PDFTron WebViewer Class: Element

Class: Element

Core .PDFNet. Element

new Element()

Element is the abstract interface used to access graphical elements used to build the display list. Just like many other classes in PDFNet (e.g. ColorSpace, Font, Annot, etc), Element class follows the composite design pattern. This means that all Elements are accessed through the same interface, but depending on the Element type (that can be obtained using GetType()), only methods related to that type can be called. For example, if GetType() returns e_image, it is illegal to call a method specific to another Element type (i.e. a call to a text specific GetTextData() will throw an Exception).

Members

<static> PathSegmentType

Properties:

Name	Type	Description
`e_moveto`	number
`e_lineto`	number
`e_cubicto`	number
`e_conicto`	number
`e_rect`	number
`e_closepath`	number

<static> Type

Properties:

Name	Type	Description
`e_null`	number
`e_path`	number
`e_text_begin`	number
`e_text`	number
`e_text_new_line`	number
`e_text_end`	number
`e_image`	number
`e_inline_image`	number
`e_shading`	number
`e_form`	number
`e_group_begin`	number
`e_group_end`	number
`e_marked_content_begin`	number
`e_marked_content_end`	number
`e_marked_content_point`	number

Methods

getBBox()

Obtains the bounding box for a graphical element. Calculates the bounding box for a graphical element (i.e. an Element that belongs to one of following types: e_path, e_text, e_image, e_inline_image, e_shading e_form). The returned bounding box is guaranteed to encompass the Element, but is not guaranteed to be the smallest box that could contain the element. For example, for Bezier curves the bounding box will enclose all control points, not just the curve itself.

Returns:

A promise that resolves to a rectangle specifying the bounding box of Element (a rectangle that surrounds the entire element). The coordinates are represented in the default PDF page coordinate system and are using units called points ( 1 point = 1/72 inch = 2.54 /72 centimeter). The bounding box already accounts for the effects of current transformation matrix (CTM), text matrix, font size, and other properties in the graphics state. If this is a non-graphical element, the bounding box is undefined.

Type: Promise.<Rect>

getBitsPerComponent()

Returns:

A promise that resolves to the number of bits used to represent each color component. Only a single value may be specified; the number of bits is the same for all color components. Valid values are 1, 2, 4, and 8.

Type: Promise.<number>

getCharIterator()

Returns:

A promise that resolves to a CharIterator addressing the first CharData element in the text run. CharIterator points to CharData. CharData is a data structure that contains the char_code number (used to retrieve glyph outlines, to map to Unicode, etc.), character positioning information (x, y), and the number of bytes taken by the character within the text buffer. Note: CharIterator follows the standard STL forward-iterator interface. An example of how to use CharIterator.

    for (CharIterator itr = element.GetCharIterator(); itr.HasNext(); itr.Next()) {
			unsigned int char_code = itr.Current().char_code;
			double char_pos_x = itr.Current().x;
			double char_pos_y = itr.Current().y;
    }

Note: Character positioning information (x, y) is represented in text space. In order to get the positioning in the user space, the returned value should be scaled using the text matrix (GetTextMatrix()) and the current transformation matrix (GetCTM()). See section 4.2 'Other Coordinate Spaces' in PDF Reference Manual for details and PDFNet FAQ "How do I get absolute/relative text and character positioning?". Note: within a text run a character may occupy more than a single byte (e.g. in case of composite/Type0 fonts). The role of CharIterator/CharData is to provide a uniform and easy to use interface to access character information.

Type: Promise.<Core.PDFNet.Iterator.<Core.PDFNet.CharData>>

getComponentNum()

Returns:

A promise that resolves to the number of color components per sample.

Type: Promise.<number>

getCTM()

Returns:

A promise that resolves to current Transformation Matrix (CTM) that maps coordinates to the initial user space.

Type: Promise.<Core.PDFNet.Matrix2D>

getDecodeArray()

Returns:

A promise that resolves to decode array or NULL if the parameter is not specified. A decode object is an array of numbers describing how to map image samples into the range of values appropriate for the color space of the image. If ImageMask is true, the array must be either [0 1] or [1 0]; otherwise, its length must be twice the number of color components required by ColorSpace. Default value depends on the color space, See Table 4.36 in PDF Ref. Manual.

Type: Promise.<Core.PDFNet.Obj>

getGState()

Returns:

A promise that resolves to gState of this Element

Type: Promise.<Core.PDFNet.GState>

getImageColorSpace()

Returns:

A promise that resolves to the SDF object representing the color space in which image are specified or NULL if the image is an image mask The returned color space may be any type of color space except Pattern.

Type: Promise.<Core.PDFNet.ColorSpace>

getImageData()

Returns:

A promise that resolves to a stream (filter) containing decoded image data

Type: Promise.<Core.PDFNet.Filter>

getImageDataSize()

Returns:

A promise that resolves to the size of image data in bytes

Type: Promise.<number>

getImageHeight()

Returns:

A promise that resolves to the height of the image, in samples.

Type: Promise.<number>

getImageRenderingIntent()

Returns:

A promise that resolves to the color rendering intent to be used in rendering the image.

Type: Promise.<number>

Example

Return value enum:
<pre>
PDFNet.GState.RenderingIntent = {
	e_absolute_colorimetric : 0
	e_relative_colorimetric : 1
	e_saturation : 2
	e_perceptual : 3
}
</pre>

getImageWidth()

Returns:

A promise that resolves to the width of the image, in samples.

Type: Promise.<number>

getMask()

Returns:

A promise that resolves to an image XObject defining an image mask to be applied to this image (See 'Explicit Masking', 4.8.5), or an array specifying a range of colors to be applied to it as a color key mask (See 'Color Key Masking'). If IsImageMask() return true, this method will return NULL.

Type: Promise.<Core.PDFNet.Obj>

getMCPropertyDict()

Returns:

A promise that resolves to a dictionary containing the property list or NULL if property dictionary is not present. Note: the function automatically looks under Properties sub-dictionary of the current resource dictionary if the dictionary is not in-line. Therefore you can assume that returned Obj is dictionary if it is not NULL.

Type: Promise.<Core.PDFNet.Obj>

getMCTag()

Returns:

A promise that resolves to a tag is a name object indicating the role or significance of the marked content point/sequence.

Type: Promise.<Core.PDFNet.Obj>

getNewTextLineOffset()

returns the offset (out_x, out_y) to the start of the current line relative to the beginning of the previous line. out_x and out_y are numbers expressed in unscaled text space units. The returned numbers correspond to the arguments of 'Td' operator.

Returns:

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

Type: Promise.<Object>

getParentStructElement()

Returns:

A promise that resolves to parent logical structure element (such as 'span' or 'paragraph'). If the Element is not associated with any structure element, the returned SElement will not be valid (i.e. selem.IsValid() -> false).

Type: Promise.<Core.PDFNet.SElement>

getPosAdjustment()

Returns:

A promise that resolves to the number used to adjust text matrix in horizontal direction when drawing text. The number is expressed in thousandths of a unit of text space. The returned number corresponds to a number value within TJ array. For 'Tj' text strings the returned value is always 0. Note: because CharIterator positioning information already accounts for TJ adjustments this method is rarely used.

Type: Promise.<number>

getShading()

Returns:

A promise that resolves to the SDF object of the Shading object.

Type: Promise.<Core.PDFNet.Shading>

getStructMCID()

Returns:

A promise that resolves to marked Content Identifier (MCID) for this Element or a negative number if the element is not assigned an identifier/MCID. Marked content identifier can be used to associate an Element with logical structure element that refers to the Element.

Type: Promise.<number>

getTextData()

Returns:

A promise that resolves to a pointer to the internal text buffer for this text element. Note: GetTextData() returns the raw text data and not a Unicode string. In PDF text can be encoded using various encoding schemes so it is necessary to consider Font encoding while processing the content of this buffer. Note: Most of the time GetTextString() is what you are looking for instead. GetTextString() maps the raw text directly into Unicode (as specified by Adobe Glyph List (AGL) ). Even if you would prefer to decode text yourself it is more convenient to use CharIterators returned by CharBegin()/CharEnd() and PDF::Font code mapping methods. Note: the buffer owner is the current element (i.e. ElementReader or ElementBuilder).

Type: Promise.<number>

getTextLength()

Returns:

A promise that resolves to the text advance distance in text space. The total sum of all of the advance values from rendering all of the characters within this element, including the advance value on the glyphs, the effect of properties such as 'char-spacing', 'word-spacing' and positioning adjustments on 'TJ' elements. Note: Computed text length is represented in text space. In order to get the length of the text run in the user space, the returned value should be scaled using the text matrix (GetTextMatrix()) and the current transformation matrix (GetCTM()). See section 4.2 'Other Coordinate Spaces' in PDF Reference Manual for details.

Type: Promise.<number>

getTextMatrix()

Returns:

A promise that resolves to a reference to the current text matrix (Tm).

Type: Promise.<Core.PDFNet.Matrix2D>

getTextString()

Returns:

A promise that resolves to a pointer to Unicode string for this text Element. The function maps character codes to Unicode array defined by Adobe Glyph List (http://partners.adobe.com/asn/developer/type/glyphlist.txt). Note: In PDF text can be encoded using various encoding schemes and in some cases it is not possible to extract Unicode encoding. If it is not possible to map charcode to Unicode the function will map a character to undefined code, 0xFFFD. This code is defined in private Unicode range. Note: If you would like to map raw text to Unicode (or some other encoding) yourself use CharIterators returned by CharBegin()/CharEnd() and PDF::Font code mapping methods. Note: The string owner is the current element (i.e. ElementReader or ElementBuilder).

Type: Promise.<string>

getType()

Returns:

A promise that resolves to the current element type.

Type: Promise.<number>

Example

Return value enum:
<pre>
PDFNet.Element.Type = {
	e_null : 0
	e_path : 1
	e_text_begin : 2
	e_text : 3
	e_text_new_line : 4
	e_text_end : 5
	e_image : 6
	e_inline_image : 7
	e_shading : 8
	e_form : 9
	e_group_begin : 10
	e_group_end : 11
	e_marked_content_begin : 12
	e_marked_content_end : 13
	e_marked_content_point : 14
}
</pre>

getXObject()

Returns:

A promise that resolves to the SDF object of the Image/Form object.

Type: Promise.<Core.PDFNet.Obj>

hasTextMatrix()

Returns:

A promise that resolves to true if this element is directly associated with a text matrix (that is Tm operator is just before this text element) or false if the text matrix is default or is inherited from previous text elements.

Type: Promise.<boolean>

isClippingPath()

Returns:

A promise that resolves to true if the current path element is a clipping path and should be added to clipping path stack.

Type: Promise.<boolean>

isClipWindingFill()

Returns:

A promise that resolves to true if the current clip path is using non-zero winding rule, or false for even-odd rule.

Type: Promise.<boolean>

isFilled()

Returns:

A promise that resolves to true if the current path element should be filled

Type: Promise.<boolean>

isImageInterpolate()

Returns:

A promise that resolves to a boolean indicating whether image interpolation is to be performed.

Type: Promise.<boolean>

isImageMask()

Returns:

A promise that resolves to a boolean indicating whether the inline image is to be treated as an image mask.

Type: Promise.<boolean>

isOCVisible()

Returns:

A promise that resolves to true if this element is visible in the optional-content context (OCG::Context). The method considers the context's current OCMD stack, the group ON-OFF states, the non-OC drawing status, the drawing and enumeration mode, and the intent. When enumerating page content, OCG::Context can be passed as a parameter in ElementReader.Begin() method. When using PDFDraw, PDFRasterizer, or PDFView class to render PDF pages use PDFDraw::SetOCGContext() method to select an OC context.

Type: Promise.<boolean>

isStroked()

Returns:

A promise that resolves to true if the current path element should be stroked

Type: Promise.<boolean>

isWindingFill()

Returns:

A promise that resolves to true if the current path should be filled using non-zero winding rule, or false if the path should be filled using even-odd rule. According non-zero winding rule, you can determine whether a test point is inside or outside a closed curve as follows: Draw a line from a test point to a point that is distant from the curve. Count the number of times the curve crosses the test line from left to right, and count the number of times the curve crosses the test line from right to left. If those two numbers are the same, the test point is outside the curve; otherwise, the test point is inside the curve. According to even-odd rule, you can determine whether a test point is inside or outside a closed curve as follows: Draw a line from the test point to a point that is distant from the curve. If that line crosses the curve an odd number of times, the test point is inside the curve; otherwise, the test point is outside the curve.

Type: Promise.<boolean>

setClipWindingFill(winding_rule)

sets clipping path's fill rule.

Parameters:

Name	Type	Description
`winding_rule`	boolean	if winding_rule is true clipping should use non-zero winding rule, or false for even-odd rule.

Returns:

Type: Promise.<void>

setNewTextLineOffset(dx, dy)

sets the offset (dx, dy) to the start of the current line relative to the beginning of the previous line.

Parameters:

Name	Type	Description
`dx`	number	horizontal offset to the start of the curret line
`dy`	number	vertical offset to the start of the current line

Returns:

Type: Promise.<void>

setPathClip(clip)

indicate whether the path is a clipping path or non-clipping path

Parameters:

Name	Type	Description
`clip`	boolean	true to set path to clipping path. False for non-clipping path.

Returns:

Type: Promise.<void>

setPathFill(fill)

indicate whether the path should be filled

Parameters:

Name	Type	Description
`fill`	boolean	true to set path to be filled. False for no fill path.

Returns:

Type: Promise.<void>

setPathStroke(stroke)

indicate whether the path should be stroked

Parameters:

Name	Type	Description
`stroke`	boolean	true to set path to be stroked. False for no stroke path.

Returns:

Type: Promise.<void>

setPathTypes(in_seg_types, count)

Parameters:

Name	Type	Description
`in_seg_types`	string
`count`	number

Returns:

Type: Promise.<void>

setPosAdjustment(adjust)

Parameters:

Name	Type	Description
`adjust`	number	number to set the horizontal adjustment to Note: Positive values move the current text element backwards (along text direction). Negative values move the current text element forward (along text direction).

Returns:

Type: Promise.<void>

setTextData(buf_text_data)

set the text data for the current e_text Element.

Parameters:

Name	Type	Description
`buf_text_data`	ArrayBuffer \| Int8Array \| Uint8Array \| Uint8ClampedArray	a pointer to a buffer containing text.

Returns:

Type: Promise.<void>

setTextMatrix(mtx)

Sets the text matrix for a text element.

Parameters:

Name	Type	Description
`mtx`	Core.PDFNet.Matrix2D	The new text matrix for this text element

Returns:

Type: Promise.<void>

setTextMatrixEntries(a, b, c, d, h, v)

Sets the text matrix for a text element. This method accepts text transformation matrix components directly. A transformation matrix in PDF is specified by six numbers, usually in the form of an array containing six elements. In its most general form, this array is denoted [a b c d h v]; it can represent any linear transformation from one coordinate system to another. For more information about PDF matrices please refer to section 4.2.2 'Common Transformations' in PDF Reference Manual, and to documentation for Matrix2D class.

Parameters:

Name	Type	Description
`a`	number	horizontal 'scaling' component of the new text matrix.
`b`	number	'rotation' component of the new text matrix.
`c`	number	'rotation' component of the new text matrix.
`d`	number	vertical 'scaling' component of the new text matrix.
`h`	number	horizontal translation component of the new text matrix.
`v`	number	vertical translation component of the new text matrix.

Returns:

Type: Promise.<void>

setWindingFill(winding_rule)

sets path's fill rule.

Parameters:

Name	Type	Description
`winding_rule`	boolean	if winding_rule is true path will be filled using non-zero winding fill rule, otherwise even-odd fill will be used.

Returns:

Type: Promise.<void>

updateTextMetrics()

Recompute the character positioning information (i.e. CharIterator-s) and text length. Element objects caches text length and character positioning information. If the user modifies the text data or graphics state the cached information is not correct. UpdateTextMetrics() can be used to recalculate the correct positioning and length information.

Returns:

Type: Promise.<void>