public abstract class ResolutionSyntax extends Object implements Serializable, Cloneable
A resolution attribute's value consists of two items, the cross feed
direction resolution and the feed direction resolution. A resolution
attribute may be constructed by supplying the two values and indicating the
units in which the values are measured. Methods are provided to return a
resolution attribute's values, indicating the units in which the values are
to be returned. The two most common resolution units are dots per inch (dpi)
and dots per centimeter (dpcm), and exported constants DPI
and DPCM
are provided for
indicating those units.
Once constructed, a resolution attribute's value is immutable.
Design
A resolution attribute's cross feed direction resolution and feed direction resolution values are stored internally using units of dots per 100 inches (dphi). Storing the values in dphi rather than, say, metric units allows precise integer arithmetic conversions between dpi and dphi and between dpcm and dphi: 1 dpi = 100 dphi, 1 dpcm = 254 dphi. Thus, the values can be stored into and retrieved back from a resolution attribute in either units with no loss of precision. This would not be guaranteed if a floating point representation were used. However, roundoff error will in general occur if a resolution attribute's values are created in one units and retrieved in different units; for example, 600 dpi will be rounded to 236 dpcm, whereas the true value (to five figures) is 236.22 dpcm.
Storing the values internally in common units of dphi lets two resolution attributes be compared without regard to the units in which they were created; for example, 300 dpcm will compare equal to 762 dpi, as they both are stored as 76200 dphi. In particular, a lookup service can match resolution attributes based on equality of their serialized representations regardless of the units in which they were created. Again, using integers for internal storage allows precise equality comparisons to be done, which would not be guaranteed if a floating point representation were used.
The exported constant DPI
is actually the
conversion factor by which to multiply a value in dpi to get the value in
dphi. Likewise, the exported constant DPCM
is the
conversion factor by which to multiply a value in dpcm to get the value in
dphi. A client can specify a resolution value in units other than dpi or dpcm
by supplying its own conversion factor. However, since the internal units of
dphi was chosen with supporting only the external units of dpi and dpcm in
mind, there is no guarantee that the conversion factor for the client's units
will be an exact integer. If the conversion factor isn't an exact integer,
resolution values in the client's units won't be stored precisely.
Modifier and Type | Field and Description |
---|---|
static int |
DPCM
Value to indicate units of dots per centimeter (dpcm).
|
static int |
DPI
Value to indicate units of dots per inch (dpi).
|
Constructor and Description |
---|
ResolutionSyntax(int crossFeedResolution,
int feedResolution,
int units)
Construct a new resolution attribute from the given items.
|
Modifier and Type | Method and Description |
---|---|
boolean |
equals(Object object)
Returns whether this resolution attribute is equivalent to the passed in
object.
|
int |
getCrossFeedResolution(int units)
Returns this resolution attribute's cross feed direction resolution in
the given units.
|
protected int |
getCrossFeedResolutionDphi()
Returns this resolution attribute's cross feed direction resolution in
units of dphi.
|
int |
getFeedResolution(int units)
Returns this resolution attribute's feed direction resolution in the
given units.
|
protected int |
getFeedResolutionDphi()
Returns this resolution attribute's feed direction resolution in units
of dphi.
|
int[] |
getResolution(int units)
Get this resolution attribute's resolution values in the given units.
|
int |
hashCode()
Returns a hash code value for this resolution attribute.
|
boolean |
lessThanOrEquals(ResolutionSyntax other)
Determine whether this resolution attribute's value is less than or
equal to the given resolution attribute's value.
|
String |
toString()
Returns a string version of this resolution attribute.
|
String |
toString(int units,
String unitsName)
Returns a string version of this resolution attribute in the given units.
|
public static final int DPI
public static final int DPCM
public ResolutionSyntax(int crossFeedResolution, int feedResolution, int units)
crossFeedResolution
- Cross feed direction resolution.feedResolution
- Feed direction resolution.units
- Unit conversion factor, e.g. DPI
or
DPCM
.IllegalArgumentException
- (unchecked exception) Thrown if crossFeedResolution < 1
or feedResolution < 1
or units < 1
.public int[] getResolution(int units)
units
- Unit conversion factor, e.g. DPI
or
DPCM
.IllegalArgumentException
- (unchecked exception) Thrown if units < 1
.public int getCrossFeedResolution(int units)
units
- Unit conversion factor, e.g. DPI
or
DPCM
.IllegalArgumentException
- (unchecked exception) Thrown if units < 1
.public int getFeedResolution(int units)
units
- Unit conversion factor, e.g. DPI
or DPCM
.IllegalArgumentException
- (unchecked exception) Thrown if units < 1
.public String toString(int units, String unitsName)
"CxF U"
,
where C is the cross feed direction resolution, F is the
feed direction resolution, and U is the units name. The values are
rounded to the nearest integer.units
- Unit conversion factor, e.g. CODE>DPI
or DPCM
.unitsName
- Units name string, e.g. "dpi"
or "dpcm"
. If
null, no units name is appended to the result.IllegalArgumentException
- (unchecked exception) Thrown if units < 1
.public boolean lessThanOrEquals(ResolutionSyntax other)
other
attribute's cross feed direction resolution.
other
attribute's feed direction resolution.
other
- Resolution attribute to compare with.other
resolution attribute, false otherwise.NullPointerException
- (unchecked exception) Thrown if other
is null.public boolean equals(Object object)
object
is not null.
object
is an instance of class ResolutionSyntax.
object
's cross feed direction resolution.
object
's feed direction resolution.
equals
in class Object
object
- Object to compare to.object
is equivalent to this resolution
attribute, false otherwise.Object.hashCode()
,
HashMap
public int hashCode()
hashCode
in class Object
Object.equals(java.lang.Object)
,
System.identityHashCode(java.lang.Object)
public String toString()
"CxF dphi"
, where C is the
cross feed direction resolution and F is the feed direction
resolution. The values are reported in the internal units of dphi.protected int getCrossFeedResolutionDphi()
protected int getFeedResolutionDphi()
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