mod_ijl_jpg.bas

打印预览程序

Attribute VB_Name = "IJL"
Rem
Rem
Rem
Rem               INTEL CORPORATION PROPRIETARY INFORMATION
Rem  This software is supplied under the terms of a license agreement or
Rem  nondisclosure agreement with Intel Corporation and may not be copied
Rem  or disclosed except in accordance with the terms of that agreement.
Rem      Copyright (c) 1998 Intel Corporation. All Rights Reserved.
Rem
Rem
Rem  File:
Rem    ijl.bas
Rem
Rem  Purpose:
Rem    Intel(R) JPEG Library Visual Basic interface module
Rem
Rem  Version:
Rem    1.2
Rem
Rem


Option Explicit

Global Const JBUFSIZE  As Long = 4096




Rem
Rem//////////////////////////////////////////////////////////////////////////
Rem  Name:        IJLibVersion
Rem
Rem  Purpose:     Stores library version info.
Rem
Rem  Context:
Rem
Rem  Example:
Rem   major           - 1
Rem   minor           - 0
Rem   build           - 1
Rem   Name            - "ijl10.dll"
Rem   Version         - "1.0.1 Beta 1"
Rem   InternalVersion - "1.0.1.1"
Rem   BuildDate       - "Sep 22 1998"
Rem   CallConv        - "DLL"
Rem
Rem//////////////////////////////////////////////////////////////////////////
Rem

Public Type IJLibVersion
  major           As Long
  minor           As Long
  build           As Long
  Name            As Long 'pointer to C-style string
  Version         As Long 'pointer to C-style string
  InternalVersion As Long 'pointer to C-style string
  BuildDate       As Long 'pointer to C-style string
  CallConv        As Long 'pointer to C-style string
End Type


Rem/*D*
Rem////////////////////////////////////////////////////////////////////////////
Rem// Name:        IJL_RECT
Rem//
Rem// Purpose:     Keep coordinates for rectangle region of image
Rem//
Rem// Context:     Used to specify roi
Rem//
Rem// Fields:
Rem//
Rem////////////////////////////////////////////////////////////////////////////
Rem*D*/

Public Type IJL_RECT
  left   As Long
  top    As Long
  right  As Long
  bottom As Long
End Type


Rem
Rem//////////////////////////////////////////////////////////////////////////
Rem  Name:       IJLIOTYPE
Rem
Rem  Purpose:    Possible types of data read/write/other operations to be
Rem              performed by the functions IJL_Read and IJL_Write.
Rem
Rem              See the Developer's Guide for details on appropriate usage.
Rem
Rem  Fields:
Rem
Rem    IJL_JFILE_XXXXXXX   Indicates JPEG data in a stdio file.
Rem
Rem    IJL_JBUFF_XXXXXXX   Indicates JPEG data in an addressable buffer.
Rem
Rem//////////////////////////////////////////////////////////////////////////
Rem

Public Enum IJLIOTYPE
  IJL_SETUP = -1
    
  ' Read JPEG parameters (i.e., height, width, channels, sampling, etc.)
  ' from a JPEG bit stream.
  IJL_JFILE_READPARAMS = 0
  IJL_JBUFF_READPARAMS = 1
    
  ' Read a JPEG Interchange Format image.
  IJL_JFILE_READWHOLEIMAGE = 2
  IJL_JBUFF_READWHOLEIMAGE = 3
    
  ' Read JPEG tables from a JPEG Abbreviated Format bit stream.
  IJL_JFILE_READHEADER = 4
  IJL_JBUFF_READHEADER = 5
    
  ' Read image info from a JPEG Abbreviated Format bit stream.
  IJL_JFILE_READENTROPY = 6
  IJL_JBUFF_READENTROPY = 7
    
  ' Write an entire JFIF bit stream.
  IJL_JFILE_WRITEWHOLEIMAGE = 8
  IJL_JBUFF_WRITEWHOLEIMAGE = 9
    
  ' Write a JPEG Abbreviated Format bit stream.
  IJL_JFILE_WRITEHEADER = 10
  IJL_JBUFF_WRITEHEADER = 11
    
  ' Write image info to a JPEG Abbreviated Format bit stream.
  IJL_JFILE_WRITEENTROPY = 12
  IJL_JBUFF_WRITEENTROPY = 13
    
  ' Scaled Decoding Options:

  ' Reads a JPEG image scaled to 1/2 size.
  IJL_JFILE_READONEHALF = 14
  IJL_JBUFF_READONEHALF = 15
    
  ' Reads a JPEG image scaled to 1/4 size.
  IJL_JFILE_READONEQUARTER = 16
  IJL_JBUFF_READONEQUARTER = 17
    
  ' Reads a JPEG image scaled to 1/8 size.
  IJL_JFILE_READONEEIGHTH = 18
  IJL_JBUFF_READONEEIGHTH = 19
    
  ' Reads an embedded thumbnail from a JFIF bit stream.
  IJL_JFILE_READTHUMBNAIL = 20
  IJL_JBUFF_READTHUMBNAIL = 21
End Enum


Rem
Rem//////////////////////////////////////////////////////////////////////////
Rem  Name:        IJL_COLOR
Rem
Rem  Purpose:     Possible color space formats.
Rem
Rem  Note these formats do *not* necessarily denote
Rem  the number of channels in the color space.
Rem  There exists separate "channel" fields in the
Rem  JPEG_CORE_PROPERTIES data structure specifically
Rem  for indicating the number of channels in the
Rem  JPEG and/or DIB color spaces.
Rem
Rem  See the Developer's Guide for details on appropriate usage.
Rem
Rem//////////////////////////////////////////////////////////////////////////
Rem

Public Enum IJL_COLOR
  IJL_RGB = 1        ' Red-Green-Blue color space.
  IJL_BGR = 2        ' Reversed channel ordering from IJL_RGB.
  IJL_YCBCR = 3      ' Luminance-Chrominance color space as defined
                     ' by CCIR Recommendation 601.
  IJL_G = 4          ' Grayscale color space.
  IJL_RGBA_FPX = 5   ' FlashPix RGB 4 channel color space that
                     ' has pre-multiplied opacity.
  IJL_YCBCRA_FPX = 6 ' FlashPix YCbCr 4 channel color space that
                     ' has pre-multiplied opacity.
  IJL_OTHER = 255    ' Some other color space not defined by the IJL.
                     ' (This means no color space conversion will be
                     ' done by the IJL.)
End Enum


Rem
Rem//////////////////////////////////////////////////////////////////////////
Rem  Name:        IJL_JPGSUBSAMPLING
Rem
Rem  Purpose:     Possible subsampling formats used in the JPEG.
Rem
Rem               See the Developer's Guide for details on appropriate usage.
Rem
Rem//////////////////////////////////////////////////////////////////////////
Rem

Public Enum IJL_JPGSUBSAMPLING
  IJL_NONE = 0  ' Corresponds to "No Subsampling".
                ' Valid on a JPEG w/ any number of channels.
  IJL_411 = 1   ' Valid on a JPEG w/ 3 channels.
  IJL_422 = 2   ' Valid on a JPEG w/ 3 channels.
  
  IJL_4114 = 3  ' Valid on a JPEG w/ 4 channels.
  IJL_4224 = 4  ' Valid on a JPEG w/ 4 channels.
End Enum


Rem
Rem//////////////////////////////////////////////////////////////////////////
Rem  Name:        IJL_DIBSUBSAMPLING
Rem
Rem  Purpose:     Possible subsampling formats used in the DIB.
Rem
Rem  See the Developer's Guide for details on appropriate usage.
Rem
Rem//////////////////////////////////////////////////////////////////////////
Rem

Public Enum IJL_DIBSUBSAMPLING
  IJL_NONE = 0  ' Corresponds to "No Subsampling".
                ' Valid on a DIB w/ any number of channels.
  IJL_422 = 2   ' Valid on a DIB with YCbYCr color.
  
End Enum


Rem
Rem//////////////////////////////////////////////////////////////////////////
Rem  Name:        HUFFMAN_TABLE
Rem
Rem  Purpose:     Stores Huffman table information in a fast-to-use format.
Rem
Rem  Context:     Used by Huffman encoder/decoder to access Huffman table
Rem               data.  Raw Huffman tables are formatted to fit this
Rem               structure prior to use.
Rem
Rem  Fields:
Rem    huff_class  0 == DC Huffman or lossless table, 1 == AC table.
Rem    ident       Huffman table identifier, 0-3 valid (Extended Baseline).
Rem    huffelem    Huffman elements for codes <= 8 bits long;
Rem                contains both zero run-length and symbol length in bits.
Rem    huffval     Huffman values for codes 9-16 bits in length.
Rem    mincode     Smallest Huffman code of length n.
Rem    maxcode     Largest Huffman code of length n.
Rem    valptr      Starting index into huffval[] for symbols of length k.
Rem
Rem//////////////////////////////////////////////////////////////////////////
Rem

Public Type HUFFMAN_TABLE
  huff_class         As Long
  ident              As Long
  huffelem(0 To 255) As Long
  huffval(0 To 255)  As Integer
  mincode(0 To 16)   As Integer
  maxcode(0 To 17)   As Integer
  valptr(0 To 16)    As Integer
End Type


Rem
Rem//////////////////////////////////////////////////////////////////////////
Rem  Name:        JPEGHuffTable
Rem
Rem  Purpose:     Stores pointers to JPEG-binary spec compliant
Rem               Huffman table information.
Rem
Rem  Context:     Used by interface and table methods to specify encoder
Rem               tables to generate and store JPEG images.
Rem
Rem  Fields:
Rem    bits        Points to number of codes of length i (<=16 supported).
Rem    vals        Value associated with each Huffman code.
Rem    hclass      0 == DC table, 1 == AC table.
Rem    ident       Specifies the identifier for this table.
Rem                0-3 for extended JPEG compliance.
Rem
Rem//////////////////////////////////////////////////////////////////////////
Rem

Public Type JPEGHuffTable
  bits   As Long
  vals   As Long
  hclass As Byte
  ident  As Byte
  ' IJL use 8 byte pack structures
  pad0   As Byte
  pad1   As Byte
End Type


Rem
Rem//////////////////////////////////////////////////////////////////////////
Rem  Name:        QUANT_TABLE
Rem
Rem  Purpose:     Stores quantization table information in a
Rem               fast-to-use format.
Rem
Rem  Context:     Used by quantizer/dequantizer to store formatted
Rem               quantization tables.
Rem
Rem  Fields:
Rem    precision   0 => elements contains 8-bit elements,
Rem                1 => elements contains 16-bit elements.
Rem    ident       Table identifier (0-3).
Rem    elements    Pointer to 64 table elements + 16 extra elements to catch
Rem                input data errors that may cause malfunction of the
Rem                Huffman decoder.
Rem    elarray     Space for elements (see above) plus 8 bytes to align
Rem                to a quadword boundary.
Rem
Rem//////////////////////////////////////////////////////////////////////////
Rem

Public Type QUANT_TABLE
  precision        As Long
  ident            As Long
  elements         As Long
  elarray(0 To 83) As Integer
End Type


Rem
Rem//////////////////////////////////////////////////////////////////////////
Rem  Name:        JPEGQuantTable
Rem
Rem  Purpose:     Stores pointers to JPEG binary spec compliant
Rem               quantization table information.
Rem
Rem  Context:     Used by interface and table methods to specify encoder
Rem               tables to generate and store JPEG images.
Rem
Rem  Fields:
Rem    quantizer   Zig-zag order elements specifying quantization factors.
Rem    ident       Specifies identifier for this table.
Rem                0-3 valid for Extended Baseline JPEG compliance.
Rem
Rem//////////////////////////////////////////////////////////////////////////
Rem

Public Type JPEGQuantTable
  quantizer As Long
  ident     As Byte
  ' IJL use 8 byte pack structures
  pad0      As Byte
  pad1      As Byte
  pad2      As Byte
End Type


Rem
Rem///////////////////////////////////////////////////////////////////////////
Rem  Name:        FRAME_COMPONENT
Rem
Rem  Purpose:     One frame-component structure is allocated per component
Rem               in a frame.
Rem
Rem  Context:     Used by Huffman decoder to manage components.
Rem
Rem  Fields:
Rem    ident       Component identifier.  The tables use this ident to
Rem                determine the correct table for each component.
Rem    hsampling   Horizontal subsampling factor for this component,
Rem                1-4 are legal.
Rem    vsampling   Vertical subsampling factor for this component,
Rem                1-4 are legal.
Rem    quant_sel   Quantization table selector.  The quantization table
Rem                used by this component is determined via this selector.
Rem
Rem//////////////////////////////////////////////////////////////////////////