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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 | 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x 24x | import { validateParameterUndefinedOrNull } from './validator';
import getImageSize from './getImageSize';
import { IImage } from '../../../../types';
/**
* Calculates the horizontal, vertical and minimum scale factor for an image
@param canvas - The window size where the image is displayed. This can be any HTML element or structure with a width, height fields (e.g. canvas).
* @param image - The cornerstone image object
* @param rotation - The rotation angle of the image.
* @returns The calculated horizontal, vertical and minimum scale factor
*/
export default function (
canvas: HTMLCanvasElement,
image: IImage,
rotation: number | null = null
): {
verticalScale: number;
horizontalScale: number;
scaleFactor: number;
} {
validateParameterUndefinedOrNull(
canvas,
'getImageScale: parameter canvas must not be undefined'
);
validateParameterUndefinedOrNull(
image,
'getImageScale: parameter image must not be undefined'
);
const imageSize = getImageSize(image, rotation);
const rowPixelSpacing = image.rowPixelSpacing || 1;
const columnPixelSpacing = image.columnPixelSpacing || 1;
let verticalRatio = 1;
let horizontalRatio = 1;
Iif (rowPixelSpacing < columnPixelSpacing) {
horizontalRatio = columnPixelSpacing / rowPixelSpacing;
} else {
// even if they are equal we want to calculate this ratio (the ration might be 0.5)
verticalRatio = rowPixelSpacing / columnPixelSpacing;
}
const verticalScale = canvas.height / imageSize.height / verticalRatio;
const horizontalScale = canvas.width / imageSize.width / horizontalRatio;
// Fit image to window
return {
verticalScale,
horizontalScale,
scaleFactor: Math.min(horizontalScale, verticalScale),
};
}
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