AbstractPainterGRAY4

The AbstractPainterGRAY4 class is an abstract class for creating a painter to draw on a GRAY4 display using CanvasWidgetRenderer.

See: AbstractPainter

Inherits from: AbstractPainter

Inherited by: PainterGRAY4, PainterGRAY4Bitmap

Public Functions

	AbstractPainterGRAY4()
virtual void	render(uint8_t ptr, int x, int xAdjust, int y, unsigned count, const uint8_t covers)
	Paint a designated part of the RenderingBuffer with respect to the amount of coverage of each pixel given by the parameter covers.

Protected Functions

virtual bool	renderInit()
	Initialize rendering of a single scan line of pixels for the render.
virtual bool	renderNext(uint8_t & gray, uint8_t & alpha)
	Get the color of the next pixel in the scan line to blend into the framebuffer.
virtual void	renderPixel(uint8_t * p, uint16_t offset, uint8_t gray)
	Renders (writes) the specified color into the framebuffer.

Protected Attributes

int	currentX
	Current x coordinate relative to the widget.
int	currentY
	Current y coordinate relative to the widget.

Additional inherited members

Public Functions inherited from AbstractPainter

	AbstractPainter()
	Initializes a new instance of the AbstractPainter class.
virtual	~AbstractPainter()
	Finalizes an instance of the AbstractPainter class.

Protected Functions inherited from AbstractPainter

void	setAreaOffset(uint16_t offsetX, uint16_t offsetY)
	Sets the offset of the area being drawn.
void	setWidgetAlpha(const uint8_t alpha)
	Sets the widget alpha to allow an entire canvas widget to easily be faded without changing the painter of the widget.
FORCE_INLINE_FUNCTION bool	compatibleFramebuffer(Bitmap::BitmapFormat format)
	Helper function to check if the provided bitmap format matches the current framebuffer format.

Protected Attributes inherited from AbstractPainter

int16_t	areaOffsetX
	The offset x coordinate of the area being drawn.
int16_t	areaOffsetY
	The offset y coordinate of the area being drawn.
uint8_t	widgetAlpha
	The alpha of the widget using the painter.

Public Functions Documentation

AbstractPainterGRAY4

AbstractPainterGRAY4	(			)

render

virtual void render	(	uint8_t *	ptr ,
		int	x ,
		int	xAdjust ,
		int	y ,
		unsigned	count ,
		const uint8_t *	covers
		)

Paint a designated part of the RenderingBuffer with respect to the amount of coverage of each pixel given by the parameter covers.

The cover is the alpha for each pixel, which is what makes it possible to have smooth anti-aliased edges on the shapes drawn with CanvasWidgetRenderer.

Parameters:

ptr	Pointer to the row in the RenderingBuffer.
x	The x coordinate.
xAdjust	The minor adjustment of x (used when a pixel is smaller than a byte to specify that the ptr should have been advanced "xAdjust" pixels futher into the byte).
y	The y coordinate.
count	Number of pixels to fill.
covers	The coverage in of each pixel.

Note

The implementation of render() in the AbstractPainter classes is a generic (i.e. slow) implementation that should be completely implemented in subclasses of AbstractPainter for better performance.

Reimplements: touchgfx::AbstractPainter::render

Reimplemented by: touchgfx::PainterGRAY4::render, touchgfx::PainterGRAY4Bitmap::render

Protected Functions Documentation

renderInit

virtual bool renderInit	(			)

Initialize rendering of a single scan line of pixels for the render.

If renderInit returns false, the scanline will not be rendered.

Returns:

true if it succeeds, false if it fails.

Reimplemented by: touchgfx::PainterGRAY4Bitmap::renderInit

renderNext

virtual bool renderNext	(	uint8_t &	gray ,
		uint8_t &	alpha
		)

Get the color of the next pixel in the scan line to blend into the framebuffer.

Parameters:

gray	The gray color (0-15).
alpha	The alpha.

Returns:

true if the pixel should be painted, false otherwise.

Reimplemented by: touchgfx::PainterGRAY4::renderNext

renderPixel

virtual void renderPixel	(	uint8_t *	p ,
		uint16_t	offset ,
		uint8_t	gray
		)

Renders (writes) the specified color into the framebuffer.

Parameters:

p	pointer into the framebuffer where the given color should be written.
offset	The offset to the pixel from the given pointer.
gray	The gray color.

Protected Attributes Documentation

currentX

int currentX

Current x coordinate relative to the widget.

currentY

int currentY

Current y coordinate relative to the widget.