Images
Many classes have shortcut names used when creating (instantiating) a class with a
configuration object. The shortcut name is referred to as an alias (or xtype if the
class extends Ext.Component). The alias/xtype is listed next to the class name of
applicable classes for quick reference.
Framework classes or their members may be specified as private or protected. Else,
the class / member is public. Public, protected, and private are access
descriptors used to convey how and when the class or class member should be used.
Public classes and class members are available for use by any other class or application code and may be relied upon as a stable and persistent within major product versions. Public classes and members may safely be extended via a subclass.
Protected class members are stable public members intended to be used by the
owning class or its subclasses. Protected members may safely be extended via a subclass.
Private classes and class members are used internally by the framework and are not intended to be used by application developers. Private classes and members may change or be omitted from the framework at any time without notice and should not be relied upon in application logic.
static label next to the
method name. *See Static below.Below is an example class member that we can disect to show the syntax of a class member (the lookupComponent method as viewed from the Ext.button.Button class in this case).
Let's look at each part of the member row:
lookupComponent in this example)( item ) in this example)Ext.Component in this case). This may be omitted for methods that do not
return anything other than undefined or may display as multiple possible values
separated by a forward slash / signifying that what is returned may depend on the
results of the method call (i.e. a method may return a Component if a get method calls is
successful or false if unsuccessful which would be displayed as
Ext.Component/Boolean).PROTECTED in
this example - see the Flags section below)Ext.container.Container in this example). The source
class will be displayed as a blue link if the member originates from the current class
and gray if it is inherited from an ancestor or mixed-in class.view source in the example)item : Object in the example).undefined a "Returns" section
will note the type of class or object returned and a description (Ext.Component in the
example)Available since 3.4.0 - not pictured in
the example) just after the member descriptionDefaults to: false)The API documentation uses a number of flags to further commnicate the class member's function and intent. The label may be represented by a text label, an abbreviation, or an icon.
classInstance.method1().method2().etc();false is returned from
an event handler- Indicates a framework class
- A singleton framework class. *See the singleton flag for more information
- A component-type framework class (any class within the Ext JS framework that extends Ext.Component)
- Indicates that the class, member, or guide is new in the currently viewed version
- Indicates a class member of type config
- Indicates a class member of type property
- Indicates a class member of type
method
- Indicates a class member of type event
- Indicates a class member of type
theme variable
- Indicates a class member of type
theme mixin
- Indicates that the class, member, or guide is new in the currently viewed version
Just below the class name on an API doc page is a row of buttons corresponding to the types of members owned by the current class. Each button shows a count of members by type (this count is updated as filters are applied). Clicking the button will navigate you to that member section. Hovering over the member-type button will reveal a popup menu of all members of that type for quick navigation.
Getting and setter methods that correlate to a class config option will show up in the methods section as well as in the configs section of both the API doc and the member-type menus just beneath the config they work with. The getter and setter method documentation will be found in the config row for easy reference.
Your page history is kept in localstorage and displayed (using the available real estate) just below the top title bar. By default, the only search results shown are the pages matching the product / version you're currently viewing. You can expand what is displayed by clicking on the button on the right-hand side of the history bar and choosing the "All" radio option. This will show all recent pages in the history bar for all products / versions.
Within the history config menu you will also see a listing of your recent page visits. The results are filtered by the "Current Product / Version" and "All" radio options. Clicking on the button will clear the history bar as well as the history kept in local storage.
If "All" is selected in the history config menu the checkbox option for "Show product details in the history bar" will be enabled. When checked, the product/version for each historic page will show alongside the page name in the history bar. Hovering the cursor over the page names in the history bar will also show the product/version as a tooltip.
Both API docs and guides can be searched for using the search field at the top of the page.
On API doc pages there is also a filter input field that filters the member rows
using the filter string. In addition to filtering by string you can filter the class
members by access level and inheritance. This is done using the checkboxes at the top of
the page. Note that filtering out private members also filters the API class
navigation tree.
Clicking on an empty search field will show your last 10 searches for quick navigation.
Each API doc page (with the exception of Javascript primitives pages) has a menu view of metadata relating to that class. This metadata view will have one or more of the following:
Ext.button.Button class has an alternate class name of Ext.Button). Alternate class
names are commonly maintained for backward compatibility.Runnable examples (Fiddles) are expanded on a page by default. You can collapse and expand example code blocks individually using the arrow on the top-left of the code block. You can also toggle the collapse state of all examples using the toggle button on the top-right of the page. The toggle-all state will be remembered between page loads.
Class members are collapsed on a page by default. You can expand and collapse members using the arrow icon on the left of the member row or globally using the expand / collapse all toggle button top-right.
Viewing the docs on narrower screens or browsers will result in a view optimized for a smaller form factor. The primary differences between the desktop and "mobile" view are:
The class source can be viewed by clicking on the class name at the top of an API doc page. The source for class members can be viewed by clicking on the "view source" link on the right-hand side of the member row.
Creating and uploading images is a common feature, and Sencha Web Application Manager makes it easy to include this functionality in apps. The process is straightforward:
Sencha Web Application Client provides APIs to facilitate all of these steps.
Many different types of applications benefit from access to a device's or
system's on-board camera. Sencha Web Application Client includes a
promise-based camera API that makes it easy to acquire images and get them into
your app. It consists of one basic method, Ext.space.Camera.capture(), which
is configured by an options object controlling its behavior. The default
behavior is to return the acquired image data as a parameter to the promise
handler:
var promise = Ext.space.Camera.capture({
width: 1920, // pixels
height: 1080, // pixels
quality: 80 // percent
});
promise.then(function(imageData) {
// got it
});
Unless otherwise requested, the image data will be returned directly in JPG
format (you can specify this explicitly with encoding: "jpg"). If for
whatever reason you need a lossless image, Sencha Web Application Client
supports encoding: "png" as an option as well.
Sencha Web Application Client lets you easily choose the source for acquired
images. The default source for images is the camera itself (source:
"camera"), to allow the user to take new photos and use them immediately.
However, sometimes users want to choose from existing photos; for such cases,
Sencha Web Application Client supports source: "library" or source: "album"
to launch a native image picker interface, select an image, and provide it to
your application.
When an image already exists on the Web somewhere, use Sencha Web Applicaiton Client's Download API to fetch it. All you need is the image's URL:
var download = Ext.space.Downloads.download({ url: theImageUrl });
This download() method returns Ext.space.files.Download object instances which
act like promises and let you provide handler functions for various life cycle
events. The simplest usage is to simply attach a handler with the normal then()
method:
download.then(function(fileObj, downloadObj) {
// inspect the completed download object, or do something
// with the saved Ext.space.files.File
// for example, if you need to retrieve the stored file's contents:
fileObj.getContents(function(imageData) {
// process the imageData, presumably
});
});
Depending on the application's requirements, it may be necessary to manipulate
the acquired image data in some way before storing it. Other times, all that is
required is to save images immediately. In the case of downloaded images,
Sencha Web Application Client will save them to the filesystem automatically,
so applications that need to process them will want to load them with
.getContents() as above, then save the new contents after processing; if no
processing is required, then all that needs to happen is to let the download
complete.
For images acquired via the Camera API, the process of saving images to the
filesystem depends on how the .capture() method is invoked.
When an application needs to process an image before storing it, the best thing to do is to use Sencha Web Application Client's default behavior and retrieve the image data as a JavaScript variable, then process it, then save it to the filesystem.
var promise = Ext.space.Camera.capture({
width: 1920, // pixels
height: 1080, // pixels
quality: 80, // percent
encoding: "jpg" // format
});
promise.then(function(data) {
var collection = Ext.space.SecureFiles.get("userpics");
var processedData = processImage(data); // or whatever you need to do
var fileOptions = {
name: "newImage.jpg",
type: "image/jpeg"
};
collection.set(fileOptions, processedData).then(function(file) {
// do anything necessary with the saved Ext.space.files.File
});
});
Often, however, an application doesn't need to manipulate an image in any way
once acquired, and all it needs to do is write it as a file for use later.
Rather than force you to go through all the steps yourself as above, Sencha Web
Application Client will do it directly if you pass destination: "file" (as
opposed to destination: "data"). In this case, the promise handler will
receive an Ext.space.files.File object representing the saved file. If
desired, you can also specify the collection into which the file will be saved.
For example:
var promise = Ext.space.Camera.capture({
width: 1920, // pixels
height: 1080, // pixels
quality: 80, // percent
encoding: "jpg", // format
destination: "file", // to save to the filesystem
collection: "userpics" // name of the destination collection
});
promise.then(function(file) {
// got a Ext.space.files.File object
});
For some applications, simply manipulating and/or storing images to the system is not enough; sometimes requirements dictate that an application upload a file to a Web service somewhere. Sencha Web Application Client provides an Upload API that facilitates this.
The first step is to get the image onto the filesystem, using any of the methods
described above. Then, call the file's .upload() method to POST it to a URL. For
example, using a new photo:
var promise = Ext.space.Camera.capture({
width: 1920, // pixels
height: 1080, // pixels
quality: 80, // percent
encoding: "jpg", // format
destination: "file", // to save to the filesystem
collection: "userpics" // name of the destination collection
});
promise.then(function(file) {
// got a file, now upload it to an HTTP form handler:
var uploadPromise = file.upload({
url: "http://example.com/some/path/upload",
fileFieldName: "uploadFile"
// params: { /* optional extra POST data */ },
// headers: { /* optional request headers */ }
});
uploadPromise.then(function(response) {
// inspect the response, if desired:
// response.statusCode, .headers, .body
});
});
The .upload() method's returned promise resolves when the file is finished
uploading. If your application needs to keep the file, there's no need to do anything
further; however, for files you no longer need, you can easily remove them with
the .remove() method on the file object itself.
There are many use cases for applications needing to acquire and process images. Combining Sencha Web Application Client's Camera, SecureFiles, Downloads, and Uploads APIs puts unparalleled rich functionality within the reach of Web applications in a simple consistent way.
Sencha Web Application Manager 6.0.0 | Terms of Use