MICROSOFT_PRESS_EBOOK_PROGRAMMING_WINDOWS_8_APPS_WITH_HTML_CSS_AND_JAVASCRIPT_PDF

var ImageProperties = {};
function openHandler() {
// Keep data in-scope across multiple asynchronous methods.
var file = {};
Helpers.getFileFromOpenPickerAsync().then(function (_file) {
file = _file;
return file.properties.getImagePropertiesAsync();
}).then(function (imageProps) {
ImageProperties = imageProps;
var requests = [
"System.Photo.ExposureTime",
"System.Photo.FNumber"
];
// In seconds
// F-stop values defined by EXIF spec
}
return ImageProperties.retrievePropertiesAsync(requests);
}).done(function (retrievedProps) {
// Format the properties into text to display in the UI.
displayImageUI(file, getImagePropertiesForDisplay(retrievedProps));
});
function getImagePropertiesForDisplay(retrievedProps) {
// If the specified property doesn't exist, its value will be null.
var orientationText = Helpers.getOrientationString(ImageProperties.orientation);
var exposureText = retrievedProps.lookup("System.Photo.ExposureTime") ?
retrievedProps.lookup("System.Photo.ExposureTime") * 1000 + " ms" : "";
var fNumberText = retrievedProps.lookup("System.Photo.FNumber") ?
retrievedProps.lookup("System.Photo.FNumber").toFixed(1) : "";
// Omitted: Code to convert ImageProperties.latitude and ImageProperties.longitude to
// degrees, minutes, seconds, and direction
}
return {
"title": ImageProperties.title,
"keywords": ImageProperties.keywords, // array of strings
"rating": ImageProperties.rating, // number
"dateTaken": ImageProperties.dateTaken,
"make": ImageProperties.cameraManufacturer,
"model": ImageProperties.cameraModel,
"orientation": orientationText,
// Omitted: lat/long properties
"exposure": exposureText,
"fNumber": fNumberText
};
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