Graphics Reference
In-Depth Information
in the public APIs. Quite a few of the items listed in this section were not available in
Cocoa Touch until the iPhone 3.0 SDK.
The Good
Core Animation is already “turned on” for every
UIView
in the user interface on Cocoa
Touch. Although you still need to import the
QuartzCore
framework to get access to its
header files, you do not need to implicitly turn on layers on any
UIView
element.
The Bad
Core Animation on Cocoa Touch is significantly limited compared to its desktop version.
A number of the features that we expect on the desktop simply are not available (at this
time) within Cocoa Touch. Many of the features listed here are currently unavailable in
Cocoa Touch, but they might become available at a later date:
.
Borders
(
not available before 3.0
)
Prior to the release of version 3.0 of the iPhone OS, borders were not public and,
therefore, we could not access them. However, they are now fully available for our
use. You can see a demonstration of them in Chapter 11, “User Interaction.”
.
Corners
(
not available before 3.0
)
As with borders, adjusting the corner radius is not available prior to 3.0.
.
Masks
(
not available before 3.0
)
As with Borders and Corners, masks are not available before 3.0.
.
Shadows
Currently, there is no shadow support in Cocoa Touch. Whether this is a permanent
situation is unknown; Apple hasn't used Shadows in its own applications. This
might be due to the lack of Core Image filters in Cocoa Touch.
.
Layout Managers
At first glance, this one seems surprising. However, unlike its desktop cousin, the
user interface of Cocoa Touch has exactly two sizes, 480
480.
Therefore, a Layout Manager would be rather heavy for just those two situations.
×
320 and 320
×
.
Core Image
Core Image is currently not avail-
able for Cocoa Touch. Although
the
CALayer
objects have the capa-
bility to accept filters, because of
the lack of Core Image there are
no filters that can be applied to
layers. Therefore the filters
property on
CALayer
objects is
undefined.
NOTE
New features are being added and existing
features are being exposed to the public with
each release of Cocoa Touch and the iPhone
SDK. If you are a registered iPhone devel-
oper (see
http://developer.apple.com/
iphone
), you should receive an email when-
ever there is an update to the SDK.
