
int EGifPutCode(GifFileType *GifFile, int GifCodeSize,
                const GifByteType *GifCodeBlock);
int EGifPutCodeNext(GifFileType *GifFile, const GifByteType *GifCodeBlock);

/******************************************************************************
 GIF decoding routines
******************************************************************************/

/* Main entry points */
GifFileType *DGifOpenFileName(const char *GifFileName, int *Error);
GifFileType *DGifOpenFileHandle(int GifFileHandle, int *Error);
int DGifSlurp(GifFileType *GifFile);
GifFileType *DGifOpen(void *userPtr, InputFunc readFunc,
                      int *Error); /* new one (TVT) */
int DGifCloseFile(GifFileType *GifFile, int *ErrorCode);

#define D_GIF_SUCCEEDED 0
#define D_GIF_ERR_OPEN_FAILED 101 /* And DGif possible errors. */
#define D_GIF_ERR_READ_FAILED 102
#define D_GIF_ERR_NOT_GIF_FILE 103
#define D_GIF_ERR_NO_SCRN_DSCR 104
#define D_GIF_ERR_NO_IMAG_DSCR 105
#define D_GIF_ERR_NO_COLOR_MAP 106
#define D_GIF_ERR_WRONG_RECORD 107
#define D_GIF_ERR_DATA_TOO_BIG 108
#define D_GIF_ERR_NOT_ENOUGH_MEM 109
#define D_GIF_ERR_CLOSE_FAILED 110
#define D_GIF_ERR_NOT_READABLE 111
#define D_GIF_ERR_IMAGE_DEFECT 112
#define D_GIF_ERR_EOF_TOO_SOON 113

/* These are legacy.  You probably do not want to call them directly */
int DGifGetScreenDesc(GifFileType *GifFile);
int DGifGetRecordType(GifFileType *GifFile, GifRecordType *GifType);
int DGifGetImageHeader(GifFileType *GifFile);
int DGifGetImageDesc(GifFileType *GifFile);
int DGifGetLine(GifFileType *GifFile, GifPixelType *GifLine, int GifLineLen);
int DGifGetPixel(GifFileType *GifFile, GifPixelType GifPixel);
int DGifGetExtension(GifFileType *GifFile, int *GifExtCode,
                     GifByteType **GifExtension);
int DGifGetExtensionNext(GifFileType *GifFile, GifByteType **GifExtension);
int DGifGetCode(GifFileType *GifFile, int *GifCodeSize,
                GifByteType **GifCodeBlock);
int DGifGetCodeNext(GifFileType *GifFile, GifByteType **GifCodeBlock);
int DGifGetLZCodes(GifFileType *GifFile, int *GifCode);
const char *DGifGetGifVersion(GifFileType *GifFile);

/******************************************************************************
 Error handling and reporting.
******************************************************************************/
extern const char *GifErrorString(int ErrorCode); /* new in 2012 - ESR */

/*****************************************************************************
 Everything below this point is new after version 1.2, supporting `slurp
 mode' for doing I/O in two big belts with all the image-bashing in core.
******************************************************************************/

/******************************************************************************
 Color map handling from gif_alloc.c
******************************************************************************/

extern ColorMapObject *GifMakeMapObject(int ColorCount,
                                        const GifColorType *ColorMap);
extern void GifFreeMapObject(ColorMapObject *Object);
extern ColorMapObject *GifUnionColorMap(const ColorMapObject *ColorIn1,
                                        const ColorMapObject *ColorIn2,
                                        GifPixelType ColorTransIn2[]);
extern int GifBitSize(int n);

/******************************************************************************
 Support for the in-core structures allocation (slurp mode).
******************************************************************************/

extern void GifApplyTranslation(SavedImage *Image,
                                const GifPixelType Translation[]);
extern int GifAddExtensionBlock(int *ExtensionBlock_Count,
                                ExtensionBlock **ExtensionBlocks, int Function,
                                unsigned int Len, unsigned char ExtData[]);
extern void GifFreeExtensions(int *ExtensionBlock_Count,
                              ExtensionBlock **ExtensionBlocks);
extern SavedImage *GifMakeSavedImage(GifFileType *GifFile,
                                     const SavedImage *CopyFrom);
extern void GifFreeSavedImages(GifFileType *GifFile);

/******************************************************************************
 5.x functions for GIF89 graphics control blocks
******************************************************************************/

int DGifExtensionToGCB(const size_t GifExtensionLength,
                       const GifByteType *GifExtension,
                       GraphicsControlBlock *GCB);
size_t EGifGCBToExtension(const GraphicsControlBlock *GCB,
                          GifByteType *GifExtension);

int DGifSavedExtensionToGCB(GifFileType *GifFile, int ImageIndex,
                            GraphicsControlBlock *GCB);
int EGifGCBToSavedExtension(const GraphicsControlBlock *GCB,
                            GifFileType *GifFile, int ImageIndex);

/******************************************************************************
 The library's internal utility font
******************************************************************************/

#define GIF_FONT_WIDTH 8
#define GIF_FONT_HEIGHT 8
extern const unsigned char GifAsciiTable8x8[][GIF_FONT_WIDTH];

extern void GifDrawText8x8(SavedImage *Image, const int x, const int y,
                           const char *legend, const int color);

extern void GifDrawBox(SavedImage *Image, const int x, const int y, const int w,
                       const int d, const int color);

extern void GifDrawRectangle(SavedImage *Image, const int x, const int y,
                             const int w, const int d, const int color);

extern void GifDrawBoxedText8x8(SavedImage *Image, const int x, const int y,
                                const char *legend, const int border,
                                const int bg, const int fg);

#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* _GIF_LIB_H */

/* end */
