Image

touchgfx/widgets/Image.hpp

Simple widget capable of showing a bitmap on the display. The bitmap can be alpha-blended with the background (or whichever other Drawable might be "underneath" the Image). The bitmap can and have areas of varying opacity.

The conversion from image.bmp or image.png to a bitmap that can be used in TouchGFX is handled by the Image Converter as part of compiling the project. Each image is assigned a unique BITMAP identifier which.

See: Bitmap

Inherits from: Widget, Drawable

Inherited by: AnimatedImage, ScalableImage, TextureMapper, TiledImage

Public Functions

virtual void	draw(const Rect & invalidatedArea) const
	Draw this drawable.
uint8_t	getAlpha() const
	Gets the current alpha value of the widget.
Bitmap	getBitmap() const
	Gets the Bitmap currently assigned to the Image widget.
BitmapId	getBitmapId() const
	Gets the BitmapId currently assigned to the Image widget.
virtual Rect	getSolidRect() const
	Get (the largest possible) rectangle that is guaranteed to be solid (opaque).
	Image(const Bitmap & bmp =Bitmap())
	Constructs a new Image with a default alpha value of 255 (solid) and a default Bitmap (undefined) if none is specified.
virtual void	invalidateContent() const
	Tell the framework that the contents of the Drawable needs to be redrawn.
void	setAlpha(uint8_t newAlpha)
	Sets the opacity (alpha value).
virtual void	setBitmap(const Bitmap & bmp)
	Sets the bitmap for this Image and updates the width and height of this widget to match those of the Bitmap.

Protected Attributes

uint8_t	alpha
	The Alpha for this image.
Bitmap	bitmap
	The Bitmap to display.

Additional inherited members

Public Functions inherited from Widget

virtual void	getLastChild(int16_t , int16_t , Drawable ** last)
	Since a Widget is only one Drawable, Widget::getLastChild simply yields itself as result, but only if the Widget isVisible and isTouchable.

Public Functions inherited from Drawable

void	center()
	Centers the Drawable inside its parent.
void	centerX()
	Center the Drawable horizontally inside its parent.
void	centerY()
	Center the Drawable vertically inside its parent.
virtual void	childGeometryChanged()
	This function can be called on parent nodes to signal that the size or position of one or more of its children has changed.
	Drawable()
	Initializes a new instance of the Drawable class.
void	drawToDynamicBitmap(BitmapId id)
	Render the Drawable object into a dynamic bitmap.
void	expand(int margin =0)
	Expands the Drawable to have the same size as its parent with a given margin around the edge.
Rect	getAbsoluteRect() const
	Helper function for obtaining the rectangle this Drawable covers, expressed in absolute coordinates.
virtual Drawable *	getFirstChild()
	Function for obtaining the first child of this drawable if any.
int16_t	getHeight() const
	Gets the height of this Drawable.
virtual void	getLastChild(int16_t x, int16_t y, Drawable ** last) =0
	Function for obtaining the the last child of this drawable that intersects with the specified point.
Drawable *	getNextSibling()
	Gets the next sibling node.
Drawable *	getParent() const
	Returns the parent node.
const Rect &	getRect() const
	Gets the rectangle this Drawable covers, in coordinates relative to its parent.
virtual Rect	getSolidRectAbsolute()
	Helper function for obtaining the largest solid rect (as implemented by getSolidRect()) expressed in absolute coordinates.
virtual void	getVisibleRect(Rect & rect) const
	Function for finding the visible part of this drawable.
int16_t	getWidth() const
	Gets the width of this Drawable.
int16_t	getX() const
	Gets the x coordinate of this Drawable, relative to its parent.
int16_t	getY() const
	Gets the y coordinate of this Drawable, relative to its parent.
virtual void	handleClickEvent(const ClickEvent & event)
	Defines the event handler interface for ClickEvents.
virtual void	handleDragEvent(const DragEvent & event)
	Defines the event handler interface for DragEvents.
virtual void	handleGestureEvent(const GestureEvent & event)
	Defines the event handler interface for GestureEvents.
virtual void	handleTickEvent()
	Called periodically by the framework if the Drawable instance has subscribed to timer ticks.
virtual void	invalidate() const
	Tell the framework that this entire Drawable needs to be redrawn.
virtual void	invalidateRect(Rect & invalidatedArea) const
	Request that a region of this drawable is redrawn.
bool	isTouchable() const
	Gets whether this Drawable receives touch events or not.
bool	isVisible() const
	Gets whether this Drawable is visible.
virtual void	moveRelative(int16_t x, int16_t y)
	Moves the drawable.
virtual void	moveTo(int16_t x, int16_t y)
	Moves the drawable.
virtual void	setHeight(int16_t height)
	Sets the height of this drawable.
void	setPosition(const Drawable & drawable)
	Sets the position of the Drawable to the same as the given Drawable.
void	setPosition(int16_t x, int16_t y, int16_t width, int16_t height)
	Sets the size and position of this Drawable, relative to its parent.
void	setTouchable(bool touch)
	Controls whether this Drawable receives touch events or not.
void	setVisible(bool vis)
	Controls whether this Drawable should be visible.
virtual void	setWidth(int16_t width)
	Sets the width of this drawable.
void	setWidthHeight(const Bitmap & bitmap)
	Sets the dimensions (width and height) of the Drawable without changing the x and y coordinates).
void	setWidthHeight(const Drawable & drawable)
	Sets the dimensions (width and height) of the Drawable without changing the x and y coordinates).
void	setWidthHeight(const Rect & other)
	Sets the dimensions (width and height) of the Drawable without changing the x and y coordinates).
void	setWidthHeight(int16_t width, int16_t height)
	Sets the dimensions (width and height) of the Drawable without changing the x and y coordinates).
virtual void	setX(int16_t x)
	Sets the x coordinate of this Drawable, relative to its parent.
void	setXY(const Drawable & drawable)
	Sets the x and y coordinates of this Drawable.
void	setXY(int16_t x, int16_t y)
	Sets the x and y coordinates of this Drawable, relative to its parent.
virtual void	setY(int16_t y)
	Sets the y coordinate of this Drawable, relative to its parent.
virtual void	translateRectToAbsolute(Rect & r) const
	Helper function for converting a region of this Drawable to absolute coordinates.
virtual	~Drawable()
	Finalizes an instance of the Drawable class.

Protected Attributes inherited from Drawable

Drawable *	nextSibling
	Pointer to the next Drawable.
Drawable *	parent
	Pointer to this drawable's parent.
Rect	rect
	The coordinates of this Drawable, relative to its parent.
bool	touchable
	True if this drawable should receive touch events.
bool	visible
	True if this drawable should be drawn.

Public Functions Documentation

draw

virtual void draw	(	const Rect &	invalidatedArea	)

Draw this drawable.

It is a requirement that the draw implementation does not draw outside the region specified by invalidatedArea.

Parameters:

invalidatedArea	The sub-region of this drawable that needs to be redrawn, expressed in coordinates relative to its parent (e.g. for a complete redraw, invalidatedArea will be (0, 0, width, height).

Reimplements: touchgfx::Drawable::draw

Reimplemented by: touchgfx::ScalableImage::draw, touchgfx::TextureMapper::draw, touchgfx::TiledImage::draw

getAlpha

uint8_t getAlpha	(			)	const

Gets the current alpha value of the widget.

The alpha value is in range 255 (solid) to 0 (invisible).

Returns:

The current alpha value.

See also:

setAlpha

getBitmap

Bitmap getBitmap	(			)	const

Gets the Bitmap currently assigned to the Image widget.

Returns:

The current Bitmap of the widget.

getBitmapId

BitmapId getBitmapId	(			)	const

Gets the BitmapId currently assigned to the Image widget.

Returns:

The current BitmapId of the widget.

getSolidRect

virtual Rect getSolidRect	(			)	const

Get (the largest possible) rectangle that is guaranteed to be solid (opaque).

This information is important, as any Drawable underneath the solid area does not need to be drawn.

Returns:

The solid rectangle part of the Drawable.

Note

The rectangle returned must be relative to upper left corner of the Drawable, meaning that a completely solid widget should return the full size Rect(0, 0, getWidth(), getHeight()). If no area can be guaranteed to be solid, an empty Rect must be returned. Failing to return the correct rectangle may result in errors on the display.

Reimplements: touchgfx::Drawable::getSolidRect

Reimplemented by: touchgfx::ScalableImage::getSolidRect, touchgfx::TextureMapper::getSolidRect, touchgfx::TiledImage::getSolidRect

Image

Image	(	const Bitmap &	bmp =Bitmap()	)

Constructs a new Image with a default alpha value of 255 (solid) and a default Bitmap (undefined) if none is specified.

If a Bitmap is passed to the constructor, the width and height of this widget is set to those of the bitmap.

Parameters:

bmp	(Optional) The bitmap to display.

See also:

setBitmap

invalidateContent

virtual void invalidateContent	(			)	const

Tell the framework that the contents of the Drawable needs to be redrawn.

If the Drawable is invisible, nothing happens. Subclasses of Drawable are encouraged to implement this function and invalidate as little as possible, i.e. the smallest rectangle covering the visual element(s) drawn by the widget.

Reimplements: touchgfx::Drawable::invalidateContent

Reimplemented by: touchgfx::TextureMapper::invalidateContent

setAlpha

void setAlpha	(	uint8_t	newAlpha	)

Sets the opacity (alpha value).

This can be used to fade it away by gradually decreasing the alpha value from 255 (solid) to 0 (invisible).

Parameters:

newAlpha	The new alpha value. 255=solid, 0=invisible.

Note

The user code must call invalidate() in order to update the display.

See also:

getAlpha

setBitmap

virtual void setBitmap	(	const Bitmap &	bmp	)

Sets the bitmap for this Image and updates the width and height of this widget to match those of the Bitmap.

Parameters:

bmp	The bitmap instance.

Note

The user code must call invalidate() in order to update the image on the display.

Reimplemented by: touchgfx::AnimatedImage::setBitmap, touchgfx::TextureMapper::setBitmap, touchgfx::TiledImage::setBitmap

Protected Attributes Documentation

alpha

uint8_t alpha

The Alpha for this image.

bitmap

Bitmap bitmap

The Bitmap to display.