Menu

When a menu bar is constructed, the invisible but "click-able" buttons are created. The MouseListener and MouseMotionListener, which are implemented by the PaintApp class, listen for whenever the mouse is clicked, dragged, or released inside the application. A MouseEvent is passed to methods like mousePressed() and the program can get the coordinates of where the mouse clicked.

Menu.java -- Constructor creates "click-able" menu buttons
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public Menu(PaintApp pLab, Layers lArray) { // When the menu object is constructed, the invisible but "click-able" buttons are also constructed
    paintLab = pLab;        // Initializes paintLab to the actual PaintApp, and layersArray to the actual layers array
    layersArray = lArray;   // So that Menu class' methods can access the non-static fields and methods, such as imageArray
     
    selectColor = new Color(0,0,0);
    fontColor = new Color(0,0,0);
    btnFont = new Font("Georgia",Font.BOLD,17);
    numTool =  1;
    strokeSize = 15;
     
    colorRect = new Rectangle(13, 35, 35, 35);      // Color button (invisible but "click-able")
      
    pencilRect = new Rectangle(53, 35, 80, 35);     // Tool buttons (invisible but "click-able")
    brushRect = new Rectangle(138, 35, 80, 35);
    sprayRect = new Rectangle(223, 35, 80, 35);
     
    sizeRect = new Rectangle(308, 35, 60, 35);      // Size buttons (invisible but "click-able")
     
    newRect = new Rectangle(373, 35, 70, 35);       // Layer buttons (invisible but "click-able")
    prevRect = new Rectangle(448, 35, 70, 35);
    nextRect = new Rectangle(523, 35, 70, 35);
    delRect = new Rectangle(598, 35, 70, 35);
     
    menuRect = new Rectangle(8,30,paintLab.getAppWidth(), paintLab.getMenuHeight());
}
 
				public Menu(PaintApp pLab, Layers lArray) { // When the menu object is constructed, the invisible but "click-able" buttons are also constructed
					paintLab = pLab;        // Initializes paintLab to the actual PaintApp, and layersArray to the actual layers array
					layersArray = lArray;   // So that Menu class' methods can access the non-static fields and methods, such as imageArray
					
					selectColor = new Color(0,0,0);
					fontColor = new Color(0,0,0);
					btnFont = new Font("Georgia",Font.BOLD,17);
					numTool =  1;
					strokeSize = 15;
					
					colorRect = new Rectangle(13, 35, 35, 35);      // Color button (invisible but "click-able")
					 
					pencilRect = new Rectangle(53, 35, 80, 35);     // Tool buttons (invisible but "click-able")
					brushRect = new Rectangle(138, 35, 80, 35);
					sprayRect = new Rectangle(223, 35, 80, 35);
					
					sizeRect = new Rectangle(308, 35, 60, 35);      // Size buttons (invisible but "click-able")
					
					newRect = new Rectangle(373, 35, 70, 35);       // Layer buttons (invisible but "click-able")
					prevRect = new Rectangle(448, 35, 70, 35);
					nextRect = new Rectangle(523, 35, 70, 35);
					delRect = new Rectangle(598, 35, 70, 35);
					
					menuRect = new Rectangle(8,30,paintLab.getAppWidth(), paintLab.getMenuHeight());
				}
PaintApp.java -- MouseEvents make menu buttons "click-able"
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public void mousePressed(MouseEvent e) {    // When any of the mouse buttons are pressed down
    menuBar.select(e.getX(), e.getY());
    newX = e.getX();
    newY = e.getY();
    oldX = e.getX(); 
    oldY = e.getY();
     
    if (menuBar.menuRect.contains(e.getX(),e.getY())) {
        continuePaint = false;  // After the user selects a menu item, continuePaint will prevent the area under the menu from getting painted.
        menuChange = true;
        repaint();
    }
     
    if (canvasRect.contains(e.getX(), e.getY())) {  // The application repaints if the user clicks inside the canvas
        repaint();
    }
}
 
				public void mousePressed(MouseEvent e) {    // When any of the mouse buttons are pressed down
					menuBar.select(e.getX(), e.getY());
					newX = e.getX();
					newY = e.getY();
					oldX = e.getX();  
					oldY = e.getY();
					
					if (menuBar.menuRect.contains(e.getX(),e.getY())) {
						continuePaint = false;  // After the user selects a menu item, continuePaint will prevent the area under the menu from getting painted.
						menuChange = true;
						repaint();
					}
					
					if (canvasRect.contains(e.getX(), e.getY())) {  // The application repaints if the user clicks inside the canvas
						repaint();
					}
				}

The select() calls a certain function, such as Layer's newLayer(), based on where the user clicked.

Menu.java -- Selecting a menu item
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public void select(int x, int y) {      // Selects menu items
    if (colorRect.contains(x, y)) {     // If mouse clicks on the color button
        selectColor();
    }
                     
    if (pencilRect.contains(x, y)) {    // If mouse selects a tool
        numTool = 1;
    }
    else if (brushRect.contains(x, y)) {
        numTool = 2;
    }
    else if (sprayRect.contains(x, y)) {
        numTool = 3;
    }
     
    if (sizeRect.contains(x, y)) {      // If mouse clicks on the size button
        selectSize();
    }
     
    if (newRect.contains(x, y)) {       // If mouse clicks on a layer button
        layersArray.newLayer();
    }
    else if (prevRect.contains(x, y)) {
        layersArray.previousLayer();
    }
    else if (nextRect.contains(x, y)) {
        layersArray.nextLayer();
    }
    else if (delRect.contains(x, y)) {
        layersArray.deleteLayer();
    }
}
 
				public void select(int x, int y) {      // Selects menu items
					if (colorRect.contains(x, y)) {     // If mouse clicks on the color button
						selectColor();
					}
									
					if (pencilRect.contains(x, y)) {    // If mouse selects a tool
						numTool = 1;
					}
					else if (brushRect.contains(x, y)) {
						numTool = 2;
					}
					else if (sprayRect.contains(x, y)) {
						numTool = 3;
					}
					
					if (sizeRect.contains(x, y)) {      // If mouse clicks on the size button
						selectSize();
					}
					
					if (newRect.contains(x, y)) {       // If mouse clicks on a layer button
						layersArray.newLayer();
					}
					else if (prevRect.contains(x, y)) {
						layersArray.previousLayer();
					}
					else if (nextRect.contains(x, y)) {
						layersArray.nextLayer();
					}
					else if (delRect.contains(x, y)) {
						layersArray.deleteLayer();
					}
				}