Question

What Graphics class methods do you use to perform the following tasks? a) draw a line b) draw a filled rectangle c) draw a filled oval d) draw a filled arc c) set the drawing color \(f\), draw a rectangle g) draw an oval h) draw an arc i) draw a string i) set the font

Short answer

a) Draw a line, b) draw a filled rectangle, c) draw a filled oval, d) draw a filled arc, e) set the drawing color, f) draw a rectangle, g) draw an oval, h) draw an arc, i) draw a string, j) set the font. Answer: a) drawLine(), b) fillRect(), c) fillOval(), d) fillArc(), e) setColor(), f) drawRect(), g) drawOval(), h) drawArc(), i) drawString(), j) setFont().

Step-by-step solution

a) draw a line

To draw a line, you can use the method `drawLine(int x1, int y1, int x2, int y2)`. The method accepts four parameters: starting point coordinates (x1, y1) and ending point coordinates (x2, y2).

b) draw a filled rectangle

To draw a filled rectangle, you can use the method `fillRect(int x, int y, int width, int height)`. The method accepts four parameters: upper-left corner coordinates (x, y), width, and height.

c) draw a filled oval

To draw a filled oval, you can use the method `fillOval(int x, int y, int width, int height)`. The method accepts four parameters: upper-left corner coordinates (x, y) of the bounding rectangle, width, and height.

d) draw a filled arc

To draw a filled arc, you can use the method `fillArc(int x, int y, int width, int height, int startAngle, int arcAngle)`. The method accepts six parameters: upper-left corner coordinates (x, y) of the bounding rectangle, width, height, start angle, and arc angle.

e) set the drawing color

To set the drawing color, you can use the method `setColor(Color color)`. The method accepts one parameter, which is an instance of the Color class.

f) draw a rectangle

To draw a rectangle, you can use the method `drawRect(int x, int y, int width, int height)`. The method accepts four parameters: upper-left corner coordinates (x, y), width, and height.

g) draw an oval

To draw an oval, you can use the method `drawOval(int x, int y, int width, int height)`. The method accepts four parameters: upper-left corner coordinates (x, y) of the bounding rectangle, width, and height.

h) draw an arc

To draw an arc, you can use the method `drawArc(int x, int y, int width, int height, int startAngle, int arcAngle)`. The method accepts six parameters: upper-left corner coordinates (x, y) of the bounding rectangle, width, height, start angle, and arc angle.

i) draw a string

To draw a string, you can use the method `drawString(String str, int x, int y)`. The method accepts three parameters: the text string to be drawn, and the starting point coordinates (x, y).

j) set the font

To set the font, you can use the method `setFont(Font font)`. The method accepts one parameter, which is an instance of the Font class.

Key concepts

Understanding the drawLine Method

In Java's world of graphics, the drawLine method is a fundamental tool for creating shapes or designs by connecting two points. This method is used with four integer arguments: drawLine(int x1, int y1, int x2, int y2). The first pair of coordinates, (x1, y1), marks the starting point of the line, while the second pair, (x2, y2), denotes the end point.

To correctly use this method, visualize a coordinate plane where the top-left corner of the component you're drawing on is (0,0). The x value increases as you move to the right, and the y value increases as you move down. The process of drawing a line can be seen like this:

• Select the starting point (x1, y1).
• Select the ending point (x2, y2).
• Invoke the drawLine method with these coordinates.

Executing this method 'draws' a straight line between the two points in the current drawing color, which you can define using the setColor method.

The fillOval Method Explained

Creating filled shapes is a vibrant part of graphics, and the fillOval method allows you to draw a perfectly filled oval within a bounding rectangle. When you call fillOval(int x, int y, int width, int height), you define an invisible rectangle by its upper-left corner (x, y) and specify the oval's width and height — the oval will fit exactly within this bounding rectangle.

Create an oval using these steps:

• Decide the location of the top-left corner of the imaginary rectangle that bounds your oval.
• Determine the width and height of the oval.
• Invoke fillOval with these parameters to create the filled oval.

This will result in a solidly colored shape, the color of which can be set beforehand with the setColor method. If you need a hollow oval, use the drawOval method instead of fillOval.

How to Use the setColor Method

Color adds life to your drawings, and the setColor method in Java's Graphics class sets the current drawing color. You'll find it incredibly useful to change colors between drawing operations. To use setColor(Color color), simply create a new Color object with the desired RGB values, or use predefined constants like Color.RED, and pass it as an argument.

Here's how to apply color to your graphics:

• Create an instance of the Color class with your desired RGB values or use a Color constant.
• Call setColor with this Color instance.
• Draw your shape, line, or text; it will appear in the new color.

The next drawing operation will use this color until you decide to change it again with another setColor call.

Setting the Stage with setFont

When it comes to displaying text in Java graphics, the font can define the mood and readability. The setFont method alters the font for all text operations that follow. You can personalize the text in your graphics by adjusting attributes like font family, style, and size.

Implement the setFont method by following these steps:

• Create a Font object with the desired attributes.
• Use setFont(Font font) to apply this Font object to the Graphics context.
• Any text drawn afterwards will use this newly set font.

Note that when you change the font, it remains active until you choose to set a new font. Combine this with setColor and drawString to fully customize how text appears in your Java application's graphics.