Beginning of the class named Prob04Runner
The class named Prob04Runner begins in Listing 2 .
| Listing 2 - Beginning of the class named Prob04Runner. |
|---|
class Prob04Runner{
public Prob04Runner(){System.out.println("Display your name here.");
}//end constructor//----------------------------------------------------//
public void run(){Picture pix = new Picture("Prob04a.jpg");
//Rotate and mirror the picture.pix = rotatePicture(pix,35);
pix = mirrorUpperQuads(pix);pix = mirrorHoriz(pix);
pix.explore(); |
Nothing new here
There is nothing new in Listing 2 .
After instantiating a new Picture object from the given image file, Listing 2 calls three methods to rotate, mirror, and display the picture, producing the graphic output shown in Figure 2 .
All of the code to accomplish this is essentially the same as code that I have explained in earlier modules.
Clip the picture and display your name
Then Listing 3 calls the clipToEllipse method to clip the picture to an ellipse on a red background as shown in Figure 3 . The clipToEllipse method is new to this module, so I will explain it shortly.
| Listing 3 - Clip the picture and display your name. |
|---|
pix = clipToEllipse(pix);
//Add your name and display the output picture.pix.addMessage("Display your name here.",10,20);
pix.explore();System.out.println(pix);
}//end run |
The remaining code in Listing 3 is a repeat of code that I have explained in earlier modules, so I won't have anythingfurther to say about it.
The method named clipToEllipse
The method named clipToEllipse is shown in its entirety in Listing 4 .
| Listing 4 - The method named clipToEllipse. |
|---|
private Picture clipToEllipse(Picture pix){
Picture result =new Picture(pix.getWidth(),pix.getHeight());
result.setAllPixelsToAColor(Color.RED);//Get the graphics2D object
Graphics2D g2 = (Graphics2D)(result.getGraphics());//Create an ellipse for clipping
Ellipse2D.Double ellipse =new Ellipse2D.Double(28,64,366,275);
//Use the ellipse for clippingg2.setClip(ellipse);
//Draw the imageg2.drawImage(pix.getImage(),0,0,pix.getWidth(),
pix.getHeight(),null);
return result;}//end clipToEllipse |
Behavior of the clipToEllipse method
The clipToEllipse method receives an incoming parameter that is a reference to an object of the Picture class. Basically, here is what the method does:
- Instantiate a Picture object with an all white background that is the same size as the incoming Picture object.
- Call Ericson's setAllPixelsToAColor method to convert the white background into a red background.
- Call Ericson's getGraphics method to get the Graphics object encapsulated in the red Picture object.
- Cast the Graphics object's reference to type Graphics2D .
- Construct a new Ellipse2D.Double object with the position, width, and height specified by the constructor parameters.
- Call Sun's setClip method to set the clipping area on the red Picture object to match the position and shape of the ellipse.
- Call Ericson's getImage method to get the Image object encapsulated in the incoming Picture object.
- Call Sun's drawImage method to draw that portion of the incoming picture that fits inside the ellipse on the red Picture object.