jpeg.md

jpeglib.h - JPEG Image Library

The jpeglib.h header provides the interface for libjpeg, used for compressing and decompressing JPEG images.

Facilities Overview

Facility Category	Key Symbols	Description
Decompression	jpeg_create_decompress	Initializing a decoder.
Source Management	jpeg_stdio_src	Setting the input file.
Header Parsing	jpeg_read_header	Retrieving image dimensions.
Scanline Reading	jpeg_read_scanlines	Decoding the image row by row.
Cleanup	jpeg_destroy_decompress	Releasing resources.

---

Types & Variables

jpeg_decompress_struct

Structure holding the state for a decompression operation.

jpeg_error_mgr

Structure for handling errors and warnings.

---

Functions

Decompressing JPEGs

jpeg_create_decompress

void jpeg_create_decompress(struct jpeg_decompress_struct *cinfo)

Initializes the decompression object.

Example:

#include <stdio.h>
#include <jpeglib.h>

int main(void) {
    struct jpeg_decompress_struct cinfo;
    struct jpeg_error_mgr jerr;
    cinfo.err = jpeg_std_error(&jerr);
    jpeg_create_decompress(&cinfo);
    jpeg_destroy_decompress(&cinfo);
    return 0;
}

jpeg_stdio_src

void jpeg_stdio_src(struct jpeg_decompress_struct *cinfo, FILE *infile)

Sets the input file for the decompressor.

jpeg_read_header

int jpeg_read_header(struct jpeg_decompress_struct *cinfo, boolean require_image)

---

Cleanup

jpeg_destroy_decompress

void jpeg_destroy_decompress(struct jpeg_decompress_struct *cinfo)