ScaleFilter (TwelveMonkeys :: Servlet 3.3.2 API)

java.lang.Object
- com.twelvemonkeys.servlet.GenericFilter
- - com.twelvemonkeys.servlet.image.ImageFilter
  - - com.twelvemonkeys.servlet.image.ScaleFilter

All Implemented Interfaces:

Serializable, javax.servlet.Filter, javax.servlet.FilterConfig

Direct Known Subclasses:

CropFilter
```
public class ScaleFilter
extends ImageFilter
```
This filter renders a scaled version of an image read from a given URL. The image can be output as a GIF, JPEG or PNG image or similar.

Parameters:

scaleX

integer, the new width of the image.
scaleY

integer, the new height of the image.
scaleUniform

boolean, wether or not uniform scalnig should be used. Default is true.
scaleUnits

string, one of PIXELS, PERCENT. PIXELS is default.
scaleQuality

string, one of SCALE_SMOOTH, SCALE_FAST, SCALE_REPLICATE, SCALE_AREA_AVERAGING. SCALE_DEFAULT is default (see Image.getScaledInstance(int,int,int), Image for more details).

Version:

$Id: ScaleFilter.java#1 $

Author:

Harald Kuhr, last modified by $Author: haku $

See Also:

Serialized Form

Field Summary

Fields
Modifier and Type	Field and Description
`protected int`	`defaultScaleQuality`
`protected static String`	`PARAM_IMAGE` `image`
`protected static String`	`PARAM_SCALE_QUALITY` `scaleQuality`
`protected static String`	`PARAM_SCALE_UNIFORM` `scaleUniform`
`protected static String`	`PARAM_SCALE_UNITS` `scaleUnits`
`protected static String`	`PARAM_SCALE_X` `scaleX`
`protected static String`	`PARAM_SCALE_Y` `scaleY`
`static int`	`UNITS_PERCENT` Width and height are percentage of original width and height.
`static int`	`UNITS_PIXELS` Width and height are absolute pixels.
`static int`	`UNITS_UNKNOWN` Unknown units.

Fields inherited from class com.twelvemonkeys.servlet.image.ImageFilter
triggerParams

Fields inherited from class com.twelvemonkeys.servlet.GenericFilter
oncePerRequest

Constructor Summary

Constructors
Constructor and Description

ScaleFilter()

Constructors
Constructor and Description
`ScaleFilter()`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`protected RenderedImage`	`doFilter(BufferedImage pImage, javax.servlet.ServletRequest pRequest, ImageServletResponse pResponse)` Reads the image from the requested URL, scales it, and returns it in the Servlet stream.
`protected Dimension`	`getDimensions(Image pImage, int pWidth, int pHeight, int pUnits, boolean pUniformScale)` Gets the dimensions (height and width) of the scaled image.
`protected int`	`getQuality(String pQualityStr)` Gets the quality constant for the scaling, from the string argument.
`protected int`	`getUnits(String pUnitStr)` Gets the units constant for the width and height arguments, from the given string argument.
`void`	`setDefaultScaleQuality(String pDefaultScaleQuality)`

Methods inherited from class com.twelvemonkeys.servlet.image.ImageFilter
doFilterImpl, setTriggerParams, trigger

Methods inherited from class com.twelvemonkeys.servlet.GenericFilter
destroy, doFilter, getFilterConfig, getFilterName, getInitParameter, getInitParameterNames, getServletContext, init, init, log, log, setFilterConfig, setOncePerRequest

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - UNITS_PIXELS
```
public static final int UNITS_PIXELS
```
    Width and height are absolute pixels. The default.
    
    See Also:
    
    Constant Field Values
  - UNITS_PERCENT
```
public static final int UNITS_PERCENT
```
    Width and height are percentage of original width and height.
    
    See Also:
    
    Constant Field Values
  - UNITS_UNKNOWN
```
public static final int UNITS_UNKNOWN
```
    Unknown units.
    
    See Also:
    
    Constant Field Values
  - PARAM_SCALE_QUALITY
```
protected static final String PARAM_SCALE_QUALITY
```
    scaleQuality
    
    See Also:
    
    Constant Field Values
  - PARAM_SCALE_UNITS
```
protected static final String PARAM_SCALE_UNITS
```
    scaleUnits
    
    See Also:
    
    Constant Field Values
  - PARAM_SCALE_UNIFORM
```
protected static final String PARAM_SCALE_UNIFORM
```
    scaleUniform
    
    See Also:
    
    Constant Field Values
  - PARAM_SCALE_X
```
protected static final String PARAM_SCALE_X
```
    scaleX
    
    See Also:
    
    Constant Field Values
  - PARAM_SCALE_Y
```
protected static final String PARAM_SCALE_Y
```
    scaleY
    
    See Also:
    
    Constant Field Values
  - PARAM_IMAGE
```
protected static final String PARAM_IMAGE
```
    image
    
    See Also:
    
    Constant Field Values
  - defaultScaleQuality
```
protected int defaultScaleQuality
```
- Constructor Detail
  - ScaleFilter
```
public ScaleFilter()
```
- Method Detail
  - doFilter
```
protected RenderedImage doFilter(BufferedImage pImage,
                                 javax.servlet.ServletRequest pRequest,
                                 ImageServletResponse pResponse)
```
    Reads the image from the requested URL, scales it, and returns it in the Servlet stream. See above for details on parameters.
    
    Specified by:
    
    doFilter in class ImageFilter
    
    Parameters:
    
    pImage - the image to filter
    
    pRequest - the servlet request
    
    pResponse - the servlet response
    
    Returns:
    
    the filtered image
  - getQuality
```
protected int getQuality(String pQualityStr)
```
    Gets the quality constant for the scaling, from the string argument.
    
    Parameters:
    
    pQualityStr - The string representation of the scale quality constant.
    
    Returns:
    
    The matching quality constant, or the default quality if none was found.
    
    See Also:
    
    Image, Image.getScaledInstance(int,int,int)
  - setDefaultScaleQuality
```
public void setDefaultScaleQuality(String pDefaultScaleQuality)
```
  - getUnits
```
protected int getUnits(String pUnitStr)
```
    Gets the units constant for the width and height arguments, from the given string argument.
    
    Parameters:
    
    pUnitStr - The string representation of the units constant, can be one of "PIXELS" or "PERCENT".
    
    Returns:
    
    The mathcing units constant, or UNITS_UNKNOWN if none was found.
  - getDimensions
```
protected Dimension getDimensions(Image pImage,
                                  int pWidth,
                                  int pHeight,
                                  int pUnits,
                                  boolean pUniformScale)
```
    Gets the dimensions (height and width) of the scaled image. The dimensions are computed based on the old image's dimensions, the units used for specifying new dimensions and whether or not uniform scaling should be used (se algorithm below).
    
    Parameters:
    
    pImage - the image to be scaled
    
    pWidth - the new width of the image, or -1 if unknown
    
    pHeight - the new height of the image, or -1 if unknown
    
    pUnits - the constant specifying units for width and height parameter (UNITS_PIXELS or UNITS_PERCENT)
    
    pUniformScale - boolean specifying uniform scale or not
    
    Returns:
    
    a Dimension object, with the correct width and heigth in pixels, for the scaled version of the image.

Class ScaleFilter

Field Summary

Fields inherited from class com.twelvemonkeys.servlet.image.ImageFilter

Fields inherited from class com.twelvemonkeys.servlet.GenericFilter

Constructor Summary

Method Summary

Methods inherited from class com.twelvemonkeys.servlet.image.ImageFilter

Methods inherited from class com.twelvemonkeys.servlet.GenericFilter

Methods inherited from class java.lang.Object

Field Detail

UNITS_PIXELS

UNITS_PERCENT

UNITS_UNKNOWN

PARAM_SCALE_QUALITY

PARAM_SCALE_UNITS

PARAM_SCALE_UNIFORM

PARAM_SCALE_X

PARAM_SCALE_Y

PARAM_IMAGE

defaultScaleQuality

Constructor Detail

ScaleFilter

Method Detail

doFilter

getQuality

setDefaultScaleQuality

getUnits

getDimensions