Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 81Java2D Graphics3/19/20092Opening Discussion■Let's look at solutions to the interclass problem.■Making a linked list in C.■Think of an iterator as an object that encapsulates the elements you need to make a for loop.■Do you have any questions about the assignment?■Do you have any questions about the reading?3Graphics in Java■You can do lots of things with the standard GUI elements in Swing. We've been able to set up quite a bit of a GUI using that. However, no GUI can predict everything that you will want to do and we want to be able to add custom drawing to our application.■For this we will rely on the Java2D library. Java2D was added about the same time Swing was and it is fundamentally based on the Graphics2D class. There is also a Graphics class that provides more basic custom graphics capabilities. Graphics2D inherits from Graphics so it can do all the same things and more.4Making Custom Drawn Components■There are three steps to making a component class that we can do custom drawing to.Make a new class and have it inherit from JComponent or a subtype of it. We'll use JPanel.Override the paintComponent method in your class.Draw with the Graphics object that was passed into the paintComponent method.■Let's look a bit at the Graphics2D class to see what some of the possibilities might be for what we can draw.■Now we can do these steps in our program to make a central panel we can draw to.5Settings■There are several things that we can set on the Graphics2D object that are used when we draw things. Here are some:Paint – could be a color, but there are also gradients and texturesStroke – determines how lines are drawnFont – how you want text to appearTransform – AffineTransform allows translate, rotate, scale, or shearComposite – how colors combine when you draw over old stuffClip – where your drawings will appearRender hints – other things like antialiasing6More General Drawing■Of course, Graphics2D objects aren't limited to just drawing on components.■The Image class (and it's subtype BufferedImage) will let you get Graphics objects that you can draw to and what you draw will be on the image.■We'll typically do this even if we are drawing to a component to implement buffering which reduces flicker.7Coding■Let's play with our panel some to experiment with the drawing options.8Minute Essay■What do you think we should try adding to our drawing program given that we now know how to draw?■Interclass Problem – Write a simple drawing program similar to Paint. Use buttons for selecting at least rectangles, ellipses, and lines. Use the mouse to draw things. Have color options with
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