Package com.sixlegs.png

Class PngConfig.Builder

java.lang.Object

com.sixlegs.png.PngConfig.Builder

Enclosing class:

PngConfig

public static final class PngConfig.Builder
extends java.lang.Object

Builder class used to construct PngConfig instances. Each "setter" method returns an reference to the instance to enable chaining multiple calls. Call build() to construct a new PngConfig instance using the current Builder settings. Example:

PngConfig config = new PngConfig.Builder()
        .readLimit(PngConfig.READ_EXCEPT_METADATA)
        .warningsFatal(true)
        .build();

Constructor Summary

Constructors

Constructor	Description
Builder()	Create a new builder using default values.
Builder(PngConfig cfg)	Create a builder using values from the given configuration.

Method Summary

Modifier and Type	Method	Description
PngConfig	build()	Create a configuration using the current values of this builder.
PngConfig.Builder	convertIndexed(boolean convertIndexed)	Whether to convert images with an indexed color model (paletted and 1/2/4/8-bit grayscale) to use a component color model.
PngConfig.Builder	defaultGamma(float defaultGamma)	Sets the default gamma value.
PngConfig.Builder	displayExponent(float displayExponent)	Sets the default display exponent.
PngConfig.Builder	gammaCorrect(boolean gammaCorrect)	Enables or disables gamma correction.
PngConfig.Builder	progressive(boolean progressive)	Enables or disables progressive display for interlaced images.
PngConfig.Builder	readLimit(int readLimit)	Configures how much of the image to read.
PngConfig.Builder	reduce16(boolean reduce16)	Enables or disables 16-bit reduction.
PngConfig.Builder	sourceRegion(java.awt.Rectangle sourceRegion)	Decode only a particular region of the source image.
PngConfig.Builder	sourceSubsampling(int xsub, int ysub, int xoff, int yoff)	Reduce the size of the decoded image (or source region) by only using periodic rows and/or columns of the image.
PngConfig.Builder	warningsFatal(boolean warningsFatal)	Configures whether warnings should be treated as fatal errors.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Builder

public Builder()

Create a new builder using default values.

Builder

public Builder(PngConfig cfg)

Create a builder using values from the given configuration.

Parameters:

cfg - the configuration to copy

Method Detail

build

public PngConfig build()

Create a configuration using the current values of this builder.

reduce16

public PngConfig.Builder reduce16(boolean reduce16)

Enables or disables 16-bit reduction. If enabled, 16-bit samples are reduced to 8-bit samples by shifting to the right by 8 bits. Default is true.

Parameters:

reduce16 - enable 16-bit reduction

defaultGamma

public PngConfig.Builder defaultGamma(float defaultGamma)

Sets the default gamma value. This value is used unless the image contains an explicit gamma value. Initial value is 1/45455.

Parameters:

defaultGamma - the default gamma value

displayExponent

public PngConfig.Builder displayExponent(float displayExponent)

Sets the default display exponent. The proper setting depends on monitor and OS gamma lookup table settings, if any. The default value of 2.2 should work well with most PC displays. If the operating system has a gamma lookup table (e.g. Macintosh) the display exponent should be lower.

Parameters:

displayExponent - the display exponent

gammaCorrect

public PngConfig.Builder gammaCorrect(boolean gammaCorrect)

Enables or disables gamma correction. If enabled, decoded images will be gamma corrected. Sets to false if your application will perform gamma correctly manually. Default is true.

Parameters:

gammaCorrect - use gamma correction

See Also:

PngImage.getGamma(), PngImage.getGammaTable()

progressive

public PngConfig.Builder progressive(boolean progressive)

Enables or disables progressive display for interlaced images. If enabled, each received pixel is expanded (replicated) to fill a rectangle covering the yet-to-be-transmitted pixel positions below and to the right of the received pixel. This produces a "fade-in" effect as the new image gradually replaces the old, at the cost of some additional processing time. Default is false.

Parameters:

progressive - use progressive display

See Also:

PngImage.handlePass(java.awt.image.BufferedImage, int)

readLimit

public PngConfig.Builder readLimit(int readLimit)

Configures how much of the image to read. Useful when one is interested in only a portion of the image metadata, and would like to avoid reading and/or decoding the actual image data.

Parameters:

readLimit - READ_ALL,
READ_HEADER,
READ_UNTIL_DATA,
READ_EXCEPT_DATA,
or READ_EXCEPT_METADATA

warningsFatal

public PngConfig.Builder warningsFatal(boolean warningsFatal)

Configures whether warnings should be treated as fatal errors. All non-fatal PngException exceptions are caught and passed to the PngImage.handleWarning(com.sixlegs.png.PngException) method. If warnings are configured as fatal, that method will re-throw the exception, which will abort image processing. Default is false.

Parameters:

warningsFatal - true if warnings should be treated as fatal errors

See Also:

PngImage.handleWarning(com.sixlegs.png.PngException)

sourceRegion

public PngConfig.Builder sourceRegion(java.awt.Rectangle sourceRegion)

Decode only a particular region of the source image. See the equivalent ImageIO method for full documentation.

sourceSubsampling

public PngConfig.Builder sourceSubsampling(int xsub,
                                           int ysub,
                                           int xoff,
                                           int yoff)

Reduce the size of the decoded image (or source region) by only using periodic rows and/or columns of the image. See the equivalent ImageIO method for full documentation.

convertIndexed

public PngConfig.Builder convertIndexed(boolean convertIndexed)

Whether to convert images with an indexed color model (paletted and 1/2/4/8-bit grayscale) to use a component color model.