@ue-too/board / index / minZoomLevelBaseOnDimensions

函式: minZoomLevelBaseOnDimensions()

minZoomLevelBaseOnDimensions(boundaries, canvasWidth, canvasHeight, cameraRotation): number | undefined

定義於: packages/board/src/utils/zoomlevel-adjustment.ts:57

Calculates minimum zoom level to fit boundaries within canvas at any rotation.

參數

boundaries

The world-space boundaries to fit

Boundaries | undefined

canvasWidth

number

Canvas width in pixels

canvasHeight

number

Canvas height in pixels

cameraRotation

number

Camera rotation angle in radians

回傳

number | undefined

Minimum zoom level, or undefined if boundaries are incomplete

備註

This function ensures the entire boundary region remains visible regardless of camera rotation. It considers both width and height projections of the rotated boundaries.

When boundaries are rotated, they occupy a larger axis-aligned bounding box. This function calculates the minimum zoom needed to fit that box:

For each dimension (width/height):

1. Project boundary width onto canvas width axis: width * cos(rotation)
2. Project boundary height onto canvas width axis: height * cos(rotation)
3. Calculate zoom needed for each projection
4. Take the maximum of all zoom levels

Returns undefined if boundaries don't have both width and height defined.

Used when canvas is resized to automatically adjust zoom to keep content visible.

範例

const boundaries = {
  min: { x: 0, y: 0 },
  max: { x: 1000, y: 500 }
};

// No rotation, 800x600 canvas
const zoom1 = minZoomLevelBaseOnDimensions(boundaries, 800, 600, 0);
// Result: 1.2 (600/500, height is limiting)

// 45 degree rotation
const zoom2 = minZoomLevelBaseOnDimensions(
  boundaries, 800, 600, Math.PI / 4
);
// Result: higher zoom (rotated bounds need more space)

參閱

• minZoomLevelBaseOnWidth for width-only calculation
• minZoomLevelBaseOnHeight for height-only calculation