Package net.codecrete.qrbill.canvas

Class PNGCanvas

java.lang.Object

net.codecrete.qrbill.canvas.AbstractCanvas

net.codecrete.qrbill.canvas.Graphics2DCanvas

net.codecrete.qrbill.canvas.PNGCanvas

All Implemented Interfaces:

Closeable, AutoCloseable, ByteArrayResult, Canvas

public class PNGCanvas
extends Graphics2DCanvas
implements ByteArrayResult

Canvas for generating PNG files.

PNGs are not an optimal file format for QR bills. Vector formats such a SVG or PDF are of better quality and use far less processing power to generate.

Nested Class Summary

Nested classes/interfaces inherited from interface net.codecrete.qrbill.canvas.Canvas

Canvas.LineStyle

Field Summary

Fields inherited from class net.codecrete.qrbill.canvas.AbstractCanvas

fontMetrics, MM_TO_PT

Constructor Summary

Constructors

Constructor	Description
PNGCanvas(double width, double height, int resolution, String fontFamilyList)	Creates a new instance with the specified image size, resolution and font family.

Method Summary

Modifier and Type	Method	Description
void	close()
void	saveAs(Path path)	Saves the resulting PNG image to the specified path.
byte[]	toByteArray()	Gets the resulting graphics as a byte array.
void	writeTo(OutputStream os)	Writes the resulting PNG image to the specified output stream.

Methods inherited from class net.codecrete.qrbill.canvas.Graphics2DCanvas

addRectangle, closeSubpath, cubicCurveTo, fillPath, initGraphics, lineTo, moveTo, putText, setOffset, setTransformation, startPath, strokePath

Methods inherited from class net.codecrete.qrbill.canvas.AbstractCanvas

getAscender, getDescender, getLineHeight, getTextWidth, putTextLines, setupFontMetrics, splitLines

Methods inherited from class java.lang.Object

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

Constructor Details

PNGCanvas

public PNGCanvas(double width,
 double height,
 int resolution,
 String fontFamilyList)

Creates a new instance with the specified image size, resolution and font family.

It is recommended to use at least 144 dpi for a readable result.

The first font family in the list is used.

Parameters:

width - image width, in mm

height - image height, in mm

resolution - resolution of the result (in dpi)

fontFamilyList - list of font families (comma separated, CSS syntax)

Method Details

toByteArray

public byte[] toByteArray()
                   throws IOException

Description copied from interface: ByteArrayResult

Gets the resulting graphics as a byte array.

Specified by:

toByteArray in interface ByteArrayResult

Returns:

the byte array

Throws:

IOException - thrown if the construction of the byte array fails

writeTo

public void writeTo(OutputStream os)
             throws IOException

Writes the resulting PNG image to the specified output stream.

Parameters:

os - the output stream

Throws:

IOException - thrown if the image cannot be written

saveAs

public void saveAs(Path path)
            throws IOException

Saves the resulting PNG image to the specified path.

Parameters:

path - the path to write to

Throws:

IOException - thrown if the image cannot be written

close

public void close()

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class Graphics2DCanvas