Class 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( );
     <p>
     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
    • Constructor Detail

      • DimensionHandle

        public DimensionHandle​(DesignElementHandle element,
                               org.eclipse.birt.report.model.core.StructureContext context)
        Constructs a dimension handle for a member of a structure. This member must be a dimension type.
        Parameters:
        element - the design element handle
        context - the context for the member property
      • DimensionHandle

        @Deprecated
        public DimensionHandle​(DesignElementHandle element,
                               org.eclipse.birt.report.model.core.MemberRef context)
        Deprecated.
        Constructs a dimension handle for a member of a structure. This member must be a dimension type.
        Parameters:
        element - the design element handle
        context - the context 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.
        • UNITS_IN
        • UNITS_CM
        • UNITS_MM
        • UNITS_PT
        • UNITS_PC
        • UNITS_PX
        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