org.alfresco.repo.rendition.executer
Class ImageRenderingEngine

java.lang.Object
  extended by org.alfresco.repo.action.CommonResourceAbstractBase
      extended by org.alfresco.repo.action.ParameterizedItemAbstractBase
          extended by org.alfresco.repo.action.executer.ActionExecuterAbstractBase
              extended by org.alfresco.repo.rendition.executer.AbstractRenderingEngine
                  extended by org.alfresco.repo.rendition.executer.AbstractTransformationRenderingEngine
                      extended by org.alfresco.repo.rendition.executer.ImageRenderingEngine
All Implemented Interfaces:
ActionExecuter, org.springframework.beans.factory.BeanNameAware

public class ImageRenderingEngine
extends AbstractTransformationRenderingEngine

This class is the implementation of the RenditionService's "imageRenderingEngine" rendering engine. This action renders a piece of content in the same MIME type as its source node, having been rescaled as requested.

Since:
3.3

Nested Class Summary
 
Nested classes/interfaces inherited from class org.alfresco.repo.rendition.executer.AbstractRenderingEngine
AbstractRenderingEngine.RenderingContext
 
Field Summary
static java.lang.String NAME
           
static java.lang.String PARAM_ALLOW_ENLARGEMENT
          This optional Boolean flag parameter specifies whether image resizing should produce an enlarged image, based on the resizing parameters and the size of the original image.
static java.lang.String PARAM_COMMAND_OPTIONS
          This optional String parameter specifies any additional ImageMagick commands, that the user wishes to add.
static java.lang.String PARAM_CROP_GRAVITY
          This optional String parameter determines the 'zero' position from which offsets are measured and also determines the direction of offsets.
static java.lang.String PARAM_CROP_HEIGHT
          This optional Integer or Float parameter specifies the height of the image after cropping.
static java.lang.String PARAM_CROP_WIDTH
          This optional Integer or Float parameter specifies the width of the image after cropping.
static java.lang.String PARAM_CROP_X_OFFSET
          This optional Integer parameter specifies the horizontal position of the start point of the area to be cropped.
static java.lang.String PARAM_CROP_Y_OFFSET
          This optional Integer parameter specifies the vertical position of the start point of the area to be cropped.
static java.lang.String PARAM_IS_PERCENT_CROP
          This optional Boolean flag parameter specifies how the PARAM_CROP_HEIGHT and PARAM_CROP_WIDTH parameters are interpreted.
static java.lang.String PARAM_IS_PERCENT_RESIZE
          This optional Boolean flag parameter specifies how the PARAM_RESIZE_HEIGHT and PARAM_RESIZE_WIDTH parameters are interpreted.
static java.lang.String PARAM_MAINTAIN_ASPECT_RATIO
          This optional Boolean flag parameter determines whether the rendered image maintains its original aspect ratio or is stretched to fit the specified height and width.
static java.lang.String PARAM_RESIZE_HEIGHT
          This optional Integer or Float parameter specifies the height of the image after resizing.
static java.lang.String PARAM_RESIZE_TO_THUMBNAIL
          This optional Boolean flag parameter specifies a mode for dramatically shrinking large images in a performant way.
If set to true the rendering process will be more performant for large images but the rendered image will be of lower quality.
static java.lang.String PARAM_RESIZE_WIDTH
          This optional Integer or Float parameter specifies the width of the image after resizing.
 
Fields inherited from class org.alfresco.repo.rendition.executer.AbstractRenderingEngine
CONTENT_READER_NOT_FOUND_MESSAGE, contentService, mimetypeMap, nodeService, PARAM_ENCODING, PARAM_MIME_TYPE, PARAM_PLACEHOLDER_RESOURCE_PATH, PARAM_RUN_AS, PARAM_SOURCE_CONTENT_PROPERTY, PARAM_TARGET_CONTENT_PROPERTY, PARAM_UPDATE_RENDITIONS_ON_ANY_PROPERTY_CHANGE
 
Fields inherited from class org.alfresco.repo.action.executer.ActionExecuterAbstractBase
actionDefinition, applicableTypes, publicAction
 
Fields inherited from class org.alfresco.repo.action.ParameterizedItemAbstractBase
DISPLAY_LABEL, runtimeActionService
 
Fields inherited from class org.alfresco.repo.action.CommonResourceAbstractBase
name
 
Fields inherited from interface org.alfresco.repo.action.executer.ActionExecuter
PARAM_RESULT
 
Constructor Summary
ImageRenderingEngine()
           
 
Method Summary
protected  void checkParameterValues(Action action)
          This method can be overridden by subclasses to provide checking of parameter values.
protected  java.util.Collection getParameterDefinitions()
          Supplies the list of parameters required by this rendering engine.
protected  java.lang.String getTargetMimeType(AbstractRenderingEngine.RenderingContext context)
           
protected  TransformationOptions getTransformOptions(AbstractRenderingEngine.RenderingContext context)
           
 
Methods inherited from class org.alfresco.repo.rendition.executer.AbstractTransformationRenderingEngine
render
 
Methods inherited from class org.alfresco.repo.rendition.executer.AbstractRenderingEngine
addParameterDefinitions, checkActionIsRenditionDefinition, checkSourceNodeExists, createActionDefinition, executeImpl, executeImpl, executeRenditionImpl, getCheckedParam, getDefaultRenditionContentProp, getDefaultRenditionNodeType, getParamDisplayLabel, getParamWithDefault, getRenditionContentProperty, getTargetEncoding, notifyCallbackOfException, notifyCallbackOfResult, resolveRenditionLocation, setBehaviourFilter, setContentService, setDefaultRenditionContentProp, setDefaultRenditionNodeType, setMimetypeMap, setNodeService, setRenditionLocationResolver, setRenditionService, switchToFinalRenditionNode, tagSourceNodeAsRenditioned, throwWrappedException
 
Methods inherited from class org.alfresco.repo.action.executer.ActionExecuterAbstractBase
execute, getActionDefinition, getIgnoreLock, getQueueName, getTrackStatus, init, setApplicableTypes, setBaseNodeService, setIgnoreLock, setLockService, setPublicAction, setQueueName, setTrackStatus
 
Methods inherited from class org.alfresco.repo.action.ParameterizedItemAbstractBase
checkMandatoryProperties, getAdhocPropertiesAllowed, getDescriptionKey, getParameterDefintions, getTitleKey, setRuntimeActionService, toString
 
Methods inherited from class org.alfresco.repo.action.CommonResourceAbstractBase
setBeanName
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

NAME

public static final java.lang.String NAME
See Also:
Constant Field Values

PARAM_RESIZE_WIDTH

public static final java.lang.String PARAM_RESIZE_WIDTH
This optional Integer or Float parameter specifies the width of the image after resizing. This may be expressed as pixels or it may represent a percentage of the original image width, depending on the value of the PARAM_IS_PERCENT_RESIZE parameter.
If no value is specified for this parameter then the width of the image will be unchanged.
If an image is being cropped and resized then the cropping happens first, followed by resizing of the cropped image.

See Also:
Constant Field Values

PARAM_RESIZE_HEIGHT

public static final java.lang.String PARAM_RESIZE_HEIGHT
This optional Integer or Float parameter specifies the height of the image after resizing. This may be expressed as pixels or it may represent a percentage of the original image width, depending on the value of the PARAM_IS_PERCENT_RESIZE parameter.
If no value is specified for this parameter then the height of the image will be unchanged.
If an image is being cropped and resized then the cropping happens first, followed by resizing of the cropped image.

See Also:
Constant Field Values

PARAM_IS_PERCENT_RESIZE

public static final java.lang.String PARAM_IS_PERCENT_RESIZE
This optional Boolean flag parameter specifies how the PARAM_RESIZE_HEIGHT and PARAM_RESIZE_WIDTH parameters are interpreted. If this parameter is set to true then the rendition height and width are represented as a percentage of the original image height and width. If this parameter is set to false then the rendition height and width are represented as pixels. This parameter defaults to false.

See Also:
Constant Field Values

PARAM_MAINTAIN_ASPECT_RATIO

public static final java.lang.String PARAM_MAINTAIN_ASPECT_RATIO
This optional Boolean flag parameter determines whether the rendered image maintains its original aspect ratio or is stretched to fit the specified height and width.
If this parameter is true then the rendered image will always maintain its aspect ratio and will be resized to best fit within the given width and height. For example if an image starts at 100x200 pixels and it is resized to 50x50 pixels then the rendered image will actually be 25x50 pixels.
If this parameter is false then the image will be stretched or compressed to fit the given height and width, regardless of the original aspect ratio.
This parameter defaults to false

See Also:
Constant Field Values

PARAM_RESIZE_TO_THUMBNAIL

public static final java.lang.String PARAM_RESIZE_TO_THUMBNAIL
This optional Boolean flag parameter specifies a mode for dramatically shrinking large images in a performant way.
If set to true the rendering process will be more performant for large images but the rendered image will be of lower quality.
If set to false the rendering process will take longer but the resulting image will usually be of better quality.

See Also:
Constant Field Values

PARAM_ALLOW_ENLARGEMENT

public static final java.lang.String PARAM_ALLOW_ENLARGEMENT
This optional Boolean flag parameter specifies whether image resizing should produce an enlarged image, based on the resizing parameters and the size of the original image. If true (the default), images may be enlarged. If false, resize operations that would enlarge the image will instead produce a copy of the original image at the same size.

Since:
4.0
See Also:
Constant Field Values

PARAM_CROP_WIDTH

public static final java.lang.String PARAM_CROP_WIDTH
This optional Integer or Float parameter specifies the width of the image after cropping. This may be expressed as pixels or it may represent a percentage of the original image width, depending on the value of the PARAM_IS_PERCENT_CROP parameter.
If no value is specified for this parameter then the width of the image will be unchanged.
If an image is being cropped and resized then the cropping happens first, followed by resizing of the cropped image.

See Also:
Constant Field Values

PARAM_CROP_HEIGHT

public static final java.lang.String PARAM_CROP_HEIGHT
This optional Integer or Float parameter specifies the height of the image after cropping. This may be expressed as pixels or it may represent a percentage of the original image width, depending on the value of the PARAM_IS_PERCENT_CROP parameter.
If no value is specified for this parameter then the width of the image will be unchanged.
If an image is being cropped and resized then the cropping happens first, followed by resizing of the cropped image.

See Also:
Constant Field Values

PARAM_CROP_X_OFFSET

public static final java.lang.String PARAM_CROP_X_OFFSET
This optional Integer parameter specifies the horizontal position of the start point of the area to be cropped. By default this parameter sets the distance, in pixels, from the left-hand edge of the image to the start position of the crop area. By default a positive value will shift the start-position to the right, while a negative value will shift the start position to the left. Setting the PARAM_CROP_GRAVITY parameter may change this, however.
If this parameter is not set it is assumed to be 0.

See Also:
Constant Field Values

PARAM_CROP_Y_OFFSET

public static final java.lang.String PARAM_CROP_Y_OFFSET
This optional Integer parameter specifies the vertical position of the start point of the area to be cropped. By default this parameter sets the distance, in pixels, from the top edge of the image to the start position of the crop area. By default a positive value will shift the start-position downwards, while a negative value will shift the start position upwards. Setting the PARAM_CROP_GRAVITY parameter may change this, however.
If this parameter is not set it is assumed to be 0.

See Also:
Constant Field Values

PARAM_CROP_GRAVITY

public static final java.lang.String PARAM_CROP_GRAVITY
This optional String parameter determines the 'zero' position from which offsets are measured and also determines the direction of offsets. The allowed values of gravity are the four cardinal points (North, East, etc.), the four ordinal points (NorhtWest, SouthEast, etc) and Center. By default NorthWest gravity is used.

If an ordinal gravity is set then the point from which offsets originate will be the appropriate corner. For example, NorthWest gravity would originate at teh top-left corner while SouthWest origin would originate at the bottom-left corner. Cardinal gravity sets the origin at the center of the appropriate edge. Center origin sets the origin at the center of the image.

Gravity also affects the direction of offsets and how the offset position relates to the cropped image. For example, NorthWest gravity sets positive horizontal offset direction to right, positive vertical direction to down and sets the cropped image origin to the top-left corner. Northerly gavities set the positive vertical direction to down. Southerly gavities set teh positive vertical direction to up. Easterly gavities set teh positive horizontal positive direction to left. Westerly gavities set teh positive horizontal positive direction to right.

Some gravity values do not specify a horizontal or a vertical direction explicitly. For example North does not specify a horizontal direction, while Center does not specify either horizontal or vertical direction. In thse cases the positive horizontal offset direction is always right and the positive vertical offset direction is always down.

The gravity also affects how the cropped image relates to the offset position. For example, NorthWest gravity causes the top-left corner of the cropped area to be the offset position, while NorthEast gravity would set the top-right corner of the cropped are to the offset position. When a direction is not explicitly specified then the center of the cropped area is placed at the offset position. For example, with North gravity the horizontal position is unspecified so the cropped area would be horizontally centered on the offset position, but the top edge of the cropped area would be at the offset position. For Center gravity the cropped area will be centered over the offset position both horizontally and vertically.

See Also:
Constant Field Values

PARAM_IS_PERCENT_CROP

public static final java.lang.String PARAM_IS_PERCENT_CROP
This optional Boolean flag parameter specifies how the PARAM_CROP_HEIGHT and PARAM_CROP_WIDTH parameters are interpreted. If this parameter is set to true then the cropped image height and width are represented as a percentage of the original image height and width. If this parameter is set to false then the rendition height and width are represented as pixels. This parameter defaults to false.

See Also:
Constant Field Values

PARAM_COMMAND_OPTIONS

public static final java.lang.String PARAM_COMMAND_OPTIONS
This optional String parameter specifies any additional ImageMagick commands, that the user wishes to add. These commands are appended after the various crop and resize options.

See Also:
Constant Field Values
Constructor Detail

ImageRenderingEngine

public ImageRenderingEngine()
Method Detail

getTransformOptions

protected TransformationOptions getTransformOptions(AbstractRenderingEngine.RenderingContext context)
Specified by:
getTransformOptions in class AbstractTransformationRenderingEngine

getTargetMimeType

protected java.lang.String getTargetMimeType(AbstractRenderingEngine.RenderingContext context)
Overrides:
getTargetMimeType in class AbstractRenderingEngine

checkParameterValues

protected void checkParameterValues(Action action)
Description copied from class: AbstractRenderingEngine
This method can be overridden by subclasses to provide checking of parameter values. If a parameter value is illegal or inappropriate, an exception should be thrown.

Overrides:
checkParameterValues in class AbstractRenderingEngine

getParameterDefinitions

protected java.util.Collection getParameterDefinitions()
Description copied from class: AbstractRenderingEngine
Supplies the list of parameters required by this rendering engine.

Overrides:
getParameterDefinitions in class AbstractRenderingEngine
Returns:


Copyright © 2005 - 2010 Alfresco Software, Inc. All Rights Reserved.