269 lines
11 KiB
C
269 lines
11 KiB
C
#ifndef STBI_INCLUDE_STB_IMAGE_H
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#define STBI_INCLUDE_STB_IMAGE_H
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// To get a header file for this, either cut and paste the header,
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// or create stb_image.h, #define STBI_HEADER_FILE_ONLY, and
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// then include stb_image.c from it.
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//// begin header file ////////////////////////////////////////////////////
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//
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// Limitations:
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// - no jpeg progressive support
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// - non-HDR formats support 8-bit samples only (jpeg, png)
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// - no delayed line count (jpeg) -- IJG doesn't support either
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// - no 1-bit BMP
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// - GIF always returns *comp=4
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//
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// Basic usage (see HDR discussion below):
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// int x,y,n;
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// unsigned char *data = stbi_load(filename, &x, &y, &n, 0);
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// // ... process data if not NULL ...
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// // ... x = width, y = height, n = # 8-bit components per pixel ...
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// // ... replace '0' with '1'..'4' to force that many components per pixel
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// // ... but 'n' will always be the number that it would have been if you said 0
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// stbi_image_free(data)
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//
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// Standard parameters:
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// int *x -- outputs image width in pixels
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// int *y -- outputs image height in pixels
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// int *comp -- outputs # of image components in image file
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// int req_comp -- if non-zero, # of image components requested in result
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//
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// The return value from an image loader is an 'unsigned char *' which points
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// to the pixel data. The pixel data consists of *y scanlines of *x pixels,
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// with each pixel consisting of N interleaved 8-bit components; the first
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// pixel pointed to is top-left-most in the image. There is no padding between
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// image scanlines or between pixels, regardless of format. The number of
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// components N is 'req_comp' if req_comp is non-zero, or *comp otherwise.
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// If req_comp is non-zero, *comp has the number of components that _would_
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// have been output otherwise. E.g. if you set req_comp to 4, you will always
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// get RGBA output, but you can check *comp to easily see if it's opaque.
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//
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// An output image with N components has the following components interleaved
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// in this order in each pixel:
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//
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// N=#comp components
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// 1 grey
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// 2 grey, alpha
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// 3 red, green, blue
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// 4 red, green, blue, alpha
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//
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// If image loading fails for any reason, the return value will be NULL,
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// and *x, *y, *comp will be unchanged. The function stbi_failure_reason()
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// can be queried for an extremely brief, end-user unfriendly explanation
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// of why the load failed. Define STBI_NO_FAILURE_STRINGS to avoid
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// compiling these strings at all, and STBI_FAILURE_USERMSG to get slightly
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// more user-friendly ones.
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//
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// Paletted PNG, BMP, GIF, and PIC images are automatically depalettized.
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//
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// ===========================================================================
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//
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// iPhone PNG support:
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//
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// By default we convert iphone-formatted PNGs back to RGB; nominally they
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// would silently load as BGR, except the existing code should have just
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// failed on such iPhone PNGs. But you can disable this conversion by
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// by calling stbi_convert_iphone_png_to_rgb(0), in which case
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// you will always just get the native iphone "format" through.
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//
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// Call stbi_set_unpremultiply_on_load(1) as well to force a divide per
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// pixel to remove any premultiplied alpha *only* if the image file explicitly
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// says there's premultiplied data (currently only happens in iPhone images,
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// and only if iPhone convert-to-rgb processing is on).
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//
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// ===========================================================================
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//
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// HDR image support (disable by defining STBI_NO_HDR)
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//
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// stb_image now supports loading HDR images in general, and currently
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// the Radiance .HDR file format, although the support is provided
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// generically. You can still load any file through the existing interface;
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// if you attempt to load an HDR file, it will be automatically remapped to
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// LDR, assuming gamma 2.2 and an arbitrary scale factor defaulting to 1;
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// both of these constants can be reconfigured through this interface:
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//
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// stbi_hdr_to_ldr_gamma(2.2f);
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// stbi_hdr_to_ldr_scale(1.0f);
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//
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// (note, do not use _inverse_ constants; stbi_image will invert them
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// appropriately).
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//
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// Additionally, there is a new, parallel interface for loading files as
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// (linear) floats to preserve the full dynamic range:
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//
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// float *data = stbi_loadf(filename, &x, &y, &n, 0);
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//
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// If you load LDR images through this interface, those images will
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// be promoted to floating point values, run through the inverse of
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// constants corresponding to the above:
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//
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// stbi_ldr_to_hdr_scale(1.0f);
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// stbi_ldr_to_hdr_gamma(2.2f);
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//
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// Finally, given a filename (or an open file or memory block--see header
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// file for details) containing image data, you can query for the "most
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// appropriate" interface to use (that is, whether the image is HDR or
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// not), using:
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//
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// stbi_is_hdr(char *filename);
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//
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// ===========================================================================
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//
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// I/O callbacks
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//
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// I/O callbacks allow you to read from arbitrary sources, like packaged
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// files or some other source. Data read from callbacks are processed
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// through a small internal buffer (currently 128 bytes) to try to reduce
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// overhead.
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//
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// The three functions you must define are "read" (reads some bytes of data),
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// "skip" (skips some bytes of data), "eof" (reports if the stream is at the end).
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#ifndef STBI_NO_STDIO
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#if defined(_MSC_VER) && _MSC_VER >= 0x1400
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#define _CRT_SECURE_NO_WARNINGS // suppress bogus warnings about fopen()
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#endif
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#include <stdio.h>
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#endif
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#define STBI_VERSION 1
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enum
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{
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STBI_default = 0, // only used for req_comp
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STBI_grey = 1,
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STBI_grey_alpha = 2,
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STBI_rgb = 3,
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STBI_rgb_alpha = 4
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};
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typedef unsigned char stbi_uc;
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#ifdef __cplusplus
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extern "C" {
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#endif
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//////////////////////////////////////////////////////////////////////////////
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//
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// PRIMARY API - works on images of any type
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//
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//
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// load image by filename, open file, or memory buffer
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//
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extern stbi_uc* stbi_load_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp, int req_comp);
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#ifndef STBI_NO_STDIO
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extern stbi_uc* stbi_load(char const* filename, int* x, int* y, int* comp, int req_comp);
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extern stbi_uc* stbi_load_from_file(FILE* f, int* x, int* y, int* comp, int req_comp);
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// for stbi_load_from_file, file pointer is left pointing immediately after image
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#endif
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typedef struct
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{
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int (*read) (void* user, char* data, int size); // fill 'data' with 'size' bytes. return number of bytes actually read
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void (*skip) (void* user, unsigned n); // skip the next 'n' bytes
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int (*eof) (void* user); // returns nonzero if we are at end of file/data
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} stbi_io_callbacks;
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extern stbi_uc* stbi_load_from_callbacks(stbi_io_callbacks const* clbk, void* user, int* x, int* y, int* comp, int req_comp);
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#ifndef STBI_NO_HDR
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extern float* stbi_loadf_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp, int req_comp);
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#ifndef STBI_NO_STDIO
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extern float* stbi_loadf(char const* filename, int* x, int* y, int* comp, int req_comp);
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extern float* stbi_loadf_from_file(FILE* f, int* x, int* y, int* comp, int req_comp);
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#endif
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extern float* stbi_loadf_from_callbacks(stbi_io_callbacks const* clbk, void* user, int* x, int* y, int* comp, int req_comp);
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extern void stbi_hdr_to_ldr_gamma(float gamma);
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extern void stbi_hdr_to_ldr_scale(float scale);
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extern void stbi_ldr_to_hdr_gamma(float gamma);
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extern void stbi_ldr_to_hdr_scale(float scale);
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#endif // STBI_NO_HDR
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// stbi_is_hdr is always defined
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extern int stbi_is_hdr_from_callbacks(stbi_io_callbacks const* clbk, void* user);
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extern int stbi_is_hdr_from_memory(stbi_uc const* buffer, int len);
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#ifndef STBI_NO_STDIO
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extern int stbi_is_hdr(char const* filename);
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extern int stbi_is_hdr_from_file(FILE* f);
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#endif // STBI_NO_STDIO
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// get a VERY brief reason for failure
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// NOT THREADSAFE
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extern const char* stbi_failure_reason(void);
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// free the loaded image -- this is just free()
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extern void stbi_image_free(void* retval_from_stbi_load);
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// get image dimensions & components without fully decoding
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extern int stbi_info_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp);
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extern int stbi_info_from_callbacks(stbi_io_callbacks const* clbk, void* user, int* x, int* y, int* comp);
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#ifndef STBI_NO_STDIO
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extern int stbi_info(char const* filename, int* x, int* y, int* comp);
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extern int stbi_info_from_file(FILE* f, int* x, int* y, int* comp);
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#endif
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// for image formats that explicitly notate that they have premultiplied alpha,
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// we just return the colors as stored in the file. set this flag to force
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// unpremultiplication. results are undefined if the unpremultiply overflow.
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extern void stbi_set_unpremultiply_on_load(int flag_true_if_should_unpremultiply);
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// indicate whether we should process iphone images back to canonical format,
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// or just pass them through "as-is"
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extern void stbi_convert_iphone_png_to_rgb(int flag_true_if_should_convert);
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// ZLIB client - used by PNG, available for other purposes
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extern char* stbi_zlib_decode_malloc_guesssize(const char* buffer, int len, int initial_size, int* outlen);
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extern char* stbi_zlib_decode_malloc(const char* buffer, int len, int* outlen);
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extern int stbi_zlib_decode_buffer(char* obuffer, int olen, const char* ibuffer, int ilen);
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extern char* stbi_zlib_decode_noheader_malloc(const char* buffer, int len, int* outlen);
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extern int stbi_zlib_decode_noheader_buffer(char* obuffer, int olen, const char* ibuffer, int ilen);
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// define faster low-level operations (typically SIMD support)
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#ifdef STBI_SIMD
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typedef void (*stbi_idct_8x8)(stbi_uc* out, int out_stride, short data[64], unsigned short* dequantize);
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// compute an integer IDCT on "input"
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// input[x] = data[x] * dequantize[x]
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// write results to 'out': 64 samples, each run of 8 spaced by 'out_stride'
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// CLAMP results to 0..255
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typedef void (*stbi_YCbCr_to_RGB_run)(stbi_uc* output, stbi_uc const* y, stbi_uc const* cb, stbi_uc const* cr, int count, int step);
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// compute a conversion from YCbCr to RGB
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// 'count' pixels
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// write pixels to 'output'; each pixel is 'step' bytes (either 3 or 4; if 4, write '255' as 4th), order R,G,B
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// y: Y input channel
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// cb: Cb input channel; scale/biased to be 0..255
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// cr: Cr input channel; scale/biased to be 0..255
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extern void stbi_install_idct(stbi_idct_8x8 func);
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extern void stbi_install_YCbCr_to_RGB(stbi_YCbCr_to_RGB_run func);
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#endif // STBI_SIMD
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#ifdef __cplusplus
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}
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#endif
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//
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//
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//// end header file /////////////////////////////////////////////////////
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#endif // STBI_INCLUDE_STB_IMAGE_H
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