/**
* Calculate the scale factor needed to fit device dimensions within max dimension.
* Returns 1.0 if no scaling needed.
*/
export function calculateScaleFactor(
deviceWidth: number,
deviceHeight: number,
maxDimension: number
): number {
const longestSide = Math.max(deviceWidth, deviceHeight);
if (longestSide <= maxDimension) {
return 1.0;
}
return longestSide / maxDimension;
}
export interface Bounds {
left: number;
top: number;
right: number;
bottom: number;
}
/**
* Convert device coordinates to image coordinates.
*/
export function toImageSpace(
deviceX: number,
deviceY: number,
scaleFactor: number
): { x: number; y: number } {
if (scaleFactor === 1.0) {
return { x: deviceX, y: deviceY };
}
return {
x: Math.round(deviceX / scaleFactor),
y: Math.round(deviceY / scaleFactor),
};
}
/**
* Convert image coordinates to device coordinates.
*/
export function toDeviceSpace(
imageX: number,
imageY: number,
scaleFactor: number
): { x: number; y: number } {
if (scaleFactor === 1.0) {
return { x: imageX, y: imageY };
}
return {
x: Math.round(imageX * scaleFactor),
y: Math.round(imageY * scaleFactor),
};
}
/**
* Convert bounds from device space to image space.
*/
export function boundsToImageSpace(bounds: Bounds, scaleFactor: number): Bounds {
if (scaleFactor === 1.0) {
return bounds;
}
return {
left: Math.round(bounds.left / scaleFactor),
top: Math.round(bounds.top / scaleFactor),
right: Math.round(bounds.right / scaleFactor),
bottom: Math.round(bounds.bottom / scaleFactor),
};
}
