Package com.twelvemonkeys.servlet.image

Interface ImageServletResponse

  • All Superinterfaces:
    javax.servlet.ServletResponse
    public interface ImageServletResponse
extends javax.servlet.ServletResponse
    ImageServletResponse.

    The request attributes regarding image size and source region (AOI) are used in the decoding process, and must be set before the first invocation of getImage() to have any effect.

    Version:
    $Id: ImageServletResponse.java#4 $
    Author:
    Harald Kuhr

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static java.lang.String ATTRIB_AOI
      Request attribute of type Rectangle controlling image source region (area of interest).
      static java.lang.String ATTRIB_AOI_PERCENT
      Request attribute of type Boolean controlling image AOI.
      static java.lang.String ATTRIB_AOI_UNIFORM
      Request attribute of type Boolean controlling image AOI.
      static java.lang.String ATTRIB_BG_COLOR
      Request attribute of type Color controlling background color for any transparent/translucent areas of the image.
      static java.lang.String ATTRIB_IMAGE_RESAMPLE_ALGORITHM
      Request attribute of type Integer controlling image resample algorithm.
      static java.lang.String ATTRIB_OUTPUT_QUALITY
      Request attribute of type Float controlling image output compression/quality.
      static java.lang.String ATTRIB_READ_SUBSAMPLING_FACTOR
      Request attribute of type Double controlling image read subsampling factor.
      static java.lang.String ATTRIB_SIZE
      Request attribute of type Dimension controlling image size.
      static java.lang.String ATTRIB_SIZE_PERCENT
      Request attribute of type Boolean controlling image sizing.
      static java.lang.String ATTRIB_SIZE_UNIFORM
      Request attribute of type Boolean controlling image sizing.

    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      void flush()
      Writes the image to the original ServletOutputStream.
      java.awt.image.BufferedImage getImage()
      Gets the decoded image from the response.
      java.lang.String getOutputContentType()
      Gets the image format for this response, such as "image/gif" or "image/jpeg".
      void setImage​(java.awt.image.RenderedImage pImage)
      Sets the image for this response.
      void setOutputContentType​(java.lang.String pImageFormat)
      Sets the image format for this response, such as "image/gif" or "image/jpeg".

      • Methods inherited from interface javax.servlet.ServletResponse

        flushBuffer, getBufferSize, getCharacterEncoding, getContentType, getLocale, getOutputStream, getWriter, isCommitted, reset, resetBuffer, setBufferSize, setCharacterEncoding, setContentLength, setContentLengthLong, setContentType, setLocale

    • Field Detail

      • ATTRIB_SIZE

        static final java.lang.String ATTRIB_SIZE
        Request attribute of type Dimension controlling image size. If either width or height is negative, the size is computed, using uniform scaling. Else, if SIZE_UNIFORM is true, the size will be computed to the largest possible area (with correct aspect ratio) fitting inside the target area. Otherwise, the image is scaled to the given size, with no regard to aspect ratio.

        Defaults to null (original image size).

        See Also:
        Constant Field Values

      • ATTRIB_SIZE_UNIFORM

        static final java.lang.String ATTRIB_SIZE_UNIFORM
        Request attribute of type Boolean controlling image sizing.

        Defaults to Boolean.TRUE.

        See Also:
        Constant Field Values

      • ATTRIB_SIZE_PERCENT

        static final java.lang.String ATTRIB_SIZE_PERCENT
        Request attribute of type Boolean controlling image sizing.

        Defaults to Boolean.FALSE.

        See Also:
        Constant Field Values

      • ATTRIB_AOI

        static final java.lang.String ATTRIB_AOI
        Request attribute of type Rectangle controlling image source region (area of interest).

        Defaults to null (the entire image).

        See Also:
        Constant Field Values

      • ATTRIB_AOI_UNIFORM

        static final java.lang.String ATTRIB_AOI_UNIFORM
        Request attribute of type Boolean controlling image AOI.

        Defaults to Boolean.FALSE.

        See Also:
        Constant Field Values

      • ATTRIB_AOI_PERCENT

        static final java.lang.String ATTRIB_AOI_PERCENT
        Request attribute of type Boolean controlling image AOI.

        Defaults to Boolean.FALSE.

        See Also:
        Constant Field Values

      • ATTRIB_BG_COLOR

        static final java.lang.String ATTRIB_BG_COLOR
        Request attribute of type Color controlling background color for any transparent/translucent areas of the image.

        Defaults to null (keeps the transparent areas transparent).

        See Also:
        Constant Field Values

      • ATTRIB_OUTPUT_QUALITY

        static final java.lang.String ATTRIB_OUTPUT_QUALITY
        Request attribute of type Float controlling image output compression/quality. Used for formats that accepts compression or quality settings, like JPEG (quality), PNG (compression only) etc.

        Defaults to 0.8f for JPEG.

        See Also:
        Constant Field Values

      • ATTRIB_READ_SUBSAMPLING_FACTOR

        static final java.lang.String ATTRIB_READ_SUBSAMPLING_FACTOR
        Request attribute of type Double controlling image read subsampling factor. Controls the maximum sample pixels in each direction, that is read per pixel in the output image, if the result will be downscaled. Larger values will result in better quality, at the expense of higher memory consumption and CPU usage. However, using values above 3.0 will usually not improve image quality. Legal values are in the range [1.0 .. positive infinity>.

        Defaults to 2.0.

        See Also:
        Constant Field Values

      • ATTRIB_IMAGE_RESAMPLE_ALGORITHM

        static final java.lang.String ATTRIB_IMAGE_RESAMPLE_ALGORITHM
        Request attribute of type Integer controlling image resample algorithm. Legal values are SCALE_DEFAULT, SCALE_FAST or SCALE_SMOOTH.

        Note: When using a value of SCALE_FAST, you should also use a subsampling factor of 1.0, for fast read/scale. Otherwise, use a subsampling factor of 2.0 for better quality.

        Defaults to SCALE_DEFAULT.

        See Also:
        Constant Field Values

    • Method Detail

      • getOutputContentType

        java.lang.String getOutputContentType()
        Gets the image format for this response, such as "image/gif" or "image/jpeg". If not set, the default format is that of the original image.
        Returns:
        the image format for this response.
        See Also:
        setOutputContentType(String)

      • setOutputContentType

        void setOutputContentType​(java.lang.String pImageFormat)
        Sets the image format for this response, such as "image/gif" or "image/jpeg".

        As an example, a custom filter could do content negotiation based on the request header fields and write the image back in an appropriate format.

        If not set, the default format is that of the original image.

        Parameters:
        pImageFormat - the image format for this response.

      • flush

        void flush()
    throws java.io.IOException
        Writes the image to the original ServletOutputStream. If no format is set in this response, the image is encoded in the same format as the original image.
        Throws:
        java.io.IOException - if an I/O exception occurs during writing

      • getImage

        java.awt.image.BufferedImage getImage()
                               throws java.io.IOException
        Gets the decoded image from the response.
        Returns:
        a BufferedImage or null if the image could not be read.
        Throws:
        java.io.IOException - if an I/O exception occurs during reading

      • setImage

        void setImage​(java.awt.image.RenderedImage pImage)
        Sets the image for this response.
        Parameters:
        pImage - the new response image.