BaseDrawSurface

Class

Source: BaseDrawSurface.h

Inherits from: DrawSurface

Description

Optional base class for DrawSurface implementations providing default primitive rendering.

Users can inherit from this class to avoid implementing every single primitive. At minimum, a subclass must implement:

• init() — initialize the hardware or window
• drawPixel() — draw a single pixel (all other primitives delegate here)
• sendBuffer() — transfer framebuffer to physical display
• clearBuffer() — fill framebuffer with background color

The default implementations use Bresenham-style algorithms for lines, rectangles, circles, and bitmaps, all building on drawPixel(). These are slow but correct; override in performance-critical drivers.

Inheritance

DrawSurface → BaseDrawSurface

Methods

void setTextColor(uint16_t color)

Description:

Sets the text color.

Parameters:

• color: 16-bit RGB565 text color.

void setTextSize(uint8_t size)

Description:

Sets the text size multiplier.

Parameters:

• size: Size multiplier (1 = normal, 2 = double, etc.).

void setCursor(int16_t x, int16_t y)

Description:

Sets the text cursor position.

Parameters:

• x: X coordinate in pixels.
• y: Y coordinate in pixels.

void setContrast(uint8_t level)

Description:

Sets the display brightness.

Parameters:

• level: Contrast level (0–255).

void setRotation(uint16_t rot)

Description:

Sets the display rotation.

Parameters:

• rot: Rotation index (0, 1, 2, 3) or degrees (0, 90, 180, 270).

void setDisplaySize(int w, int h)

Description:

Sets the logical rendering resolution.

Parameters:

• w: Logical width in pixels.
• h: Logical height in pixels.

void setPhysicalSize(int w, int h)

Description:

Sets the physical display resolution.

Parameters:

• w: Physical width in pixels.
• h: Physical height in pixels.

void setOffset(int x, int y)

Description:

Sets the display origin offset.

Parameters:

• x: Horizontal offset in pixels.
• y: Vertical offset in pixels.

void present()

Description:

Transfers the framebuffer to the physical display.

uint16_t color565(uint8_t r, uint8_t g, uint8_t b)

Description:

Converts 24-bit RGB to RGB565.

Parameters:

• r: Red component (0-255).
• g: Green component (0-255).
• b: Blue component (0-255).

Returns: 16-bit RGB565 color.

void drawLine(int x1, int y1, int x2, int y2, uint16_t color)

Description:

Draws a line between two points (Bresenham algorithm).

Parameters:

• x1: Start X coordinate.
• y1: Start Y coordinate.
• x2: End X coordinate.
• y2: End Y coordinate.
• color: 16-bit RGB565 line color.

void drawRectangle(int x, int y, int w, int h, uint16_t color)

Description:

Draws a rectangle outline.

Parameters:

• x: Top-left X coordinate.
• y: Top-left Y coordinate.
• w: Width in pixels.
• h: Height in pixels.
• color: 16-bit RGB565 outline color.

void drawFilledRectangle(int x, int y, int w, int h, uint16_t color)

Description:

Draws a filled rectangle.

Parameters:

• x: Top-left X coordinate.
• y: Top-left Y coordinate.
• w: Width in pixels.
• h: Height in pixels.
• color: 16-bit RGB565 fill color.

void drawCircle(int x0, int y0, int r, uint16_t color)

Description:

Draws a circle outline (midpoint algorithm).

Parameters:

• x0: Center X coordinate.
• y0: Center Y coordinate.
• r: Radius in pixels.
• color: 16-bit RGB565 outline color.

void drawFilledCircle(int x0, int y0, int r, uint16_t color)

Description:

Draws a filled circle (midpoint algorithm).

Parameters:

• x0: Center X coordinate.
• y0: Center Y coordinate.
• r: Radius in pixels.
• color: 16-bit RGB565 fill color.

void drawBitmap(int x, int y, int w, int h, const uint8_t *bitmap, uint16_t color)

Description:

Draws a 1bpp bitmap, rendering only non-zero pixels.

Parameters:

• x: Top-left X coordinate.
• y: Top-left Y coordinate.
• w: Width in pixels.
• h: Height in pixels.
• bitmap: Pointer to packed 1bpp row data (byte per row, MSB left).
• color: 16-bit RGB565 color for "on" pixels.