Samantha Yu

Field Detail

• paintLab

  PaintApp paintLab

  A PaintApp object has only one instance and allows this class to access its non-static methods and fields. I did not make PaintApp's fields static, because those fields refer to the one and same object, the paint program. I did not want to place the Layer's methods into PaintApp, because those methods belong in its own separate category. So, this Layers class must be able to access and change the graphical output of PaintApp such as the PaintApp methods like repaint().

• imageArray

  private java.util.ArrayList<java.awt.image.BufferedImage> imageArray

  An ArrayList stores BufferedImages of each layer.

• cLayerNum

  private int cLayerNum

  Index of imageArray allows access to the current layer and is used to make a graphical context for that layer.

• deleteLayer

  public boolean deleteLayer

  Variables used as "switches" during program execution.

• changeLayer

  public boolean changeLayer

  Variables used as "switches" during program execution.

Constructor Detail

• Layers

  public Layers(PaintApp pLab)

  A Layers object is constructed that controls the creation and deletion of layers, and what happens when the user wants to move to a different layer.

  Parameters:

  pLab - The driver class, PaintApp, passes itself to the Menu() constructor to ensure that its Menu object has sufficient access to its methods and variables.

Method Detail

• newLayer

  public void newLayer()

  This method creates a new layer after the current layer by adding a new BufferedImage after the index cLayerNum to the imageArray.

• previousLayer

  public void previousLayer()

  When the user switches to the previous layer, the method first checks whether the new index exists in the the imageArray. If a previous layer does not exist, a notification pops up that erases some of the graphics. repaint() is called to paint the current layer's graphics on top and ensure that the graphics do not accidentally disappear.

• nextLayer

  public void nextLayer()

  When the user switches to the next layer, the method first checks whether the new index exists in the the imageArray. If the next layer does not exist, a notification pops up the erases some of the graphics. repaint() is called to paint the current layer's graphics on top and ensure that the graphics do not accidentally disappear.

• deleteLayer

  public void deleteLayer()

  When the user has decided to delete a layer, the method checks that the user-requested layer is not the only layer left. Next, the layer is set to a blank BufferedImage. When paint() is called, the canvas is cleared with this blank image before the other layers are drawn on top.

• getImageArray

  public java.util.ArrayList<java.awt.image.BufferedImage> getImageArray()

  Returns the ArrayList of BufferedImages, which store the layers

  Returns:

  imageArray

• getcLayerNum

  public int getcLayerNum()

  Returns the current index of imageArray

  Returns:

  cLayerNum

• setcLayerNum

  public void setcLayerNum(int cNum)

  This method updates the current index of imageArray.

  Parameters:

  cNum - cLayerNum is set to the parameter passed to setcLayerNum.