TFT_eSPI_Drawer
ClassSource: TFT_eSPI_Drawer.h
Inherits from: BaseDrawSurface
Description
Concrete implementation of DrawSurface for ESP32 using the TFT_eSPI library.
This class handles low-level interaction with the display hardware via SPI. It uses a sprite (framebuffer) to minimize flickering and tearing.
Inheritance
BaseDrawSurface → TFT_eSPI_Drawer
Methods
void init()
Description:
Initializes the TFT_eSPI library and the sprite buffer. Sets up the SPI communication and allocates memory for the framebuffer.
void setRotation(uint16_t rotation)
Description:
Sets the screen rotation.
Parameters:
rotation: 0-3 corresponding to 0, 90, 180, 270 degrees.
void clearBuffer()
Description:
Fills the sprite buffer with black color.
void sendBuffer()
Description:
Pushes the sprite buffer to the physical display. This is the "flip" operation in double buffering.
void drawFilledCircle(int x, int y, int radius, uint16_t color)
void drawCircle(int x, int y, int radius, uint16_t color)
void drawRectangle(int x, int y, int width, int height, uint16_t color)
void drawFilledRectangle(int x, int y, int width, int height, uint16_t color)
void drawLine(int x1, int y1, int x2, int y2, uint16_t color)
void drawBitmap(int x, int y, int width, int height, const uint8_t *bitmap, uint16_t color)
void drawPixel(int x, int y, uint16_t color)
void drawTileDirect(uint16_t x, uint16_t y, uint16_t width, uint16_t height, const uint8_t* data)
Description:
Direct tile write to sprite buffer (optimized for tilemap rendering).
Parameters:
x: Tile X position in sprite coordinatesy: Tile Y position in sprite coordinateswidth: Tile width in pixelsheight: Tile height in pixelsdata: Pointer to 8bpp tile data (one byte per pixel, index into palette)
uint8_t* getSpriteBuffer()
Description:
Get pointer to sprite buffer for direct manipulation.
Returns: Pointer to 8bpp sprite buffer, or nullptr if sprite not created
bool processEvents()
Description:
Processes system events. Always true for embedded.
void waitForPendingDMA()
Description:
Blocks until the DMA transfer deferred by sendBufferScaled() completes.
void flushPendingTransfers()
Description:
Settles the deferred transfer on a frame the engine chose not to present. Implements the DrawSurface hook in terms of waitForPendingDMA().
TIP
Do NOT move this into processEvents() to "always be safe". Engine runs processEvents() BEFORE draw(), so flushing there would wait out the DMA before the CPU does the work meant to overlap it, destroying the deferral this exists to protect.
Safe to call when nothing is pending (no-op), so drivers that transfer synchronously simply inherit the base no-op instead of overriding.
bool needsScaling() const
Description:
Checks if scaling is needed.
Returns: true if logical != physical resolution.
void buildScaleLUTs()
Description:
Builds the X and Y scaling lookup tables.
void freeScalingBuffers()
Description:
Frees scaling-related memory.
void sendBufferScaled()
Description:
Sends the buffer using hardware DMA and software scaling.
void scaleLine(const uint8_t* spriteBase, int srcY, uint16_t* dst)
Description:
Scales a single line from 8bpp logical to 16bpp physical.
void convertBlockRgb444(const uint8_t* spriteBase, int startY, int endY, bool is2x, uint8_t* dst)
Description:
Converts one block of physical lines into the packed RGB444 stream.
Parameters:
spriteBase: Base of the 8bpp sprite framebuffer.startY: First physical line of the block.endY: One past the last physical line of the block.is2x: True when the frame is an exact 2x integer upscale.dst: Destination line buffer, viewed as raw bytes.
void scaleLine444(const uint8_t* spriteBase, int srcY, uint8_t* dst)
Description:
Scales a single line from 8bpp logical to packed RGB444 physical.
int bytesPerLine444() const
Description:
Bytes one physical line occupies in the packed RGB444 stream.