Graphics Reference
In-Depth Information
blurry so our starting value,
fromValue
, is set to
0.0
and our ending value,
toValue
, is set
to
5.0
. However, if the toggle is set, we want to animate to clear so the starting value is
5.0
and our ending value is
0.0
.
Notice also that Listing 6-7 doesn't contain the -
setAutoreverses
call that's found in
Listing 6-6. This call must be removed or set to
NO
for the effect to be “sticky”; otherwise
it returns to its starting value and overrides -
setFillMode:
.
Next, we have changed the
-setRemovedOnCompletion
call to
NO
. This tells the layer not to
remove the animation when it has completed.
Finally, we have added a call to
-setFillMode:kCAFillModeForwards
that tells the anima-
tion to leave the resulting value at whatever we specified in the -
setToValue
field.
Each icon now retains the blur on the first click and returns to its original value on a
second click, making the Core Animation layer-based-button “sticky.” In Figure 6-4, you
can see that two of the icons are blurry because they have each been clicked once and
retain their sticky state.
FIGURE 6-4
Sticky Blur
Filter parameters are accessible and modifiable using KVC. This enables you to use data
bindings to create layers with complex filtering and control those filters using standard
Cocoa controls, such as sliders.
You might recall from the previous section that when we instantiated the
CABasic
Animation
object on a mouse down event, we used the key-path
filters.blur.
inputRadius
on the layer.
filters
represents the NSArray of filters available,
blur
is the
