Wt::Render::WPdfRenderer Class Reference

An XHTML to PDF renderer. More...

#include <Wt/Render/WPdfRenderer.h>

Inheritance diagram for Wt::Render::WPdfRenderer:

Public Member Functions
	WPdfRenderer (HPDF_Doc pdf, HPDF_Page page=nullptr)
	Creates a new PDF renderer. More...
void	setMargin (double cm, WFlags< Side > sides=AllSides)
	Sets the page margins. More...
void	setDpi (int dpi)
	Sets the resolution. More...
void	addFontCollection (const std::string &directory, bool recursive=true)
	Adds a font collection. More...
void	setCurrentPage (HPDF_Page page)
	Sets the current page.
HPDF_Page	currentPage () const
	Returns the current page. More...
virtual double	pageWidth (int page) const override
	Returns the page width. More...
virtual double	pageHeight (int page) const override
	Returns the page height. More...
virtual double	margin (Side side) const override
	Returns the margin. More...
virtual WPaintDevice *	startPage (int page) override
	Returns a paint device to render a given page. More...
virtual void	endPage (WPaintDevice *device) override
	Stops painting on the given page.
virtual WPainter *	getPainter (WPaintDevice *device) override
	Returns a painter for the current page.
virtual HPDF_Page	createPage (int page)
	Creates a new page. More...
Public Member Functions inherited from Wt::Render::WTextRenderer
virtual	~WTextRenderer ()
	Destructor.
double	render (const WString &text, double y=0)
	Renders an XHTML fragment. More...
bool	setStyleSheetText (const WString &contents)
	Sets the contents of a cascading style sheet (CSS). More...
bool	useStyleSheet (const WString &filename)
	Appends an external cascading style sheet (CSS). More...
void	clearStyleSheet ()
	Clears the used stylesheet. More...
WString	styleSheetText () const
	Returns the CSS in use. More...
std::string	getStyleSheetParseErrors () const
	Returns all parse error information of the last call to setStyleSheetText. More...
double	textWidth (int page) const
	Returns the page text width. More...
double	textHeight (int page) const
	Returns the page text height. More...
void	setFontScale (double scale)
	Sets the scaling factor used for font rendering. More...
double	fontScale () const
	Returns the font scaling factor. More...
virtual void	paintNode (WPainter &painter, const Node &node)
	Paints an XHTML node. More...

Additional Inherited Members
Protected Member Functions inherited from Wt::Render::WTextRenderer
	WTextRenderer ()
	Constructor.

Detailed Description

An XHTML to PDF renderer.

This class implements an XHTML to PDF renderer. The rendering engine supports only a subset of XHTML. See the documentation of WTextRenderer for more information.

The renderer renders to a libharu PDF document (using WPdfImage).

By default it uses a pixel resolution of 72 DPI, which is the default for a WPdfImage, but differs from the default used by most browsers (which is 96 DPI and has nothing to do with the actual screen resolution). The pixel resolution can be configured using setDpi(). Increasing the resolution has the effect of scaling down the rendering. This can be used in conjunction with setFontScale() to scale the font size differently than other content.

Usage example:

extern "C" {
  HPDF_STATUS HPDF_UseUTFEncodings(HPDF_Doc pdf);
}
 
HPDF_Doc pdf = HPDF_New(error_handler, 0);
HPDF_UseUTFEncodings(pdf); // enables UTF-8 encoding with true type fonts
HPDF_Page page = HPDF_AddPage(pdf);
HPDF_Page_SetSize(page, HPDF_PAGE_SIZE_A4, HPDF_PAGE_PORTRAIT);
 
Render::WPdfRenderer renderer(pdf, page);
renderer.setMargin(2.54);
renderer.setDpi(96);
 
renderer.render("<p style=\"background-color: #c11\">Hello, world !</p>");
 
HPDF_SaveToFile(pdf, "hello.pdf");
HPDF_Free(pdf);

Font information is embedded in the PDF. Fonts supported are native PostScript fonts (Base-14) (only ASCII-7), or true type fonts (Unicode). See addFontCollection() for more information on how fonts are located.

Constructor & Destructor Documentation

WPdfRenderer()

Wt::Render::WPdfRenderer::WPdfRenderer	(	HPDF_Doc	pdf,
		HPDF_Page	page = nullptr
	)

Creates a new PDF renderer.

The PDF renderer will render on the given pdf (starting). If the page is not 0, then rendering will happen on this first page (and its page sizes will be taken into account).

Default margins are 0, and the default DPI is 72.

Member Function Documentation

addFontCollection()

void Wt::Render::WPdfRenderer::addFontCollection	(	const std::string &	directory,
		bool	recursive = true
	)

Adds a font collection.

If Wt has been configured to use libpango, then font matching and character selection is done by libpango, and calls to this method are ignored. See WPdfImage::addFontCollection() for more details.

If Wt was not configured to use libpango, you will have to add the directories where Wt should look for fonts. You will also have to specify the required font in the HTML source, e.g.:

Render::WPdfRenderer renderer(pdf, page);
// ...
renderer.render(Wt::utf8(u8"<p style=\"font-family: 'DejaVuSans', Arial\">\u00e9l\u00e8ve, fen\u00eatre, \u00e2me</p>"));

See also

WPdfImage::addFontCollection()

createPage()

HPDF_Page Wt::Render::WPdfRenderer::createPage ( int  page )

virtual

Creates a new page.

The default implementation creates a new page with the same dimensions as the previous page.

You may want to specialize this method to add e.g.~headers and footers.

currentPage()

HPDF_Page Wt::Render::WPdfRenderer::currentPage

(

)

const

Returns the current page.

This returns the page last created using createPage(), or the page set with setCurrentPage() page.

margin()

double Wt::Render::WPdfRenderer::margin ( Side  side ) const

overridevirtual

Returns the margin.

Returns the margin at given side (in pixel units).

Implements Wt::Render::WTextRenderer.

pageHeight()

double Wt::Render::WPdfRenderer::pageHeight ( int  page ) const

overridevirtual

Returns the page height.

Returns the total page height (in pixel units), including vertical margins.

Implements Wt::Render::WTextRenderer.

pageWidth()

double Wt::Render::WPdfRenderer::pageWidth ( int  page ) const

overridevirtual

Returns the page width.

Returns the total page width (in pixel units), including horizontal margins.

Implements Wt::Render::WTextRenderer.

setDpi()

void Wt::Render::WPdfRenderer::setDpi

(

int

dpi

)

Sets the resolution.

The resolution used between CSS pixels and actual page dimensions. Note that his does not have an effect on the de facto standard CSS resolution of 96 DPI that is used to convert between physical WLength units (like cm, inch and point) and pixels. Instead it has the effect of scaling down or up the rendered XHTML on the page.

The dpi setting also affects the pageWidth(), pageHeight(), and margin() pixel calculations.

The default resolution is 72 DPI.

setMargin()

void Wt::Render::WPdfRenderer::setMargin	(	double	cm,
		WFlags< Side >	sides = AllSides
	)

Sets the page margins.

This sets page margins, in cm, for one or more sides.

startPage()

WPaintDevice * Wt::Render::WPdfRenderer::startPage ( int  page )

overridevirtual

Returns a paint device to render a given page.

The render() method calls this function once for each page it wants to render.

Implements Wt::Render::WTextRenderer.