Did you get it? We just applied the previously learned principles. This is exactly what the decorators do in Python! They wrap a function and modify its behaviour in one way or the another. Now you might be wondering that we did not use the @ anywhere in our code? That is just a short way of making up a decorated function. Here is how we could have run the previous code sample using @.
Now, assume one also desires the ability to add borders to windows. Again, the original Window class has no support. The ScrollingWindow subclass now poses a problem, because it has effectively created a new kind of window. If one wishes to add border support to many but not all windows, one must create subclasses WindowWithBorder and ScrollingWindowWithBorder etc. This problem gets worse with every new feature or window subtype to be added. For the decorator solution, we simply create a new BorderedWindowDecorator—at runtime, we can decorate existing windows with the ScrollingWindowDecorator or the BorderedWindowDecorator or both, as we see fit. Notice that if the functionality needs to be added to all Windows, you could modify the base class and that will do. On the other hand, sometimes (e.g., using external frameworks) it is not possible, legal, or convenient to modify the base class.
Heller’s protagonist, Jim Stegner, is an unschooled but talented painter who struggles with drink, with womanizing, and with his temper. These traits have led him to be a killer, although Heller goes to great pains to let us know these acts are not premeditated. They’ve also, in accordance with these United States’ innate streak of violence, allowed him to be a cult figure - a talent around whom one feels it necessary to walk on eggshells. (For what it’s worth, this trait is to this reader and social observer the cause of a hollowness within the national psyche.) Stegner wants atonement for his acts, but he doesn’t know how to go about that. So Heller must allow Stegner to be the subject of retributive violence, which allows the painter, as might happen to a pre-adolescent child, to have atonement forced on him. Stegner is as a person and as a literary creation, a mess. Perhaps Heller intends him to be a faux Hemingway: hard drinking, bullying and a crybaby when those tables are turned on him. Stegner doesn’t seem to have the backbone about which an anti-hero’s fatal flaws can be built, though; he’s too much at the whims of fate for that. Heller tries to create philosophical depth for Stegner, but these attempts ring hollow. What he has created in Stegner, however, is a depiction of an instinctive artist, something the American psyche always seeks: talent and success untrammeled by subjecting that psyche to training and the lessons of culture and history. That Stegner is, in the end, a talented but pitiful figure, should tell the reader something very important: instinct that refuses at least a small measure of acculturation eventually become debased.
A veduta is a highly detailed, usually large-scale painting of a cityscape or some other vista. This genre of landscape originated in Flanders, where artists such as Paul Bril painted vedute as early as the 16th century. As the itinerary of the Grand Tour became somewhat standardized, vedute of familiar scenes like the Roman Forum or the Grand Canal recalled early ventures to the Continent for aristocratic Englishmen. In the later 19th century, more personal impressions of cityscapes replaced the desire for topographical accuracy, which was satisfied instead by painted panoramas.
Color, made up of hue, saturation, and value, dispersed over a surface is the essence of painting, just as pitch and rhythm are the essence of music. Color is highly subjective, but has observable psychological effects, although these can differ from one culture to the next. Black is associated with mourning in the West, but in the East, white is. Some painters, theoreticians, writers and scientists, including Goethe, Kandinsky, and Newton, have written their own color theory.