stb_image_aug.h

/* stbi-1.16 - public domain JPEG/PNG reader - http://nothings.org/stb_image.c
                      when you control the images you're loading

   QUICK NOTES:
      Primarily of interest to game developers and other people who can
          avoid problematic images and only need the trivial interface

      JPEG baseline (no JPEG progressive, no oddball channel decimations)
      PNG non-interlaced
      BMP non-1bpp, non-RLE
      TGA (not sure what subset, if a subset)
      PSD (composited view only, no extra channels)
      HDR (radiance rgbE format)
      writes BMP,TGA (define STBI_NO_WRITE to remove code)
      decoded from memory or through stdio FILE (define STBI_NO_STDIO to remove code)
      supports installable dequantizing-IDCT, YCbCr-to-RGB conversion (define STBI_SIMD)
        
   TODO:
      stbi_info_*
  
   history:
      1.16   major bugfix - convert_format converted one too many pixels
      1.15   initialize some fields for thread safety
      1.14   fix threadsafe conversion bug; header-file-only version (#define STBI_HEADER_FILE_ONLY before including)
      1.13   threadsafe
      1.12   const qualifiers in the API
      1.11   Support installable IDCT, colorspace conversion routines
      1.10   Fixes for 64-bit (don't use "unsigned long")
             optimized upsampling by Fabian "ryg" Giesen
      1.09   Fix format-conversion for PSD code (bad global variables!)
      1.08   Thatcher Ulrich's PSD code integrated by Nicolas Schulz
      1.07   attempt to fix C++ warning/errors again
      1.06   attempt to fix C++ warning/errors again
      1.05   fix TGA loading to return correct *comp and use good luminance calc
      1.04   default float alpha is 1, not 255; use 'void *' for stbi_image_free
      1.03   bugfixes to STBI_NO_STDIO, STBI_NO_HDR
      1.02   support for (subset of) HDR files, float interface for preferred access to them
      1.01   fix bug: possible bug in handling right-side up bmps... not sure
             fix bug: the stbi_bmp_load() and stbi_tga_load() functions didn't work at all
      1.00   interface to zlib that skips zlib header
      0.99   correct handling of alpha in palette
      0.98   TGA loader by lonesock; dynamically add loaders (untested)
      0.97   jpeg errors on too large a file; also catch another malloc failure
      0.96   fix detection of invalid v value - particleman@mollyrocket forum
      0.95   during header scan, seek to markers in case of padding
      0.94   STBI_NO_STDIO to disable stdio usage; rename all #defines the same
      0.93   handle jpegtran output; verbose errors
      0.92   read 4,8,16,24,32-bit BMP files of several formats
      0.91   output 24-bit Windows 3.0 BMP files
      0.90   fix a few more warnings; bump version number to approach 1.0
      0.61   bugfixes due to Marc LeBlanc, Christopher Lloyd
      0.60   fix compiling as c++
      0.59   fix warnings: merge Dave Moore's -Wall fixes
      0.58   fix bug: zlib uncompressed mode len/nlen was wrong endian
      0.57   fix bug: jpg last huffman symbol before marker was >9 bits but less
                      than 16 available
      0.56   fix bug: zlib uncompressed mode len vs. nlen
      0.55   fix bug: restart_interval not initialized to 0
      0.54   allow NULL for 'int *comp'
      0.53   fix bug in png 3->4; speedup png decoding
      0.52   png handles req_comp=3,4 directly; minor cleanup; jpeg comments
      0.51   obey req_comp requests, 1-component jpegs return as 1-component,
             on 'test' only check type, not whether we support this variant
*/

#ifndef HEADER_STB_IMAGE_AUGMENTED
#define HEADER_STB_IMAGE_AUGMENTED

////   begin header file  ////////////////////////////////////////////////////
//
// Limitations:
//    - no progressive/interlaced support (jpeg, png)
//    - 8-bit samples only (jpeg, png)
//    - not threadsafe
//    - channel subsampling of at most 2 in each dimension (jpeg)
//    - no delayed line count (jpeg) -- IJG doesn't support either
//
// Basic usage (see HDR discussion below):
//    int x,y,n;
//    unsigned char *data = stbi_load(filename, &x, &y, &n, 0);
//    // ... process data if not NULL ... 
//    // ... x = width, y = height, n = # 8-bit components per pixel ...
//    // ... replace '0' with '1'..'4' to force that many components per pixel
//    stbi_image_free(data)
//
// Standard parameters:
//    int *x       -- outputs image width in pixels
//    int *y       -- outputs image height in pixels
//    int *comp    -- outputs # of image components in image file
//    int req_comp -- if non-zero, # of image components requested in result
//
// The return value from an image loader is an 'unsigned char *' which points
// to the pixel data. The pixel data consists of *y scanlines of *x pixels,
// with each pixel consisting of N interleaved 8-bit components; the first
// pixel pointed to is top-left-most in the image. There is no padding between
// image scanlines or between pixels, regardless of format. The number of
// components N is 'req_comp' if req_comp is non-zero, or *comp otherwise.
// If req_comp is non-zero, *comp has the number of components that _would_
// have been output otherwise. E.g. if you set req_comp to 4, you will always
// get RGBA output, but you can check *comp to easily see if it's opaque.
//
// An output image with N components has the following components interleaved
// in this order in each pixel:
//
//     N=#comp     components
//       1           grey
//       2           grey, alpha
//       3           red, green, blue
//       4           red, green, blue, alpha
//
// If image loading fails for any reason, the return value will be NULL,
// and *x, *y, *comp will be unchanged. The function stbi_failure_reason()
// can be queried for an extremely brief, end-user unfriendly explanation
// of why the load failed. Define STBI_NO_FAILURE_STRINGS to avoid
// compiling these strings at all, and STBI_FAILURE_USERMSG to get slightly
// more user-friendly ones.
//
// Paletted PNG and BMP images are automatically depalettized.
//
//
// ===========================================================================
//
// HDR image support   (disable by defining STBI_NO_HDR)
//
// stb_image now supports loading HDR images in general, and currently
// the Radiance .HDR file format, although the support is provided
// generically. You can still load any file through the existing interface;
// if you attempt to load an HDR file, it will be automatically remapped to
// LDR, assuming gamma 2.2 and an arbitrary scale factor defaulting to 1;
// both of these constants can be reconfigured through this interface:
//
//     stbi_hdr_to_ldr_gamma(2.2f);
//     stbi_hdr_to_ldr_scale(1.0f);
//
// (note, do not use _inverse_ constants; stbi_image will invert them
// appropriately).
//
// Additionally, there is a new, parallel interface for loading files as
// (linear) floats to preserve the full dynamic range:
//
//    float *data = stbi_loadf(filename, &x, &y, &n, 0);
// 
// If you load LDR images through this interface, those images will
// be promoted to floating point values, run through the inverse of
// constants corresponding to the above:
//
//     stbi_ldr_to_hdr_scale(1.0f);
//     stbi_ldr_to_hdr_gamma(2.2f);
//
// Finally, given a filename (or an open file or memory block--see header
// file for details) containing image data, you can query for the "most
// appropriate" interface to use (that is, whether the image is HDR or
// not), using:
//
//     stbi_is_hdr(char *filename);

#ifndef STBI_NO_STDIO
#include <stdio.h>
#endif

#define STBI_VERSION 1

enum
{
   STBI_default = 0, // only used for req_comp

   STBI_grey       = 1,
   STBI_grey_alpha = 2,
   STBI_rgb        = 3,
   STBI_rgb_alpha  = 4,
};

typedef unsigned char stbi_uc;

#ifdef __cplusplus
extern "C" {
#endif

// WRITING API

#if !defined(STBI_NO_WRITE) && !defined(STBI_NO_STDIO)
// write a BMP/TGA file given tightly packed 'comp' channels (no padding, nor bmp-stride-padding)
// (you must include the appropriate extension in the filename).
// returns TRUE on success, FALSE if couldn't open file, error writing file
extern int      stbi_write_bmp       (char const *filename,     int x, int y, int comp, void *data);
extern int      stbi_write_tga       (char const *filename,     int x, int y, int comp, void *data);
#endif

// PRIMARY API - works on images of any type

// load image by filename, open file, or memory buffer
#ifndef STBI_NO_STDIO
extern stbi_uc *stbi_load            (char const *filename,     int *x, int *y, int *comp, int req_comp);
extern stbi_uc *stbi_load_from_file  (FILE *f,                  int *x, int *y, int *comp, int req_comp);
extern int      stbi_info_from_file  (FILE *f,                  int *x, int *y, int *comp);
#endif
extern stbi_uc *stbi_load_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp);
// for stbi_load_from_file, file pointer is left pointing immediately after image

#ifndef STBI_NO_HDR
#ifndef STBI_NO_STDIO
extern float *stbi_loadf            (char const *filename,     int *x, int *y, int *comp, int req_comp);
extern float *stbi_loadf_from_file  (FILE *f,                  int *x, int *y, int *comp, int req_comp);
#endif
extern float *stbi_loadf_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp);

extern void   stbi_hdr_to_ldr_gamma(float gamma);
extern void   stbi_hdr_to_ldr_scale(float scale);

extern void   stbi_ldr_to_hdr_gamma(float gamma);
extern void   stbi_ldr_to_hdr_scale(float scale);

#endif // STBI_NO_HDR

// get a VERY brief reason for failure
// NOT THREADSAFE
extern char    *stbi_failure_reason  (void); 

// free the loaded image -- this is just free()
extern void     stbi_image_free      (void *retval_from_stbi_load);

// get image dimensions & components without fully decoding
extern int      stbi_info_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp);
extern int      stbi_is_hdr_from_memory(stbi_uc const *buffer, int len);
#ifndef STBI_NO_STDIO
extern int      stbi_info            (char const *filename,     int *x, int *y, int *comp);
extern int      stbi_is_hdr          (char const *filename);
extern int      stbi_is_hdr_from_file(FILE *f);
#endif

// ZLIB client - used by PNG, available for other purposes

extern char *stbi_zlib_decode_malloc_guesssize(const char *buffer, int len, int initial_size, int *outlen);
extern char *stbi_zlib_decode_malloc(const char *buffer, int len, int *outlen);
extern int   stbi_zlib_decode_buffer(char *obuffer, int olen, const char *ibuffer, int ilen);

extern char *stbi_zlib_decode_noheader_malloc(const char *buffer, int len, int *outlen);
extern int   stbi_zlib_decode_noheader_buffer(char *obuffer, int olen, const char *ibuffer, int ilen);

// TYPE-SPECIFIC ACCESS

// is it a jpeg?
extern int      stbi_jpeg_test_memory     (stbi_uc const *buffer, int len);
extern stbi_uc *stbi_jpeg_load_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp);
extern int      stbi_jpeg_info_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp);

#ifndef STBI_NO_STDIO
extern stbi_uc *stbi_jpeg_load            (char const *filename,     int *x, int *y, int *comp, int req_comp);
extern int      stbi_jpeg_test_file       (FILE *f);
extern stbi_uc *stbi_jpeg_load_from_file  (FILE *f,                  int *x, int *y, int *comp, int req_comp);

extern int      stbi_jpeg_info            (char const *filename,     int *x, int *y, int *comp);
extern int      stbi_jpeg_info_from_file  (FILE *f,                  int *x, int *y, int *comp);
#endif

// is it a png?
extern int      stbi_png_test_memory      (stbi_uc const *buffer, int len);
extern stbi_uc *stbi_png_load_from_memory (stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp);
extern int      stbi_png_info_from_memory (stbi_uc const *buffer, int len, int *x, int *y, int *comp);

#ifndef STBI_NO_STDIO
extern stbi_uc *stbi_png_load             (char const *filename,     int *x, int *y, int *comp, int req_comp);
extern int      stbi_png_info             (char const *filename,     int *x, int *y, int *comp);
extern int      stbi_png_test_file        (FILE *f);
extern stbi_uc *stbi_png_load_from_file   (FILE *f,                  int *x, int *y, int *comp, int req_comp);
extern int      stbi_png_info_from_file   (FILE *f,                  int *x, int *y, int *comp);
#endif

// is it a bmp?
extern int      stbi_bmp_test_memory      (stbi_uc const *buffer, int len);

extern stbi_uc *stbi_bmp_load             (char const *filename,     int *x, int *y, int *comp, int req_comp);
extern stbi_uc *stbi_bmp_load_from_memory (stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp);
#ifndef STBI_NO_STDIO
extern int      stbi_bmp_test_file        (FILE *f);
extern stbi_uc *stbi_bmp_load_from_file   (FILE *f,                  int *x, int *y, int *comp, int req_comp);
#endif

// is it a tga?
extern int      stbi_tga_test_memory      (stbi_uc const *buffer, int len);

extern stbi_uc *stbi_tga_load             (char const *filename,     int *x, int *y, int *comp, int req_comp);
extern stbi_uc *stbi_tga_load_from_memory (stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp);
#ifndef STBI_NO_STDIO
extern int      stbi_tga_test_file        (FILE *f);
extern stbi_uc *stbi_tga_load_from_file   (FILE *f,                  int *x, int *y, int *comp, int req_comp);
#endif

// is it a psd?
extern int      stbi_psd_test_memory      (stbi_uc const *buffer, int len);

extern stbi_uc *stbi_psd_load             (char const *filename,     int *x, int *y, int *comp, int req_comp);
extern stbi_uc *stbi_psd_load_from_memory (stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp);
#ifndef STBI_NO_STDIO
extern int      stbi_psd_test_file        (FILE *f);
extern stbi_uc *stbi_psd_load_from_file   (FILE *f,                  int *x, int *y, int *comp, int req_comp);
#endif

// is it an hdr?
extern int      stbi_hdr_test_memory      (stbi_uc const *buffer, int len);

extern float *  stbi_hdr_load             (char const *filename,     int *x, int *y, int *comp, int req_comp);
extern float *  stbi_hdr_load_from_memory (stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp);
extern stbi_uc *stbi_hdr_load_rgbe        (char const *filename,           int *x, int *y, int *comp, int req_comp);
extern float *  stbi_hdr_load_from_memory (stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp);
#ifndef STBI_NO_STDIO
extern int      stbi_hdr_test_file        (FILE *f);
extern float *  stbi_hdr_load_from_file   (FILE *f,                  int *x, int *y, int *comp, int req_comp);
extern stbi_uc *stbi_hdr_load_rgbe_file   (FILE *f,                  int *x, int *y, int *comp, int req_comp);
#endif

// define new loaders
typedef struct
{
   int       (*test_memory)(stbi_uc const *buffer, int len);
   stbi_uc * (*load_from_memory)(stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp);
   #ifndef STBI_NO_STDIO
   int       (*test_file)(FILE *f);
   stbi_uc * (*load_from_file)(FILE *f, int *x, int *y, int *comp, int req_comp);
   #endif
} stbi_loader;

// register a loader by filling out the above structure (you must defined ALL functions)
// returns 1 if added or already added, 0 if not added (too many loaders)
// NOT THREADSAFE
extern int stbi_register_loader(stbi_loader *loader);

// define faster low-level operations (typically SIMD support)
#if STBI_SIMD
typedef void (*stbi_idct_8x8)(uint8 *out, int out_stride, short data[64], unsigned short *dequantize);
// compute an integer IDCT on "input"
//     input[x] = data[x] * dequantize[x]
//     write results to 'out': 64 samples, each run of 8 spaced by 'out_stride'
//                             CLAMP results to 0..255
typedef void (*stbi_YCbCr_to_RGB_run)(uint8 *output, uint8 const *y, uint8 const *cb, uint8 const *cr, int count, int step);
// compute a conversion from YCbCr to RGB
//     'count' pixels
//     write pixels to 'output'; each pixel is 'step' bytes (either 3 or 4; if 4, write '255' as 4th), order R,G,B
//     y: Y input channel
//     cb: Cb input channel; scale/biased to be 0..255
//     cr: Cr input channel; scale/biased to be 0..255

extern void stbi_install_idct(stbi_idct_8x8 func);
extern void stbi_install_YCbCr_to_RGB(stbi_YCbCr_to_RGB_run func);
#endif // STBI_SIMD

#ifdef __cplusplus
}
#endif

//
//
////   end header file   /////////////////////////////////////////////////////
#endif // STBI_INCLUDE_STB_IMAGE_H