public class

Flattener

extends Object
implements AutoCloseable
java.lang.Object
   ↳ com.pdftron.pdf.Flattener

Class Overview

Flattener is a optional PDFNet add-on that can be used to simplify and optimize existing PDF's to render faster on devices with lower memory and speeds. PDF documents can frequently contain very complex page description (e.g. thousands of paths, different shadings, color spaces, blend modes, large images etc.) that may not be suitable for interactive viewing on mobile devices. Flattener can be used to speed-up PDF rendering on mobile devices and on the Web by simplifying page content (e.g. flattening complex graphics into images) while maintaining vector text whenever possible. By using the FlattenMode::e_simple option each page in the PDF will be reduced to a single background image, with the remaining text over top in vector format. Some text may still get flattened, in particular any text that is clipped, or underneath, other content that will be flattened. On the other hand the FlattenMode::e_fast will not flatten simple content, such as simple straight lines, nor will it flatten Type3 fonts.

Note: 'Flattener' is available as a separately licensable add-on to PDFNet core license.

Note: See 'pdftron.PDF.Optimizer' for alternate approach to optimize PDFs with focus on file size reduction.

Summary

Constants
int e_default Render text that are somewhat clipped or occluded.
int e_fast Feature reduce PDF while trying to preserve some complex PDF features (such as vector figures, transparency, shadings, blend modes, Type3 fonts etc.) for pages that are already fast to render.
int e_keep_all Only render text that are completely occluded, or used as a clipping path.
int e_keep_most Only render text that are seriously clipped or occluded.
int e_simple Feature reduce PDF to a simple two layer representation consisting of a single background RGB image and a simple top text layer.
int e_strict Render text that are marginally clipped or occluded.
int e_very_strict Render (flatten) any text that is clipped or occluded.
Public Constructors
Flattener()
Default constructor.
Public Methods
void Process(PDFDoc doc, int mode)
Process each page in the PDF, flattening content that matches the mode criteria.
void SetThreshold(int threshold)
Used to control how precise or relaxed text flattening is.
void close()
Frees the native memory of the object.
void destroy()
Frees the native memory of the object.
void setDPI(int dpi)
The output resolution, from 1 to 1000, in Dots Per Inch (DPI) at which to render elements which cannot be directly converted.
void setJPGQuality(int quality)
Specifies the compression quality to use when generating JPEG images.
void setMaximumImagePixels(int max_pixels)
Specifies the maximum image size in pixels.
void setPreferJPG(boolean jpg)
Specifies whether to leave images in existing compression, or as JPEG.
[Expand]
Inherited Methods
From class java.lang.Object
From interface java.lang.AutoCloseable

Constants

public static final int e_default

Render text that are somewhat clipped or occluded.

Constant Value: 2 (0x00000002)

public static final int e_fast

Feature reduce PDF while trying to preserve some complex PDF features (such as vector figures, transparency, shadings, blend modes, Type3 fonts etc.) for pages that are already fast to render. This option can also result in smaller & faster files compared to e_simple, but the pages may have more complex structure.

Constant Value: 1 (0x00000001)

public static final int e_keep_all

Only render text that are completely occluded, or used as a clipping path.

Constant Value: 4 (0x00000004)

public static final int e_keep_most

Only render text that are seriously clipped or occluded.

Constant Value: 3 (0x00000003)

public static final int e_simple

Feature reduce PDF to a simple two layer representation consisting of a single background RGB image and a simple top text layer.

Constant Value: 0 (0x00000000)

public static final int e_strict

Render text that are marginally clipped or occluded.

Constant Value: 1 (0x00000001)

public static final int e_very_strict

Render (flatten) any text that is clipped or occluded.

Constant Value: 0 (0x00000000)

Public Constructors

public Flattener ()

Default constructor.

Throws
PDFNetException

Public Methods

public void Process (PDFDoc doc, int mode)

Process each page in the PDF, flattening content that matches the mode criteria.

Parameters
doc the document to flatten.
mode indicates the criteria for which elements are flattened.
Throws
PDFNetException

public void SetThreshold (int threshold)

Used to control how precise or relaxed text flattening is. When some text is preserved (not flattened to image) the visual appearance of the document may be altered.

Parameters
threshold the threshold setting to use.
Throws
PDFNetException

public void close ()

Frees the native memory of the object. This can be explicity called to control the deallocation of native memory and avoid situations where the garbage collector does not free the object in a timely manner.

Throws
PDFNetException

public void destroy ()

Frees the native memory of the object. This can be explicity called to control the deallocation of native memory and avoid situations where the garbage collector does not free the object in a timely manner.

public void setDPI (int dpi)

The output resolution, from 1 to 1000, in Dots Per Inch (DPI) at which to render elements which cannot be directly converted. the default value is 150 Dots Per Inch

Parameters
dpi the resolution in Dots Per Inch
Throws
PDFNetException

public void setJPGQuality (int quality)

Specifies the compression quality to use when generating JPEG images.

Parameters
quality the JPEG compression quality, from 0(highest compression) to 100(best quality).
Throws
PDFNetException

public void setMaximumImagePixels (int max_pixels)

Specifies the maximum image size in pixels.

Parameters
max_pixels the maximum number of pixels an image can have.
Throws
PDFNetException

public void setPreferJPG (boolean jpg)

Specifies whether to leave images in existing compression, or as JPEG.

Parameters
jpg if true PDF will contain all JPEG images.
Throws
PDFNetException