FrameBufferAllocator

touchgfx/hal/FrameBufferAllocator.hpp

This class is an abstract interface for a class allocating partial framebuffer blocks. The interface must be implemented by a subclass.

See: ManyBlockAllocator

Inherited by: ManyBlockAllocator< block_size, blocks, bytes_pr_pixel >

Protected Types


enum	BlockState { EMPTY, ALLOCATED, DRAWN, SENDING }
	BlockState is used for internal state of each block.

Public Functions


virtual uint16_t	allocateBlock(const uint16_t x, const uint16_t y, const uint16_t width, const uint16_t height, uint8_t ** block) =0
	Allocates a framebuffer block.

virtual void	freeBlockAfterTransfer() =0
	Free a block after transfer to the LCD.

virtual const uint8_t *	getBlockForTransfer(Rect & rect) =0
	Get the block ready for transfer.

virtual bool	hasBlockReadyForTransfer() =0
	Check if a block is ready for transfer to the LCD.

virtual bool	hasEmptyBlock() =0
	Check if a block is ready for drawing (the block is empty).

virtual void	markBlockReadyForTransfer() =0
	Marks a previously allocated block as ready to be transferred to the LCD.

virtual const Rect &	peekBlockForTransfer() =0
	Get the Rect of the next block to transfer.

virtual	~FrameBufferAllocator()
	Finalizes an instance of the FrameBufferAllocator class.

Protected Types Documentation

BlockState

BlockState is used for internal state of each block.


EMPTY	Block is empty, can be allocated.
ALLOCATED	Block is allocated for drawing.
DRAWN	Block has been drawn to, can be send.
SENDING	Block is being transmitted to the display.

Public Functions Documentation

allocateBlock


virtual uint16_t allocateBlock	(	const uint16_t	x ,	=0
		const uint16_t	y ,	=0
		const uint16_t	width ,	=0
		const uint16_t	height ,	=0
		uint8_t **	block	=0
		)	=0

Allocates a framebuffer block.

The block will have at least the width requested. The height of the allocated block can be lower than requested if not enough memory is available.

Parameters:


x	The absolute x coordinate of the block on the screen.
y	The absolute y coordinate of the block on the screen.
width	The width of the block.
height	The height of the block.
block	Pointer to pointer to return the block address in.

Returns:

The height of the allocated block.

Reimplemented by: touchgfx::ManyBlockAllocator::allocateBlock

freeBlockAfterTransfer


virtual void freeBlockAfterTransfer	(			)	=0

Free a block after transfer to the LCD.

Marks a previously allocated block as transferred and ready to reuse.

Reimplemented by: touchgfx::ManyBlockAllocator::freeBlockAfterTransfer

getBlockForTransfer

Get the block ready for transfer.

Parameters:


rect	Reference to rect to write block x, y, width, and height.

Returns:

Returns the address of the block ready for transfer.

Reimplemented by: touchgfx::ManyBlockAllocator::getBlockForTransfer

hasBlockReadyForTransfer


virtual bool hasBlockReadyForTransfer	(			)	=0

Check if a block is ready for transfer to the LCD.

Returns:

True if a block is ready for transfer.

Reimplemented by: touchgfx::ManyBlockAllocator::hasBlockReadyForTransfer

hasEmptyBlock


virtual bool hasEmptyBlock	(			)	=0

Check if a block is ready for drawing (the block is empty).

Returns:

True if a block is empty.

Reimplemented by: touchgfx::ManyBlockAllocator::hasEmptyBlock

markBlockReadyForTransfer


virtual void markBlockReadyForTransfer	(			)	=0

Marks a previously allocated block as ready to be transferred to the LCD.

Reimplemented by: touchgfx::ManyBlockAllocator::markBlockReadyForTransfer

peekBlockForTransfer


virtual const Rect & peekBlockForTransfer	(			)	=0

Get the Rect of the next block to transfer.

Returns:

Rect ready for transfer.

Note

This function should only be called when the allocator has a block ready for transfer.