org.eclipse.birt.report.model.api
Class DimensionHandle

java.lang.Object
  extended by org.eclipse.birt.report.model.api.ElementDetailHandle
      extended by org.eclipse.birt.report.model.api.ValueHandle
          extended by org.eclipse.birt.report.model.api.ComplexValueHandle
              extended by org.eclipse.birt.report.model.api.DimensionHandle

public class DimensionHandle
extends ComplexValueHandle

Simplifies working with dimension properties. A dimension property consists of a measure and a dimension. This handle helps assemble and disassemble dimension property values. The dimension property itself can be either a top-level element property, or the member of a property structure.

Note that this handle cannot translate a dimension property into a physical dimension. BIRT uses the CSS dimension system and requires a CSS User Agent (UA) to compute the physical layout of a report given a report design. These calculations often require context (to compute relative dimensions) and knowledge of item contents to compute the sizes of items that expand to fit their content.

This handle works with individual dimensions, the application-provided UA uses these properties (and information about the overall report design) to produce physical, absolute dimensions.

The application generally does not create dimension handles directly. It uses the method in DesignElementHandle to get a dimension handle. For example:

 DesignElementHandle elementHandle = element.handle( );
 

DimensionHandle dimensionHandle = elementHandle .getDimensionProperty( Style.FONT_SIZE_PROP );

The value of the dimension can be a standard format such as 1pt, 100% etc. This kind of value represents a standard dimension, or it can be a CSS (predefined) value such as XX-SMALL, X-SMALL. The CSS values are defined in DesignChoiceConstants.

See Also:
DesignChoiceConstants

Field Summary
 
Fields inherited from class org.eclipse.birt.report.model.api.ComplexValueHandle
memberRef, propDefn
 
Fields inherited from class org.eclipse.birt.report.model.api.ElementDetailHandle
elementHandle
 
Constructor Summary
DimensionHandle(DesignElementHandle element, org.eclipse.birt.report.model.metadata.ElementPropertyDefn thePropDefn)
          Constructs a dimension handle for a element property.
DimensionHandle(DesignElementHandle element, org.eclipse.birt.report.model.core.MemberRef memberRef)
          Constructs a dimension handle for a member of a structure.
 
Method Summary
 DimensionValue getAbsoluteValue()
          Returns the absolute dimension value with the following units.
 IChoice[] getAllowedUnits()
          Returns an array of allowed units.
 java.lang.String getDefaultUnit()
          Gets the default unit of the property.
 double getMeasure()
          Returns the numeric measure part of the dimension.
 java.lang.String getUnits()
          Returns the code for the units portion of the dimension.
 boolean isKeyword()
          Determines if the dimension is given by a standard format or by a pre-defined constant.
 void setAbsolute(double value)
          Sets the value of a dimension in default units.
 
Methods inherited from class org.eclipse.birt.report.model.api.ComplexValueHandle
getDefn, getDisplayValue, getPropertyDefn, getReference, getStringValue, getValue, isSet, setStringValue, setValue
 
Methods inherited from class org.eclipse.birt.report.model.api.ElementDetailHandle
getDesign, getElement, getElementHandle, getModule
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

DimensionHandle

public DimensionHandle(DesignElementHandle element,
                       org.eclipse.birt.report.model.core.MemberRef memberRef)
Constructs a dimension handle for a member of a structure. This member must be a dimension type.

Parameters:
element - the design element handle
memberRef - the memberRef for the member property

DimensionHandle

public DimensionHandle(DesignElementHandle element,
                       org.eclipse.birt.report.model.metadata.ElementPropertyDefn thePropDefn)
Constructs a dimension handle for a element property. This property must be a dimension type.

Parameters:
element - handle to the element that defined the property.
thePropDefn - definition of the dimension property.
Method Detail

isKeyword

public boolean isKeyword()
Determines if the dimension is given by a standard format or by a pre-defined constant.

Returns:
true if the dimension is given by an pre-defined constant false if the dimension is given by a standard dimension.

getMeasure

public double getMeasure()
Returns the numeric measure part of the dimension. For example, if the dimension value is "2.3cm", the measure is 2.3.

Returns:
the numeric measure of the dimension, return 0.0 if the dimension from an choice.

getAllowedUnits

public IChoice[] getAllowedUnits()
Returns an array of allowed units. The set of allowed units depends on context, not all properties allow all units.

Returns:
an array of allowed unit suffixes. Each suffix is a string.

getUnits

public java.lang.String getUnits()
Returns the code for the units portion of the dimension. For example, if the dimension value is "2.3cm", then the unit is "cm".

Returns:
the units portion of the dimension. Return DimensionValue.DEFAULT_UNIT if the dimension is a predefined constant.

setAbsolute

public void setAbsolute(double value)
                 throws SemanticException
Sets the value of a dimension in default units. The default unit may be defined by the property in BIRT or the application unit defined in the design session.

Parameters:
value - the new value in application units.
Throws:
SemanticException - if the property is locked

getAbsoluteValue

public DimensionValue getAbsoluteValue()
Returns the absolute dimension value with the following units. This method tries to get the absolute value for absolute font size constants with IAbsoluteFontSizeValueProvider. Only the value of CSS property of the element which is not style is handled here. null is returned if this dimension is not CSS style property.

CSS 2.1 specification has the following statements:

Child elements do not inherit the relative values specified for their parent; they inherit the computed values.

Example(s):

In the following rules, the computed 'text-indent' value of "h1" elements will be 36px, not 45px, if "h1" is a child of the "body" element.

body { font-size: 12px; text-indent: 3em; /* i.e., 36px}}

h1 { font-size: 15px }

So when computing the value of text-indent, with this method, the value of font-size is retrieved from body, instead of h1.

Returns:
the absolute dimension value.

getDefaultUnit

public java.lang.String getDefaultUnit()
Gets the default unit of the property.

Returns:
the default unit


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