ok file formats

Decoders for PNG, JPEG, WAV, and a few other file formats

brackeen
110
14
C

ok-file-formats

C functions for reading a few different file formats. No external dependencies. Written in C99.

Library Description
ok_png Reads PNG files. Supports Apple’s proprietary CgBI chunk. Tested against the PngSuite.
ok_jpg Reads JPEG files. Baseline and progressive formats. Interprets EXIF orientation tags. No CMYK support.
ok_wav Reads WAV and CAF files. PCM, u-law, a-law, and ADPCM formats.
ok_fnt Reads AngelCode BMFont files. Binary format from AngelCode Bitmap Font Generator v1.10 or newer.
ok_csv Reads Comma-Separated Values files.
ok_mo Reads gettext MO files.

The source files do not depend on one another. If all you need is to read a PNG file, just
use ok_png.h and ok_png.c.

The CMakeLists.txt file can be used but is not required.

The ok_png, ok_jpg, and ok_wav functions include:

  • Option to use a custom allocator (ok_png_read_with_allocator, etc.)
  • Fuzz tests.

The ok_png and ok_jpg functions include these decode options:

  • Get the image dimensions without decoding image data.
  • Premultiply alpha.
  • Flip the image vertically.

Example: Decode PNG

#include <stdio.h>
#include "ok_png.h"

int main() {
    FILE *file = fopen("my_image.png", "rb");
    ok_png image = ok_png_read(file, OK_PNG_COLOR_FORMAT_RGBA | OK_PNG_PREMULTIPLIED_ALPHA | OK_PNG_FLIP_Y);
    fclose(file);
    if (image.data) {
        printf("Got image! Size: %li x %li\n", (long)image.width, (long)image.height);
        free(image.data);
    }
    return 0;
}

Recent breaking changes in ok_png, ok_jpg, and ok_wav:

  • The read functions now return the ok_png, ok_jpg, and ok_wav structs on the stack instead of the heap. (These structs are small, around 24-32 bytes).
  • Replaced ok_png_read_to_buffer with ok_png_read_with_allocator.
  • Replaced ok_png_read_from_callbacks with ok_png_read_from_input.
  • Replaced error_message with error_code.
  • Removed ok_png_free. Free png.data directly instead.