iOS Components and Frameworks: Understanding the Advanced Features of the iOS SDK

Rendering a Filtered Image

To render a filtered image, all that is required is to request the outputImage from the filter’s attributes, and to call one of the available methods to render it to a context, an image, a bitmap, or a pixel buffer. At that point the filter operations will be applied to the inputImage and the outputImage will be produced. In the sample app, this occurs in two instances: if the user taps Preview in the filter view controller (as shown in Figure 19.5), or if the user taps Add Filter. When the user taps the Preview button in ICFFilterViewController, the previewButtonTouched: method is called. This method begins by initializing a Core Image context (note that the context can be initialized once as a property, but is done ...