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pdftron::PDF::Flattener Class Reference

`#include <Flattener.h>`

## Public Types
enum | Threshold { e_very_strict , e_strict , e_default , e_keep_most , e_keep_all }
enum | FlattenMode { e_simple , e_fast }

## Public Member Functions
| Flattener ()
| ~Flattener ()
void | SetDPI (UInt32 dpi)
void | SetMaximumImagePixels (UInt32 max_pixels)
void | SetPreferJPG (bool jpg)
void | SetJPGQuality (UInt32 quality)
void | SetThreshold (enum Threshold threshold)
void | SetPathHinting (bool enable_hinting)
void | Process (pdftron::PDF::PDFDoc &doc, enum FlattenMode mode)
void | Process (PDF::Page &page, enum FlattenMode mode)
void | Destroy ()

## Detailed Description

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

Definition at line 40 of file Flattener.h.

## Member Enumeration Documentation

## ◆ FlattenMode

enum pdftron::PDF::Flattener::FlattenMode

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

Definition at line 102 of file Flattener.h.

## ◆ Threshold

enum pdftron::PDF::Flattener::Threshold

Enumerator
e_very_strict | Render (flatten) any text that is clipped or occluded.
e_strict | Render text that are marginally clipped or occluded.
e_default | Render text that are somewhat clipped or occluded.
e_keep_most | Only render text that are seriously clipped or occluded.
e_keep_all | Only render text that are completely occluded, or used as a clipping path.

Definition at line 75 of file Flattener.h.

## Constructor & Destructor Documentation

## ◆ Flattener()

pdftron::PDF::Flattener::Flattener | ( |  | ) |

Flattener constructor

## ◆ ~Flattener()

pdftron::PDF::Flattener::~Flattener | ( |  | ) |

## Member Function Documentation

## ◆ Destroy()

void pdftron::PDF::Flattener::Destroy | ( |  | ) |

Frees the native memory of the object.

## ◆ Process() [1/2]

void pdftron::PDF::Flattener::Process | ( | PDF::Page & | page,
|  | enum FlattenMode | mode )

Process the given page, flattening content that matches the mode criteria.

Parameters

  page | the page to flatten.
  mode | indicates the criteria for which elements are flattened.

## ◆ Process() [2/2]

void pdftron::PDF::Flattener::Process | ( | pdftron::PDF::PDFDoc & | doc,
|  | enum FlattenMode | 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.

## ◆ SetDPI()

void pdftron::PDF::Flattener::SetDPI | ( | UInt32 | 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

## ◆ SetJPGQuality()

void pdftron::PDF::Flattener::SetJPGQuality | ( | UInt32 | 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).

## ◆ SetMaximumImagePixels()

void pdftron::PDF::Flattener::SetMaximumImagePixels | ( | UInt32 | max_pixels | ) |

Specifies the maximum image size in pixels.

Parameters

  max_pixels | the maximum number of pixels an image can have.

## ◆ SetPathHinting()

void pdftron::PDF::Flattener::SetPathHinting | ( | bool | enable_hinting | ) |

Enable or disable path hinting.

Parameters

  enable_hinting | if true path hinting is enabled. Path hinting is used to slightly adjust paths in order to avoid or alleviate artifacts of hair line cracks between certain graphical elements. This option is turned on by default.

## ◆ SetPreferJPG()

void pdftron::PDF::Flattener::SetPreferJPG | ( | bool | jpg | ) |

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

Parameters

  jpg | if true PDF will contain all JPEG images.

## ◆ SetThreshold()

void pdftron::PDF::Flattener::SetThreshold | ( | enum Threshold | 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.

The documentation for this class was generated from the following file:

- PDF/Flattener.h