Resolution: add validation and move to utils/

src/core/gizmos.ts

 import { SpeedyMatrix } from 'speedy-vision/types/core/speedy-matrix';
 import { SpeedyKeypoint, SpeedyMatchedKeypoint } from 'speedy-vision/types/core/speedy-keypoint';
 import { SpeedyPromise } from 'speedy-vision/types/core/speedy-promise';
-import { Resolution } from './resolution';
+import { Resolution } from '../utils/resolution';
 import { Nullable, Utils } from '../utils/utils';
 import { IllegalArgumentError, IllegalOperationError, TrackingError } from '../utils/errors';
 import { Viewport } from './viewport';

src/sources/camera-source.ts

 import { SpeedyMedia } from 'speedy-vision/types/core/speedy-media';
 import { SpeedyPromise } from 'speedy-vision/types/core/speedy-promise';
 import { Utils } from '../utils/utils';
-import { Resolution } from '../core/resolution';
+import { Resolution } from '../utils/resolution';
 import { NotSupportedError, AccessDeniedError, IllegalOperationError } from '../utils/errors';
 import { VideoSource } from './video-source';
 

src/trackers/image-tracker/image-tracker.ts

 import { Tracker, TrackerOutput, TrackerResult, Trackable } from '../tracker';
 import { Session } from '../../core/session';
 import { IllegalOperationError, IllegalArgumentError } from '../../utils/errors';
-import { Resolution } from '../../core/resolution';
+import { Resolution } from '../../utils/resolution';
 import { ReferenceImage } from './reference-image';
 import { ReferenceImageDatabase } from './reference-image-database';
 import { ImageTrackerState } from './states/state';

src/trackers/image-tracker/states/training.ts

 import { SpeedyPipelineNodeResize } from 'speedy-vision/types/core/pipeline/nodes/transforms/resize';
 import { SpeedyPipelineNodeKeypointTransformer } from 'speedy-vision/types/core/pipeline/nodes/keypoints/transformer';
 import { SpeedyKeypoint } from 'speedy-vision/types/core/speedy-keypoint';
-import { Resolution } from '../../../core/resolution';
+import { Resolution } from '../../../utils/resolution';
 import { ImageTracker, ImageTrackerOutput, ImageTrackerStateName } from '../image-tracker';
 import { ImageTrackerState, ImageTrackerStateOutput } from './state';
 import { ReferenceImage } from '../reference-image';

src/core/resolution.ts → src/utils/resolution.ts

 
 import Speedy from 'speedy-vision';
 import { SpeedySize } from 'speedy-vision/types/core/speedy-size';
+import { IllegalArgumentError } from './errors';
 
 /** Resolution type */
 export type Resolution = 'xs' | 'xs+' | 'sm' | 'sm+' | 'md' | 'md+' | 'lg' | 'lg+';
     const referenceHeight = REFERENCE_HEIGHT[resolution];
     let width = 0, height = 0;
 
+    if(referenceHeight === undefined)
+        throw new IllegalArgumentError('Invalid resolution: ' + resolution);
+    else if(aspectRatio <= 0)
+        throw new IllegalArgumentError('Invalid aspect ratio: ' + aspectRatio);
+
     if(aspectRatio >= 1) {
         // landscape
         height = referenceHeight;

src/utils/utils.ts

 import Speedy from 'speedy-vision';
 import { SpeedySize } from 'speedy-vision/types/core/speedy-size';
 import { AssertionError, IllegalArgumentError } from './errors';
-import { Resolution, computeResolution } from '../core/resolution';
+import { Resolution, computeResolution } from './resolution';
 
 /**
  * Nullable type