Circle

Simple widget capable of drawing a circle, or part of a circle (an arc). The Circle can be filled or be drawn as a simple line along the circumference of the circle. Several parameters of the circle can be changed: Center, radius, line width, line cap, start angle and end angle.

Note:

Since the underlying CanwasWidgetRenderer only supports straight lines, the circle is drawn using many small straight lines segments. The granularity can be adjusted to match the requirements - large circles need more line segments, small circles need fewer line segments, to look smooth and round.
All circle parameters are internally handled as CWRUtil::Q5 which means that floating point values are rounded down to a fixed number of binary digits, for example:

Circle circle;
circle.setCircle(1.1f, 1.1f, 0.9); // Will use (35/32, 35/32, 28/32) = (1.09375f, 1.09375f, 0.875f)
int x, y, r;
circle.getCenter(&amp;x, &amp;y); // Will return (1, 1)
circle.getRadius(&amp;r); // Will return 0

Inherits from: CanvasWidget, Widget, Drawable

Public Functions


	Circle()


virtual bool	drawCanvasWidget(const Rect & invalidatedArea) const
	Draw canvas widget for the given invalidated area.

template \<typename T \> void	getArc(T & startAngle, T & endAngle) const
	Gets the start and end angles in degrees for the circle arc.

int16_t	getArcEnd() const
	Gets the end angle in degrees for the arc.

template \<typename T \> void	getArcEnd(T & angle) const
	Gets the end angle in degrees for the arc.

int16_t	getArcStart() const
	Gets the start angle in degrees for the arc.

template \<typename T \> void	getArcStart(T & angle) const
	Gets the start angle in degrees for the arc.

int	getCapPrecision() const
	Gets the precision of the ends of the Circle arc.

template \<typename T \> void	getCenter(T & x, T & y) const
	Gets the center coordinates of the Circle.

template \<typename T \> void	getLineWidth(T & width) const
	Gets line width.

virtual Rect	getMinimalRect() const
	Gets minimal rectangle containing the shape drawn by this widget.

Rect	getMinimalRect(CWRUtil::Q5 arcStart, CWRUtil::Q5 arcEnd) const
	Gets minimal rectangle containing a given circle arc using the set line width.

Rect	getMinimalRect(int16_t arcStart, int16_t arcEnd) const
	Gets minimal rectangle containing a given circle arc using the set line width.

int	getPrecision() const
	Gets the precision of the circle drawing function.

template \<typename T \> void	getRadius(T & r) const
	Gets the radius of the Circle.

void	setArc(const int16_t startAngle, const int16_t endAngle)
	Sets the start and end angles in degrees of the Circle arc.

template \<typename T \> void	setArc(const T startAngle, const T endAngle)
	Sets the start and end angles in degrees of the Circle arc.

void	setCapPrecision(const int precision)
	Sets the precision of the ends of the Circle arc.

void	setCenter(const int16_t x, const int16_t y)
	Sets the center of the Circle.

template \<typename T \> void	setCenter(const T x, const T y)
	Sets the center of the Circle.

void	setCircle(const int16_t x, const int16_t y, const int16_t r)
	Sets the center and radius of the Circle.

template \<typename T \> void	setCircle(const T x, const T y, const T r)
	Sets the center and radius of the Circle.

template \<typename T \> void	setLineWidth(const T width)
	Sets the line width for this Circle.

void	setPixelCenter(int x, int y)
	Sets the center of the circle / arc in the middle of a pixel.

void	setPrecision(const int precision)
	Sets precision of the Circle drawing function.

template \<typename T \> void	setRadius(const T r)
	Sets the radius of the Circle.

template \<typename T \> void	updateArc(const T startAngle, const T endAngle)
	Updates the start and end angle in degrees for this Circle arc.

template \<typename T \> void	updateArcEnd(const T endAngle)
	Updates the end angle in degrees for this Circle arc.

template \<typename T \> void	updateArcStart(const T startAngle)
	Updates the start angle in degrees for this Circle arc.

Protected Functions


void	updateArc(const CWRUtil::Q5 setStartAngleQ5, const CWRUtil::Q5 setEndAngleQ5)
	Updates the start and end angle in degrees for this Circle arc.

Additional inherited members

Public Functions inherited from CanvasWidget


	CanvasWidget()


virtual void	draw(const Rect & invalidatedArea) const
	Draws the given invalidated area.

virtual uint8_t	getAlpha() const
	Gets the current alpha value of the widget.

virtual AbstractPainter &	getPainter() const
	Gets the current painter for the CanvasWidget.

virtual Rect	getSolidRect() const
	Gets the largest solid (non-transparent) rectangle.

virtual void	invalidate() const
	Invalidates the area covered by this CanvasWidget.

void	resetMaxRenderLines()
	Resets the maximum render lines.

virtual void	setAlpha(uint8_t newAlpha)
	Sets the opacity (alpha value).

virtual void	setPainter(AbstractPainter & painter)
	Sets a painter for the CanvasWidget.


virtual void	getLastChild(int16_t x, int16_t y, 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.

virtual void	draw(const Rect & invalidatedArea) const =0
	Draw this drawable.

	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	getSolidRect() const =0
	Get (the largest possible) rectangle that is guaranteed to be solid (opaque).

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 & rect)
	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

Circle


Circle	(			)

drawCanvasWidget

Draw canvas widget for the given invalidated area.

Similar to draw(), but might be invoked several times with increasingly smaller areas to due to memory constraints from the underlying CanvasWidgetRenderer.

Parameters:


invalidatedArea	The invalidated area.

Returns:

true if the widget was drawn properly, false if not.

See also:

draw

Reimplements: touchgfx::CanvasWidget::drawCanvasWidget

getArc


void getArc	(	T &	startAngle ,	const
		T &	endAngle	const
		)	const

Gets the start and end angles in degrees for the circle arc.

Template Parameters:


T	Generic type parameter, either int or float.

Parameters:


startAngle	The start angle rounded down to the precision of T.
endAngle	The end angle rounded down to the precision of T.

See also:

setArc

getArcEnd


int16_t getArcEnd	(			)	const

Gets the end angle in degrees for the arc.

Returns:

The end angle for the arc rounded down to an integer.

See also:

getArc, setArc

getArcEnd

Gets the end angle in degrees for the arc.

Template Parameters:


T	Generic type parameter, either int or float.

Parameters:


angle	The end angle rounded down to the precision of T.

getArcStart


int16_t getArcStart	(			)	const

Gets the start angle in degrees for the arc.

Returns:

The starting angle for the arc rounded down to an integer.

See also:

getArc, setArc

getArcStart

Gets the start angle in degrees for the arc.

Template Parameters:


T	Generic type parameter, either int or float.

Parameters:


angle	The starting angle rounded down to the precision of T.

See also:

getArc, setArc

getCapPrecision


int getCapPrecision	(			)	const

Gets the precision of the ends of the Circle arc.

Returns:

The cap precision in degrees.

See also:

getCapPrecision

getCenter


void getCenter	(	T &	x ,	const
		T &	y	const
		)	const

Gets the center coordinates of the Circle.

Template Parameters:


T	Generic type parameter, either int or float.

Parameters:


x	The x coordinate of the center rounded down to the precision of T.
y	The y coordinate of the center rounded down to the precision of T.

See also:

setCenter

getLineWidth

Gets line width.

Template Parameters:


T	Generic type parameter, either int or float.

Parameters:


width	The line width rounded down to the precision of T.

See also:

setLineWidth

getMinimalRect


virtual Rect getMinimalRect	(			)	const

Gets minimal rectangle containing the shape drawn by this widget.

Default implementation returns the size of the entire widget, but this function should be overwritten in subclasses and return the minimal rectangle containing the shape. See classes such as Circle for example implementations.

Returns:

The minimal rectangle containing the shape drawn.

Reimplements: touchgfx::CanvasWidget::getMinimalRect

getMinimalRect


Rect getMinimalRect	(	CWRUtil::Q5	arcStart ,	const
		CWRUtil::Q5	arcEnd	const
		)	const

Gets minimal rectangle containing a given circle arc using the set line width.

Parameters:


arcStart	The arc start.
arcEnd	The arc end.

Returns:

The minimal rectangle.

getMinimalRect


Rect getMinimalRect	(	int16_t	arcStart ,	const
		int16_t	arcEnd	const
		)	const

Gets minimal rectangle containing a given circle arc using the set line width.

Parameters:


arcStart	The arc start.
arcEnd	The arc end.

Returns:

The minimal rectangle.

getPrecision


int getPrecision	(			)	const

Gets the precision of the circle drawing function.

The precision is the number of degrees used as step counter when drawing smaller line fragments around the circumference of the circle, the default being 5.

Returns:

The precision.

See also:

setPrecision

getRadius

Gets the radius of the Circle.

Template Parameters:


T	Generic type parameter, either int or float.

Parameters:


r	The radius rounded down to the precision of T.

setArc

Sets the start and end angles in degrees of the Circle arc.

0 degrees is straight up (12 o'clock) and 90 degrees is to the left (3 o'clock). Any positive or negative degrees can be used to specify the part of the Circle to draw.

Parameters:


startAngle	The start degrees.
endAngle	The end degrees.

Note

The area containing the Circle is not invalidated.

setArc

Sets the start and end angles in degrees of the Circle arc.

0 degrees is straight up (12 o'clock) and 90 degrees is to the left (3 o'clock). Any positive or negative degrees can be used to specify the part of the Circle to draw.

Template Parameters:


T	Generic type parameter, either int or float.

Parameters:


startAngle	The start degrees.
endAngle	The end degrees.

Note

The area containing the Circle is not invalidated.

setCapPrecision

Sets the precision of the ends of the Circle arc.

The precision is given in degrees where 180 is the default which results in a square ended arc (aka "butt cap"). 90 will draw "an arrow head" and smaller values gives a round cap. Larger values of precision results in faster rendering of the circle.

Parameters:


precision	The new cap precision.

Note

The circle is not invalidated. The cap precision is not used if the circle is filled (if line width is zero) or when a full circle is drawn.

setCenter

Sets the center of the Circle.

Parameters:


x	The x coordinate of center.
y	The y coordinate of center.

Note

The area containing the Circle is not invalidated.

See also:

setRadius, setCircle, getCenter

setCenter

Sets the center of the Circle.

Template Parameters:


T	Generic type parameter, either int or float.

Parameters:


x	The x coordinate of center.
y	The y coordinate of center.

Note

The area containing the Circle is not invalidated.

See also:

setRadius, setCircle, getCenter

setCircle

Sets the center and radius of the Circle.

Parameters:


x	The x coordinate of center.
y	The y coordinate of center.
r	The radius.

Note

The area containing the Circle is not invalidated.

See also:

setCenter, setRadius

setCircle

Sets the center and radius of the Circle.

Template Parameters:


T	Generic type parameter, either int or float.

Parameters:


x	The x coordinate of center.
y	The y coordinate of center.
r	The radius.

Note

The area containing the Circle is not invalidated.

See also:

setCenter, setRadius

setLineWidth

Sets the line width for this Circle.

If the line width is set to zero, the circle will be filled.

Template Parameters:


T	Generic type parameter, either int or float.

Parameters:


width	The width of the line measured in pixels.

Note

The area containing the Circle is not invalidated. if the new line with is smaller than the old width, the circle should be invalidated before updating the width to ensure that the old circle is completely erased.

setPixelCenter

Sets the center of the circle / arc in the middle of a pixel.

Normally the coordinate is between pixel number x and x+1 horizontally and between pixel y and y+1 vertically. This function will set the center in the middle of the pixel by adding 0.5 to both x and y.

Parameters:


x	The x coordinate of the center of the circle.
y	The y coordinate of the center of the circle.

setPrecision

Sets precision of the Circle drawing function.

The number given as precision is the number of degrees used as step counter when drawing the line fragments around the circumference of the circle, five being a reasonable value. Higher values results in less nice circles but faster rendering and possibly sufficient for very small circles. Large circles might require a precision smaller than five to make the edge of the circle look nice and smooth.

Parameters:


precision	The precision measured in degrees.

Note

The circle is not invalidated.

setRadius

Sets the radius of the Circle.

Template Parameters:


T	Generic type parameter, either int or float.

Parameters:


r	The radius.

Note

The area containing the Circle is not invalidated.

See also:

setCircle, setCenter, getRadius

updateArc

Updates the start and end angle in degrees for this Circle arc.

Template Parameters:


T	Generic type parameter, either int or float.

Parameters:


startAngle	The new start angle in degrees.
endAngle	The new end angle in degrees.

Note

The areas containing the updated Circle arcs are invalidated. As little as possible will be invalidated for best performance.

updateArcEnd

Updates the end angle in degrees for this Circle arc.

Template Parameters:


T	Generic type parameter, either int or float.

Parameters:


endAngle	The end angle in degrees.

Note

The area containing the updated Circle arc is invalidated.

See also:

setArc, updateArcStart, updateArc

updateArcStart

Updates the start angle in degrees for this Circle arc.

Template Parameters:


T	Generic type parameter, either int or float.

Parameters:


startAngle	The start angle in degrees.

Note

The area containing the updated Circle arc is invalidated.

See also:

setArc, updateArcEnd, updateArc

Protected Functions Documentation

updateArc

Updates the start and end angle in degrees for this Circle arc.

Parameters:


setStartAngleQ5	The new start angle in degrees.
setEndAngleQ5	The new end angle in degrees.

Note

The areas containing the updated Circle arcs are invalidated. As little as possible will be invalidated for best performance.

Public Functions​

Protected Functions​

Additional inherited members​

Public Functions inherited from CanvasWidget​

Public Functions inherited from Widget​

Public Functions inherited from Drawable​

Protected Attributes inherited from Drawable​

Public Functions Documentation​

Circle​

drawCanvasWidget​

getArc​

getArcEnd​

getArcEnd​

getArcStart​

getArcStart​

getCapPrecision​

getCenter​

getLineWidth​

getMinimalRect​

getMinimalRect​

getMinimalRect​

getPrecision​

getRadius​

setArc​

Note

setArc​

Note

setCapPrecision​

Note

setCenter​

Note

setCenter​

Note

setCircle​

Note

setCircle​

Note

setLineWidth​

Note

setPixelCenter​

setPrecision​

Note

setRadius​

Note

updateArc​

Note

updateArcEnd​

Note

updateArcStart​

Note

Protected Functions Documentation​

updateArc​

Note

Public Functions

Protected Functions

Additional inherited members

Public Functions inherited from CanvasWidget

Public Functions inherited from Widget

Public Functions inherited from Drawable

Protected Attributes inherited from Drawable

Public Functions Documentation

Circle

drawCanvasWidget

getArc

getArcEnd

getArcEnd

getArcStart

getArcStart

getCapPrecision

getCenter

getLineWidth

getMinimalRect

getMinimalRect

getMinimalRect

getPrecision

getRadius

setArc

setArc

setCapPrecision

setCenter

setCenter

setCircle

setCircle

setLineWidth

setPixelCenter

setPrecision

setRadius

updateArc

updateArcEnd

updateArcStart

Protected Functions Documentation

updateArc