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Version: 4.16

AbstractPainterBW

The AbstractPainterBW class is an abstract class for creating a painter to draw on a BW display using CanvasWidgetRenderer. Pixels are either set or removed, alpha blending (and transparency) is not supported.

See: AbstractPainter

Inherits from: AbstractPainter

Inherited by: PainterBW, PainterBWBitmap

Public Functions#

AbstractPainterBW()
virtual voidrender(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 boolrenderInit()
Initialize rendering of a single scan line of pixels for the render.
virtual boolrenderNext(uint8_t & color) =0
Get the color of the next pixel in the scan line to blend into the framebuffer.

Protected Attributes#

uint16_tcurrentX
Current x coordinate relative to the widget.
uint16_tcurrentY
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 uint8_tgetAlpha() const
Gets the current alpha value of the widget.
virtual voidsetAlpha(uint8_t newAlpha)
Sets the opacity (alpha value).
voidsetOffset(uint16_t offsetX, uint16_t offsetY)
Sets the offset of the area being drawn.
virtual ~AbstractPainter()
Finalizes an instance of the AbstractPainter class.

Protected Functions inherited from AbstractPainter#

voidsetWidgetAlpha(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 boolcompatibleFramebuffer(Bitmap::BitmapFormat format)
Helper function to check if the provided bitmap format matches the current framebuffer format.

Protected Attributes inherited from AbstractPainter#

int16_tareaOffsetX
The offset x coordinate of the area being drawn.
int16_tareaOffsetY
The offset y coordinate of the area being drawn.
uint8_tpainterAlpha
The alpha value for the painter.
uint8_twidgetAlpha
The alpha of the widget using the painter.

Public Functions Documentation#

AbstractPainterBW#

render#

virtual void render(uint8_t *ptr ,
intx ,
intxAdjust ,
inty ,
unsignedcount ,
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:
ptrPointer to the row in the RenderingBuffer.
xThe x coordinate.
xAdjustThe 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).
yThe y coordinate.
countNumber of pixels to fill.
coversThe 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::PainterBW::render, touchgfx::PainterBWBitmap::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::PainterBWBitmap::renderInit

renderNext#

virtual bool renderNext(uint8_t &color)

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

Parameters:
colorThe color (0 or 1).
Returns:

true if the pixel should be painted, false otherwise.

Reimplemented by: touchgfx::PainterBW::renderNext, touchgfx::PainterBWBitmap::renderNext

Protected Attributes Documentation#

currentX#

uint16_t currentX

Current x coordinate relative to the widget.

currentY#

uint16_t currentY

Current y coordinate relative to the widget.