Sanity check view, ROI and frame metrics

Because `roundToInt` in `Rect.setFrameRoi()` throws an
`IllegalArgumentException: Cannot round NaN value` for
some people out there.

Author: markusfisch

app/src/main/kotlin/de/markusfisch/android/binaryeye/activity/CameraActivity.kt

@@ -647,7 +647,16 @@ class CameraActivity : AppCompatActivity() {
 
 	private fun updateFrameRoiAndMappingMatrix() {
 		val viewRect = cameraView.previewRect
-		val viewRoi = if (detectorView.roi.width() < 1) {
+		if (viewRect.width() < 1 ||
+			viewRect.height() < 1 ||
+			!frameMetrics.isValid()
+		) {
+			return
+		}
+		val viewRoi = if (
+			detectorView.roi.width() < 1 ||
+			detectorView.roi.height() < 1
+		) {
 			viewRect
 		} else {
 			detectorView.roi

app/src/main/kotlin/de/markusfisch/android/binaryeye/graphics/Mapping.kt

@@ -10,7 +10,9 @@ data class FrameMetrics(
 	var width: Int = 0,
 	var height: Int = 0,
 	var orientation: Int = 0
-)
+) {
+	fun isValid() = width > 0 && height > 0
+}
 
 fun Rect.setFrameRoi(
 	frameMetrics: FrameMetrics,