gif-tools/lib/src/reader.d.ts

A robust, zero-dependency TypeScript library for creating GIF files with support for both static and animated GIFs. Built with modern TypeScript features and designed to work in both Node.js and browser environments.

/**
 * GIF Reader Implementation
 *
 * Parses existing GIF files and extracts frames, metadata, and color information.
 */
import { ImageData, RGBColor, DisposalMethod } from './types.js';
export interface GifFrame {
    /** Frame image data */
    imageData: ImageData;
    /** Frame delay in milliseconds */
    delay: number;
    /** Frame disposal method */
    disposal: DisposalMethod;
    /** Frame position */
    left: number;
    top: number;
    /** Transparent color index (-1 if none) */
    transparentIndex: number;
}
export interface GifMetadata {
    /** Extensions found in the GIF */
    extensions: string[];
    /** Comments from comment extensions */
    comments: string[];
    /** Whether any frames use interlacing */
    hasInterlacedFrames: boolean;
    /** Whether local color tables are used */
    hasLocalColorTables: boolean;
    /** Transparent frames detected */
    hasTransparency: boolean;
    /** XMP metadata if present */
    xmpData?: string;
    /** Technical details discovered during parsing */
    technicalDetails: {
        totalDataSize: number;
        compressionRatio?: number;
        averageFrameSize: number;
    };
}
export interface GifInfo {
    /** GIF dimensions */
    width: number;
    height: number;
    /** Number of frames */
    frameCount: number;
    /** Loop count (0 = infinite) */
    loops: number;
    /** Global color table */
    globalColorTable?: Uint8Array;
    /** Background color index */
    backgroundColorIndex: number;
    /** Pixel aspect ratio */
    pixelAspectRatio: number;
    /** Color resolution */
    colorResolution: number;
    /** Sort flag */
    sortFlag: boolean;
    /** Total duration in milliseconds */
    duration: number;
    /** File size in bytes */
    size: number;
    /** GIF version (87a or 89a) */
    version: string;
    /** Metadata and extension information */
    metadata: GifMetadata;
}
/**
 * Reads and parses GIF files
 */
export declare class GifReader {
    private data;
    private position;
    private info;
    private frames;
    private metadata;
    constructor(data: Uint8Array);
    /**
     * Validates GIF header
     */
    private validateHeader;
    /**
     * Reads a byte from the data
     */
    private readByte;
    /**
     * Reads a 16-bit little-endian value
     */
    private read16;
    /**
     * Reads multiple bytes
     */
    private readBytes;
    /**
     * Skips data sub-blocks
     */
    private skipDataSubBlocks;
    /**
     * Reads data sub-blocks and returns combined data
     */
    private readDataSubBlocks;
    /**
     * Creates ImageData from index data and color table
     */
    private createFrameImageData;
    /**
     * Converts interlaced index to actual pixel position
     */
    private deinterlaceIndex;
    /**
     * Converts interlaced Y coordinate to actual Y coordinate
     */
    private deinterlaceY;
    /**
     * Clears a frame area to background color
     */
    private clearFrameArea;
    /**
     * Composites a frame onto the canvas
     */
    private compositeFrame;
    /**
     * Parses the GIF and extracts all information
     */
    parse(): GifInfo;
    /**
     * Gets basic information about the GIF
     */
    getInfo(): GifInfo;
    /**
     * Extracts all frames from the GIF with proper canvas composition
     */
    getFrames(): GifFrame[];
    /**
     * Checks if the GIF is animated
     */
    isAnimated(): boolean;
    /**
     * Gets the dominant colors from the global color table
     */
    getDominantColors(count?: number): RGBColor[];
    /**
     * Gets all colors from the global color table
     */
    getAllColors(): RGBColor[];
}
/**
 * Convenience function to read GIF info from buffer
 */
export declare function readGifInfo(data: Uint8Array): GifInfo;
/**
 * Convenience function to check if data is a valid GIF
 */
export declare function isValidGif(data: Uint8Array): boolean;