.bmp file format: JavaScript parsing library

The BMP file format, also known as bitmap image file or device independent bitmap (DIB) file format or simply a bitmap, is a raster graphics image file format used to store bitmap digital images, independently of the display device (such as a graphics adapter), especially on Microsoft Windows and OS/2 operating systems.

Samples

Great collection of various BMP sample files: BMP Suite Image List (by Jason Summers)

If only there was such a comprehensive sample suite for every file format! It's like a dream for every developer of any binary file format parser. It contains a lot of different types and variations of BMP files, even the tricky ones, where it's not clear from the specification how to deal with them (marked there as "questionable").

If you make a program which will be able to read all the "good" and "questionable" BMP files and won't crash on the "bad" ones, it will definitely have one of the most extensive support of BMP files in the universe!

BITMAPV2INFOHEADER and BITMAPV3INFOHEADER

A beneficial discussion on Adobe forum (archived): Invalid BMP Format with Alpha channel

In 2010, someone noticed that Photoshop generated BMP with an odd type of header. There wasn't any documentation available for this header at the time (and still isn't). However, Chris Cox (former Adobe employee) claimed that they hadn't invented any type of proprietary header and everything they were writing was taken directly from the Microsoft documentation.

It showed up that the unknown header was called BITMAPV3INFOHEADER. Although Microsoft has apparently requested and verified the use of the header, the documentation on MSDN has probably got lost and they have probably forgotten about this type of header.

This is the only source I could find about these structures, so we could't rely on it so much, but I think supporting them as a read-only format won't harm anything. Due to the fact that it isn't documented anywhere else, most applications don't support it.

All Windows headers at once (including mentioned BITMAPV2INFOHEADER and BITMAPV3INFOHEADER):

Bitmap headers overview

Specs

This page hosts a formal specification of .bmp file format using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.

Usage

Runtime library

All parsing code for JavaScript generated by Kaitai Struct depends on the JavaScript runtime library. You have to install it before you can parse data.

The JavaScript runtime library is available at npm:

npm install kaitai-struct

Code

See the usage examples in the JavaScript notes.

Parse structure from an ArrayBuffer:

var arrayBuffer = ...;
var data = new Bmp(new KaitaiStream(arrayBuffer));

After that, one can get various attributes from the structure by accessing fields or properties like:

data.fileHdr // => get file hdr

JavaScript source code to parse .bmp file format

Bmp.js

// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild

(function (root, factory) {
  if (typeof define === 'function' && define.amd) {
    define(['kaitai-struct/KaitaiStream'], factory);
  } else if (typeof module === 'object' && module.exports) {
    module.exports = factory(require('kaitai-struct/KaitaiStream'));
  } else {
    root.Bmp = factory(root.KaitaiStream);
  }
}(this, function (KaitaiStream) {
/**
 * The **BMP file format**, also known as **bitmap image file** or **device independent
 * bitmap (DIB) file format** or simply a **bitmap**, is a raster graphics image file
 * format used to store bitmap digital images, independently of the display
 * device (such as a graphics adapter), especially on Microsoft Windows
 * and OS/2 operating systems.
 * 
 * ## Samples
 * 
 * Great collection of various BMP sample files:
 * [**BMP Suite Image List**](
 *   http://entropymine.com/jason/bmpsuite/bmpsuite/html/bmpsuite.html
 * ) (by Jason Summers)
 * 
 * If only there was such a comprehensive sample suite for every file format! It's like
 * a dream for every developer of any binary file format parser. It contains a lot of
 * different types and variations of BMP files, even the tricky ones, where it's not clear
 * from the specification how to deal with them (marked there as "**q**uestionable").
 * 
 * If you make a program which will be able to read all the "**g**ood" and "**q**uestionable"
 * BMP files and won't crash on the "**b**ad" ones, it will definitely have one of the most
 * extensive support of BMP files in the universe!
 * 
 * ## BITMAPV2INFOHEADER and BITMAPV3INFOHEADER
 * 
 * A beneficial discussion on Adobe forum (archived):
 * [**Invalid BMP Format with Alpha channel**](
 *   https://web.archive.org/web/20150127132443/https://forums.adobe.com/message/3272950
 * )
 * 
 * In 2010, someone noticed that Photoshop generated BMP with an odd type of header. There wasn't
 * any documentation available for this header at the time (and still isn't).
 * However, Chris Cox (former Adobe employee) claimed that they hadn't invented any type
 * of proprietary header and everything they were writing was taken directly
 * from the Microsoft documentation.
 * 
 * It showed up that the unknown header was called BITMAPV3INFOHEADER.
 * Although Microsoft has apparently requested and verified the use of the header,
 * the documentation on MSDN has probably got lost and they have probably
 * forgotten about this type of header.
 * 
 * This is the only source I could find about these structures, so we could't rely
 * on it so much, but I think supporting them as a read-only format won't harm anything.
 * Due to the fact that it isn't documented anywhere else, most applications don't support it.
 * 
 * All Windows headers at once (including mentioned BITMAPV2INFOHEADER and BITMAPV3INFOHEADER):
 * 
 * ![Bitmap headers overview](
 *   https://web.archive.org/web/20190527043845/https://forums.adobe.com/servlet/JiveServlet/showImage/2-3273299-47801/BMP_Headers.png
 * )
 * 
 * ## Specs
 *  * [Bitmap Storage (Windows Dev Center)](
 *      https://docs.microsoft.com/en-us/windows/win32/gdi/bitmap-storage
 *    )
 *     * BITMAPFILEHEADER
 *     * BITMAPINFOHEADER
 *     * BITMAPV4HEADER
 *     * BITMAPV5HEADER
 *  * [OS/2 Bitmap File Format](
 *       https://www.fileformat.info/format/os2bmp/egff.htm
 *    )
 *     * BITMAPFILEHEADER (OS2BMPFILEHEADER)
 *     * BITMAPCOREHEADER (OS21XBITMAPHEADER)
 *     * OS22XBITMAPHEADER
 *  * [Microsoft Windows Bitmap](
 *       http://netghost.narod.ru/gff/graphics/summary/micbmp.htm
 *    )
 *     * BITMAPFILEHEADER (WINBMPFILEHEADER)
 *     * BITMAPCOREHEADER (WIN2XBITMAPHEADER)
 *     * BITMAPINFOHEADER (WINNTBITMAPHEADER)
 *     * BITMAPV4HEADER (WIN4XBITMAPHEADER)
 */

var Bmp = (function() {
  Bmp.Intent = Object.freeze({
    BUSINESS: 1,
    GRAPHICS: 2,
    IMAGES: 4,
    ABS_COLORIMETRIC: 8,

    1: "BUSINESS",
    2: "GRAPHICS",
    4: "IMAGES",
    8: "ABS_COLORIMETRIC",
  });

  Bmp.ColorSpace = Object.freeze({
    CALIBRATED_RGB: 0,
    PROFILE_LINKED: 1279872587,
    PROFILE_EMBEDDED: 1296188740,
    WINDOWS: 1466527264,
    S_RGB: 1934772034,

    0: "CALIBRATED_RGB",
    1279872587: "PROFILE_LINKED",
    1296188740: "PROFILE_EMBEDDED",
    1466527264: "WINDOWS",
    1934772034: "S_RGB",
  });

  Bmp.Os2Rendering = Object.freeze({
    NO_HALFTONING: 0,
    ERROR_DIFFUSION: 1,
    PANDA: 2,
    SUPER_CIRCLE: 3,

    0: "NO_HALFTONING",
    1: "ERROR_DIFFUSION",
    2: "PANDA",
    3: "SUPER_CIRCLE",
  });

  Bmp.HeaderType = Object.freeze({
    BITMAP_CORE_HEADER: 12,
    BITMAP_INFO_HEADER: 40,
    BITMAP_V2_INFO_HEADER: 52,
    BITMAP_V3_INFO_HEADER: 56,
    OS2_2X_BITMAP_HEADER: 64,
    BITMAP_V4_HEADER: 108,
    BITMAP_V5_HEADER: 124,

    12: "BITMAP_CORE_HEADER",
    40: "BITMAP_INFO_HEADER",
    52: "BITMAP_V2_INFO_HEADER",
    56: "BITMAP_V3_INFO_HEADER",
    64: "OS2_2X_BITMAP_HEADER",
    108: "BITMAP_V4_HEADER",
    124: "BITMAP_V5_HEADER",
  });

  Bmp.Compressions = Object.freeze({
    RGB: 0,
    RLE8: 1,
    RLE4: 2,
    BITFIELDS: 3,
    JPEG: 4,
    PNG: 5,
    ALPHA_BITFIELDS: 6,

    0: "RGB",
    1: "RLE8",
    2: "RLE4",
    3: "BITFIELDS",
    4: "JPEG",
    5: "PNG",
    6: "ALPHA_BITFIELDS",
  });

  Bmp.Os2Compressions = Object.freeze({
    RGB: 0,
    RLE8: 1,
    RLE4: 2,
    HUFFMAN_1D: 3,
    RLE24: 4,

    0: "RGB",
    1: "RLE8",
    2: "RLE4",
    3: "HUFFMAN_1D",
    4: "RLE24",
  });

  function Bmp(_io, _parent, _root) {
    this._io = _io;
    this._parent = _parent;
    this._root = _root || this;

    this._read();
  }
  Bmp.prototype._read = function() {
    this.fileHdr = new FileHeader(this._io, this, this._root);
    this._raw_dibInfo = this._io.readBytes((this.fileHdr.ofsBitmap - 14));
    var _io__raw_dibInfo = new KaitaiStream(this._raw_dibInfo);
    this.dibInfo = new BitmapInfo(_io__raw_dibInfo, this, this._root);
    this._raw_bitmap = this._io.readBytesFull();
    var _io__raw_bitmap = new KaitaiStream(this._raw_bitmap);
    this.bitmap = new Bitmap(_io__raw_bitmap, this, this._root);
  }

  /**
   * @see {@link https://docs.microsoft.com/en-us/windows/win32/api/wingdi/ns-wingdi-ciexyz|Source}
   */

  var CieXyz = Bmp.CieXyz = (function() {
    function CieXyz(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    CieXyz.prototype._read = function() {
      this.x = new FixedPoint2Dot30(this._io, this, this._root);
      this.y = new FixedPoint2Dot30(this._io, this, this._root);
      this.z = new FixedPoint2Dot30(this._io, this, this._root);
    }

    return CieXyz;
  })();

  var RgbRecord = Bmp.RgbRecord = (function() {
    function RgbRecord(_io, _parent, _root, hasReservedField) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;
      this.hasReservedField = hasReservedField;

      this._read();
    }
    RgbRecord.prototype._read = function() {
      this.blue = this._io.readU1();
      this.green = this._io.readU1();
      this.red = this._io.readU1();
      if (this.hasReservedField) {
        this.reserved = this._io.readU1();
      }
    }

    return RgbRecord;
  })();

  /**
   * @see {@link https://docs.microsoft.com/en-us/windows/win32/api/wingdi/ns-wingdi-bitmapv5header|Source}
   */

  var BitmapV5Extension = Bmp.BitmapV5Extension = (function() {
    function BitmapV5Extension(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    BitmapV5Extension.prototype._read = function() {
      this.intent = this._io.readU4le();
      this.ofsProfile = this._io.readU4le();
      this.lenProfile = this._io.readU4le();
      this.reserved = this._io.readU4le();
    }
    Object.defineProperty(BitmapV5Extension.prototype, 'hasProfile', {
      get: function() {
        if (this._m_hasProfile !== undefined)
          return this._m_hasProfile;
        this._m_hasProfile =  ((this._parent.bitmapV4Ext.colorSpaceType == Bmp.ColorSpace.PROFILE_LINKED) || (this._parent.bitmapV4Ext.colorSpaceType == Bmp.ColorSpace.PROFILE_EMBEDDED)) ;
        return this._m_hasProfile;
      }
    });

    /**
     * @see {@link https://docs.microsoft.com/en-us/windows/win32/wcs/using-structures-in-wcs-1-0|"If the profile is embedded, profile data is the actual profile, and if it is linked, the profile data is the null-terminated file name of the profile. This cannot be a Unicode string. It must be composed exclusively of characters from the Windows character set (code page 1252)."}
     */
    Object.defineProperty(BitmapV5Extension.prototype, 'profileData', {
      get: function() {
        if (this._m_profileData !== undefined)
          return this._m_profileData;
        if (this.hasProfile) {
          var io = this._root._io;
          var _pos = io.pos;
          io.seek((14 + this.ofsProfile));
          switch (this._parent.bitmapV4Ext.colorSpaceType == Bmp.ColorSpace.PROFILE_LINKED) {
          case true:
            this._m_profileData = KaitaiStream.bytesToStr(KaitaiStream.bytesTerminate(io.readBytes(this.lenProfile), 0, false), "windows-1252");
            break;
          default:
            this._m_profileData = io.readBytes(this.lenProfile);
            break;
          }
          io.seek(_pos);
        }
        return this._m_profileData;
      }
    });

    /**
     * The offset, in bytes, from the beginning of the BITMAPV5HEADER structure to the start of the profile data.
     */

    return BitmapV5Extension;
  })();

  var ColorMask = Bmp.ColorMask = (function() {
    function ColorMask(_io, _parent, _root, hasAlphaMask) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;
      this.hasAlphaMask = hasAlphaMask;

      this._read();
    }
    ColorMask.prototype._read = function() {
      this.redMask = this._io.readU4le();
      this.greenMask = this._io.readU4le();
      this.blueMask = this._io.readU4le();
      if (this.hasAlphaMask) {
        this.alphaMask = this._io.readU4le();
      }
    }

    return ColorMask;
  })();

  /**
   * @see {@link https://docs.microsoft.com/en-us/windows/win32/api/wingdi/ns-wingdi-bitmapv4header|Source}
   */

  var BitmapV4Extension = Bmp.BitmapV4Extension = (function() {
    function BitmapV4Extension(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    BitmapV4Extension.prototype._read = function() {
      this.colorSpaceType = this._io.readU4le();
      this.endpointRed = new CieXyz(this._io, this, this._root);
      this.endpointGreen = new CieXyz(this._io, this, this._root);
      this.endpointBlue = new CieXyz(this._io, this, this._root);
      this.gammaRed = new FixedPoint16Dot16(this._io, this, this._root);
      this.gammaBlue = new FixedPoint16Dot16(this._io, this, this._root);
      this.gammaGreen = new FixedPoint16Dot16(this._io, this, this._root);
    }

    return BitmapV4Extension;
  })();

  /**
   * @see {@link https://docs.microsoft.com/en-us/previous-versions/dd183376(v=vs.85)|Source}
   */

  var BitmapInfoExtension = Bmp.BitmapInfoExtension = (function() {
    function BitmapInfoExtension(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    BitmapInfoExtension.prototype._read = function() {
      if (!(this._parent.extendsOs22xBitmap)) {
        this.compression = this._io.readU4le();
      }
      if (this._parent.extendsOs22xBitmap) {
        this.os2Compression = this._io.readU4le();
      }
      this.lenImage = this._io.readU4le();
      this.xResolution = this._io.readU4le();
      this.yResolution = this._io.readU4le();
      this.numColorsUsed = this._io.readU4le();
      this.numColorsImportant = this._io.readU4le();
    }

    /**
     * If biCompression is BI_JPEG or BI_PNG, indicates the size of the JPEG or PNG image buffer.
     * This may be set to zero for BI_RGB bitmaps.
     */

    return BitmapInfoExtension;
  })();

  var FixedPoint2Dot30 = Bmp.FixedPoint2Dot30 = (function() {
    function FixedPoint2Dot30(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    FixedPoint2Dot30.prototype._read = function() {
      this.raw = this._io.readU4le();
    }
    Object.defineProperty(FixedPoint2Dot30.prototype, 'value', {
      get: function() {
        if (this._m_value !== undefined)
          return this._m_value;
        this._m_value = ((this.raw + 0.0) / (1 << 30));
        return this._m_value;
      }
    });

    return FixedPoint2Dot30;
  })();

  /**
   * Replace with an opaque type if you care about the pixels.
   * You can look at an example of a JavaScript implementation: https://github.com/generalmimon/bmptool/blob/master/src/Bitmap.js
   * 
   * There is a proposal for adding bitmap data type to Kaitai Struct: https://github.com/kaitai-io/kaitai_struct/issues/188
   */

  var Bitmap = Bmp.Bitmap = (function() {
    function Bitmap(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    Bitmap.prototype._read = function() {
    }

    return Bitmap;
  })();

  /**
   * @see {@link https://docs.microsoft.com/en-us/windows/win32/api/wingdi/ns-wingdi-bitmapcoreheader|Source}
   * @see {@link https://www.fileformat.info/format/os2bmp/egff.htm#OS2BMP-DMYID.3.1|Source}
   */

  var BitmapHeader = Bmp.BitmapHeader = (function() {
    function BitmapHeader(_io, _parent, _root, lenHeader) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;
      this.lenHeader = lenHeader;

      this._read();
    }
    BitmapHeader.prototype._read = function() {
      switch (this.isCoreHeader) {
      case true:
        this.imageWidth = this._io.readU2le();
        break;
      case false:
        this.imageWidth = this._io.readU4le();
        break;
      }
      switch (this.isCoreHeader) {
      case true:
        this.imageHeightRaw = this._io.readS2le();
        break;
      case false:
        this.imageHeightRaw = this._io.readS4le();
        break;
      }
      this.numPlanes = this._io.readU2le();
      this.bitsPerPixel = this._io.readU2le();
      if (this.extendsBitmapInfo) {
        this.bitmapInfoExt = new BitmapInfoExtension(this._io, this, this._root);
      }
      if (this.isColorMaskHere) {
        this.colorMask = new ColorMask(this._io, this, this._root, this.lenHeader != Bmp.HeaderType.BITMAP_V2_INFO_HEADER);
      }
      if (this.extendsOs22xBitmap) {
        this.os22xBitmapExt = new Os22xBitmapExtension(this._io, this, this._root);
      }
      if (this.extendsBitmapV4) {
        this.bitmapV4Ext = new BitmapV4Extension(this._io, this, this._root);
      }
      if (this.extendsBitmapV5) {
        this.bitmapV5Ext = new BitmapV5Extension(this._io, this, this._root);
      }
    }
    Object.defineProperty(BitmapHeader.prototype, 'extendsBitmapV4', {
      get: function() {
        if (this._m_extendsBitmapV4 !== undefined)
          return this._m_extendsBitmapV4;
        this._m_extendsBitmapV4 = this.lenHeader >= Bmp.HeaderType.BITMAP_V4_HEADER;
        return this._m_extendsBitmapV4;
      }
    });
    Object.defineProperty(BitmapHeader.prototype, 'extendsOs22xBitmap', {
      get: function() {
        if (this._m_extendsOs22xBitmap !== undefined)
          return this._m_extendsOs22xBitmap;
        this._m_extendsOs22xBitmap = this.lenHeader == Bmp.HeaderType.OS2_2X_BITMAP_HEADER;
        return this._m_extendsOs22xBitmap;
      }
    });
    Object.defineProperty(BitmapHeader.prototype, 'usesFixedPalette', {
      get: function() {
        if (this._m_usesFixedPalette !== undefined)
          return this._m_usesFixedPalette;
        this._m_usesFixedPalette =  ((!( ((this.bitsPerPixel == 16) || (this.bitsPerPixel == 24) || (this.bitsPerPixel == 32)) )) && (!( ((this.extendsBitmapInfo) && (!(this.extendsOs22xBitmap)) && ( ((this.bitmapInfoExt.compression == Bmp.Compressions.JPEG) || (this.bitmapInfoExt.compression == Bmp.Compressions.PNG)) )) ))) ;
        return this._m_usesFixedPalette;
      }
    });
    Object.defineProperty(BitmapHeader.prototype, 'extendsBitmapInfo', {
      get: function() {
        if (this._m_extendsBitmapInfo !== undefined)
          return this._m_extendsBitmapInfo;
        this._m_extendsBitmapInfo = this.lenHeader >= Bmp.HeaderType.BITMAP_INFO_HEADER;
        return this._m_extendsBitmapInfo;
      }
    });
    Object.defineProperty(BitmapHeader.prototype, 'imageHeight', {
      get: function() {
        if (this._m_imageHeight !== undefined)
          return this._m_imageHeight;
        this._m_imageHeight = (this.imageHeightRaw < 0 ? -(this.imageHeightRaw) : this.imageHeightRaw);
        return this._m_imageHeight;
      }
    });
    Object.defineProperty(BitmapHeader.prototype, 'isCoreHeader', {
      get: function() {
        if (this._m_isCoreHeader !== undefined)
          return this._m_isCoreHeader;
        this._m_isCoreHeader = this.lenHeader == Bmp.HeaderType.BITMAP_CORE_HEADER;
        return this._m_isCoreHeader;
      }
    });
    Object.defineProperty(BitmapHeader.prototype, 'extendsBitmapV5', {
      get: function() {
        if (this._m_extendsBitmapV5 !== undefined)
          return this._m_extendsBitmapV5;
        this._m_extendsBitmapV5 = this.lenHeader >= Bmp.HeaderType.BITMAP_V5_HEADER;
        return this._m_extendsBitmapV5;
      }
    });
    Object.defineProperty(BitmapHeader.prototype, 'isColorMaskHere', {
      get: function() {
        if (this._m_isColorMaskHere !== undefined)
          return this._m_isColorMaskHere;
        this._m_isColorMaskHere =  ((this.lenHeader == Bmp.HeaderType.BITMAP_V2_INFO_HEADER) || (this.lenHeader == Bmp.HeaderType.BITMAP_V3_INFO_HEADER) || (this.extendsBitmapV4)) ;
        return this._m_isColorMaskHere;
      }
    });
    Object.defineProperty(BitmapHeader.prototype, 'bottomUp', {
      get: function() {
        if (this._m_bottomUp !== undefined)
          return this._m_bottomUp;
        this._m_bottomUp = this.imageHeightRaw > 0;
        return this._m_bottomUp;
      }
    });

    /**
     * Image width, px
     */

    /**
     * Image height, px (positive => bottom-up image, negative => top-down image)
     */

    /**
     * Number of planes for target device, must be 1
     */

    /**
     * Number of bits per pixel that image buffer uses (1, 4, 8, 16, 24 or 32)
     */

    return BitmapHeader;
  })();

  /**
   * @see {@link https://www.fileformat.info/format/os2bmp/egff.htm#OS2BMP-DMYID.3.2|Source}
   */

  var Os22xBitmapExtension = Bmp.Os22xBitmapExtension = (function() {
    function Os22xBitmapExtension(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    Os22xBitmapExtension.prototype._read = function() {
      this.units = this._io.readU2le();
      this.reserved = this._io.readU2le();
      this.recording = this._io.readU2le();
      this.rendering = this._io.readU2le();
      this.size1 = this._io.readU4le();
      this.size2 = this._io.readU4le();
      this.colorEncoding = this._io.readU4le();
      this.identifier = this._io.readU4le();
    }

    /**
     * Specifies how the bitmap scan lines are stored.
     * The only valid value for this field is 0, indicating that the bitmap is
     * stored from left to right and from the bottom up.
     */

    /**
     * Specifies the halftoning algorithm used on the bitmap data.
     */

    /**
     * rendering == os2_rendering::error_diffusion
     *   => error damping as a percentage in the range 0 through 100
     * rendering == os2_rendering::panda or rendering == os2_rendering::super_circle
     *   => X dimension of the pattern used in pixels
     */

    /**
     * rendering == os2_rendering::error_diffusion
     *   => not used
     * rendering == os2_rendering::panda or rendering == os2_rendering::super_circle
     *   => Y dimension of the pattern used in pixels
     */

    /**
     * Specifies the color model used to describe the bitmap data.
     * The only valid value is 0, indicating the RGB encoding scheme.
     */

    /**
     * Application-specific value
     */

    return Os22xBitmapExtension;
  })();

  var FixedPoint16Dot16 = Bmp.FixedPoint16Dot16 = (function() {
    function FixedPoint16Dot16(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    FixedPoint16Dot16.prototype._read = function() {
      this.raw = this._io.readU4le();
    }
    Object.defineProperty(FixedPoint16Dot16.prototype, 'value', {
      get: function() {
        if (this._m_value !== undefined)
          return this._m_value;
        this._m_value = ((this.raw + 0.0) / (1 << 16));
        return this._m_value;
      }
    });

    return FixedPoint16Dot16;
  })();

  var ColorTable = Bmp.ColorTable = (function() {
    function ColorTable(_io, _parent, _root, hasReservedField, numColors) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;
      this.hasReservedField = hasReservedField;
      this.numColors = numColors;

      this._read();
    }
    ColorTable.prototype._read = function() {
      this.colors = new Array(( ((this.numColors > 0) && (this.numColors < this.numColorsPresent))  ? this.numColors : this.numColorsPresent));
      for (var i = 0; i < ( ((this.numColors > 0) && (this.numColors < this.numColorsPresent))  ? this.numColors : this.numColorsPresent); i++) {
        this.colors[i] = new RgbRecord(this._io, this, this._root, this.hasReservedField);
      }
    }
    Object.defineProperty(ColorTable.prototype, 'numColorsPresent', {
      get: function() {
        if (this._m_numColorsPresent !== undefined)
          return this._m_numColorsPresent;
        this._m_numColorsPresent = Math.floor(this._io.size / (this.hasReservedField ? 4 : 3));
        return this._m_numColorsPresent;
      }
    });

    /**
     * If equal to 0, the pallete should contain as many colors as can fit into the pixel value
     * according to the `bits_per_pixel` field (if `bits_per_pixel` = 8, then the pixel can
     * represent 2 ** 8 = 256 values, so exactly 256 colors should be present). For more flexibility,
     * it reads as many colors as it can until EOS is reached (and the image data begin).
     */

    return ColorTable;
  })();

  /**
   * @see {@link https://docs.microsoft.com/en-us/windows/win32/api/wingdi/ns-wingdi-bitmapfileheader|Source}
   */

  var FileHeader = Bmp.FileHeader = (function() {
    function FileHeader(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    FileHeader.prototype._read = function() {
      this.fileType = this._io.readBytes(2);
      if (!((KaitaiStream.byteArrayCompare(this.fileType, [66, 77]) == 0))) {
        throw new KaitaiStream.ValidationNotEqualError([66, 77], this.fileType, this._io, "/types/file_header/seq/0");
      }
      this.lenFile = this._io.readU4le();
      this.reserved1 = this._io.readU2le();
      this.reserved2 = this._io.readU2le();
      this.ofsBitmap = this._io.readS4le();
    }

    /**
     * not reliable, mostly ignored by BMP decoders
     */

    /**
     * Offset to actual raw pixel data of the image
     */

    return FileHeader;
  })();

  /**
   * @see {@link https://docs.microsoft.com/en-us/windows/win32/api/wingdi/ns-wingdi-bitmapinfo|Source}
   */

  var BitmapInfo = Bmp.BitmapInfo = (function() {
    function BitmapInfo(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    BitmapInfo.prototype._read = function() {
      this.lenHeader = this._io.readU4le();
      this._raw_header = this._io.readBytes((this.lenHeader - 4));
      var _io__raw_header = new KaitaiStream(this._raw_header);
      this.header = new BitmapHeader(_io__raw_header, this, this._root, this.lenHeader);
      if (this.isColorMaskHere) {
        this.colorMask = new ColorMask(this._io, this, this._root, this.header.bitmapInfoExt.compression == Bmp.Compressions.ALPHA_BITFIELDS);
      }
      if (!(this._io.isEof())) {
        this._raw_colorTable = this._io.readBytesFull();
        var _io__raw_colorTable = new KaitaiStream(this._raw_colorTable);
        this.colorTable = new ColorTable(_io__raw_colorTable, this, this._root, !(this.header.isCoreHeader), (this.header.extendsBitmapInfo ? this.header.bitmapInfoExt.numColorsUsed : 0));
      }
    }
    Object.defineProperty(BitmapInfo.prototype, 'isColorMaskGiven', {
      get: function() {
        if (this._m_isColorMaskGiven !== undefined)
          return this._m_isColorMaskGiven;
        this._m_isColorMaskGiven =  ((this.header.extendsBitmapInfo) && ( ((this.header.bitmapInfoExt.compression == Bmp.Compressions.BITFIELDS) || (this.header.bitmapInfoExt.compression == Bmp.Compressions.ALPHA_BITFIELDS)) ) && ( ((this.isColorMaskHere) || (this.header.isColorMaskHere)) )) ;
        return this._m_isColorMaskGiven;
      }
    });
    Object.defineProperty(BitmapInfo.prototype, 'colorMaskGiven', {
      get: function() {
        if (this._m_colorMaskGiven !== undefined)
          return this._m_colorMaskGiven;
        if (this.isColorMaskGiven) {
          this._m_colorMaskGiven = (this.isColorMaskHere ? this.colorMask : this.header.colorMask);
        }
        return this._m_colorMaskGiven;
      }
    });
    Object.defineProperty(BitmapInfo.prototype, 'colorMaskBlue', {
      get: function() {
        if (this._m_colorMaskBlue !== undefined)
          return this._m_colorMaskBlue;
        this._m_colorMaskBlue = (this.isColorMaskGiven ? this.colorMaskGiven.blueMask : (this.header.bitsPerPixel == 16 ? 31 : ( ((this.header.bitsPerPixel == 24) || (this.header.bitsPerPixel == 32))  ? 255 : 0)));
        return this._m_colorMaskBlue;
      }
    });
    Object.defineProperty(BitmapInfo.prototype, 'colorMaskAlpha', {
      get: function() {
        if (this._m_colorMaskAlpha !== undefined)
          return this._m_colorMaskAlpha;
        this._m_colorMaskAlpha = ( ((this.isColorMaskGiven) && (this.colorMaskGiven.hasAlphaMask))  ? this.colorMaskGiven.alphaMask : 0);
        return this._m_colorMaskAlpha;
      }
    });
    Object.defineProperty(BitmapInfo.prototype, 'colorMaskGreen', {
      get: function() {
        if (this._m_colorMaskGreen !== undefined)
          return this._m_colorMaskGreen;
        this._m_colorMaskGreen = (this.isColorMaskGiven ? this.colorMaskGiven.greenMask : (this.header.bitsPerPixel == 16 ? 992 : ( ((this.header.bitsPerPixel == 24) || (this.header.bitsPerPixel == 32))  ? 65280 : 0)));
        return this._m_colorMaskGreen;
      }
    });
    Object.defineProperty(BitmapInfo.prototype, 'isColorMaskHere', {
      get: function() {
        if (this._m_isColorMaskHere !== undefined)
          return this._m_isColorMaskHere;
        this._m_isColorMaskHere =  ((!(this._io.isEof())) && (this.header.lenHeader == Bmp.HeaderType.BITMAP_INFO_HEADER) && ( ((this.header.bitmapInfoExt.compression == Bmp.Compressions.BITFIELDS) || (this.header.bitmapInfoExt.compression == Bmp.Compressions.ALPHA_BITFIELDS)) )) ;
        return this._m_isColorMaskHere;
      }
    });
    Object.defineProperty(BitmapInfo.prototype, 'colorMaskRed', {
      get: function() {
        if (this._m_colorMaskRed !== undefined)
          return this._m_colorMaskRed;
        this._m_colorMaskRed = (this.isColorMaskGiven ? this.colorMaskGiven.redMask : (this.header.bitsPerPixel == 16 ? 31744 : ( ((this.header.bitsPerPixel == 24) || (this.header.bitsPerPixel == 32))  ? 16711680 : 0)));
        return this._m_colorMaskRed;
      }
    });

    /**
     * Valid only for BITMAPINFOHEADER, in all headers extending it the masks are contained in the header itself.
     */

    return BitmapInfo;
  })();

  return Bmp;
})();
return Bmp;
}));