Apryse WebViewer Class: PDFRasterizer

Class: PDFRasterizer

Core .PDFNet. PDFRasterizer

new PDFRasterizer()

PDFRasterizer is a low-level PDF rasterizer. The main purpose of this class is to convert PDF pages to raster images (or bitmaps). Note: PDFRasterizer is a relatively low-level class. If you need to convert PDF page to an image format or a Bitmap, consider using PDFNet.PDFDraw. Similarly, if you are building an interactive PDF viewing application you may want to use PDFNet.PDFView instead.

Extends

Core.PDFNet.Destroyable

Members

<static> ColorPostProcessMode

Properties:

Name	Type	Description
`e_postprocess_none`	number
`e_postprocess_invert`	number
`e_postprocess_gradient_map`	number
`e_postprocess_night_mode`	number

<static> OverprintPreviewMode

Properties:

Name	Type	Description
`e_op_off`	number
`e_op_on`	number
`e_op_pdfx_on`	number

<static> Type

Properties:

Name	Type	Description
`e_BuiltIn`	number
`e_GDIPlus`	number

Methods

<static> create( [type])

PdFRasterizer constructor and destructor

Parameters:

Name	Type	Argument	Description
`type`	number	<optional>	PDFNet.PDFRasterizer.Type = { e_BuiltIn : 0 e_GDIPlus : 1 }

Returns:

A promise that resolves to an object of type: "PDFNet.PDFRasterizer"

Type: Promise.<Core.PDFNet.PDFRasterizer>

destroy()

Destructor

Inherited From:

Core.PDFNet.Destroyable#destroy

Returns:

Type: Promise.<void>

enableDisplayListCaching(enabled)

Parameters:

Name	Type	Description
`enabled`	boolean

Returns:

Type: Promise.<void>

getColorPostProcessMode()

Returns:

A promise that resolves to the current color post processing mode.

Type: Promise.<number>

Example

Return value enum:
<pre>
PDFNet.PDFRasterizer.ColorPostProcessMode = {
	e_postprocess_none : 0
	e_postprocess_invert : 1
	e_postprocess_gradient_map : 2
	e_postprocess_night_mode : 3
}
</pre>

getRasterizerType()

Returns:

A promise that resolves to the type of current rasterizer. Note: This method is deprecated, since the GDI+ rasterizer itself is deprecated and will be removed in a future version of PDFNet. It is strongly recommended to use the built-in rasterizer and to use the XPS print path where vector conversion is needed.

Type: Promise.<number>

Example

Return value enum:
<pre>
PDFNet.PDFRasterizer.Type = {
	e_BuiltIn : 0
	e_GDIPlus : 1
}
</pre>

rasterize(page, width, height, stride, num_comps, demult, device_mtx [, clip] [, scrl_clp_regions])

Draws the page into a given memory buffer.

Parameters:

Name	Type	Argument	Description
`page`	Core.PDFNet.Page		The page to rasterize.
`width`	number		The width of the target image in pixels.
`height`	number		The height of the target image in pixels (the number of rows).
`stride`	number		Stride determines the physical width (in bytes) of one row in memory. If this value is negative the direction of the Y axis is inverted. The absolute value of stride is of importance, because it allows rendering in buffers where rows are padded in memory (e.g. in Windows bitmaps are padded on 4 byte boundaries). Besides allowing rendering on the whole buffer stride parameter can be used for rendering in a rectangular subset of a buffer.
`num_comps`	number		The number (4 or 5) representing the number of color components in the device color space. For BGR+Alpha set this parameter to 4, and for CMYK+Alpha use 5. If other values are set, exceptions will be thrown.
`demult`	boolean		Specifies if the alpha is de-multiplied from the resulting color components.
`device_mtx`	Core.PDFNet.Matrix2D		Device transformation matrix that maps PDF page from PDF user space into device coordinate space (e.g. pixel space). PDF user space is represented in page units, where one unit corresponds to 1/72 of an inch.
`clip`	Core.PDFNet.Rect	<optional>	Optional parameter defining the clip region for the page. If the parameter is null or is not specified, PDFRasterizer uses page's crop box as a default clip region.
`scrl_clp_regions`	Core.PDFNet.Rect	<optional>	Optional parameter reserved for a future use.

Returns:

a memory buffer. The buffer must contain at least (stride * height) bytes.

Type: Promise.<Uint8Array>

rasterizeAnnot(annot, page, device_mtx, demult, cancel)

Parameters:

Name	Type	Description
`annot`	Core.PDFNet.Annot
`page`	Core.PDFNet.Page
`device_mtx`	Core.PDFNet.Matrix2D
`demult`	boolean
`cancel`	boolean

Returns:

A promise that resolves to an object of type: "PDFNet.OwnedBitmap"

Type: Promise.<Core.PDFNet.OwnedBitmap>

rasterizeSeparations(page, width, height, mtx, clip, cancel)

Draws the page into a given memory buffer. Note: This method is available on all platforms and in all rasterizer implementations.

Parameters:

Name	Type	Description
`page`	Core.PDFNet.Page	The page to rasterize.
`width`	number	The width of the target image in pixels.
`height`	number	The height of the target image in pixels (the number of rows).
`mtx`	Core.PDFNet.Matrix2D	Device transformation matrix that maps PDF page from PDF user space into device coordinate space (e.g. pixel space). PDF user space is represented in page units, where one unit corresponds to 1/72 of an inch.
`clip`	Core.PDFNet.Rect	Optional parameter defining the clip region for the page. If the parameter is null or is not specified, PDFRasterizer uses page's crop box as a default clip region.
`cancel`	boolean	An optional variable that can be used to stop the rendering thread.

Returns:

A promise that resolves to an object of type: "Array"

Type: Promise.<Array.<Core.PDFNet.Separation>>

setAnnotationState(annot, new_view_state)

Parameters:

Name	Type	Description
`annot`	Core.PDFNet.Annot
`new_view_state`	number	PDFNet.Annot.State = { e_normal : 0 e_rollover : 1 e_down : 2 }

Returns:

Type: Promise.<void>

setAntiAliasing(enable_aa)

Enable or disable anti-aliasing. Anti-Aliasing is a technique used to improve the visual quality of images when displaying them on low resolution devices (for example, low DPI computer monitors).

Parameters:

Name	Type	Description
`enable_aa`	boolean

Default Value:

Anti-aliasing is enabled by default.

Returns:

Type: Promise.<void>

setCaching( [enabled])

enables or disables caching. Caching can improve the rendering performance in cases where the same page will be drawn multiple times.

Parameters:

Name	Type	Argument	Description
`enabled`	boolean	<optional>	if true PDFRasterizer will cache frequently used graphics objects.

Returns:

Type: Promise.<void>

setColorPostProcessMode(mode)

Set the color post processing transformation. This transform is applied to the rasterized bitmap as the final step in the rasterization process, and is applied directly to the resulting bitmap (disregarding any color space information). Color post processing only supported for RGBA output.

Parameters:

Name	Type	Description
`mode`	number	PDFNet.PDFRasterizer.ColorPostProcessMode = { e_postprocess_none : 0 e_postprocess_invert : 1 e_postprocess_gradient_map : 2 e_postprocess_night_mode : 3 } is the specific transform to be applied

Returns:

Type: Promise.<void>

setDrawAnnotations(render_annots)

Enable or disable annotation and forms rendering. By default, annotations and forms are rendered.

Parameters:

Name	Type	Description
`render_annots`	boolean	True to draw annotations, false otherwise.

Returns:

Type: Promise.<void>

setDrawUIElements(draw_ui_elements)

Enable or disable drawing ui elements. Default is disabled.

Parameters:

Name	Type	Description
`draw_ui_elements`	boolean	true to draw ui elements, false otherwise.

Returns:

Type: Promise.<void>

setGamma(expgamma)

sets the gamma factor used for anti-aliased rendering.

Parameters:

Name	Type	Description
`expgamma`	number	is the exponent value of gamma function. Typical values are in the range from 0.1 to 3. Gamma correction can be used to improve the quality of anti-aliased image output and can (to some extent) decrease the appearance common anti-aliasing artifacts (such as pixel width lines between polygons). Note: Gamma correction is used only in the built-in rasterizer.

Returns:

Type: Promise.<void>

setHighlightFields(highlight)

Enable or disable highlighting form fields. Default is disabled.

Parameters:

Name	Type	Description
`highlight`	boolean	true to highlight, false otherwise.

Returns:

Type: Promise.<void>

setImageSmoothing( [smoothing_enabled] [, hq_image_resampling])

Enable or disable image smoothing. The rasterizer allows a tradeoff between rendering quality and rendering speed. This function can be used to indicate the preference between rendering speed and quality. Note: image smoothing option has effect only if the source image has higher resolution that the output resolution of the image on the rasterized page. PDFNet automatically controls at what resolution/zoom factor, 'image smoothing' needs to take effect.

Parameters:

Name	Type	Argument	Description
`smoothing_enabled`	boolean	<optional>	True to enable image smoothing, false otherwise.
`hq_image_resampling`	boolean	<optional>	True to use a higher quality (but slower) smoothing algorithm

Default Value:

image smoothing is enabled and hq_image_resampling is false.

Returns:

Type: Promise.<void>

setOCGContext(ctx)

sets the Optional Content Group (OCG) context that should be used when rendering the page. This function can be used to selectively render optional content (such as PDF layers) based on the states of optional content groups in the given context.

Parameters:

Name	Type	Description
`ctx`	Core.PDFNet.OCGContext	Optional Content Group (OCG) context, or NULL if the rasterizer should render all content on the page.

Returns:

Type: Promise.<void>

setOverprint(op)

enable or disable support for overprint and overprint simulation. Overprint is a device dependent feature and the results will vary depending on the output color space and supported colorants (i.e. CMYK, CMYK+spot, RGB, etc).

Parameters:

Name	Type	Description
`op`	number	PDFNet.PDFRasterizer.OverprintPreviewMode = { e_op_off : 0 e_op_on : 1 e_op_pdfx_on : 2 } e_op_on: always enabled; e_op_off: always disabled; e_op_pdfx_on: enabled for PDF/X files only.

Default Value:

By default overprint is only enabled for PDF/X files.

Returns:

Type: Promise.<void>

setPathHinting(enable_hinting)

Enable or disable path hinting.

Parameters:

Name	Type	Description
`enable_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>

setPrintMode(is_printing)

tells the rasterizer to render the page 'print' mode. Certain page elements (such as annotations or OCG-s) are meant to be visible either on the screen or on the printed paper but not both. A common example, is the "Submit" button on electronic forms.

Parameters:

Name	Type	Description
`is_printing`	boolean	set to true is the page should be rendered in print mode.

Default Value:

By default, print mode flag is set to false.

Returns:

Type: Promise.<void>

setRasterizerType(type)

Sets the core graphics library used for rasterization and rendering. Using this method it is possible to quickly switch between different implementations. By default, PDFNet uses a built-in, high-quality, and platform independent rasterizer.

Parameters:

Name	Type	Description
`type`	number	PDFNet.PDFRasterizer.Type = { e_BuiltIn : 0 e_GDIPlus : 1 } Rasterizer type. Note: This method is deprecated, since the GDI+ rasterizer itself is deprecated and will be removed in a future version of PDFNet. It is strongly recommended to use the built-in rasterizer and to use the XPS print path where vector conversion is needed.

Returns:

Type: Promise.<void>

setThinLineAdjustment(grid_fit, stroke_adjust)

Set thin line adjustment parameters.

Parameters:

Name	Type	Description
`grid_fit`	boolean	if true (horizontal/vertical) thin lines will be snapped to integer pixel positions. This helps make thin lines look sharper and clearer. This option is turned off by default and it only works if path hinting is enabled.
`stroke_adjust`	boolean	if true auto stroke adjustment is enabled. Currently, this would make lines with sub-pixel width to be one-pixel wide. This option is turned on by default.

Returns:

Type: Promise.<void>

setThinLineScaling(scaling)

This setting controls the thickness of zero-width lines when rendered. In a PDF, a line width of zero denotes the thinnest line that can be rendered at device resolution: 1 device pixel wide. However, on high-resolution devices, a single pixel can be nearly invisible.

Parameters:

Name	Type	Description
`scaling`	number	use this setting to increase the apparent thickness of these zero-width lines.

Default Value:

1.0 (1 pixel wide)

Returns:

Type: Promise.<void>

takeOwnership()

Take the ownership of this object, so that PDFNet.runWithCleanup won't destroy this object.

Inherited From:

Core.PDFNet.Destroyable#takeOwnership

Returns:

Type: void

updateBuffer()

this function is typically called for progressive rendering, in which we don't want to stop the main rendering thread. Since the rendering thread may modify separation channels, we don't consider separations in progressive rendering.

Returns:

Type: Promise.<void>