- All Implemented Interfaces:
Serializable
,Cloneable
- Direct Known Subclasses:
PrinterResolution
ResolutionSyntax
is an abstract base class providing the common
implementation of all attributes denoting a printer resolution.
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.
- See Also:
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Field Summary
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Constructor Summary
ConstructorDescriptionResolutionSyntax
(int crossFeedResolution, int feedResolution, int units) Construct a new resolution attribute from the given items. -
Method Summary
Modifier and TypeMethodDescriptionboolean
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
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
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.toString()
Returns a string version of this resolution attribute.Returns a string version of this resolution attribute in the given units.
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Field Details
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DPI
public static final int DPIValue to indicate units of dots per inch (dpi). It is actually the conversion factor by which to multiply dpi to yield dphi (100).- See Also:
-
DPCM
public static final int DPCMValue to indicate units of dots per centimeter (dpcm). It is actually the conversion factor by which to multiply dpcm to yield dphi (254).- See Also:
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Constructor Details
-
ResolutionSyntax
public ResolutionSyntax(int crossFeedResolution, int feedResolution, int units) Construct a new resolution attribute from the given items.- Parameters:
crossFeedResolution
- cross feed direction resolutionfeedResolution
- feed direction resolutionunits
- unit conversion factor, e.g.DPI
orDPCM
- Throws:
IllegalArgumentException
- ifcrossFeedResolution < 1
orfeedResolution < 1
orunits < 1
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Method Details
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getResolution
public int[] getResolution(int units) Get this resolution attribute's resolution values in the given units. The values are rounded to the nearest integer.- Parameters:
units
- unit conversion factor, e.g.DPI
orDPCM
- Returns:
- a two-element array with the cross feed direction resolution at index 0 and the feed direction resolution at index 1
- Throws:
IllegalArgumentException
- ifunits < 1
-
getCrossFeedResolution
public int getCrossFeedResolution(int units) Returns this resolution attribute's cross feed direction resolution in the given units. The value is rounded to the nearest integer.- Parameters:
units
- unit conversion factor, e.g.DPI
orDPCM
- Returns:
- cross feed direction resolution
- Throws:
IllegalArgumentException
- ifunits < 1
-
getFeedResolution
public int getFeedResolution(int units) Returns this resolution attribute's feed direction resolution in the given units. The value is rounded to the nearest integer.- Parameters:
units
- unit conversion factor, e.g.DPI
orDPCM
- Returns:
- feed direction resolution
- Throws:
IllegalArgumentException
- ifunits < 1
-
toString
Returns a string version of this resolution attribute in the given units. The string takes the form"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.- Parameters:
units
- unit conversion factor, e.g.CODE>DPI
orDPCM
unitsName
- units name string, e.g."dpi"
or"dpcm"
. Ifnull
, no units name is appended to the result.- Returns:
- string version of this resolution attribute
- Throws:
IllegalArgumentException
- ifunits < 1
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lessThanOrEquals
Determine whether this resolution attribute's value is less than or equal to the given resolution attribute's value. This is true if all of the following conditions are true:- This attribute's cross feed direction resolution is less than or
equal to the
other
attribute's cross feed direction resolution. - This attribute's feed direction resolution is less than or equal to
the
other
attribute's feed direction resolution.
- Parameters:
other
- resolution attribute to compare with- Returns:
true
if this resolution attribute is less than or equal to theother
resolution attribute,false
otherwise- Throws:
NullPointerException
- ifother
isnull
- This attribute's cross feed direction resolution is less than or
equal to the
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equals
Returns whether this resolution attribute is equivalent to the passed in object. To be equivalent, all of the following conditions must be true:object
is notnull
.object
is an instance of classResolutionSyntax
.- This attribute's cross feed direction resolution is equal to
object
's cross feed direction resolution. - This attribute's feed direction resolution is equal to
object
's feed direction resolution.
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hashCode
public int hashCode()Returns a hash code value for this resolution attribute. -
toString
Returns a string version of this resolution attribute. The string takes the form"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. -
getCrossFeedResolutionDphi
protected int getCrossFeedResolutionDphi()Returns this resolution attribute's cross feed direction resolution in units of dphi. (For use in a subclass.)- Returns:
- cross feed direction resolution
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getFeedResolutionDphi
protected int getFeedResolutionDphi()Returns this resolution attribute's feed direction resolution in units of dphi. (For use in a subclass.)- Returns:
- feed direction resolution
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