This method uses the RGB color space for specifying the required color of the annotation object, here it is the border color of the circle or ellipse.

All specified coordinates need to be set in the current units defined in the PDF document with respect to the currently located origin, related to the actual page. You can use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units and you can use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

All specified coordinates need to be set in the current units defined in the PDF document with respect to the currently located origin, related to the actual page. You can use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units and you can use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

All specified coordinates need to be set in the current units defined in the PDF document with respect to the currently located origin, related to the actual page. You can use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units and you can use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

The ellipse is clearly defined by the center and the dimensions of its bounding box. All these coordinates need to be set in the current units defined in the PDF document with respect to the currently located origin, related to the actual page. You can use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units and you can use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

Supported font file formats are:

* .fon - Font resource file

* .fnt - Raw bitmap font file

* .ttf - Raw TrueType file

* .ttc - East Asian Windows: TrueType font collection

* .fot - TrueType resource file

* .otf - PostScript OpenType font

This method uses the RGB color space for specifying the required color of the annotation object, here it is the color of the line.

The coordinates of the specified point need to be set in the current units defined in the PDF document with respect to the currently located origin, related to the actual page. You can simply use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units and you can easily use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

This method uses the RGB color space for specifying the required color of the annotation object, here it is the color of the annotation's borders.

For further assistance, please see the Actions section of the GdPicturePDF class in the Reference Guide.

This method uses the RGB color space for specifying the required color of the annotation object, here it is the color of the annotation's borders.

For further assistance, please see the Actions section of the GdPicturePDF class in the Reference Guide.

A page labeling range is a series of consecutive pages using the same numbering system. The purpose of page labels is to identify each page visually on the screen or in print. Pages, that are included in the specific labeling range, are defined by the interval starting at the first page specified by the StartPage parameter and always ending at the last page of the document.

All labeling ranges are simply indexed by an integer value from 0 to GdPicturePDF.GetPageLabelsRangeCount-1.

The CTM parameter is part of the graphics state parameters. These parameters are initialized to their default values at the beginning of each page (see PDF Reference, Section "Graphics State").

The CTM parameter is part of the graphics state parameters. These parameters are initialized to their default values at the beginning of each page (see PDF Reference, Section "Graphics State").

You can use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units and you can use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

You can subsequently use other methods for assigning more form field properties.

This method uses the RGB color space for specifying the required color of the annotation object, here it is the border color of the square or rectangle.

This method uses the RGB color space for specifying the required color of the annotation object.

PDF prescribes a set of 14 standard fonts that can be used without prior definition. These include four faces each of three Latin text typefaces (Courier, Helvetica, And Times), as well as two symbolic fonts (Symbol And ITC ZapfDingbats®). These fonts, or suitable substitute fonts with the same metrics, are required to be available in all PDF consumer applications.

This method uses the RGB color space for specifying the required (background) color of the annotation object.

Since each text annotation makes use of an associated pop-up window, adding a text annotation to your document includes at the same adding an annotation object, that represents this pop-up window. The subtype attribute of this annotation is "Popup" and therefore the resulting count of all annotations in your document increases by two. This pop-up annotation object is inscribed in the internal structure of the current document.

A transformation matrix is a part of the graphics state and it specifies the relationship between two coordinate spaces. By modifying a transformation matrix, objects can be scaled, rotated, translated, or transformed in other ways. Although the transformation parameters specify a matrix, they are written as six separate numbers. The matrix can represent any linear transformation from one coordinate system to another.

- Translations are specified as [ 1, 0, 0, 1, tx, ty ], where tx and ty are the distances to translate the origin of the coordinate system in the horizontal and vertical dimensions, respectively.

- Scaling is obtained by [ sx, 0, 0, sy, 0, 0 ]. This scales the coordinates so that 1 unit in the horizontal and vertical dimensions of the new coordinate system is the same size as sx and sy units, respectively, in the previous coordinate system.

- Rotations are produced by [ cos a, sin a, -sin a, cos a, 0, 0 ], which has the effect of rotating the coordinate system axes by an angle a counterclockwise.

- Skew is specified by [ 1, tan a, tan b, 1, 0, 0 ], which skews the x axis by an angle a and the y axis by an angle b.

For more details, please refer to the PDF Reference, Section "Common Transformations".

The TrueType font format has been adopted as a standard font format for the Microsoft Windows operating system. A TrueType font program can be embedded directly in a PDF file as a stream object.

Deskewing a page can help a lot to do OCR, OMR, barcode detection or just improve the reliability of the page itself. You can benefit from using this method especially for documents mixing vector and raster content.

The coordinates of the specified point need to be set in the current units defined in the PDF document with respect to the currently located origin, related to the actual page. You can simply use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units and you can easily use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

A form XObject is a structure within a PDF document, that describes objects (text, images, vectors, etc.) used repetitively in the document to avoid multiple referencing of these objects in the document's content. So you can draw such a form XObject multiple times and it produces the same result on each specified location.

Just to inform you, that the toolkit offers the adaptive file caching mechanism to significantly reduce memory usage while cloning large documents. The feature is available in both 32-bit and 64-bit mode by default.

This method is a alternative to GdPicturePDF.ClonePage method in cases where multiple pages need to be cloned together.

Please note that if the specified form field does not contain any items, this method will fail.

It is not allowed (see PDF Reference, Section "Page Labels") to delete the page labeling range with the index 0, if more than one labeling range is defined in the PDF document.

This method implicitly calls the GdPicturePDF.CloseDocument method.

You can simply use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units and you can easily use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

You can simply use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units and you can easily use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

You can simply use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units and you can easily use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

The coordinates and the dimensions of the destination area need to be set in the current units defined in the PDF document, related to the actual page, where the required image is to be drawn. You can use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units and you can use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

You can simply use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units and you can easily use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

You can use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units and you can use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

You can simply use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units and you can easily use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

You can simply use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units and you can easily use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

You can simply use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units and you can easily use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

You can simply use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units and you can easily use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

You can simply use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units and you can easily use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

You can use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units together with the GdPicturePDF.GetOrigin method to determine the current origin location and you can also use the GdPicturePDF.SetMeasurementUnit method to reset the units together with the GdPicturePDF.SetOrigin method to reset the origin location according to your preference.

A form XObject is a structure within a PDF document, that describes objects (text, images, vectors, etc.) used repetitively in the document to avoid multiple referencing of these objects in the document's content. Each form XObject is identified by its unique resource name defined when creating the object.

This method is particularly useful if you want to apply a common page header and footer while keeping the file size as small as possible.

Heavy text and image content can considerably increase the size of the PDF document. During the compression process, the toolkit will remove unused objects and elements. This leads to a significantly reduced file size. Therefore the compression is particularly valuable for large images. This drastic reduction however does not affect any of the file's content but it will make your PDF files compact and easy to open.

The list of compression algorithms is extensive, for example, JPEG, JPEG2000 or JBIG2 for images, Flate or LZW for text as well as images, etc. The toolkit offers the Deflate compression algorithm.

The use of this method has the same effect as constructing two identical path objects, painting the first using the GdPicturePDF.FillPath method and the second using the GdPicturePDF.StrokePath method. Therefore all details related to the GdPicturePDF.FillPath and the GdPicturePDF.StrokePath method remain in effect. Be aware of your currently defined graphics state parameters, that both filling and stroking operations put into effect.

The use of this method has the same effect as the use of the method FillAndStrokePath(), except of the rule used to fill the path. Therefore all details related to the GdPicturePDF.FillAndStrokePath method remain in effect. Be aware of your currently defined graphics state parameters, that both filling and stroking operations put into effect.

Flattening an annotation means removing the annotation object from the document's internal structure and placing its data within the PDF document as regular item, so the previously defined annotation is no longer available for user's interaction.

At this time it is supported by the toolkit to only associate one action within one annotation object.

This color is used for the following purposes:

• The background of the annotation's icon when closed.
• The title bar of the annotation's pop-up window.
• The border of a link annotation.

It can be displayed text for the annotations, that support displaying text (like free text annotations) or an additional description for the other annotations in readable form. If the specified annotation is associated with an auxiliary pop-up window, it is the content of this pop-up window.

The standard annotation types are described in the PDF Reference, Section "Annotation Types". You can subsequently use the GdPicturePDF.GetAnnotationSubType method to find out the correct subtype ("Popup", "Text", "FreeText", etc.) of the specific annotation object.

Please note that the final count of all annotation objects on the current page also includes all those Popup annotation objects, that are expressly detected in the internal structure of the currently loaded PDF document.

This color is used for the following purposes:

• To specify the interior color with which to fill the annotation’s rectangle or ellipse (for Square or Circle annotation types).
• To specify the interior color with which to fill the annotation’s line endings (for Line, Polygon or PolyLine annotation types).

You can use the GdPicturePDF.SetMeasurementUnit method to reset the units and the GdPicturePDF.SetOrigin method to reset the origin's location according to your preference.

You can use the GdPicturePDF.SetMeasurementUnit method to reset the units and the GdPicturePDF.SetOrigin method to reset the origin's location according to your preference.

Bookmarks (also called outline items in the PDF Reference) are items organized in a tree-structured hierarchy, which serves as a visual table of contents to display the document’s structure to the user.

Bookmarks (also called outline items in the PDF Reference) are items organized in a tree-structured hierarchy, which serves as a visual table of contents to display the document’s structure to the user. A root bookmark is the first top-level bookmark item in this hierarchy.

Embedded files, so called File Attachments, can be included as a whole directly to a PDF document. Be aware that PDF documents can also contain attached files as part of the file attachment annotations. You can refer to our examples how to extract embedded files in both ways.

The file's security handler provides a mechanism that not only implements encryption in PDF documents, but also stores all data related to this process. The PDF specification defines two security handlers: Standard Security Handler and Public-Key Security Handler. Other applications may provide security handlers of their own.

The PDF specification defines different algorithms to be used to encrypt and/or decrypt a PDF document's content: RC4 40 bits, RC4 128 bits, AES 128 bits, AES 256 bits.

Be aware that PDF documents can also contain embedded files as a whole. Such files are called File Attachments and they are attached directly to a PDF document. You can refer to our examples how to extract embedded files in both ways.

A font for use with a PDF consumer application is prepared in the form of a program. Such a font program is written in a special-purpose language, that is understood by a specialized font interpreter.

A font program can be embedded in a PDF file as data contained in a PDF stream object. Such a stream object is also called a font file by analogy with font programs that are available from sources external to the consumer application.

The font encoding refers to the mapping of a character code to a particular glyph (character shape) description. Each font in a PDF uses a specific type of encoding, either a standard or a custom one. The following types of encoding are supported by the PDF file format: StandardEncoding, WinAnsiEncoding, MacRomanEncoding, MacExpertEncoding, and PDFDocEncoding. For a font that is embedded in the PDF file, the implicit base encoding is the font program's built-in encoding.

This name of the font can be used to find the font's definition in the consumer application or its environment. It is also the name that is used when printing to a PostScript output device.

For example, the most popular font types are TrueType and Adobe's Type 1, another are Type 3, Composite fonts and OpenType.

At this time it is supported by the toolkit to only associate one action within one form field.

This alternate name is used in place of the actual field name wherever the field must be identified in the user interface (such as in error or status messages referring to the field). This text is also useful when extracting the document’s content in support of accessibility to users with disabilities or for other purposes. For example, it can be displayed as the field's tooltip when users are hovering with the mouse over the field.

If this flag is set, then the text field is automatically divided into as many equally spaced positions, or combs, as the value of maximum length of the field's text defines, and the text is laid out into those combs. This flag is meaningful only if the MaxLen attribute is defined for the text form field and if the Multiline, Password, and FileSelect flags are not set.

If this flag is set, then the text field does not scroll to include more text than fits within its rectangle. Once the field is full, no further text is accepted.

If this flag is set, then text entered in the form field is not spell-checked.

If this flag is set, then the text entered in the text field represents the pathname of a file whose content are to be submitted as the value of the text field. By submission it is meant the use of the submit-form action, unfortunately the GdPicturePDF doesn't support this feature yet. The current value of the specified text field always represents the text entered in this field, please do not confuse it with the content of the file, whose pathname represents the text field value.

The fully qualified field name is constructed from the partial field name of the specified field and all of its ancestors, separated by a period (.) . For a field with no parent, the partial and fully qualified names are the same. For further assistance, please refer to the PDF Reference, Section "Field Names".

If this flag set, the new value is committed as soon as a selection is made with the pointing device. This option enables applications to perform an action once a selection is made, without requiring the user to exit the field. If this flag is not set, the new value is not committed until the user exits the field.

If this flag is set, the combo box includes an editable text box as well as a drop-down list, if this flag is not set, the combo box includes only a drop-down list. In other words, if the flag is set, the combo box is editable and allows to enter custom text.

If this flag is set, the field's items should be sorted alphabetically. Be aware that this flag is only bear in mind when creating or processing forms within applications, not by PDF viewer. Viewers should simply display the options in the order in which the corresponding items are added in the form field.

The item's text is the string to be displayed as the name of the specified option, it can be different than the item's (export) value.

The item's value is an export value assigned to the specified option, it can be different than the item's text.

You can use the GdPicturePDF.SetMeasurementUnit method to reset the units and the GdPicturePDF.SetOrigin method to reset the origin's location according to your preference.

If this flag is set, then the text field can contain multiple lines of text. It it is not set, the field's text is restricted to a single line.

If this flag is set, more than one of the field's items may be selected simultaneously, if this flag is not set, no more than one item may be selected.

This caption is displayed when the button form field is not interacting with the user.

If this flag is set, then the text field is intended for entering a secure password that should not be echoed visibly to the screen. Instead, the characters typed from the keyboard should be displayed in some unreadable form, usually asterisks.

If this flag is set, a group of radio buttons within a radio button field that use the same value for the On state will turn on and off in unison; that is if one is checked, they are all checked. If this flag is not set, the buttons are mutually exclusive.

If this flag is set, then the user may not change the value of the field. Likewise, the field will not interact with the user in any way, for example, it will not respond to mouse clicks or mouse motion, etc.

If this flag is set, then the field must have a value at the time it is exported by a submit-form action. Unfortunately the GdPicturePDF doesn't support this feature yet.

If this flag is set, then the value of this text field should be represented as a rich text string. For further assistance, please refer to the PDF Reference, Section "Rich Text Strings".

Please use the GdPicturePDF.GetFormFieldId method to retrieve the unique form field identifier in order to correctly identify the specific form field object.

Sometimes fields may contain values that are not know until the document is viewed. This flag specifies whether to construct appearance streams and appearance dictionaries for form fields in the loaded document to properly render the document when viewing.

PDF Reference (see Section "Interactive Forms") defines these field types: Button Fields - these are push buttons, check boxes and radio buttons, Text Fields, Choice Fields - these are combo boxes and list boxes, and Signature Fields.

The toolkit supports XMP format of metadata, which is the standard for embedding metadata in files. For further assistance, please refer to the core XMP specification published as ISO standard 16684-1.

Optional Content Groups, also knows as Layers, are a very effective tool to control the visibility of the page content, that can be selectively viewed or hidden, by users or viewers.

The Export state indicates, if the content in this group is exported, when the document (or part of it) is saved by a viewer application to a format, that does not support optional content (for example, an earlier version of PDF or a raster image format).

The Intent setting provides a way to distinguish between different intended uses of optional content. PDF 1.5 defines two names, View and Design, to indicate the intended use of the graphics in the optional content group.

The Locked state indicates, if this group is for information only. Producers can use this state to prevent the visibility of this group from being changed by users.

The Print state indicates, if the content of this group is printable.

The View state indicates the onscreen visibility, that means if the content of this group is viewable.

It is the maximum value of a defined range of magnifications below which the content of this optional content group is best viewed.

It is the minimum value of a defined range of magnifications at which the content of this optional content group is best viewed.

You can simply use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units or you can easily use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

You can simply use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units or you can easily use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

The coordinates are expressed in the currently defined units in the PDF document with respect to the currently defined origin, related to the actual page. You can use the GdPicturePDF.SetMeasurementUnit method to reset the units and the GdPicturePDF.SetOrigin method to reset the origin's location according to your preference.

This value expresses the number of degrees by which the current page should be rotated clockwise when displayed or printed. It must always be a multiple of 90.

Just to inform you, that you can use the GdPicturePDF.GuessPageTextRotation method to determine if the presented text is rotated on the current page.

Just to inform you, that you can use the GdPicturePDF.GuessPageTextRotation method to determine if all text is rotated on the current page.

the horizontal (X) coordinate of the top left point of the rendering area + [FieldSeparator] +

the vertical (Y) coordinate of the top left point of the rendering area + [FieldSeparator] +

the horizontal (X) coordinate of the top right point of the rendering area + [FieldSeparator] +

the vertical (Y) coordinate of the top right point of the rendering area + [FieldSeparator] +

the horizontal (X) coordinate of the bottom right point of the rendering area + [FieldSeparator] +

the vertical (Y) coordinate of the bottom right point of the rendering area + [FieldSeparator] +

the horizontal (X) coordinate of the bottom left point of the rendering area + [FieldSeparator] +

the vertical (Y) coordinate of the bottom left point of the rendering area + [FieldSeparator] +

extracted word + [FieldSeparator] +

font name + [FieldSeparator] +

font box height + [FieldSeparator] +

text mode + [FieldSeparator] +

text size + EOL

The rendering area means the rectangle area on the page where the extracted word is really situated (rendered). You can use the provided coordinates to easily calculate the dimensions of this area and the text rotation angle, for more details please refer to the second example below. You can also benefit from using the GdPicturePDF.GuessPageTextRotation method if the presented text is rotated in various angles on the current page.

The result for the current page should contain exactly the same number of lines as is the count of all words including the space-words in the text on that page.

Please note that you need to create or load the PDF document properly to get the valid value, otherwise the method does nothing. At the same, the specified value only relates to the currently selected page.

You can simply use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units or you can easily use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

PDF/A is an ISO-standardized version of the PDF specialized for the digital preservation of electronic documents. It is a subset of the PDF standard which excludes those PDF features that give rise to concerns about security and the ability to archive documents long term.

At this time, the toolkit only identifies and supports the standard structure type, so-called tag type, named Document as the root element of the document's tag structure tree.

You can use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units and you can also use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

The resulting rotation value is measured considering all presented text on the page. Each single text rotation is recognised and the most represented (prevailing) value is returned.

Be aware that the text rotation is calculated relative to the page, that said the current page rotation is not considered here. You can use the GdPicturePDF.NormalizePage method to eliminate the potential page rotation before computing the text rotation.

XFA stands for XML Forms Architecture, which is Adobe’s proprietary XML-based form technology and it has not been standardized in any public specification. With introducing the first version of PDF 2.0 as ISO-32000-2 published in May 2017, XFA entries have been officially excluded from this specification Therefore this format is not supported by GdPicturePDF and we will never support it in the future as well.

Please note that you may encounter potential rendering problems when viewing a PDF document with XFA forms using GdPicturePDF. Probably you will see this fallback message introduced by Adobe: "If this message is not eventually replaced by the proper content of the document, your PDF viewer may not be able to display this type of document."

The PDF version number uses a form M.m, where M is the major version number and m is the minor version number. This version is stated in the PDF header, which is the first line in the PDF file.

Please note that you have to specify the full version number using this method. For example, for increasing to the version 1.6, you have to set the Version parameter to 1.6, or for increasing to 2.0 you have to set the Version parameter to 2.0.

Please read more about providing the passwords in the GdPicturePDF.SetPassword method.

Font embedding means that a full copy of the entire character set of a font is stored in the PDF. A font program can be embedded in a PDF file as data contained in a PDF stream object (also called a font file). Such font programs are subject to copyright, and the copyright owner may impose conditions under which a font program can be used.

Please read more about the password and permissions security in the GdPicturePDF.IsEncrypted method and in the GdPicturePDF.SetPassword method.

A PDF Portfolio contains multiple files put together into a single PDF file. The files in a PDF Portfolio can be in a wide range of file types created in different applications, but the original files hold their individual identities. You can open, read, edit, and format each component file independently of the other component files in the PDF Portfolio.

All standard structure type names (tag's names) (see PDF Reference, Section "Standard Structure Types") may be used in the PDF/UA-1 conformed documents. If other names are used, a mapping of those custom names to the standard type names must be provided in the document's RoleMap entry. This way a structure tree element (tag) name is always mapped to its corresponding name in the role map, if there is one defined.

Pages content will be appended to the first page in list in corresponding order and first page height will be incremented with each appended page.

Optional Content Groups, also knows as Layers, are a very effective tool to control the visibility of the page content, that can be selectively viewed or hidden, by users or viewers.

This method involves a rasterization process so any existing visible text within the current page will become a part of the image of that page before the OCR process starts. The same applies to the invisible text contained within the current page. It is not kept because of the rasterization process, which simply means any invisible text is removed from the page before the OCR process starts.

This method uses one thread when processing. You can also benefit from using several OCR related events like GdPicturePDF.BeforePageOcr, GdPicturePDF.OcrPagesProgress and GdPicturePDF.OcrPagesDone.

This method is useful primarily for PDF documents intended for storing or archiving to reduce its file size. The toolkit replaces the fully embedded fonts included in the document with their corresponding subsets and removes all other unnecessary data found in the existing font files as well. Be aware that subsequent editing of such optimized document may lead to insufficient rendering.

A vector-based PDF uses line segments to define all of the geometry on the page. The display of the geometry remains sharp when you zoom in to see details of the drawing, and measurements and takeoffs (as well as their calibration) are more precise in a vector PDF.

This method is particularly useful when you remove pages or split large PDF documents to smaller ones. Sometimes it happens that shared document resources are transferred to single pages when splitting, or they have been left unused after removing their source pages. You can simply use this method to eliminate such redundant resources and to reduce the file size if necessary.

XFA stands for XML Forms Architecture, which is Adobe’s proprietary XML-based form technology and it has not been standardized in any public specification. With introducing the first version of PDF 2.0 as ISO-32000-2 published in May 2017, XFA entries have been officially excluded from this specification Therefore this format is not supported by GdPicturePDF and we will never support it in the future as well.

Please note that you may encounter potential rendering problems when viewing a PDF document with XFA forms using GdPicturePDF. Probably you will see this fallback message introduced by Adobe: "If this message is not eventually replaced by the proper content of the document, your PDF viewer may not be able to display this type of document."

Please note that both parameters relate to the same image located on the current page. At the same, this method can be used for image-based pages only, as the MRC engine always draws resulting images on the entire page surface. The attached example demonstrates the proper use of the method.

The graphics on a PDF page are described by a sequence of draw operators, graphics state operators, and marked-content operators. The graphics state operators change the graphics state (set the line width, dash pattern, fill color, font size etc.) and the result of draw operators are affected by the graphics state.

According to the PDF Reference, Section "Graphics State", a PDF consumer application maintains an internal data structure called the graphics state that holds current graphics control parameters. These parameters define the global framework within which the graphics operators execute. For example, the fill operator implicitly uses the current color parameter, and the stroke operator additionally uses the current line width parameter from the graphics state. The graphics state is initialized at the beginning of each page with the values specified in the PDF Reference, Section "Graphics State".

The graphics on a PDF page are described by a sequence of draw operators, graphics state operators, and marked-content operators. The graphics state operators change the graphics state (set the line width, dash pattern, fill color, font size etc) and the result of draw operators are affected by the graphics state. Please see also the GdPicturePDF.ResetGraphicsState method for more details.

The graphics on a PDF page are described by a sequence of draw operators, graphics state operators, and marked-content operators. The graphics state operators change the graphics state (set the line width, dash pattern, fill color, font size etc) and the result of draw operators are affected by the graphics state. Please see also the GdPicturePDF.ResetGraphicsState method for more details.

The content of a PDF file can be updated incrementally without rewriting the entire file. Changes are appended to the end of the file, leaving its original content intact. The main advantage to updating a file in this way is that small changes to a large document can be saved quickly (see PDF Reference, Section "Incremental updates").

The content of a PDF file can be updated incrementally without rewriting the entire file. Changes are appended to the end of the file, leaving its original content intact. The main advantage to updating a file in this way is that small changes to a large document can be saved quickly (see PDF Reference, Section "Incremental updates").

At this time it is supported by the toolkit to only associate one action within one annotation object.

It can be displayed text for the annotations, that support displaying text (like free text annotations) or an additional description for the other annotations in readable form. If the specified annotation is associated with an auxiliary pop-up window, it is the content of this pop-up window.

If the loaded PDF document contains metadata stored in the Metadata entry in the document catalog, the newly specified Author property is synchronized with those metadata. That means, you will be able to see the changed value of this property using the Acrobat's Document Properties dialogue box.

Blending modes are used to determine how two layers are blended into each other (affect one another) through more complex methods. Some blending modes exist to create special effects, some are used to give you more control when using adjustment layers to correct photographs.

The blend mode parameter is one of the graphics state parameters. These parameters are initialized to their default values at the beginning of each page (see PDF Reference, Section "Graphics State").

Please note that firstly you need to create or load the PDF document to allow this setting to work properly. Secondly, you need to set the compression scheme before adding the required image to the current document.

Please note that firstly you need to create or load the PDF document to allow this setting to work properly. Secondly, you need to set the compression scheme before adding the required image to the current document.

If the loaded PDF document contains metadata stored in the Metadata entry in the document catalog, the newly specified Creator property is synchronized with those metadata. That means, you will be able to see the changed value of this property using the Acrobat's Document Properties dialogue box.

The alpha constant parameter is one of the graphics state parameters. These parameters are initialized to their default values at the beginning of each page (see PDF Reference, Section "Graphics State").

This alternate name is used in place of the actual field name wherever the field must be identified in the user interface (such as in error or status messages referring to the field). For example, it can be displayed as the field's tooltip when users are hovering with the mouse over the field.

This text is also useful when extracting the document’s content in support of accessibility to users with disabilities or for other purposes. For the proper usage, please refer to the GdPicturePDF.AttachTagToFormField method.

If this flag is set, then the text field is automatically divided into as many equally spaced positions, or combs, as the value of maximum length of the field's text defines, and the text is laid out into those combs. This flag is meaningful only if the MaxLen attribute is defined for the text form field and if the Multiline, Password, and FileSelect flags are not set.

If this flag is set, then the text field does not scroll to include more text than fits within its rectangle. Once the field is full, no further text is accepted.

If this flag is set, then text entered in the form field is not spell-checked.

If this flag is set, then the text entered in the text field represents the pathname of a file whose content are to be submitted as the value of the text field. By submission it is meant the use of the submit-form action, unfortunately the GdPicturePDF doesn't support this feature yet. The current value of the specified text field always represents the text entered in this field, please do not confuse it with the content of the file, whose pathname represents the text field value.

If this flag set, the new value is committed as soon as a selection is made with the pointing device. This option enables applications to perform an action once a selection is made, without requiring the user to exit the field. If this flag is not set, the new value is not committed until the user exits the field. Be aware that it is only allowed to set this flag if the MultiSelect flag is not set for a list box, otherwise the method will fail.

If this flag is set, the combo box includes an editable text box as well as a drop-down list, if this flag is not set, the combo box includes only a drop-down list. In other words, if the flag is set, the combo box is editable and allows to enter custom text.

If this flag is set, the field's items should be sorted alphabetically. Be aware that this flag is only bear in mind when creating or processing forms within applications, not by PDF viewer. Viewers should simply display the options in the order in which the corresponding items are added in the form field.

You can use the GdPicturePDF.SetMeasurementUnit method to reset the units and the GdPicturePDF.SetOrigin method to reset the origin's location according to your preference.

If this flag is set, then the text field can contain multiple lines of text. It it is not set, the field's text is restricted to a single line.

If this flag is set, more than one of the field's items may be selected simultaneously, if this flag is not set, no more than one item may be selected. If you set this flag to false when it has been previously set to true, the current selection is removed and the last item in the list box is selected by default.

Be aware that it is only allowed to set this flag if the CommitOnSelChange flag is not set for a list box, otherwise the method will fail.

This caption is displayed when the button form field is not interacting with the user.

If this flag is set, then the text field is intended for entering a secure password that should not be echoed visibly to the screen. Instead, the characters typed from the keyboard should be displayed in some unreadable form, usually asterisks.

If this flag is set, a group of radio buttons within a radio button field, that use the same value for the On state (radio button's choice attribute), will turn on and off in unison; that is if one is checked, they are all checked. If this flag is not set, the buttons in the group are mutually exclusive.

If you set this flag to true for a required radio button group, no radio button in the group is selected as On. If you set the flag to false, the first radio button in the group is selected as On.

If this flag is set, then the user may not change the value of the field. Likewise, the field will not interact with the user in any way, for example, it will not respond to mouse clicks or mouse motion, etc.

If this flag is set, then the field must have a value at the time it is exported by a submit-form action. Unfortunately the GdPicturePDF doesn't support this feature yet.

If this flag is set, then the value of this text field should be represented as a rich text string. For further assistance, please refer to the PDF Reference, Section "Rich Text Strings".

The value of the parameter Rotation must be always a multiple of 90, otherwise the method will fail. The default value is 0.

Sometimes fields may contain values that are not know until the document is viewed. This flag specifies whether to construct appearance streams and appearance dictionaries for form fields in the loaded document to properly render the document when viewing.

Please note that firstly you need to create or load the PDF document to allow this setting to work properly. Secondly, you need to set the required value before adding the source image to the current document.

Please note that firstly you need to create or load the PDF document to allow this setting to work properly. Secondly, you need to set the compression level before adding the required image to the current document.

If the loaded PDF document contains metadata stored in the Metadata entry in the document catalog, the newly specified Keywords are synchronized with those metadata. That means, you will be able to see the changed value of this property using the Acrobat's Document Properties dialogue box. At the same, if you need to add and store any kind of structured information into your existing document, you can also use the GdPicturePDF.SetMetadata method instead.

Please use comma or semi-colon as word separators in the specified Keywords parameter for single keywords.

This language serves to support the accessibility of documents to users with disabilities, specifically to enable proper vocalization, for example, through a screen reader or other text-to-speech engines. For further assistance, please refer to the PDF Reference, Section "Natural Language Specification".

The alpha constant parameter is one of the graphics state parameters. These parameters are initialized to their default values at the beginning of each page (see PDF Reference, Section "Graphics State").

The line cap parameter is one of the graphics state parameters. These parameters are initialized to their default values at the beginning of each page (see PDF Reference, Section "Graphics State").

The line join parameter is one of the graphics state parameters. These parameters are initialized to their default values at the beginning of each page (see PDF Reference, Section "Graphics State").

The line dash pattern parameter is one of the graphics state parameters. These parameters are initialized to their default values at the beginning of each page (see PDF Reference, Section "Graphics State").

The line width parameter is one of the graphics state parameters. These parameters are initialized to their default values at the beginning of each page (see PDF Reference, Section "Graphics State").

You can use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units and you can use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

The toolkit supports XMP format of metadata, which is the standard for embedding metadata in files. For further assistance, please refer to the core XMP specification published as ISO standard 16684-1.

The predefined value is -1, which means that the original resolution of the input image is used.

Smoothing improves the contrast of the image by reducing noise. That means the produced image is less pixelated, but it's file size can increase. The predefined value is true.

The Export state indicates, if the content in this group is exported, when the document (or part of it) is saved by a viewer application to a format, that does not support optional content (for example, an earlier version of PDF or a raster image format).

The Locked state indicates, if this group is for information only. Producers can use this state to prevent the visibility of this group from being changed by users.

The Print state indicates, if the content of this group is printable.

The View state indicates the onscreen visibility, that means if the content of this group is viewable.

It is the maximum value of a defined range of magnifications below which the content of this optional content group is best viewed.

It is the minimum value of a defined range of magnifications at which the content of this optional content group is best viewed.

You can simply use the GdPicturePDF.GetMeasurementUnit method to determine the currently defined units or you can easily use the GdPicturePDF.SetMeasurementUnit method to reset the units according to your preference.

Tags provide an additional information that allow page content to be extracted and reused for other purposes.

Please note that you need to create or load the PDF document properly to set the valid value, otherwise the method does nothing. At the same, the specified value only relates to the currently selected page.

Please read more about the password and permissions security in the GdPicturePDF.IsEncrypted method.

This method can be particularly useful if you need to append content on the background of the page, for example drawing an image behind existing text.

If the loaded PDF document contains metadata stored in the Metadata entry in the document catalog, the newly specified Producer property is synchronized with those metadata. That means, you will be able to see the changed value of this property using the Acrobat's Document Properties dialogue box.

A value of PdfSignatureCertificationLevel.NotCertified defines the standard (ordinary) recipient digital signature, while other values introduce an author or certifying signatures (modification detection and prevention). Hence PDF files can be certified only once, but if permissions allow, can be digitally signed many times.

Regarding certifying signatures, the level means the author’s specification of which changes to the document will invalidate the signature. A value of PdfSignatureCertificationLevel.NoChanges indicates that the document is intended to be final; that is, any changes invalidate the signature. The values PdfSignatureCertificationLevel.FormFilling and PdfSignatureCertificationLevel.FormFillingAndAnnotations permit modifications that are appropriate for form field or comment workflow.

You can find more details about the SHA algorithms in RFC 6234 US Secure Hash Algorithms (SHA And SHA-based HMAC And HKDF).

If the loaded PDF document contains metadata stored in the Metadata entry in the document catalog, the newly specified Subject property is synchronized with those metadata. That means, you will be able to see the changed value of this property using the Acrobat's Document Properties dialogue box.

It is an exact replacement text for such content, that is represented in a nonstandard way. Generally, it should apply to as small piece of content as possible.

It is a text string in the readable form providing for items, located in the PDF document, that do not translate naturally into the text, such as images, formulas, actual form field names or annotations displaying text and others.

For further assistance, please refer to the PDF Reference, Section "Language Specification Hierarchy".

It is a text string in the readable form representing the specific structure element (tag), for example, Section 1 or Volume 1, etc.

The character spacing parameter is one of the text state parameters, that only affect text. The text state parameters are initialized to their default values at the beginning of each page (see PDF Reference, Section "Text State Parameters and Operators").

Please note that you need to create or load the PDF document to allow these settings to work properly. At the same, the settings are reset to an undefined value (TextExtractionOptions.Default), when creating or loading a new PDF document.

The text rendering mode parameter is one of the text state parameters, that only affect text. The text state parameters are initialized to their default values at the beginning of each page (see PDF Reference, Section "Text State Parameters and Operators").

The text rise parameter is one of the text state parameters, that only affect text. The text state parameters are initialized to their default values at the beginning of each page (see PDF Reference, Section "Text State Parameters and Operators").

The horizontal scaling parameter is one of the text state parameters, that only affect text. The text state parameters are initialized to their default values at the beginning of each page (see PDF Reference, Section "Text State Parameters and Operators").

The text size parameter is one of the text state parameters, that only affect text. The text state parameters are initialized to their default values at the beginning of each page (see PDF Reference, Section "Text State Parameters and Operators").

The word spacing parameter is one of the text state parameters, that only affect text. The text state parameters are initialized to their default values at the beginning of each page (see PDF Reference, Section "Text State Parameters and Operators").

If the loaded PDF document contains metadata stored in the Metadata entry in the document catalog, the newly specified Title property is synchronized with those metadata. That means, you will be able to see the changed value of this property using the Acrobat's Document Properties dialogue box.

Font embedding means that a full copy of the entire character set of a font is stored in the PDF. A font program can be embedded in a PDF file as data contained in a PDF stream object (also called a font file). Embedded fonts ensure that all of the font information needed to correctly visualize the document are always present. Removing this information might lead to decrease of the document quality and in rare cases to loss of information.

Certain types of fonts like font subsets or fonts with custom character mapping can not be unembedded using this method.

Please check the corresponded GdPicturePDF.BeforePageOcrEventHandler for given parameters.

Please check the corresponded GdPicturePDF.OcrPagesDoneEventHandler for given parameters.

Please check the corresponded GdPicturePDF.OcrPagesProgressEventHandler for given parameters.

Please check the corresponded GdPicturePDF.PageBitmapOcrReadyEventHandler for given parameters.