Class BMPImageWriteParam

java.lang.Object
javax.imageio.IIOParam
javax.imageio.ImageWriteParam
com.github.jaiimageio.plugins.bmp.BMPImageWriteParam

public class BMPImageWriteParam extends ImageWriteParam
A subclass of ImageWriteParam for encoding images in the BMP format.

This class allows for the specification of various parameters while writing a BMP format image file. By default, the data layout is bottom-up, such that the pixels are stored in bottom-up order, the first scanline being stored last.

The particular compression scheme to be used can be specified by using the setCompressionType() method with the appropriate type string. The compression scheme specified will be honored if and only if it is compatible with the type of image being written. If the specified compression scheme is not compatible with the type of image being written then the IOException will be thrown by the BMP image writer. If the compression type is not set explicitly then getCompressionType() will return null. In this case the BMP image writer will select a compression type that supports encoding of the given image without loss of the color resolution.

The compression type strings and the image type(s) each supports are listed in the following table:

Compression Types
Type String Description Image Types
BI_RGB Uncompressed RLE invalid input: '<'= 8-bits/sample
BI_RLE8 8-bit Run Length Encoding invalid input: '<'= 8-bits/sample
BI_RLE4 4-bit Run Length Encoding invalid input: '<'= 4-bits/sample
BI_BITFIELDS Packed data 16 or 32 bits/sample
BI_JPEG JPEG encoded grayscale or RGB image

When BI_BITFIELDS is used, if the image encoded has a DirectColorModel, the bit mask in the color model will be written into the stream. Otherwise, only 5-5-5 16-bit image or 8-8-8 32-bit images are supported.

  • Field Details

    • VERSION_2

      public static final int VERSION_2
      Deprecated.
      Constant for BMP version 2.
      See Also:
    • VERSION_3

      public static final int VERSION_3
      Deprecated.
      Constant for BMP version 3.
      See Also:
    • VERSION_4

      public static final int VERSION_4
      Deprecated.
      Constant for BMP version 4.
      See Also:
    • VERSION_5

      public static final int VERSION_5
      Deprecated.
      Constant for BMP version 5.
      See Also:
    • topDown

      private boolean topDown
  • Constructor Details

    • BMPImageWriteParam

      public BMPImageWriteParam(Locale locale)
      Constructs a BMPImageWriteParam set to use a given Locale and with default values for all parameters.
      Parameters:
      locale - a Locale to be used to localize compression type names and quality descriptions, or null.
    • BMPImageWriteParam

      public BMPImageWriteParam()
      Constructs an BMPImageWriteParam object with default values for all parameters and a null Locale.
  • Method Details

    • getVersion

      public int getVersion()
      Deprecated.
      Returns the BMP version to be used. The default is VERSION_3.
      Returns:
      the BMP version number.
    • setTopDown

      public void setTopDown(boolean topDown)
      If set, the data will be written out in a top-down manner, the first scanline being written first. Any compression other than BI_RGB or BI_BITFIELDS is incompatible with the data being written in top-down order. Setting the topDown argument to true will be honored only when the compression type at the time of writing the image is one of the two mentioned above. Otherwise, the topDown setting will be ignored.
      Parameters:
      topDown - whether the data are written in top-down order.
    • isTopDown

      public boolean isTopDown()
      Returns the value of the topDown parameter. The default is false.
      Returns:
      whether the data are written in top-down order.
    • setCompressionType

      public void setCompressionType(String compressionType)
      Sets the compression type to one of the values indicated by getCompressionTypes. If a value of null is passed in, any previous setting is removed.

      The method first invokes

      invalid @link
      {@link javax.imageio.ImageWriteParam.#setCompressionType(String)
      setCompressionType()} with the supplied value of compressionType. Next, if isTopDown() returns true and the value of compressionType is incompatible with top-down order, setTopDown(boolean) is invoked with parameter topDown set to false. The image will then be written in bottom-up order with the specified compressionType.

      Overrides:
      setCompressionType in class ImageWriteParam
      Parameters:
      compressionType - one of the Strings returned by getCompressionTypes, or null to remove any previous setting.
      Throws:
      UnsupportedOperationException - if the writer does not support compression.
      IllegalStateException - if the compression mode is not MODE_EXPLICIT.
      UnsupportedOperationException - if there are no settable compression types.
      IllegalArgumentException - if compressionType is non-null but is not one of the values returned by getCompressionTypes.
      See Also: