/**
* Convert a measure from one units to another. The application units, target units and base size
* units must be one of the absolute units(CM, IN, MM, PT, PC). The input dimension value must be
* one of the following types:
*
* <ul>
* <li><code>String</code>. It must be a legal dimension value, measure part and units part such
* as '10 em', '+3.5pt', '10%' or only measure part, such as 10.12, 45, +4.
* <li><code>DimensionValue</code>
* <li><code>DimensionHandle</code>
* </ul>
*
* @param value the input dimension value to be converted
* @param appUnits the application units, used as the original units to convert from when units
* part of the input value is empty or null.It must be one of the absolute unit(CM, IN, MM,
* PT, PC).
* @param targetUnits the desired units, it must be one of the absolute unit(CM, IN, MM, PT, PC).
* @param baseSize the base size to convert value with relative units, such as em, ex and %
* @param baseSizeUnits the units for the base size. It must be one of the absolute units(CM, IN,
* MM, PT, PC). By default it is <code>DesignChoiceConstants.UNITS_PT</code>
* @param dpi int value that represents the pixel per inch
* @return double value in the target unit.
*/
public static double convertTo(
Object value,
String appUnits,
String targetUnits,
double baseSize,
String baseSizeUnits,
int dpi) {
if (value == null) return 0.0;
double measure = 0.0;
String fromUnits = ""; // $NON-NLS-1$
// get the measure and unit from the value
if (value instanceof String) {
try {
DimensionValue parsedValue = DimensionValue.parse((String) value);
// the value can not be null
measure = parsedValue.getMeasure();
fromUnits = parsedValue.getUnits();
} catch (PropertyValueException e) {
// TODO: support the font-size choices?
throw new IllegalArgumentException(
"Given string is not well-formatted dimension!"); //$NON-NLS-1$
}
} else if (value instanceof DimensionValue) {
DimensionValue parsedValue = (DimensionValue) value;
measure = parsedValue.getMeasure();
fromUnits = parsedValue.getUnits();
} else if (value instanceof DimensionHandle) {
DimensionHandle dimensionHandle = (DimensionHandle) value;
measure = dimensionHandle.getMeasure();
fromUnits = dimensionHandle.getUnits();
if (StringUtil.isBlank(fromUnits)) fromUnits = dimensionHandle.getDefaultUnit();
}
// not supported value format
else
throw new IllegalArgumentException(
"Given dimension value is a not supported format!"); //$NON-NLS-1$
// if units is null or empty, set it to application unit
if (StringUtil.isBlank(fromUnits)) fromUnits = appUnits;
// if baseSizeUnit is empty or null, set it to 'pt'
if (StringUtil.isBlank(baseSizeUnits)) baseSizeUnits = DesignChoiceConstants.UNITS_PT;
DimensionValue convertedValue = null;
// do some prepare for the relative units
if (DesignChoiceConstants.UNITS_EM.equals(fromUnits)) {
convertedValue = DimensionUtil.convertTo(measure * baseSize, baseSizeUnits, targetUnits);
} else if (DesignChoiceConstants.UNITS_EX.equals(fromUnits)) {
convertedValue = DimensionUtil.convertTo(measure * baseSize / 3, baseSizeUnits, targetUnits);
} else if (DesignChoiceConstants.UNITS_PERCENTAGE.equals(fromUnits)) {
convertedValue =
DimensionUtil.convertTo(measure * baseSize / 100, baseSizeUnits, targetUnits);
} else if (DesignChoiceConstants.UNITS_PX.equals(fromUnits)) {
convertedValue = convertTo(measure / dpi, DesignChoiceConstants.UNITS_IN, targetUnits);
} else convertedValue = convertTo(measure, fromUnits, targetUnits);
return convertedValue.getMeasure();
}
/**
* Return if the given unit is a relative unit or not. The following units defined in <code>
* DesignChoiceConstants</code> are considered as relative:
*
* <ul>
* <li>UNITS_EM
* <li>UNITS_EX
* <li>UNITS_PERCENTAGE
* <li>UNITS_PX
* </ul>
*
* @param unit a given unit.
* @return <code>true</code> if the unit is a relative unit like em, ex, % and px. Return <code>
* false</code> if the unit is not a relative unit.( it can be an absolute relative unit like
* "mm", or even an unrecognized unit. )
*/
public static final boolean isRelativeUnit(String unit) {
return DesignChoiceConstants.UNITS_EM.equalsIgnoreCase(unit)
|| DesignChoiceConstants.UNITS_EX.equalsIgnoreCase(unit)
|| DesignChoiceConstants.UNITS_PERCENTAGE.equalsIgnoreCase(unit)
|| DesignChoiceConstants.UNITS_PX.equalsIgnoreCase(unit);
}