luciad::IIconPainter Class Reference

An icon painter can paint an icon as an Image. More...

#include <luciad/drawing/IIcon.h>

Public Member Functions
virtual	~IIconPainter ()=default
virtual double	getAnchorX () const =0
	Returns the x coordinate of the anchor point in pixels. More...
virtual double	getAnchorY () const =0
	Returns the y coordinate of the anchor point in pixels. More...
virtual double	getDisplayScale () const =0
	Returns the display scale for which this painter is optimized. More...
virtual size_t	getHeight () const =0
	Returns the height of this icon. More...
virtual size_t	getWidth () const =0
	Returns the width of this icon. More...
virtual std::shared_ptr< Image >	paint ()=0
	Paints the IIcon as an image. More...

Detailed Description

An icon painter can paint an icon as an Image.

This class can be used on any thread, so its implementation must be thread-safe.

Performance considerations: to make sure the rendering backend can avoid as much work as possible

• IIconPainter::paint must be as performant as possible. This can for example be done by implementing this function lazily, i.e. avoid generating the image in the constructor of the IIconPainter implementation.
• The same goes for the getWidth/getHeight, getAnchorX/getAnchorY methods. If possible, make these as performant as possible. If there is a more performant way to calculate these without painting the image, that is preferred. The reason is that the rendering backend might need these properties to determine if an icon should effectively be visible or not on the Map.

Since

2022.0

Constructor & Destructor Documentation

~IIconPainter()

virtual luciad::IIconPainter::~IIconPainter ( )

virtualdefault

Member Function Documentation

getAnchorX()

virtual double luciad::IIconPainter::getAnchorX ( ) const

pure virtual

Returns the x coordinate of the anchor point in pixels.

The anchor point is the location of the icon that (by default) is attached to an other object, e.g. a location on the map. This must be a value in the [0, getWidth()] range. A good default implementation is to return getWidth() / 2.0.

Remarks

This method may be invoked from different threads.

Returns

the x coordinate of the anchor point in pixels.

getAnchorY()

virtual double luciad::IIconPainter::getAnchorY ( ) const

pure virtual

Returns the y coordinate of the anchor point in pixels.

The anchor point is the location of the icon that (by default) is attached to an other object, e.g. a location on the map. This must be a value in the [0, getHeight()] range. A good default implementation is to return getHeight() / 2.0.

Remarks

This method may be invoked from different threads.

Returns

the y coordinate of the anchor point in pixels.

getDisplayScale()

virtual double luciad::IIconPainter::getDisplayScale ( ) const

pure virtual

Returns the display scale for which this painter is optimized.

This is not necessarily the same display as the one that was used to create this painter. Some icons may only have a limited number scaled versions of their icon available. This method can then be used by the rendering backend to discover this, and to paint it at the intended size.

Remarks

This method may be invoked from different threads.

Returns

the display scale for which this painter is optimized.

getHeight()

virtual size_t luciad::IIconPainter::getHeight ( ) const

pure virtual

Returns the height of this icon.

I.e. the height of the Image that is returned by IIconPainter::paint

Remarks

This method may be invoked from different threads.

Returns

the height of this icon.

getWidth()

virtual size_t luciad::IIconPainter::getWidth ( ) const

pure virtual

Returns the width of this icon.

I.e. the width of the Image that is returned by IIconPainter::paint.

Remarks

This method may be invoked from different threads.

• Returns

  the width of this icon.

paint()

virtual std::shared_ptr< Image > luciad::IIconPainter::paint ( )

pure virtual

Paints the IIcon as an image.

Returns

the image of this icon, never nullptr.

Remarks

This method may be invoked from different threads.