com.aspose.imaging.imageoptions

Class PngOptions

java.lang.Object

com.aspose.imaging.DisposableObject

com.aspose.imaging.ImageOptionsBase

com.aspose.imaging.imageoptions.PngOptions

All Implemented Interfaces:

IHasExifData, IHasMetadata, IMetadataContainer, IHasXmpData, com.aspose.ms.System.IDisposable, Closeable, AutoCloseable

Direct Known Subclasses:

ApngOptions

public class PngOptions
extends ImageOptionsBase

Create high-quality Portable Network Graphics (PNG) raster images effortlessly with our API, offering customizable options for compression levels, bits per pixel depths, and alpha bits. Seamlessly process XMP metadata containers, ensuring comprehensive image metadata management, and empowering you to tailor PNG images to your exact specifications with ease.

Code example:

This example demonstrates the use of different classes from SaveOptions Namespace for export purposes. An image of type Gif is loaded into an instance of Image and then exported out to several formats.

String dir = "c:\\temp\\";

//Load an existing image (of type Gif) in an instance of Image class
com.aspose.imaging.Image image = com.aspose.imaging.Image.load(dir + "sample.gif");
try {
    //Export to BMP file format using the default options
    image.save(dir + "output.bmp", new com.aspose.imaging.imageoptions.BmpOptions());

    //Export to JPEG file format using the default options
    image.save(dir + "output.jpeg", new com.aspose.imaging.imageoptions.JpegOptions());

    //Export to PNG file format using the default options
    image.save(dir + "output.png", new com.aspose.imaging.imageoptions.PngOptions());

    //Export to TIFF file format using the default options
    image.save(dir + "output.tif", new com.aspose.imaging.imageoptions.TiffOptions(com.aspose.imaging.fileformats.tiff.enums.TiffExpectedFormat.Default));
} finally {
    image.dispose();
}

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_COMPRESSION_LEVEL The default compression level.

Constructor Summary

Constructors

Constructor and Description
PngOptions() Initializes a new instance of the PngOptions class.
PngOptions(PngOptions pngOptions) Initializes a new instance of the PngOptions class.

Method Summary

Modifier and Type	Method and Description
byte	getBitDepth() Gets the bit depth values in range of 1, 2, 4, 8, 16.
int	getColorType() Gets the type of the color.
int	getCompressionLevel() Deprecated. This property is obsolete. Use PngCompressionLevel instead.
int	getFilterType() Gets the filter type used during png file save process.
int	getPngCompressionLevel() Gets the PngImage compression level.
boolean	getProgressive() Gets a value indicating whether a PngImage is progressive.
void	setBitDepth(byte value) Sets the bit depth values in range of 1, 2, 4, 8, 16.
void	setColorType(int value) Sets the type of the color.
void	setCompressionLevel(int value) Deprecated. This property is obsolete. Use PngCompressionLevel instead.
void	setFilterType(int value) Sets the filter type used during png file save process.
void	setPngCompressionLevel(int value) Sets the PngImage compression level.
void	setProgressive(boolean value) Sets a value indicating whether a PngImage is progressive.

Methods inherited from class com.aspose.imaging.ImageOptionsBase

deepClone, getBufferSizeHint, getExifData, getFullFrame, getMultiPageOptions, getPalette, getProgressEventHandler, getResolutionSettings, getSource, getVectorRasterizationOptions, getXmpData, isKeepMetadata, setBufferSizeHint, setExifData, setFullFrame, setKeepMetadata, setMultiPageOptions, setPalette, setProgressEventHandler, setResolutionSettings, setSource, setVectorRasterizationOptions, setXmpData, trySetMetadata

Methods inherited from class com.aspose.imaging.DisposableObject

close, dispose, getDisposed

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_COMPRESSION_LEVEL

public static final int DEFAULT_COMPRESSION_LEVEL

The default compression level.

See Also:

Constant Field Values

Constructor Detail

PngOptions

public PngOptions()

Initializes a new instance of the PngOptions class.

PngOptions

public PngOptions(PngOptions pngOptions)

Initializes a new instance of the PngOptions class.

Parameters:

pngOptions - The PNG options.

Method Detail

getColorType

public final int getColorType()

Gets the type of the color.

Value: The type of the color.

Returns:

the type of the color.

setColorType

public final void setColorType(int value)

Sets the type of the color.

Value: The type of the color.

Parameters:

value - the type of the color.

Code example:

The following example shows how to compress a PNG image, using indexed color with best fit palette

// Loads png image        
String sourceFilePath = "OriginalRings.png";
String outputFilePath = "OriginalRingsOutput.png";
try (com.aspose.imaging.Image image = com.aspose.imaging.Image.load(sourceFilePath))
{
    com.aspose.imaging.imageoptions.PngOptions options = new com.aspose.imaging.imageoptions.PngOptions();
    options.setProgressive(true);
    // Use indexed color type
    options.setColorType(com.aspose.imaging.fileformats.png.PngColorType.IndexedColor);
    // Use maximal compression
    options.setCompressionLevel(9);
    // Get the closest 8-bit color palette which covers as many pixels as possible, so that a palettized image
    // is almost visually indistinguishable from a non-palletized one.
    options.setPalette(com.aspose.imaging.ColorPaletteHelper.getCloseImagePalette((com.aspose.imaging.RasterImage)image, 
                                256, Aspose.Imaging.PaletteMiningMethod.Histogram));
                     
    image.save(outputFilePath, options);
}
// The output file size should be significantly reduced

getProgressive

public final boolean getProgressive()

Gets a value indicating whether a PngImage is progressive.

Value: if progressive; otherwise, .

Returns:

a value indicating whether a PngImage is progressive.

setProgressive

public final void setProgressive(boolean value)

Sets a value indicating whether a PngImage is progressive.

Value: if progressive; otherwise, .

Parameters:

value - a value indicating whether a PngImage is progressive.

Code example:

The following example shows how to compress a PNG image, using indexed color with best fit palette

// Loads png image        
String sourceFilePath = "OriginalRings.png";
String outputFilePath = "OriginalRingsOutput.png";
try (com.aspose.imaging.Image image = com.aspose.imaging.Image.load(sourceFilePath))
{
    com.aspose.imaging.imageoptions.PngOptions options = new com.aspose.imaging.imageoptions.PngOptions();
    options.setProgressive(true);
    // Use indexed color type
    options.setColorType(com.aspose.imaging.fileformats.png.PngColorType.IndexedColor);
    // Use maximal compression
    options.setCompressionLevel(9);
    // Get the closest 8-bit color palette which covers as many pixels as possible, so that a palettized image
    // is almost visually indistinguishable from a non-palletized one.
    options.setPalette(com.aspose.imaging.ColorPaletteHelper.getCloseImagePalette((com.aspose.imaging.RasterImage)image, 
                                256, Aspose.Imaging.PaletteMiningMethod.Histogram));
                     
    image.save(outputFilePath, options);
}
// The output file size should be significantly reduced

getFilterType

public final int getFilterType()

Gets the filter type used during png file save process.

Returns:

the filter type used during png file save process.

setFilterType

public final void setFilterType(int value)

Sets the filter type used during png file save process.

Parameters:

value - the filter type used during png file save process.

See Also:

PngFilterType

Code example:

The following example shows how different filter types affect the size of the output PNG image.

// Helper class
class Utils {
    public String getPngFilterTypeString(int filterType) {
        switch (filterType) {
            case com.aspose.imaging.fileformats.png.PngFilterType.None:
                return "None";

            case com.aspose.imaging.fileformats.png.PngFilterType.Up:
                return "Up";

            case com.aspose.imaging.fileformats.png.PngFilterType.Sub:
                return "Sub";

            case com.aspose.imaging.fileformats.png.PngFilterType.Paeth:
                return "Paeth";

            case com.aspose.imaging.fileformats.png.PngFilterType.Avg:
                return "Avg";

            case com.aspose.imaging.fileformats.png.PngFilterType.Adaptive:
                return "Adaptive";

            default:
                throw new IllegalArgumentException("filterType");
        }
    }
}

// Here is the main example
Utils utils = new Utils();

int[] filterTypes = new int[]
        {
                com.aspose.imaging.fileformats.png.PngFilterType.None,
                com.aspose.imaging.fileformats.png.PngFilterType.Up,
                com.aspose.imaging.fileformats.png.PngFilterType.Sub,
                com.aspose.imaging.fileformats.png.PngFilterType.Paeth,
                com.aspose.imaging.fileformats.png.PngFilterType.Avg,
                com.aspose.imaging.fileformats.png.PngFilterType.Adaptive,
        };

for (int filterType : filterTypes) {
    com.aspose.imaging.imageoptions.PngOptions options = new com.aspose.imaging.imageoptions.PngOptions();
    com.aspose.imaging.Image image = com.aspose.imaging.Image.load("c:\\temp\\sample.png");
    try {
        // Set a filter type
        options.setFilterType(filterType);

        java.io.ByteArrayOutputStream stream = new java.io.ByteArrayOutputStream();
        try {
            image.save(stream, options);
            System.out.printf("The filter type is %s, the output image size is %s bytes.", utils.getPngFilterTypeString(filterType), stream.size());
        } finally {
            stream.close();
        }
    } finally {
        image.dispose();
    }
}

//The output may look like this:
//The filter type is None, the output image size is 116845 bytes.
//The filter type is Up, the output image size is 86360 bytes.
//The filter type is Sub, the output image size is 94907 bytes.
//The filter type is Paeth, the output image size is 86403 bytes.
//The filter type is Avg, the output image size is 89956 bytes.
//The filter type is Adaptive, the output image size is 97248 bytes.

getCompressionLevel

@Deprecated
public final int getCompressionLevel()

Deprecated. This property is obsolete. Use PngCompressionLevel instead.

Gets the PngImage compression level.

Returns:

the PngImage compression level.

See Also:

PngCompressionLevel

setCompressionLevel

@Deprecated
public final void setCompressionLevel(int value)

Deprecated. This property is obsolete. Use PngCompressionLevel instead.

Sets the PngImage compression level.

Parameters:

value - the PngImage compression level.

See Also:

PngCompressionLevel

Code example:

The following example shows how to compress a PNG image, using indexed color with best fit palette

// Loads png image        
String sourceFilePath = "OriginalRings.png";
String outputFilePath = "OriginalRingsOutput.png";
try (com.aspose.imaging.Image image = com.aspose.imaging.Image.load(sourceFilePath))
{
    com.aspose.imaging.imageoptions.PngOptions options = new com.aspose.imaging.imageoptions.PngOptions();
    options.setProgressive(true);
    // Use indexed color type
    options.setColorType(com.aspose.imaging.fileformats.png.PngColorType.IndexedColor);
    // Use maximal compression
    options.setCompressionLevel(9);
    // Get the closest 8-bit color palette which covers as many pixels as possible, so that a palettized image
    // is almost visually indistinguishable from a non-palletized one.
    options.setPalette(com.aspose.imaging.ColorPaletteHelper.getCloseImagePalette((com.aspose.imaging.RasterImage)image, 
                                256, Aspose.Imaging.PaletteMiningMethod.Histogram));
                     
    image.save(outputFilePath, options);
}
// The output file size should be significantly reduced

getPngCompressionLevel

public final int getPngCompressionLevel()

Gets the PngImage compression level.

Returns:

the PngImage compression level.

See Also:

PngCompressionLevel

setPngCompressionLevel

public final void setPngCompressionLevel(int value)

Sets the PngImage compression level.

Parameters:

value - the PngImage compression level.

See Also:

PngCompressionLevel

getBitDepth

public final byte getBitDepth()

Gets the bit depth values in range of 1, 2, 4, 8, 16.

Mind the next limits:

PngColorType.IndexedColor supports bit depth of 1, 2, 4, 8.

PngColorType.Grayscale, PngColorType.GrayscaleWithAlpha support bits depth of 8.

PngColorType.Truecolor, PngColorType.TruecolorWithAlpha support bits depth of 8, 16.

Returns:

the bit depth values in range of 1, 2, 4, 8, 16.

setBitDepth

public final void setBitDepth(byte value)

Sets the bit depth values in range of 1, 2, 4, 8, 16.

Mind the next limits:

PngColorType.IndexedColor supports bit depth of 1, 2, 4, 8.

PngColorType.Grayscale, PngColorType.GrayscaleWithAlpha support bits depth of 8.

PngColorType.Truecolor, PngColorType.TruecolorWithAlpha support bits depth of 8, 16.

Parameters:

value - the bit depth values in range of 1, 2, 4, 8, 16.

Code example:

The following example shows how to save an image to PNG format using various options.

String dir = "c:\\temp\\";

// Create a PNG image of 100x100 px.
// You can also load image of any supported format from a file or a stream.
com.aspose.imaging.fileformats.png.PngImage pngImage = new com.aspose.imaging.fileformats.png.PngImage(100, 100);
try {
    com.aspose.imaging.brushes.LinearGradientBrush gradientBrush = new com.aspose.imaging.brushes.LinearGradientBrush(
            new com.aspose.imaging.Point(0, 0),
            new com.aspose.imaging.Point(pngImage.getWidth(), pngImage.getHeight()),
            com.aspose.imaging.Color.getBlue(),
            com.aspose.imaging.Color.getTransparent());

    com.aspose.imaging.Graphics graphics = new com.aspose.imaging.Graphics(pngImage);

    // Fill the image with the blue-transparent gradient.
    graphics.fillRectangle(gradientBrush, pngImage.getBounds());

    com.aspose.imaging.imageoptions.PngOptions saveOptions = new com.aspose.imaging.imageoptions.PngOptions();

    // Use progressive loading.
    saveOptions.setProgressive(true);

    // Set the horizontal and vertical resolution to 96 pixels per inch.
    saveOptions.setResolutionSettings(new com.aspose.imaging.ResolutionSetting(96.0, 96.0));

    // Each pixel is a (red, green, blue) triple followed by alpha.
    saveOptions.setColorType(com.aspose.imaging.fileformats.png.PngColorType.TruecolorWithAlpha);

    // Set the maximum level of compression.
    saveOptions.setCompressionLevel(9);

    // This is the best compression, but the slowest execution time.
    // Adaptive filtering means that saving process will choose most sutable filter for each data row.
    saveOptions.setFilterType(com.aspose.imaging.fileformats.png.PngFilterType.Adaptive);

    // The number of bits per channel.
    saveOptions.setBitDepth((byte) 8);

    // Save to a file.
    pngImage.save(dir + "output.png", saveOptions);
} finally {
    pngImage.dispose();
}