2D Display & Sprites APICopy Anchor Link

KryonOS uses a direct-to-glass rendering pipeline powered by high-speed SPI DMA hardware transfers. User scripts can draw directly to the physical display glass or to off-screen RAM double-buffers (Sprites) to eliminate visual tearing and flickering.

Driver implementations and pinouts are located in the KryonOS GitHub Repository.

1. Color System (16-bit RGB565)Copy Anchor Link

The display uses the 16-bit RGB565 color format (5 bits red, 6 bits green, 5 bits blue). Colors can be supplied directly as hex literals or computed dynamically.

Standard Color ConstantsCopy Anchor Link

System.color(r, g, b)Copy Anchor Link

Packs 24-bit RGB values (0-255 each) into the 16-bit integer expected by the hardware.

• Parameters:
  • r (Integer, 0 to 255)
  • g (Integer, 0 to 255)
  • b (Integer, 0 to 255)
• Returns: Integer (16-bit packed color)

2. 2D Drawing PrimitivesCopy Anchor Link

System.fillScreen(color)Copy Anchor Link

Clears the entire display canvas with a solid color via SPI DMA.

• Parameters: color (Integer)

System.drawPixel(x, y, color)Copy Anchor Link

Renders a single pixel.

• Parameters: x (Integer), y (Integer), color (Integer)

System.drawLine(x1, y1, x2, y2, color)Copy Anchor Link

Draws a line between two coordinates using Bresenham's line algorithm.

• Parameters: x1, y1, x2, y2 (Integer), color (Integer)

System.drawRect(x, y, w, h, color) / System.fillRect(x, y, w, h, color)Copy Anchor Link

Renders hollow or filled rectangles.

• Parameters: x, y, w, h (Integer), color (Integer)

System.drawRoundRect(x, y, w, h, radius, color) / System.fillRoundRect(...)Copy Anchor Link

Renders rectangles with rounded corner radiuses.

• Parameters: x, y, w, h, radius (Integer), color (Integer)

System.drawCircle(x, y, radius, color) / System.fillCircle(...)Copy Anchor Link

Renders hollow or filled circles.

• Parameters: x, y, radius (Integer), color (Integer)

System.drawTriangle(x1, y1, x2, y2, x3, y3, color) / System.fillTriangle(...)Copy Anchor Link

Renders hollow or filled 2D triangles.

• Parameters: x1, y1, x2, y2, x3, y3 (Integer), color (Integer)

System.drawFastVLine(x, y, h, color) / System.drawFastHLine(x, y, w, color)Copy Anchor Link

Hardware-accelerated vertical and horizontal line rendering.

3. Direct BMP Image StreamingCopy Anchor Link

System.drawBMP(path, x, y)Copy Anchor Link

Streams a 16-bit, 24-bit, or 32-bit .bmp image from /local/ or /sd/ directly to the display glass via SPI DMA without consuming JavaScript heap RAM.

• Parameters:
  • path (String): File path (e.g. "/sd/assets/logo.bmp")
  • x, y (Integer): Destination screen coordinates
• Returns: Boolean (true on success)

4. Typography & Text RenderingCopy Anchor Link

System.setTextColor(fg_color, bg_color)Copy Anchor Link

Sets text foreground and optional background color. Setting bg_color enables hardware overwriting, clearing old character pixels without requiring rectangle fills.

• Parameters:
  • fg_color (Integer): Text color
  • bg_color (Integer, optional): Background fill color

System.setTextSize(size)Copy Anchor Link

Sets the font scale multiplier (1 to 5).

• Parameters: size (Integer)

System.drawString(text, x, y, font)Copy Anchor Link

Renders text using hardware-embedded bitmap fonts.

• Parameters:
  • text (String)
  • x, y (Integer)
  • font (Integer): 1 (compact 6x8), 2 (standard 8x12), or 4 (large 12x16).

5. Hardware Double Buffering (Mini-Sprites)Copy Anchor Link

Double buffering prevents screen flickering during high-frequency animations by rendering into an off-screen RAM buffer before pushing it to the glass in a single SPI burst.

Double-Buffering LifecycleCopy Anchor Link

// Allocate a 120x60 pixel off-screen sprite buffer
if (System.createSprite(120, 60)) {
  
  // Direct all drawing commands to the sprite
  System.bindSprite(true);
  
  System.fillScreen(0x000000);
  System.drawCircle(60, 30, 20, 0x00FFC2);
  System.drawString("Mini-HUD", 20, 24, 2);
  
  // Stop sprite redirection
  System.bindSprite(false);
  
  // Push the completed frame to screen coordinates (60, 100)
  System.pushSprite(60, 100);
  
  // Release buffer memory when finished
  System.deleteSprite();
}