Package image

An image creation package mimics the Racket's 2htdp/image library.

See:
Description

Class Summary

Circle	A Class representing a Circle Image.
ColorDatabase	Manages color names and translation to implementation-dependent Color structures.
Ellipse	Represents an Image of an Ellipse.
EmptyScene	Represents the empty (blank) Scene (a cropped Image).
FromFile	Represents an Image from a file.
FromResource	Represents an image from a JAR resource (an Image file within the currently executing JAR).
FromURL	Represents an image from a URL.
Image	An abstract class representing an Image.
Line	Class representing a Line from (0,0) to the given (X,Y).
Overlay	Represents the Overlaying of two or more images.
OverlayXY	Represents the Overlaying of two images after moving the bottom image by the given offset.
RasterImage	Represents a raster Image drawn into a Buffer.
Rectangle	Represents an Image of a Rectangle.
RegularPolygon	Represents an Image of a Regular Polygon, e.g., a Square, Pentagon, Octagon, etc.
RoundRectangle	Represents an Image of a Rectangle with rounded corners.
Scene	An abstract Class representing a Scene (a cropped Image).
Square	Represents an Image of a Square.
Star	Represents an Image of a Star.
Text	A Class representing an Image of a String.
Triangle	Represents an Image of a Triangle.
Widget	Represents a wrapper for Java Swing Components.

Exception Summary

ColorDatabase.InvalidColorException

Thrown when an invalid color is used

Package image Description

An image creation package mimics the Racket's 2htdp/image library. Instead of functions we have specific instances of Image subclasses that serve the same purpose(s).

One of the main differences between this library and 2htdp/image (besides the implementation language) is that we draw a distinction between normal Images, and Scenes. The latter being a special form of image that is cropped to a specific size when drawn. But the uses will be clearer with a few examples.

The code that generated all the examples presented here is located in the source of WriteTests (available in the JAR distribution), and the examples were mostly taken from the original 2htdp/image documentation, which, for the most part, can be used as a supplement, though not all the fancy features are supported.

Modes and Colors

Image mode

Each closed image (e.g., Circle, or RegularPolygon, but not Line or Overlay) has an associated mode String, which is either "outline" or "solid". This refers whether the image is simply drawn as a single stroke (outline), or is filled (solid). If an image is constructed with a mode string other than outline or solid then an appropriate RuntimeException is thrown.

Colors

All basic images have an associated color, also given as a String. Color names are managed by the ColorDatabase class, which has a comprehensive list of predefined colors. Names are case-insensitive.

Custom Colors

Besides the named colors like "blue" or "goldenrod", the color string may also be a custom RGB color (in 6-digit hexidecimal format) by placing a pound/hash character (#) at the front of the string. For instance, an alternative to "blue" would be "#0000FF", and an alternative to "goldenrod" would be "#DAA520". If transparency is required you may use an 8 digit hexidecimal number where the first component is Alpha and the following 6 characters are RGB, e.g., "#FFFF0000" for Opaque Red, or "#8800FF00" for Half-Transparent Green.

Examples

Each of the classes has its own documentation, but it's better to see what kinds of images each one produces.

Shapes

The image package contains lots of different basic shapes.

    new Circle(30, "outline", "red")

    new Circle(20, "solid", "blue")

    new Ellipse(40, 20, "outline", "black")

    new Ellipse(20, 40, "solid", "blue")

    new Line(30, 30, "black")

    new Line(-30, 20, "red")

    new Line(30, -20, "red")

    new Text("Hello", 24, "olive")

    new Text("Goodbye", 36, "indigo")

    new Triangle(40, "solid", "tan")

    new Triangle(60, "outline", "purple")

    new Square(40, "solid", "slateblue")

    new Square(50, "outline", "darkmagenta")

    new Rectangle(40, 20, "outline", "black")

    new Rectangle(20, 40, "solid", "blue")

    new RoundRectangle(40, 20, 10, "outline", "black")

    new RoundRectangle(20, 40, 10, 20, "solid", "blue")

    new Star(40, 5, "solid", "gray")

    new Star(40, 7, "outline", "red")

    new Star(40, 30, 10, "solid", "cornflowerblue")

    new RegularPolygon(50, 3, "outline", "red")

    new RegularPolygon(40, 4, "outline", "blue")

    new RegularPolygon(20, 8, "solid", "red")

From Files / URLs

    new FromUrl("http://maps.google.com/maps/api/staticmap?center=42.358,-71.06&zoom=15&size=200x200&sensor=false")

    new FromFile("imagetutor/images/jurassic.png")

Image Combinations

    new Overlay(new Rectangle(30, 60, "solid", "orange"),
                new Ellipse(60, 30, "solid", "purple"))

    new Overlay(new Ellipse(10, 10, "solid", "red"),
                new Ellipse(20, 20, "solid", "black"),
                new Ellipse(30, 30, "solid", "red"),
                new Ellipse(40, 40, "solid", "black"),
                new Ellipse(50, 50, "solid", "red"),
                new Ellipse(60, 60, "solid", "black"))

    new Overlay(new RegularPolygon(20, 5, "solid", "#3232FF"),
                new RegularPolygon(26, 5, "solid", "#6464FF"),
                new RegularPolygon(32, 5, "solid", "#9696FF"),
                new RegularPolygon(38, 5, "solid", "#C8C8FF"),
                new RegularPolygon(44, 5, "solid", "#FAFAFF"))

    new OverlayXY(new Rectangle(20, 20, "outline", "black"),
                20, 0, new Rectangle(20, 20, "outline", "black"))

    new OverlayXY(new Rectangle(20, 20, "solid", "red"),
                20, 20,
                new Rectangle(20, 20, "solid", "black"))

    new OverlayXY(new Rectangle(20, 20, "solid", "red"),
                -20, -20,
                new Rectangle(20, 20, "solid", "black"))

    new OverlayXY(
           new OverlayXY(new Ellipse(40, 40, "outline", "black"),
                 10, 15, new Ellipse(10, 10, "solid", "forestgreen")),
                 20, 15, new Ellipse(10, 10, "solid", "forestgreen"))

Image overlays are also available as methods on Images.

    new Ellipse(60, 30, "solid", "purple")
        .overlay(new Rectangle(30, 60, "solid", "orange"))

    new Ellipse(60, 60, "solid", "black")
        .overlay(new Ellipse(10, 10, "solid", "red"),
                 new Ellipse(20, 20, "solid", "black"),
                 new Ellipse(30, 30, "solid", "red"),
                 new Ellipse(40, 40, "solid", "black"),
                 new Ellipse(50, 50, "solid", "red"))

    new RegularPolygon(44, 5, "solid", "#FAFAFF")
        .overlay(new RegularPolygon(20, 5, "solid", "#3232FF"),
                 new RegularPolygon(26, 5, "solid", "#6464FF"),
                 new RegularPolygon(32, 5, "solid", "#9696FF"),
                 new RegularPolygon(38, 5, "solid", "#C8C8FF"))

    new Rectangle(20, 20, "outline", "black")
        .overlayxy(new Rectangle(20, 20, "outline", "black"), 20, 0)

    new Rectangle(20, 20, "solid", "black")
        .overlayxy(new Rectangle(20, 20, "solid", "red"), 20, 20)

    new Rectangle(20, 20, "solid", "black")
        .overlayxy(new Rectangle(20, 20, "solid", "red"), -20, -20)

    new Ellipse(10, 10, "solid", "forestgreen")
        .overlayxy(20, 15, new Ellipse(10, 10, "solid", "forestgreen")
                               .overlayxy(10, 15, new Ellipse(40, 40, "outline", "black"))

Transparency/Alpha

    new Circle(25, "solid", "#55FF0000")
      .overlayxy(new Circle(25, "solid", "#5500FF00")
                   .overlayxy(new Circle(25, "solid", "#550000FF"), -30, 0),
                 15, -15)

    new Circle(25, "solid", ColorDatabase.makeColor(0.7, 1.0, 0, 0))
      .overlayxy(new Circle(25, "solid", ColorDatabase.makeColor(179, 0, 255, 0))
                   .overlayxy(new Circle(25, "solid", "#B30000FF"), -30, 0),
                 15, -15)

Image Rotation and Transformation

    new Rectangle(60, 20, "solid", "black").rotate(10)

         
    new Star(20, "outline", "blue").rotate(30)

    new Star(20, "solid", "chartreuse").rotate(60)

    new Triangle(30, "solid", "tomato").rotate(-30)

    new OverlayXY(new Text("Up...", 30, "deepskyblue").rotate(90),
                  20, 0,
                  new Text("Down", 30, "magenta").rotate(-90))

    new Text("Horizontal", 20, "blue").flipHorizontal()

    new Text("Vertical", 20, "red").flipVertical()

Scenes

    new EmptyScene(160, 90)

    new EmptyScene(48, 48).placeImage(new Triangle(32, "solid", "red"), 24, 24)

    new EmptyScene(48, 48).placeImage(new Triangle(64, "solid", "red"), 24, 24)

    new EmptyScene(48, 48).addLine(0, 0, 48, 48, "blue")

    new EmptyScene(48, 48).addLine(4, 24, 44, 24, "green")

    new EmptyScene(50, 50)
         .placeImage(new Overlay(new Circle(20, "outline", "black"),
                                 new Circle(20, "solid", "wheat")), 25, 25)
         .placeImage(new Circle(5, "solid", "lightblue"), 18, 20)
         .placeImage(new Rectangle(10, 3, "solid", "lightblue"), 33, 20)
         .placeImage(new Ellipse(20, 8, "solid", "red"), 25, 35)