ImageGear v26.4 - Updated
Developer Guide / File Formats and Compressions
In This Topic
    File Formats and Compressions
    In This Topic

    This section provides detailed information about the image formats and compressions that ImageGear supports.

    • File Formats provides background information about different types of file formats, and contains additional topics that provide information on the following:
      • What's the Best Format for...? lists which formats best support various types of images (for example, which formats support an alpha channel). This section provides you with a starting point for deciding which file formats to use in your application.
      • Format Bit Depths is a table that lists the bit depths and the read/write capabilities of the supported formats. Using this table, you can easily find out whether an image can be converted to a particular format.
      • File Formats Reference provides information about every ImageGear supported format, its ID, supported versions, encoding type, multi-page and alpha channel support, supported compressions, color spaces and bit depths for read and write, as well as information about ImageGear supported features and filter control parameters.
      • Metadata Structures provides detailed information about ImageGear supported metadata.
    • Compressions provides information about every ImageGear supported imaging compression.

    Supported Formats and Compressions

    ImageGear supports the following formats and compressions in the following categories:

    Raster Color and Grayscale

    Format Full Name Support
    BMP Microsoft Windows Bitmap RW
    CLP Windows Clipboard RW
    CUR Windows cursor RW
    DIB DIB (Microsoft Windows Device Independent Bitmap) RW
    DNG Digital Negative file format R
    GIF CompuServe Graphics Interchange Format (GIF) RW
    JPEG JPEG File Interchange Format RW
    PNG Portable Network Graphics RW
    TIFF Tagged Image File Format RW

    Vector

    Format Full Name Support
    PDF Adobe Portable Document Format RW
    SVG Scalable Vector Graphics W

    Email

    Format Full Name Support
    EML Internet Message Format R
    MSG Outlook Message Format R

    Office

    Format Full Name Support
    DOCX Office Open XML Word Format R
    DOC Microsoft Office Word 97-2003 Format R
    PPTX Office Open XML PowerPoint Format R
    PPT Microsoft Office PowerPoint 97-2003 Format R
    XLSX Office Open XML Excel Format R
    XLS Microsoft Office Excel 97-2003 Format R

    Compressions

    Format Full Name Formats Supported
    CCITT Group 3 Compression CCITT Group 3 Adobe PDF, PS, TIFF
    CCITT Group 3 2D Compression CCITT Group 3 2D Adobe PDF, PS, TIFF
    CCITT Group 4 Compression CCITT Group 4 Adobe PDF, PS, TIFF
    Deflate Compression Deflate Compression PDF, PS, TIFF, PNG
    Huffman Compression Huffman Encoding TIFF
    JPEG Compressions JPEG Compression
    LZW (Lempel-Ziv-Welch) Compression Lempel-Zif-Welch (LZW) Compression GIF, Adobe PDF, PS, TIFF
    Packbits Compression Packed Bits Compression TIFF
    RLE Compression Run Length Encoding Compression BMP, CLP, Adobe PDF

    Encoding vs. Compressing

    These two words are often used interchangeably in discussions of graphics file formats. Encoding is actually a broad term under which compression falls. For the sake of clarity, use these terms separately with the following intended meanings:

    • Encoding - The manner that data is stored when uncompressed (binary, ASCII, etc.), how it is packed (e.g., 4-bit pixels may be packed at a rate of two pixels per byte), and the unique set of symbols used to represent the range of data items.
    • Compressing - A "physical" rewriting of the graphics data so that it is represented by a smaller set of data.