uk.ac.starlink.ttools.plot

Class PdfGraphicExporter

java.lang.Object

uk.ac.starlink.ttools.plot.GraphicExporter

uk.ac.starlink.ttools.plot.PdfGraphicExporter

public abstract class PdfGraphicExporter
extends GraphicExporter

GraphicExporter implementation that exports to PDF format. The best way to turn fonts are turned into graphics in PDFs is not obvious, so this class parameterises the options. Static members provide ways of getting useful instances.

Since:

12 Feb 2013

Author:

Mark Taylor

Field Summary

Fields

Modifier and Type	Field and Description
static PdfGraphicExporter	BASIC Exporter which uses the default font mapper.
static PdfGraphicExporter	GLYPH_TEXT Exporter which writes text as shapes not using fonts.

Fields inherited from class uk.ac.starlink.ttools.plot.GraphicExporter

EPS, EPS_GZIP, GIF, JPEG, PNG, PNG_TRANSPARENT, SVG

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	PdfGraphicExporter() Constructor.

Method Summary

Modifier and Type	Method and Description
static PdfGraphicExporter	createExternalFontExporter(URL fontsUrl) Returns an exporter which uses externally stored fonts.
abstract Graphics2D	createGraphics(com.lowagie.text.pdf.PdfContentByte pcb, int width, int height) Returns a graphics context which can be used to write to a given PDF content object.
void	exportGraphic(Picture picture, OutputStream out) Paints the given picture to an output stream using some graphics format or other.

Methods inherited from class uk.ac.starlink.ttools.plot.GraphicExporter

getContentEncoding, getDescription, getFileSuffixes, getKnownExporters, getMimeType, getName, isVector, toPicture, toString

Methods inherited from class java.lang.Object

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

Field Detail

BASIC

public static PdfGraphicExporter BASIC

Exporter which uses the default font mapper. OK for standard fonts.

GLYPH_TEXT

public static PdfGraphicExporter GLYPH_TEXT

Exporter which writes text as shapes not using fonts. Will generate reasonable output for any font without additional preparation. However, the output shapes are not perfect (visible only at huge magnification) and it may be less efficient if there's a lot of text (though possibly more efficient if there's very little).

Constructor Detail

PdfGraphicExporter

protected PdfGraphicExporter()

Constructor.

Method Detail

createExternalFontExporter

public static PdfGraphicExporter createExternalFontExporter(URL fontsUrl)

Returns an exporter which uses externally stored fonts. Output is perfect. A location must be provided for a resource giving a list of font locations. If the fonts can't be found, behaviour reverts to that of GLYPH_TEXT.

Parameters:

fontsUrl - location of a text file of font resource strings (typically file names or URLs of .ttf files)

Returns:

new exporter using external fonts

exportGraphic

public void exportGraphic(Picture picture,
                          OutputStream out)
                   throws IOException

Description copied from class: GraphicExporter

Paints the given picture to an output stream using some graphics format or other. This method should not close the stream.

Specified by:

exportGraphic in class GraphicExporter

Parameters:

picture - picture to draw

out - destination output stream

Throws:

IOException

createGraphics

public abstract Graphics2D createGraphics(com.lowagie.text.pdf.PdfContentByte pcb,
                                          int width,
                                          int height)

Returns a graphics context which can be used to write to a given PDF content object. There is not a single obvious implementation of this method; the best way to do it depends on how text glyphs are to be rendered.

Parameters:

pcb - PDF content object

width - in pixels

height - in pixels

Returns:

new graphics context