PDFTron WebViewer

Class: Flattener

PDFNet. Flattener

new Flattener()

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.

Extends

Members

<static> Mode

Properties:
Name Type Description
e_simple number
e_fast number

<static> Threshold

Properties:
Name Type Description
e_very_strict number
e_strict number
e_default number
e_keep_most number
e_keep_all number

Methods

<static> create()

Flattener constructor
Returns:
A promise that resolves to an object of type: "PDFNet.Flattener"
Type
Promise.<PDFNet.Flattener>

destroy()

Destructor
Inherited From:
Returns:
Type
Promise.<void>

process(doc, mode)

Process each page in the PDF, flattening content that matches the mode criteria.
Parameters:
Name Type Description
doc PDFNet.PDFDoc | PDFNet.SDFDoc | PDFNet.FDFDoc the document to flatten.
mode number 
PDFNet.Flattener.Mode = {
	e_simple : 0
	e_fast : 1
}
indicates the criteria for which elements are flattened.
Returns:
Type
Promise.<void>

processPage(page, mode)

Process the given page, flattening content that matches the mode criteria.
Parameters:
Name Type Description
page PDFNet.Page the page to flatten.
mode number 
PDFNet.Flattener.Mode = {
	e_simple : 0
	e_fast : 1
}
indicates the criteria for which elements are flattened.
Returns:
Type
Promise.<void>

setDPI(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:
Name Type Description
dpi number the resolution in Dots Per Inch
Returns:
Type
Promise.<void>

setJPGQuality(quality)

Specifies the compression quality to use when generating JPEG images.
Parameters:
Name Type Description
quality number the JPEG compression quality, from 0(highest compression) to 100(best quality).
Returns:
Type
Promise.<void>

setMaximumImagePixels(max_pixels)

Specifies the maximum image size in pixels.
Parameters:
Name Type Description
max_pixels number the maximum number of pixels an image can have.
Returns:
Type
Promise.<void>

setPathHinting(hinting)

Enable or disable path hinting.
Parameters:
Name Type Description
hinting boolean 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.
Returns:
Type
Promise.<void>

setPreferJPG(jpg)

Specifies whether to leave images in existing compression, or as JPEG.
Parameters:
Name Type Description
jpg boolean if true PDF will contain all JPEG images.
Returns:
Type
Promise.<void>

setThreshold(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:
Name Type Description
threshold number 
PDFNet.Flattener.Threshold = {
	e_very_strict : 0
	e_strict : 1
	e_default : 2
	e_keep_most : 3
	e_keep_all : 4
}
the threshold setting to use.
Returns:
Type
Promise.<void>

takeOwnership()

Take the ownership of this object, so that PDFNet.runWithCleanup won't destroy this object.
Inherited From:
Returns:
Type
void