Canvas, safe-area and reel geometry specifications

Updated 2026-08-24

Delivered canvases

These are normalized output sizes. Provider canvases may be a few pixels larger to use supported multiples, but integration uses the delivered files and manifest dimensions.

Dimensions describe files, not stage positions. Placement comes from the preview-layout rectangles in asset-set.json. The production asset checklist covers the handoff.

Two stages are two compositions

The desktop background establishes the location. The phone background uses it as an identity reference and redraws the same architecture, materials, weather, time of day and light for a vertical camera. It is not a central 9:16 crop of the 16:9 art.

The cabinet occupies most of a phone's width, so a landscape landmark or desktop mascot gutter may disappear. The portrait prompt reorganizes the location vertically: landmark or depth destination in the upper third, a calm middle band for the cabinet and grounded foreground below.

The reel-safe area is not a blank panel. The environment continues through it with restrained local contrast and no focal objects. The cabinet is composited over it as a separate opaque asset.

Five-by-three reel geometry

The nominal opening is calculated separately for each stage. It targets 56% of stage height, caps width at 86% of stage width and centres at 55% of stage height. Width and height remain exactly 5:3. This is the fallback when the cabinet cannot be measured.

The generated cabinet has a darker inner panel. After fitting the cabinet, the pipeline moves a grayscale probe from the centre toward the rails and detects the midpoint between panel and frame. It fits the largest 5:3 rectangle inside a plausible result. If contrast, size or centring checks fail, the nominal opening prevents symbols from overlapping an incorrectly detected rail.

Each cell:

cell width = opening width / 5

cell height = opening height / 3

At 5:3 these values match, producing square cells. An old 2.07:1 opening cropped square symbols in preview; preserving 5:3 removes that mismatch.

Cabinet specification

The rail is one quarter of a reel cell on every side. Five cells plus two quarter-cell rails produce 5.5 cells across; three cells plus the same rails produce 3.5 cells down. The cabinet is therefore 11:7 on every stage, with a 1408×896 generation canvas.

Fit the cabinet uniformly into its published rectangle. Independent display width and height turn round fittings into ellipses. One 11:7 source serves both stages because its proportions do not change.

Symbol fill and safe margins

Post-processing measures alpha bounds and rescales each subject to its tier target. This corrects renders that are too small or touch the edge. It cannot repair an unclear silhouette, a cropped source or excessive internal detail.

The 96-pixel readability test

1. Composite each symbol over the actual cabinet panel, not a white review page.
2. Display the complete cell at 96×96 without sharpening it for the test.
3. Identify the subject from its outer silhouette before inspecting internal marks.
4. Compare Wild and Scatter beside each other. Closed/external light and open/internal light must survive.
5. Compare one high with one low. The material depth and plaque should lift the high without making the low illegible.
6. Spin the reels. Fine details that appear static may merge in motion.

For the logic behind the tier budgets, see slot symbol tiers and paytable art.

Mascot and portrait framing

The mascot output is exactly 512×1536. Its alpha-cropped figure fills no more than 98% of the width and 93% of the height, with the baseline at 96.5% of canvas height. A small piece of footing preserves the contact point over any background. The 1:3 shape fits a gutter near full board height without entering the opening.

Portraits are separate assets. They use 768×1024 canvases and may show a waist-up or full figure at 84–90% of canvas height. Portrait faces are judged at 256 pixels; the mascot bust must remain identifiable at 96. Cropping a portrait into a reel icon does not meet the same specification. The slot mascot guide explains the identity handoff.

Manifest rules for integrators

• Read stage dimensions, background asset, board rectangle, reel window, title slot, mascot slot and corner flips for the active orientation.
• Use one uniform scale per asset inside its published box.
• Keep the base symbol and registered layers on the same origin.
• Do not patch a visual mismatch in the scene. If the preview and client disagree, correct the published manifest geometry.
• On orientation change, reposition existing sprites for the second stage instead of treating portrait as a desktop crop.

Preserve these rectangles in bonus mode unless the game design has an explicit mechanical reason to change them. Bonus contrast comes from light, not new geometry.