stdlib.StdDraw

All Implemented Interfaces:: ActionListener, KeyListener, MouseListener, MouseMotionListener, EventListener

public final class StdDraw extends Object implements ActionListener, MouseListener, MouseMotionListener, KeyListener

This class provides a basic capability for creating drawings with your programs. It uses a simple graphics model that allows you to create drawings consisting of points, lines, squares, circles, and other geometric shapes in a window on your computer and to save the drawings to a file. Standard drawing also includes facilities for text, color, pictures, and animation, along with user interaction via the keyboard and mouse.

Points and lines. ou can draw points and line segments with the following methods:

point(double x, double y)
line(double x1, double y1, double x2, double y2)

The x- and y-coordinates must be in the drawing area (between 0 and 1 and by default) or the points and lines will not be visible.

Squares, circles, rectangles, and ellipses. You can draw squares, circles, rectangles, and ellipses using the following methods:

circle(double x, double y, double radius)
ellipse(double x, double y, double semiMajorAxis, double semiMinorAxis)
square(double x, double y, double radius)
rectangle(double x, double y, double halfWidth, double halfHeight)

All of these methods take as arguments the location and size of the shape. The location is always specified by the x- and y-coordinates of its center. The size of a circle is specified by its radius and the size of an ellipse is specified by the lengths of its semi-major and semi-minor axes. The size of a square or rectangle is specified by its half-width or half-height. The convention for drawing squares and rectangles is parallel to those for drawing circles and ellipses, but may be unexpected to the uninitiated.

The methods above trace outlines of the given shapes. The following methods draw filled versions:

filledCircle(double x, double y, double radius)
filledEllipse(double x, double y, double semiMajorAxis, double semiMinorAxis)
filledSquare(double x, double y, double radius)
filledRectangle(double x, double y, double halfWidth, double halfHeight)

Circular arcs. You can draw circular arcs with the following method:

arc(double x, double y, double radius, double angle1, double angle2)

The arc is from the circle centered at (x, y) of the specified radius. The arc extends from angle1 to angle2. By convention, the angles are polar (counterclockwise angle from the x-axis) and represented in degrees. For example, StdDraw.arc(0.0, 0.0, 1.0, 0, 90) draws the arc of the unit circle from 3 o'clock (0 degrees) to 12 o'clock (90 degrees).

Polygons. You can draw polygons with the following methods:

polygon(double[] x, double[] y)
filledPolygon(double[] x, double[] y)

The points in the polygon are (x[i], y[i]). For example, the following code fragment draws a filled diamond with vertices (0.1, 0.2), (0.2, 0.3), (0.3, 0.2), and (0.2, 0.1):

  double[] x = { 0.1, 0.2, 0.3, 0.2 };
  double[] y = { 0.2, 0.3, 0.2, 0.1 };
  StdDraw.filledPolygon(x, y);

Pen size. The pen is circular, so that when you set the pen radius to r and draw a point, you get a circle of radius r. Also, lines are of thickness 2r and have rounded ends. The default pen radius is 0.005 and is not affected by coordinate scaling. This default pen radius is about 1/200 the width of the default canvas, so that if you draw 100 points equally spaced along a horizontal or vertical line, you will be able to see individual circles, but if you draw 200 such points, the result will look like a line.

setPenRadius(double radius)

For example, StdDraw.setPenRadius(0.025) makes the thickness of the lines and the size of the points to be five times the 0.005 default. To draw points with the minimum possible radius (one pixel on typical displays), set the pen radius to 0.0.

Pen color. All geometric shapes (such as points, lines, and circles) are drawn using the current pen color. By default, it is black. You can change the pen color with the following methods:

setPenColor(int red, int green, int blue)
setPenColor(RGBColor color)

The first method allows you to specify colors using the RGB color system. This color picker is a convenient way to find a desired color. The second method allows you to specify colors using the RGBColor data type that is discussed in Chapter 3. Until then, you can use this method with one of these predefined colors in standard drawing: BLACK, BLUE, CYAN, DARK_GRAY, GRAY, GREEN, LIGHT_GRAY, MAGENTA, ORANGE, PINK, RED, WHITE, and YELLOW. For example, StdDraw.setPenColor(StdDraw.MAGENTA) sets the pen color to magenta.

Canvas size. By default, all drawing takes places in a 512-by-512 canvas. The canvas does not include the window title or window border. You can change the size of the canvas with the following method:

setCanvasSize(int width, int height)

This sets the canvas size to be width-by-height pixels. It also erases the current drawing and resets the coordinate system, pen radius, pen color, and font back to their default values. Ordinarly, this method is called once, at the very beginning of a program. For example, StdDraw.setCanvasSize(800, 800) sets the canvas size to be 800-by-800 pixels.

Canvas scale and coordinate system. By default, all drawing takes places in the unit square, with (0, 0) at lower left and (1, 1) at upper right. You can change the default coordinate system with the following methods:

setXscale(double xmin, double xmax)
setYscale(double ymin, double ymax)
setScale(double min, double max)

The arguments are the coordinates of the minimum and maximum x- or y-coordinates that will appear in the canvas. For example, if you wish to use the default coordinate system but leave a small margin, you can call StdDraw.setScale(-.05, 1.05).

These methods change the coordinate system for subsequent drawing commands; they do not affect previous drawings. These methods do not change the canvas size; so, if the x- and y-scales are different, squares will become rectangles and circles will become ellipses.

Text. You can use the following methods to annotate your drawings with text:

text(double x, double y, String text)
text(double x, double y, String text, double degrees)
textLeft(double x, double y, String text)
textRight(double x, double y, String text)

The first two methods write the specified text in the current font, centered at (x, y). The second method allows you to rotate the text. The last two methods either left- or right-align the text at (x, y).

The default font is a Sans Serif font with point size 16. You can use the following method to change the font:

setFont(Font font)

You use the Font data type to specify the font. This allows you to choose the face, size, and style of the font. For example, the following code fragment sets the font to Arial Bold, 60 point.

  Font font = new Font("Arial", Font.BOLD, 60);
  StdDraw.setFont(font);
  StdDraw.text(0.5, 0.5, "Hello, World");

Images. You can use the following methods to add images to your drawings:

picture(double x, double y, String filename)
picture(double x, double y, String filename, double degrees)
picture(double x, double y, String filename, double scaledWidth, double scaledHeight)
picture(double x, double y, String filename, double scaledWidth, double scaledHeight, double degrees)

These methods draw the specified image, centered at (x, y). The supported image formats are JPEG, PNG, and GIF. The image will display at its native size, independent of the coordinate system. Optionally, you can rotate the image a specified number of degrees counterclockwise or rescale it to fit snugly inside a width-by-height bounding box.

Saving to a file. You save your image to a file using the File → Save menu option. You can also save a file programatically using the following method:

save(String filename)

The supported image formats are JPEG and PNG. The filename must have either the extension .jpg or .png. We recommend using PNG for drawing that consist solely of geometric shapes and JPEG for drawings that contains pictures.

Clearing the canvas. To clear the entire drawing canvas, you can use the following methods:

clear()
clear(RGBColor color)

The first method clears the canvas to white; the second method allows you to specify a color of your choice. For example, StdDraw.clear(StdDraw.LIGHT_GRAY) clears the canvas to a shade of gray.

Computer animations and double buffering. Double buffering is one of the most powerful features of standard drawing, enabling computer animations. The following methods control the way in which objects are drawn:

enableDoubleBuffering()
disableDoubleBuffering()
show()
pause(int t)

By default, double buffering is disabled, which means that as soon as you call a drawing method—such as point() or line()—the results appear on the screen.

When double buffering is enabled by calling enableDoubleBuffering(), all drawing takes place on the offscreen canvas. The offscreen canvas is not displayed. Only when you call show() does your drawing get copied from the offscreen canvas to the onscreen canvas, where it is displayed in the standard drawing window. You can think of double buffering as collecting all of the lines, points, shapes, and text that you tell it to draw, and then drawing them all simultaneously, upon request.

The most important use of double buffering is to produce computer animations, creating the illusion of motion by rapidly displaying static drawings. To produce an animation, repeat the following four steps:

Clear the offscreen canvas.
Draw objects on the offscreen canvas.
Copy the offscreen canvas to the onscreen canvas.
Wait for a short while.

The clear(), show(), and pause(int t) methods support the first, third, and fourth of these steps, respectively.

For example, this code fragment animates two balls moving in a circle.

  StdDraw.setScale(-2, +2);
  StdDraw.enableDoubleBuffering();

  for (double t = 0.0; true; t += 0.02) {
      double x = Math.sin(t);
      double y = Math.cos(t);
      StdDraw.clear();
      StdDraw.filledCircle(x, y, 0.05);
      StdDraw.filledCircle(-x, -y, 0.05);
      StdDraw.show();
      StdDraw.pause(20);
  }

Keyboard and mouse inputs. Standard drawing has very basic support for keyboard and mouse input. It is much less powerful than most user interface libraries provide, but also much simpler. You can use the following methods to intercept mouse events:

isMousePressed()
mouseX()
mouseY()

The first method tells you whether a mouse button is currently being pressed. The last two methods tells you the x- and y-coordinates of the mouse's current position, using the same coordinate system as the canvas (the unit square, by default). You should use these methods in an animation loop that waits a short while before trying to poll the mouse for its current state. You can use the following methods to intercept keyboard events:

hasNextKeyTyped()
nextKeyTyped()
isKeyPressed(int keycode)

If the user types lots of keys, they will be saved in a list until you process them. The first method tells you whether the user has typed a key (that your program has not yet processed). The second method returns the next key that the user typed (that your program has not yet processed) and removes it from the list of saved keystrokes. The third method tells you whether a key is currently being pressed.

Accessing control parameters. You can use the following methods to access the current pen color, pen radius, and font:

getPenColor()
getPenRadius()
getFont()

These methods are useful when you want to temporarily change a control parameter and reset it back to its original value.

Corner cases. Here are some corner cases.

Drawing an object outside (or partly outside) the canvas is permitted. However, only the part of the object that appears inside the canvas will be visible.
Any method that is passed a null argument will throw an IllegalArgumentException.
Any method that is passed a Double.NaN, Double.POSITIVE_INFINITY, or Double.NEGATIVE_INFINITY argument will throw an IllegalArgumentException.
Due to floating-point issues, an object drawn with an x- or y-coordinate that is way outside the canvas (such as the line segment from (0.5, –10^308) to (0.5, 10^308) may not be visible even in the part of the canvas where it should be.

Performance tricks. Standard drawing is capable of drawing large amounts of data. Here are a few tricks and tips:

Use double buffering for static drawing with a large number of objects. That is, call enableDoubleBuffering() before the sequence of drawing commands and call show() afterwards. Incrementally displaying a complex drawing while it is being created can be intolerably inefficient on many computer systems.
When drawing computer animations, call show() only once per frame, not after drawing each individual object.
If you call picture() multiple times with the same filename, Java will cache the image, so you do not incur the cost of reading from a file each time.

Known bugs and issues.

The picture() methods may not draw the portion of the image that is inside the canvas if the center point (x, y) is outside the canvas. This bug appears only on some systems.

Reference. For additional documentation, see Section 1.5 of Computer Science: An Interdisciplinary Approach by Robert Sedgewick and Kevin Wayne.

Author:: Robert Sedgewick, Kevin Wayne

Field Summary

Fields

Modifier and Type

Field

Description

static final RGBColor

BLACK

The color black.

static final RGBColor

BLUE

The color blue.

static final RGBColor

CYAN

The color cyan.

static final RGBColor

DARK_GRAY

The color dark gray.

static final RGBColor

GRAY

The color gray.

static final RGBColor

GREEN

The color green.

static final RGBColor

LIGHT_GRAY

The color light gray.

static final RGBColor

MAGENTA

The color magenta.

static final RGBColor

ORANGE

The color orange.

static final RGBColor

PINK

The color pink.

static final RGBColor

RED

The color red.

static final RGBColor

WHITE

The color white.

static final RGBColor

YELLOW

The color yellow.
Method Summary

Modifier and Type

Method

Description

void

actionPerformed(ActionEvent e)

This method cannot be called directly.

static void

arc(double x, double y, double radius, double angle1, double angle2)

Draws a circular arc of the specified radius, centered at (x, y), from angle1 to angle2 (in degrees).

static void

circle(double x, double y, double radius)

Draws a circle of the specified radius, centered at (x, y).

static void

clear()

Clears the screen to the default color (white).

static void

clear(RGBColor color)

Clears the screen to the specified color.

static void

disableDoubleBuffering()

Disables double buffering.

static void

ellipse(double x, double y, double semiMajorAxis, double semiMinorAxis)

Draws an ellipse with the specified semimajor and semiminor axes, centered at (x, y).

static void

enableDoubleBuffering()

Enables double buffering.

static void

filledCircle(double x, double y, double radius)

Draws a filled circle of the specified radius, centered at (x, y).

static void

filledEllipse(double x, double y, double semiMajorAxis, double semiMinorAxis)

Draws an ellipse with the specified semimajor and semiminor axes, centered at (x, y).

static void

filledPolygon(double[] x, double[] y)

Draws a polygon with the vertices (x₀, y₀), (x₁, y₁), ..., (x_n–1, y_n–1).

static void

filledRectangle(double x, double y, double halfWidth, double halfHeight)

Draws a filled rectangle of the specified size, centered at (x, y).

static void

filledSquare(double x, double y, double halfLength)

Draws a filled square of the specified size, centered at (x, y).

static Font

getFont()

Returns the current font.

static RGBColor

getPenColor()

Returns the current pen color.

static double

getPenRadius()

Returns the current pen radius.

static boolean

hasNextKeyTyped()

Returns true if the user has typed a key (that has not yet been processed).

static boolean

isKeyPressed(int keycode)

Returns true if the given key is being pressed.

static boolean

isMousePressed()

Returns true if the mouse is being pressed.

void

keyPressed(KeyEvent e)

This method cannot be called directly.

void

keyReleased(KeyEvent e)

This method cannot be called directly.

void

keyTyped(KeyEvent e)

This method cannot be called directly.

static void

line(double x0, double y0, double x1, double y1)

Draws a line segment between (x₀, y₀) and (x₁, y₁).

static void

main(String[] args)

Test client.

void

mouseClicked(MouseEvent e)

This method cannot be called directly.

void

mouseDragged(MouseEvent e)

This method cannot be called directly.

void

mouseEntered(MouseEvent e)

This method cannot be called directly.

void

mouseExited(MouseEvent e)

This method cannot be called directly.

void

mouseMoved(MouseEvent e)

This method cannot be called directly.

void

mousePressed(MouseEvent e)

This method cannot be called directly.

void

mouseReleased(MouseEvent e)

This method cannot be called directly.

static double

mouseX()

Returns the x-coordinate of the mouse.

static double

mouseY()

Returns the y-coordinate of the mouse.

static char

nextKeyTyped()

Returns the next key that was typed by the user (that your program has not already processed).

static void

pause(int t)

Pauses for t milliseconds.

static void

picture(double x, double y, String filename)

Draws the specified image centered at (x, y).

static void

picture(double x, double y, String filename, double degrees)

Draws the specified image centered at (x, y), rotated given number of degrees.

static void

picture(double x, double y, String filename, double scaledWidth, double scaledHeight)

Draws the specified image centered at (x, y), rescaled to the specified bounding box.

static void

picture(double x, double y, String filename, double scaledWidth, double scaledHeight, double degrees)

Draws the specified image centered at (x, y), rotated given number of degrees, and rescaled to the specified bounding box.

static void

point(double x, double y)

Draws a point centered at (x, y).

static void

polygon(double[] x, double[] y)

Draws a polygon with the vertices (x₀, y₀), (x₁, y₁), ..., (x_n–1, y_n–1).

static void

rectangle(double x, double y, double halfWidth, double halfHeight)

Draws a rectangle of the specified size, centered at (x, y).

static void

save(String filename)

Saves the drawing to using the specified filename.

static void

setCanvasSize()

Sets the canvas (drawing area) to be 512-by-512 pixels.

static void

setCanvasSize(int canvasWidth, int canvasHeight)

Sets the canvas (drawing area) to be width-by-height pixels.

static void

setFont()

Sets the font to the default font (sans serif, 16 point).

static void

setFont(Font font)

Sets the font to the specified value.

static void

setPenColor()

Sets the pen color to the default color (black).

static void

setPenColor(int red, int green, int blue)

Sets the pen color to the specified RGB color.

static void

setPenColor(RGBColor color)

Sets the pen color to the specified color.

static void

setPenRadius()

Sets the pen size to the default size (0.002).

static void

setPenRadius(double radius)

Sets the radius of the pen to the specified size.

static void

setScale()

Sets the x-scale and y-scale to be the default (between 0.0 and 1.0).

static void

setScale(double min, double max)

Sets both the x-scale and y-scale to the (same) specified range.

static void

setXscale()

Sets the x-scale to be the default (between 0.0 and 1.0).

static void

setXscale(double min, double max)

Sets the x-scale to the specified range.

static void

setYscale()

Sets the y-scale to be the default (between 0.0 and 1.0).

static void

setYscale(double min, double max)

Sets the y-scale to the specified range.

static void

show()

Copies offscreen buffer to onscreen buffer.

static void

square(double x, double y, double halfLength)

Draws a square of side length 2r, centered at (x, y).

static void

text(double x, double y, String text)

Writes the given text string in the current font, centered at (x, y).

static void

text(double x, double y, String text, double degrees)

Writes the given text string in the current font, centered at (x, y) and rotated by the specified number of degrees.

static void

textLeft(double x, double y, String text)

Writes the given text string in the current font, left-aligned at (x, y).

static void

textRight(double x, double y, String text)

Writes the given text string in the current font, right-aligned at (x, y).

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details
- BLACK
  
  public static final RGBColor BLACK
  
  The color black.
- BLUE
  
  public static final RGBColor BLUE
  
  The color blue.
- CYAN
  
  public static final RGBColor CYAN
  
  The color cyan.
- DARK_GRAY
  
  public static final RGBColor DARK_GRAY
  
  The color dark gray.
- GRAY
  
  public static final RGBColor GRAY
  
  The color gray.
- GREEN
  
  public static final RGBColor GREEN
  
  The color green.
- LIGHT_GRAY
  
  public static final RGBColor LIGHT_GRAY
  
  The color light gray.
- MAGENTA
  
  public static final RGBColor MAGENTA
  
  The color magenta.
- ORANGE
  
  public static final RGBColor ORANGE
  
  The color orange.
- PINK
  
  public static final RGBColor PINK
  
  The color pink.
- RED
  
  public static final RGBColor RED
  
  The color red.
- WHITE
  
  public static final RGBColor WHITE
  
  The color white.
- YELLOW
  
  public static final RGBColor YELLOW
  
  The color yellow.
Method Details
- setCanvasSize
  
  public static void setCanvasSize()
  
  Sets the canvas (drawing area) to be 512-by-512 pixels. This also erases the current drawing and resets the coordinate system, pen radius, pen color, and font back to their default values. Ordinarly, this method is called once, at the very beginning of a program.
- setCanvasSize
  
  public static void setCanvasSize(int canvasWidth, int canvasHeight)
  
  Sets the canvas (drawing area) to be width-by-height pixels. This also erases the current drawing and resets the coordinate system, pen radius, pen color, and font back to their default values. Ordinarly, this method is called once, at the very beginning of a program.
  
  Parameters:
  
  canvasWidth - the width as a number of pixels
  
  canvasHeight - the height as a number of pixels
  
  Throws:
  
  IllegalArgumentException - unless both canvasWidth and canvasHeight are positive
- setXscale
  
  public static void setXscale()
  
  Sets the x-scale to be the default (between 0.0 and 1.0).
- setYscale
  
  public static void setYscale()
  
  Sets the y-scale to be the default (between 0.0 and 1.0).
- setScale
  
  public static void setScale()
  
  Sets the x-scale and y-scale to be the default (between 0.0 and 1.0).
- setXscale
  
  public static void setXscale(double min, double max)
  
  Sets the x-scale to the specified range.
  
  Parameters:
  
  min - the minimum value of the x-scale
  
  max - the maximum value of the x-scale
  
  Throws:
  
  IllegalArgumentException - if (max == min)
  
  IllegalArgumentException - if either min or max is either NaN or infinite
- setYscale
  
  public static void setYscale(double min, double max)
  
  Sets the y-scale to the specified range.
  
  Parameters:
  
  min - the minimum value of the y-scale
  
  max - the maximum value of the y-scale
  
  Throws:
  
  IllegalArgumentException - if (max == min)
  
  IllegalArgumentException - if either min or max is either NaN or infinite
- setScale
  
  public static void setScale(double min, double max)
  
  Sets both the x-scale and y-scale to the (same) specified range.
  
  Parameters:
  
  min - the minimum value of the x- and y-scales
  
  max - the maximum value of the x- and y-scales
  
  Throws:
  
  IllegalArgumentException - if (max == min)
  
  IllegalArgumentException - if either min or max is either NaN or infinite
- clear
  
  public static void clear()
  
  Clears the screen to the default color (white).
- clear
  
  public static void clear(RGBColor color)
  
  Clears the screen to the specified color.
  
  Parameters:
  
  color - the color to make the background
  
  Throws:
  
  IllegalArgumentException - if color is null
- getPenRadius
  
  public static double getPenRadius()
  
  Returns the current pen radius.
  
  Returns:
  
  the current value of the pen radius
- setPenRadius
  
  public static void setPenRadius()
  
  Sets the pen size to the default size (0.002). The pen is circular, so that lines have rounded ends, and when you set the pen radius and draw a point, you get a circle of the specified radius. The pen radius is not affected by coordinate scaling.
- setPenRadius
  
  public static void setPenRadius(double radius)
  
  Sets the radius of the pen to the specified size. The pen is circular, so that lines have rounded ends, and when you set the pen radius and draw a point, you get a circle of the specified radius. The pen radius is not affected by coordinate scaling.
  
  Parameters:
  
  radius - the radius of the pen
  
  Throws:
  
  IllegalArgumentException - if radius is negative, NaN, or infinite
- getPenColor
  
  public static RGBColor getPenColor()
  
  Returns the current pen color.
  
  Returns:
  
  the current pen color
- setPenColor
  
  public static void setPenColor()
  
  Sets the pen color to the default color (black).
- setPenColor
  
  public static void setPenColor(RGBColor color)
  
  Sets the pen color to the specified color.
  The predefined pen colors are StdDraw.BLACK, StdDraw.BLUE, StdDraw.CYAN, StdDraw.DARK_GRAY, StdDraw.GRAY, StdDraw.GREEN, StdDraw.LIGHT_GRAY, StdDraw.MAGENTA, StdDraw.ORANGE, StdDraw.PINK, StdDraw.RED, StdDraw.WHITE, and StdDraw.YELLOW.
  
  Parameters:
  
  color - the color to make the pen
  
  Throws:
  
  IllegalArgumentException - if color is null
- setPenColor
  
  public static void setPenColor(int red, int green, int blue)
  
  Sets the pen color to the specified RGB color.
  
  Parameters:
  
  red - the amount of red (between 0 and 255)
  
  green - the amount of green (between 0 and 255)
  
  blue - the amount of blue (between 0 and 255)
  
  Throws:
  
  IllegalArgumentException - if red, green, or blue is outside its prescribed range
- getFont
  
  public static Font getFont()
  
  Returns the current font.
  
  Returns:
  
  the current font
- setFont
  
  public static void setFont()
  
  Sets the font to the default font (sans serif, 16 point).
- setFont
  
  public static void setFont(Font font)
  
  Sets the font to the specified value.
  
  Parameters:
  
  font - the font
  
  Throws:
  
  IllegalArgumentException - if font is null
- line
  
  public static void line(double x0, double y0, double x1, double y1)
  
  Draws a line segment between (x₀, y₀) and (x₁, y₁).
  
  Parameters:
  
  x0 - the x-coordinate of one endpoint
  
  y0 - the y-coordinate of one endpoint
  
  x1 - the x-coordinate of the other endpoint
  
  y1 - the y-coordinate of the other endpoint
  
  Throws:
  
  IllegalArgumentException - if any coordinate is either NaN or infinite
- point
  
  public static void point(double x, double y)
  
  Draws a point centered at (x, y). The point is a filled circle whose radius is equal to the pen radius. To draw a single-pixel point, first set the pen radius to 0.
  
  Parameters:
  
  x - the x-coordinate of the point
  
  y - the y-coordinate of the point
  
  Throws:
  
  IllegalArgumentException - if either x or y is either NaN or infinite
- circle
  
  public static void circle(double x, double y, double radius)
  
  Draws a circle of the specified radius, centered at (x, y).
  
  Parameters:
  
  x - the x-coordinate of the center of the circle
  
  y - the y-coordinate of the center of the circle
  
  radius - the radius of the circle
  
  Throws:
  
  IllegalArgumentException - if radius is negative
  
  IllegalArgumentException - if any argument is either NaN or infinite
- filledCircle
  
  public static void filledCircle(double x, double y, double radius)
  
  Draws a filled circle of the specified radius, centered at (x, y).
  
  Parameters:
  
  x - the x-coordinate of the center of the circle
  
  y - the y-coordinate of the center of the circle
  
  radius - the radius of the circle
  
  Throws:
  
  IllegalArgumentException - if radius is negative
  
  IllegalArgumentException - if any argument is either NaN or infinite
- ellipse
  
  public static void ellipse(double x, double y, double semiMajorAxis, double semiMinorAxis)
  
  Draws an ellipse with the specified semimajor and semiminor axes, centered at (x, y).
  
  Parameters:
  
  x - the x-coordinate of the center of the ellipse
  
  y - the y-coordinate of the center of the ellipse
  
  semiMajorAxis - is the semimajor axis of the ellipse
  
  semiMinorAxis - is the semiminor axis of the ellipse
  
  Throws:
  
  IllegalArgumentException - if either semiMajorAxis or semiMinorAxis is negative
  
  IllegalArgumentException - if any argument is either NaN or infinite
- filledEllipse
  
  public static void filledEllipse(double x, double y, double semiMajorAxis, double semiMinorAxis)
  
  Draws an ellipse with the specified semimajor and semiminor axes, centered at (x, y).
  
  Parameters:
  
  x - the x-coordinate of the center of the ellipse
  
  y - the y-coordinate of the center of the ellipse
  
  semiMajorAxis - is the semimajor axis of the ellipse
  
  semiMinorAxis - is the semiminor axis of the ellipse
  
  Throws:
  
  IllegalArgumentException - if either semiMajorAxis or semiMinorAxis is negative
  
  IllegalArgumentException - if any argument is either NaN or infinite
- arc
  
  public static void arc(double x, double y, double radius, double angle1, double angle2)
  
  Draws a circular arc of the specified radius, centered at (x, y), from angle1 to angle2 (in degrees).
  
  Parameters:
  
  x - the x-coordinate of the center of the circle
  
  y - the y-coordinate of the center of the circle
  
  radius - the radius of the circle
  
  angle1 - the starting angle. 0 would mean an arc beginning at 3 o'clock.
  
  angle2 - the angle at the end of the arc. For example, if you want a 90 degree arc, then angle2 should be angle1 + 90.
  
  Throws:
  
  IllegalArgumentException - if radius is negative
  
  IllegalArgumentException - if any argument is either NaN or infinite
- square
  
  public static void square(double x, double y, double halfLength)
  
  Draws a square of side length 2r, centered at (x, y).
  
  Parameters:
  
  x - the x-coordinate of the center of the square
  
  y - the y-coordinate of the center of the square
  
  halfLength - one half the length of any side of the square
  
  Throws:
  
  IllegalArgumentException - if halfLength is negative
  
  IllegalArgumentException - if any argument is either NaN or infinite
- filledSquare
  
  public static void filledSquare(double x, double y, double halfLength)
  
  Draws a filled square of the specified size, centered at (x, y).
  
  Parameters:
  
  x - the x-coordinate of the center of the square
  
  y - the y-coordinate of the center of the square
  
  halfLength - one half the length of any side of the square
  
  Throws:
  
  IllegalArgumentException - if halfLength is negative
  
  IllegalArgumentException - if any argument is either NaN or infinite
- rectangle
  
  public static void rectangle(double x, double y, double halfWidth, double halfHeight)
  
  Draws a rectangle of the specified size, centered at (x, y).
  
  Parameters:
  
  x - the x-coordinate of the center of the rectangle
  
  y - the y-coordinate of the center of the rectangle
  
  halfWidth - one half the width of the rectangle
  
  halfHeight - one half the height of the rectangle
  
  Throws:
  
  IllegalArgumentException - if either halfWidth or halfHeight is negative
  
  IllegalArgumentException - if any argument is either NaN or infinite
- filledRectangle
  
  public static void filledRectangle(double x, double y, double halfWidth, double halfHeight)
  
  Draws a filled rectangle of the specified size, centered at (x, y).
  
  Parameters:
  
  x - the x-coordinate of the center of the rectangle
  
  y - the y-coordinate of the center of the rectangle
  
  halfWidth - one half the width of the rectangle
  
  halfHeight - one half the height of the rectangle
  
  Throws:
  
  IllegalArgumentException - if either halfWidth or halfHeight is negative
  
  IllegalArgumentException - if any argument is either NaN or infinite
- polygon
  
  public static void polygon(double[] x, double[] y)
  
  Draws a polygon with the vertices (x₀, y₀), (x₁, y₁), ..., (x_n–1, y_n–1).
  
  Parameters:
  
  x - an array of all the x-coordinates of the polygon
  
  y - an array of all the y-coordinates of the polygon
  
  Throws:
  
  IllegalArgumentException - unless x[] and y[] are of the same length
  
  IllegalArgumentException - if any coordinate is either NaN or infinite
  
  IllegalArgumentException - if either x[] or y[] is null
- filledPolygon
  
  public static void filledPolygon(double[] x, double[] y)
  
  Draws a polygon with the vertices (x₀, y₀), (x₁, y₁), ..., (x_n–1, y_n–1).
  
  Parameters:
  
  x - an array of all the x-coordinates of the polygon
  
  y - an array of all the y-coordinates of the polygon
  
  Throws:
  
  IllegalArgumentException - unless x[] and y[] are of the same length
  
  IllegalArgumentException - if any coordinate is either NaN or infinite
  
  IllegalArgumentException - if either x[] or y[] is null
- picture
  
  public static void picture(double x, double y, String filename)
  
  Draws the specified image centered at (x, y). The supported image formats are JPEG, PNG, and GIF. As an optimization, the picture is cached, so there is no performance penalty for redrawing the same image multiple times (e.g., in an animation). However, if you change the picture file after drawing it, subsequent calls will draw the original picture.
  
  Parameters:
  
  x - the center x-coordinate of the image
  
  y - the center y-coordinate of the image
  
  filename - the name of the image/picture, e.g., "ball.gif"
  
  Throws:
  
  IllegalArgumentException - if the image filename is invalid
  
  IllegalArgumentException - if either x or y is either NaN or infinite
- picture
  
  public static void picture(double x, double y, String filename, double degrees)
  
  Draws the specified image centered at (x, y), rotated given number of degrees. The supported image formats are JPEG, PNG, and GIF.
  
  Parameters:
  
  x - the center x-coordinate of the image
  
  y - the center y-coordinate of the image
  
  filename - the name of the image/picture, e.g., "ball.gif"
  
  degrees - is the number of degrees to rotate counterclockwise
  
  Throws:
  
  IllegalArgumentException - if the image filename is invalid
  
  IllegalArgumentException - if x, y, degrees is NaN or infinite
  
  IllegalArgumentException - if filename is null
- picture
  
  public static void picture(double x, double y, String filename, double scaledWidth, double scaledHeight)
  
  Draws the specified image centered at (x, y), rescaled to the specified bounding box. The supported image formats are JPEG, PNG, and GIF.
  
  Parameters:
  
  x - the center x-coordinate of the image
  
  y - the center y-coordinate of the image
  
  filename - the name of the image/picture, e.g., "ball.gif"
  
  scaledWidth - the width of the scaled image (in screen coordinates)
  
  scaledHeight - the height of the scaled image (in screen coordinates)
  
  Throws:
  
  IllegalArgumentException - if either scaledWidth or scaledHeight is negative
  
  IllegalArgumentException - if the image filename is invalid
  
  IllegalArgumentException - if x or y is either NaN or infinite
  
  IllegalArgumentException - if filename is null
- picture
  
  public static void picture(double x, double y, String filename, double scaledWidth, double scaledHeight, double degrees)
  
  Draws the specified image centered at (x, y), rotated given number of degrees, and rescaled to the specified bounding box. The supported image formats are JPEG, PNG, and GIF.
  
  Parameters:
  
  x - the center x-coordinate of the image
  
  y - the center y-coordinate of the image
  
  filename - the name of the image/picture, e.g., "ball.gif"
  
  scaledWidth - the width of the scaled image (in screen coordinates)
  
  scaledHeight - the height of the scaled image (in screen coordinates)
  
  degrees - is the number of degrees to rotate counterclockwise
  
  Throws:
  
  IllegalArgumentException - if either scaledWidth or scaledHeight is negative
  
  IllegalArgumentException - if the image filename is invalid
- text
  
  public static void text(double x, double y, String text)
  
  Writes the given text string in the current font, centered at (x, y).
  
  Parameters:
  
  x - the center x-coordinate of the text
  
  y - the center y-coordinate of the text
  
  text - the text to write
  
  Throws:
  
  IllegalArgumentException - if text is null
  
  IllegalArgumentException - if x or y is either NaN or infinite
- text
  
  public static void text(double x, double y, String text, double degrees)
  
  Writes the given text string in the current font, centered at (x, y) and rotated by the specified number of degrees.
  
  Parameters:
  
  x - the center x-coordinate of the text
  
  y - the center y-coordinate of the text
  
  text - the text to write
  
  degrees - is the number of degrees to rotate counterclockwise
  
  Throws:
  
  IllegalArgumentException - if text is null
  
  IllegalArgumentException - if x, y, or degrees is either NaN or infinite
- textLeft
  
  public static void textLeft(double x, double y, String text)
  
  Writes the given text string in the current font, left-aligned at (x, y).
  
  Parameters:
  
  x - the x-coordinate of the text
  
  y - the y-coordinate of the text
  
  text - the text
  
  Throws:
  
  IllegalArgumentException - if text is null
  
  IllegalArgumentException - if x or y is either NaN or infinite
- textRight
  
  public static void textRight(double x, double y, String text)
  
  Writes the given text string in the current font, right-aligned at (x, y).
  
  Parameters:
  
  x - the x-coordinate of the text
  
  y - the y-coordinate of the text
  
  text - the text to write
  
  Throws:
  
  IllegalArgumentException - if text is null
  
  IllegalArgumentException - if x or y is either NaN or infinite
- pause
  
  public static void pause(int t)
  
  Pauses for t milliseconds. This method is intended to support computer animations.
  
  Parameters:
  
  t - number of milliseconds
- show
  
  public static void show()
  
  Copies offscreen buffer to onscreen buffer. There is no reason to call this method unless double buffering is enabled.
- enableDoubleBuffering
  
  public static void enableDoubleBuffering()
  
  Enables double buffering. All subsequent calls to drawing methods such as line(), circle(), and square() will be deffered until the next call to show(). Useful for animations.
- disableDoubleBuffering
  
  public static void disableDoubleBuffering()
  
  Disables double buffering. All subsequent calls to drawing methods such as line(), circle(), and square() will be displayed on screen when called. This is the default.
- save
  
  public static void save(String filename)
  
  Saves the drawing to using the specified filename. The supported image formats are JPEG and PNG; the filename suffix must be .jpg or .png.
  
  Parameters:
  
  filename - the name of the file with one of the required suffixes
  
  Throws:
  
  IllegalArgumentException - if filename is null
- actionPerformed
  
  public void actionPerformed(ActionEvent e)
  
  This method cannot be called directly.
  
  Specified by:
  
  actionPerformed in interface ActionListener
- isMousePressed
  
  public static boolean isMousePressed()
  
  Returns true if the mouse is being pressed.
  
  Returns:
  
  true if the mouse is being pressed; false otherwise
- mouseX
  
  public static double mouseX()
  
  Returns the x-coordinate of the mouse.
  
  Returns:
  
  the x-coordinate of the mouse
- mouseY
  
  public static double mouseY()
  
  Returns the y-coordinate of the mouse.
  
  Returns:
  
  y-coordinate of the mouse
- mouseClicked
  
  public void mouseClicked(MouseEvent e)
  
  This method cannot be called directly.
  
  Specified by:
  
  mouseClicked in interface MouseListener
- mouseEntered
  
  public void mouseEntered(MouseEvent e)
  
  This method cannot be called directly.
  
  Specified by:
  
  mouseEntered in interface MouseListener
- mouseExited
  
  public void mouseExited(MouseEvent e)
  
  This method cannot be called directly.
  
  Specified by:
  
  mouseExited in interface MouseListener
- mousePressed
  
  public void mousePressed(MouseEvent e)
  
  This method cannot be called directly.
  
  Specified by:
  
  mousePressed in interface MouseListener
- mouseReleased
  
  public void mouseReleased(MouseEvent e)
  
  This method cannot be called directly.
  
  Specified by:
  
  mouseReleased in interface MouseListener
- mouseDragged
  
  public void mouseDragged(MouseEvent e)
  
  This method cannot be called directly.
  
  Specified by:
  
  mouseDragged in interface MouseMotionListener
- mouseMoved
  
  public void mouseMoved(MouseEvent e)
  
  This method cannot be called directly.
  
  Specified by:
  
  mouseMoved in interface MouseMotionListener
- hasNextKeyTyped
  
  public static boolean hasNextKeyTyped()
  
  Returns true if the user has typed a key (that has not yet been processed).
  
  Returns:
  
  true if the user has typed a key (that has not yet been processed by nextKeyTyped(); false otherwise
- nextKeyTyped
  
  public static char nextKeyTyped()
  
  Returns the next key that was typed by the user (that your program has not already processed). This method should be preceded by a call to hasNextKeyTyped() to ensure that there is a next key to process. This method returns a Unicode character corresponding to the key typed (such as 'a' or 'A'). It cannot identify action keys (such as F1 and arrow keys) or modifier keys (such as control).
  
  Returns:
  
  the next key typed by the user (that your program has not already processed).
  
  Throws:
  
  NoSuchElementException - if there is no remaining key
- isKeyPressed
  
  public static boolean isKeyPressed(int keycode)
  
  Returns true if the given key is being pressed.
  This method takes the keycode (corresponding to a physical key) as an argument. It can handle action keys (such as F1 and arrow keys) and modifier keys (such as shift and control). See KeyEvent for a description of key codes.
  
  Parameters:
  
  keycode - the key to check if it is being pressed
  
  Returns:
  
  true if keycode is currently being pressed; false otherwise
- keyTyped
  
  public void keyTyped(KeyEvent e)
  
  This method cannot be called directly.
  
  Specified by:
  
  keyTyped in interface KeyListener
- keyPressed
  
  public void keyPressed(KeyEvent e)
  
  This method cannot be called directly.
  
  Specified by:
  
  keyPressed in interface KeyListener
- keyReleased
  
  public void keyReleased(KeyEvent e)
  
  This method cannot be called directly.
  
  Specified by:
  
  keyReleased in interface KeyListener
- main
  
  public static void main(String[] args)
  
  Test client.
  
  Parameters:
  
  args - the command-line arguments

Class StdDraw

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Details

BLACK

BLUE

CYAN

DARK_GRAY

GRAY

GREEN

LIGHT_GRAY

MAGENTA

ORANGE

PINK

RED

WHITE

YELLOW

Method Details

setCanvasSize

setCanvasSize

setXscale

setYscale

setScale

setXscale

setYscale

setScale

clear

clear

getPenRadius

setPenRadius

setPenRadius

getPenColor

setPenColor

setPenColor

setPenColor

getFont

setFont

setFont

line

point

circle

filledCircle

ellipse

filledEllipse

arc

square

filledSquare

rectangle

filledRectangle

polygon

filledPolygon

picture

picture

picture

picture

text

text

textLeft

textRight

pause

show

enableDoubleBuffering

disableDoubleBuffering

save

actionPerformed

isMousePressed

mouseX

mouseY

mouseClicked

mouseEntered

mouseExited

mousePressed

mouseReleased

mouseDragged

mouseMoved

hasNextKeyTyped

nextKeyTyped

isKeyPressed

keyTyped