Package org.ngengine.stbimage

Class PngDecoder

java.lang.Object

org.ngengine.stbimage.PngDecoder

All Implemented Interfaces:

StbDecoder

public class PngDecoder
extends Object
implements StbDecoder

PNG decoder with zlib decompression. Supports 1/2/4/8/16-bit depths, all color types (grayscale, RGB, RGBA, palette).

Constructor Summary

Constructors

Constructor	Description
PngDecoder(ByteBuffer buffer, IntFunction<ByteBuffer> allocator, boolean flipVertically)	Creates a PNG decoder instance.

Method Summary

Modifier and Type	Method	Description
IntFunction<ByteBuffer>	getAllocator()	Returns the allocator used by this decoder for output buffers.
StbImageInfo	info()	Reads image metadata without fully decoding pixel data.
static boolean	isPng(ByteBuffer buffer)	Tests whether the buffer starts with a PNG signature.
StbImageResult	load(int desiredChannels)	Decodes image pixels.
void	setConvertIphonePngToRgb(boolean convertIphonePngToRgb)	Enables/disables iPhone CgBI BGR(A)-to-RGB(A) conversion.
void	setUnpremultiplyOnLoad(boolean unpremultiplyOnLoad)	Enables/disables iPhone PNG unpremultiply by alpha.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.ngengine.stbimage.StbDecoder

load16, loadAllFrames, loadf, loadNextFrame

Constructor Details

PngDecoder

public PngDecoder(ByteBuffer buffer,
 IntFunction<ByteBuffer> allocator,
 boolean flipVertically)

Creates a PNG decoder instance.

Parameters:

buffer - source data

allocator - output allocator

flipVertically - true to flip decoded rows

Method Details

isPng

public static boolean isPng(ByteBuffer buffer)

Tests whether the buffer starts with a PNG signature.

Parameters:

buffer - source bytes

Returns:

true if signature matches PNG

setConvertIphonePngToRgb

public void setConvertIphonePngToRgb(boolean convertIphonePngToRgb)

Enables/disables iPhone CgBI BGR(A)-to-RGB(A) conversion.

Parameters:

convertIphonePngToRgb - true to convert channels

setUnpremultiplyOnLoad

public void setUnpremultiplyOnLoad(boolean unpremultiplyOnLoad)

Enables/disables iPhone PNG unpremultiply by alpha.

Parameters:

unpremultiplyOnLoad - true to unpremultiply on decode

getAllocator

public IntFunction<ByteBuffer> getAllocator()

Returns the allocator used by this decoder for output buffers.

Specified by:

getAllocator in interface StbDecoder

Returns:

allocator function

info

public StbImageInfo info()

Reads image metadata without fully decoding pixel data.

Specified by:

info in interface StbDecoder

Returns:

image information

load

public StbImageResult load(int desiredChannels)

Decodes image pixels.

Specified by:

load in interface StbDecoder

Parameters:

desiredChannels - requested output channels (0 keeps source/default behavior)

Returns:

decoded image result