Oberon Object Tiler

To understand the Object Tiler, one must first understand the Oberon philosophy: the distinction between an "application" and a "document" is artificial. In modern operating systems, you open an application to view a document. In Oberon, you open a document, and the tools to manipulate it appear contextually.

The display was not a collection of floating windows with title bars and close buttons. Instead, it was a vertical stack of "tracks" (narrow system tracks on the left, wide user tracks on the right) containing a linear sequence of text and graphics. This was the domain of the Object Tiler.

The Oberon screen was treated as a single, cohesive "display file" or raster. The Object Tiler is the mechanism responsible for breaking this abstract display file into visual pieces and mapping them onto the physical screen. Oberon Object Tiler

A simplified fragment of the tiler’s split procedure (from System.Tool in ETH Oberon):

PROCEDURE SplitViewer*(V: Viewer; x, y: INTEGER);
  VAR newV: Viewer; splitX: INTEGER;
BEGIN
  splitX := x;
  IF (splitX > V.frame.X) & (splitX < V.frame.X + V.frame.W) THEN
    NEW(newV);
    newV.frame.X := splitX;
    newV.frame.Y := V.frame.Y;
    newV.frame.W := V.frame.X + V.frame.W - splitX;
    newV.frame.H := V.frame.H;
    V.frame.W := splitX - V.frame.X;
    newV.obj := V.obj;   (* same object, different view *)
    InsertViewer(V, newV);
    Restore(V);
    Restore(newV)
  END
END SplitViewer;

This is the magic sauce. In Oberon, the tiler doesn't just tile "windows"; it tiles "Objects." A Text object, a Graphic object, and a System object (the command shell) all respond to the same tiler commands. Because they are objects, the tiler can ask them to redraw themselves at any size instantly. To understand the Object Tiler, one must first

If you have millions of objects that only cover 1 pixel each, the per-tile overhead of storing pointers can exceed the cost of just drawing them. Solution: Implement a hybrid approach—particles under a certain size bypass the tiler and use a traditional particle system.

If you are a developer inspired by this article, here is a pseudo-code skeleton of how the Oberon Object Tiler partitions space: This is the magic sauce

class Tiler:
    def __init__(self, x, y, w, h):
        self.x = x; self.y = y; self.w = w; self.h = h
        self.left = None
        self.right = None
        self.orientation = None  # 'H' or 'V'
def split(self, orientation, ratio):
    self.orientation = orientation
    if orientation == 'V':  # Vertical split (left/right)
        split_point = self.w * ratio
        self.left = Tiler(self.x, self.y, split_point, self.h)
        self.right = Tiler(self.x + split_point, self.y, self.w - split_point, self.h)
    else:  # Horizontal split (top/bottom)
        split_point = self.h * ratio
        self.left = Tiler(self.x, self.y, self.w, split_point)
        self.right = Tiler(self.x, self.y + split_point, self.w, self.h - split_point)

This recursive structure is exactly how the Oberon Object Tiler achieves its legendary speed and simplicity.

Oberon Object Tiler is a technique/tool for dividing complex Oberon-system data structures (objects, records, modules) into manageable, cache-friendly, or displayable tiles—useful for memory layout, incremental rendering, or editor views in Oberon-like languages and systems.