O1Library Docs
Fall 2025
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This document is part of the ebook for O1 (aka CS-A1110 Programming 1), a course at Aalto University.
This document is part of the ebook for O1 (aka CS-A1110 Programming 1), a course at Aalto University.
O1Library Docs/o1/o1.gui

o1.gui

package o1.gui

Members list

Packages

package o1.gui.colors
package o1.gui.event
package o1.gui.font
package o1.gui.layout
package o1.gui.viewimpl

Type members

Classlikes

object Align

The Align singleton provides tools for describing the horizontal and vertical alignment of graphical elements.

The Align singleton provides tools for describing the horizontal and vertical alignment of graphical elements.

Attributes

Supertypes
class Object
trait Matchable
class Any
Self type
Align.type
final class Animation(frames: Iterable[Pic], val frameRate: Double, val terminateOnClose: Boolean, val atEnd: AtEnd)

An Animation object has an iterable sequence of Pics which it can show in a separate window (a simple View).

An Animation object has an iterable sequence of Pics which it can show in a separate window (a simple View).

Parameters

atEnd

what should happen once the animation reaches the final Pic

frameRate

a target speed (in Pics per second), which the Animation will roughly observe if possible

frames

the Pics that the animation consists of, in order; they should be identical in size

terminateOnClose

whether the entire application should exit when the animation window is closed

Attributes

Companion
object
Supertypes
class Object
trait Matchable
class Any
Self type
object Animation

This companion object of class Animation provides a couple of convenience methods (show, generate) for starting animations and an enumeration (AtEnd) for use with the class.

This companion object of class Animation provides a couple of convenience methods (show, generate) for starting animations and an enumeration (AtEnd) for use with the class.

Attributes

Companion
class
Supertypes
class Object
trait Matchable
class Any
Self type
Animation.type
object Color

This companion object of class Color provides methods for creating new Color objects. There is also a small selection of related utility methods and constants.

This companion object of class Color provides methods for creating new Color objects. There is also a small selection of related utility methods and constants.

For many constants of type Color that represent different preset colors, see o1.gui.colors.

This object has an alias in the top-level package o1, so it’s accessible to students simply via import o1.*.

Attributes

Companion
class
Supertypes
class Object
trait Matchable
class Any
Self type
Color.type
final class Color extends Fill

Each instance of this class represents a color. The class uses the RGB color scheme: each color is a combination of a red, green, and blue components; there’s also a fourth component of opacity. Color objects are immutable.

Each instance of this class represents a color. The class uses the RGB color scheme: each color is a combination of a red, green, and blue components; there’s also a fourth component of opacity. Color objects are immutable.

You don’t instantiate Color directly; instead, you create Colors with the methods on the Color companion object (e.g., Color(200, 150, 255)) or use one of the named color constants in o1.gui.colors. There are also a few methods in this class that returns new Color objects defined in terms of existing ones (e.g., lighter, edit).

This class has an alias in the top-level package o1, so it’s accessible to students simply via import o1.*.

Parameters

blue

the amount of blue in the color, between Color.Min and Color.Max; that is, 0–255

green

the amount of green in the color, between Color.Min and Color.Max; that is, 0–255

opacity

the color’s opacity, between Color.Min and Color.Max; that is, 0–255

presetName

the name of a color contant in “regular form”, i.e., with spaces and largely in lower case (e.g., "saddle blue", "Irish green")

red

the amount of red in the color, between Color.Min and Color.Max; that is, 0–255

Attributes

Companion
object
Supertypes
trait Fill
class Object
trait Matchable
class Any
trait DefaultFrameSettings extends Frame

Giving this convenience trait to a Swing GUI frame will place the frame at (120, 120) and set it as unresizeable.

Giving this convenience trait to a Swing GUI frame will place the frame at (120, 120) and set it as unresizeable.

Attributes

Supertypes
class Frame
trait RichWindow
class Window
trait RootPanel
trait Container
trait UIElement
trait Publisher
trait Reactor
trait Proxy
class Object
trait Matchable
class Any
Show all
Known subtypes
class SimpleFrame
object Dialog

This object provides convenience methods for displaying messages and reading user input via simple Swing dialogs.

This object provides convenience methods for displaying messages and reading user input via simple Swing dialogs.

Attributes

Supertypes
class Object
trait Matchable
class Any
Self type
Dialog.type
trait Escapable extends Frame

Give this convenience trait to a Swing GUI frame to make it close when the Escape key is pressed.

Give this convenience trait to a Swing GUI frame to make it close when the Escape key is pressed.

Attributes

Supertypes
class Frame
trait RichWindow
class Window
trait RootPanel
trait Container
trait UIElement
trait Publisher
trait Reactor
trait Proxy
class Object
trait Matchable
class Any
Show all
trait Fill

A supertype for objects that “can be used as paint” to define the fill color(s) of a shape. The simplest sort of fill is a Color, but gradients and other more complex fills may also be defined.

A supertype for objects that “can be used as paint” to define the fill color(s) of a shape. The simplest sort of fill is a Color, but gradients and other more complex fills may also be defined.

Attributes

Companion
object
Supertypes
class Object
trait Matchable
class Any
Known subtypes
class Color
object None
object Fill

This companion object of class Fill provides a singleton object for the special case where there is no fill at all.

This companion object of class Fill provides a singleton object for the special case where there is no fill at all.

Attributes

Companion
trait
Supertypes
class Object
trait Matchable
class Any
Self type
Fill.type
object Line

The Line singleton provides tools for specifying what a line-drawing style — a Stroke — is like.

The Line singleton provides tools for specifying what a line-drawing style — a Stroke — is like.

Attributes

Supertypes
class Object
trait Matchable
class Any
Self type
Line.type
object Pic

The primary purpose of this companion object of class Pic is to provide methods for creating new Pic instances: (apply, generate, circle, etc. There is also a small selection of related utility methods.

The primary purpose of this companion object of class Pic is to provide methods for creating new Pic instances: (apply, generate, circle, etc. There is also a small selection of related utility methods.

This object has an alias in the top-level package o1, so it’s accessible to students simply via import o1.*. The shape-creating methods of this object (such as circle) are also available as functions in package o1.

Attributes

Companion
class
Supertypes
class Object
trait Matchable
class Any
Self type
Pic.type
final class Pic extends HasAnchor

Each instance of this class represents a picture: an immutable two-dimensional image.

Each instance of this class represents a picture: an immutable two-dimensional image.

You don’t instantiate Pic directly; instead, you create Pics with the methods on the Pic companion object. For instance, you can:

  • load existing images: Pic("mypic.png") or Pic("http://address.of/mypic.png")),
  • create Pics of shapes (e.g., circle(150, Red) or star(100, Black)); or
  • generate the pixels of a Pic with a function.

Moreover, many of the methods of a Pic object create and return new Pics that represent combinations or transformations of existing Pics.

This class has an alias in the top-level package o1, so it’s accessible to students simply via import o1.*.

The examples below illustrate a few of the methods (assuming the above import):

val background = rectangle(400, 300, Red)
val rotatedSquare = square(50, Blue).clockwise(30)
val squareAgainstBg = background.place(rotatedSquare, Pos(100, 100))
squareAgainstBg.show()

val ladybug = Pic("ladybug.png").scaleTo(100).flipHorizontal
val combination = circle(100, Red).leftOf(ladybug)
val part = combination.crop(Pos(10, 10), 180, 80)
val negative = part.transformColors( _.negative )
negative.show()

Some of the methods of a Pic that use Pos objects or plain x and y coordinates to indicate positions within the Pic (e.g., place and crop above). All these methods consider the origo to be at the top left-hand corner or the Pic, with x values increasing downwards and y values rightwards. The coordinates are in pixels.

Each image has an anchor that defines where it connects to other Pics. By default, the anchor is Center; for example, the place method call above puts the center of the square at Pos(100, 100) within the background.

Here is a list of the main types of operations as methods on a Pic, and examples of each type:

  • Combining Pics by positioning them relative to each other: above, below, leftOf, rightOf, onto, against, place.

  • Rotations (*): clockwise, counterclockwise

  • Changing size (*): scaleBy, scaleTo

  • Selecting and moving pixels (**): crop, shift, flipHorizontal, flipVertical

  • Examining and manipulating individual pixels (**): pixelColor, transformXY, transformColors, combine

  • Convenience methods for experimentation and debugging: show, hide.

Notes on implementation and efficiency:

Internally, a Pic stores its contents either as vector-based graphics, as a bitmap (raster), or as a combination of the two. By design, that internal representation is meant to be largely opaque to the user of the Pic class: students in O1 working on O1’s standard assignments generally shouldn’t need to know or care about it. Nevertheless, whether a particular Pic is stored in vector or bitmap form does have a very substantial effect on efficiency in some contexts; Pic, like the rest of O1Library, is not designed for high-performance graphics.

Some users of this class may wish to know the following:

  • Pics start out in either vector form or bitmap form, depending on which method created them. Specifically, the shape-creating methods (like rectangle and circle). produce Pics in vector form.

  • No operation on a Pic ever changes an already rasterized bitmap into vector graphics.

  • Some operations always produce a rasterized Pic. These are marked with a double asterisk (**) in the list above. Some operations sometimes produce rasterized Pics but may retain the vector-based representation in simple cases. These are marked with a single asterisk (*).

  • Operations like leftOf can produce a Pic that is stored as a combination of a vector graphic and a bitmap.

  • You can call freeze to force rasterization.

Attributes

Companion
object
Supertypes
trait HasAnchor
trait HasSize
class Object
trait Matchable
class Any
open class SimpleFrame(initialTitle: String) extends Frame, DefaultFrameSettings

Inherit this class to obtain a Swing GUI frame that has the DefaultFrameSettings and the given title.

Inherit this class to obtain a Swing GUI frame that has the DefaultFrameSettings and the given title.

Attributes

Supertypes
class Frame
trait RichWindow
class Window
trait RootPanel
trait Container
trait UIElement
trait Publisher
trait Reactor
trait Proxy
class Object
trait Matchable
class Any
Show all
sealed class Stroke(val fill: Fill, val thickness: Double, val cap: Cap, val join: Join, val onTop: Boolean)

A Stroke is a style for drawing shape outlines and other lines. A Stroke object defines, among other things, the color and width of lines drawn using the stroke.

A Stroke is a style for drawing shape outlines and other lines. A Stroke object defines, among other things, the color and width of lines drawn using the stroke.

Parameters

cap

the style of the cap (end point) for lines drawn using this stroke; the default is a square cap.

fill

a fill style for lines drawn using this stroke; this can be a Color or a gradient, for example

join

the style in which lines drawn using this stroke join up with each other; the default is a miter join

onTop

a value that affects filled shapes that have an outline drawn using this stroke: if true, the outline will be drawn on top of the filled shape and fully visible; if false, the outline will be below the fill and partially invisible. Defaults to true.

thickness

the width of lines drawn using this stroke; defaults to 1

Attributes

Supertypes
class Object
trait Matchable
class Any
Known subtypes
object None
trait TerminatesOnClose extends Window

Give this convenience trait to a Swing GUI frame to make it terminate the application when closed.

Give this convenience trait to a Swing GUI frame to make it terminate the application when closed.

Attributes

Supertypes
class Window
trait RootPanel
trait Container
trait UIElement
trait Publisher
trait Reactor
trait Proxy
class Object
trait Matchable
class Any
Show all
object View

This object holds miscellaneous utilities (traits, constants, etc.) that can be used in combinations with Views. These utilities are generic to the o1.gui.mutable and o1.gui.immutable View variants.

This object holds miscellaneous utilities (traits, constants, etc.) that can be used in combinations with Views. These utilities are generic to the o1.gui.mutable and o1.gui.immutable View variants.

Note to students: You’re unlikely to need this for anything in O1.

Attributes

Supertypes
class Object
trait Matchable
class Any
Self type
View.type
object immutable

This subpackage contains a version of Views that is not much used in O1: views to immutable domain models. In O1, the other implementation in o1.gui.mutable is more relevant.

This subpackage contains a version of Views that is not much used in O1: views to immutable domain models. In O1, the other implementation in o1.gui.mutable is more relevant.

Attributes

Supertypes
class Object
trait Matchable
class Any
Self type
immutable.type
object mutable

This subpackage contains the version of Views that we primarily use in O1: views to mutable domain models.

This subpackage contains the version of Views that we primarily use in O1: views to mutable domain models.

The top-level package o1 provides an alias to the ViewFrame class in this package, so it is available to students as View simply by importing o1.*.

There is an alternative implementation of Views in o1.gui.immutable.

Attributes

Supertypes
class Object
trait Matchable
class Any
Self type
mutable.type
object swingops

Life-quality improvements for working with the Swing GUI library in Scala.

Life-quality improvements for working with the Swing GUI library in Scala.

Attributes

Supertypes
class Object
trait Matchable
class Any
Self type
swingops.type

Types

type Anchor = Anchor

The Anchor type represents anchoring points of two-dimensional elements (such as Pics) within other such elements; it is an alias for the type of the same name in o1.world.objects.

The Anchor type represents anchoring points of two-dimensional elements (such as Pics) within other such elements; it is an alias for the type of the same name in o1.world.objects.

Attributes

type Bounds = Bounds

The Bounds type represents rectangular boundaries on a two-dimensional plane; it is an alias for the class of the same name in o1.world.

The Bounds type represents rectangular boundaries on a two-dimensional plane; it is an alias for the class of the same name in o1.world.

Attributes

type HasAnchor = HasAnchor

A supertype for two-dimensional elements that have an anchoring point; this is an alias for the trait of the same name in o1.world.objects.

A supertype for two-dimensional elements that have an anchoring point; this is an alias for the trait of the same name in o1.world.objects.

Attributes

type Key = scala.swing.event.Key

The Key type represents keys on the keyboard; it is an alias for the corresponding type in Scala’s Swing GUI library

The Key type represents keys on the keyboard; it is an alias for the corresponding type in Scala’s Swing GUI library

Attributes

type Pos = Pos

The Pos type represents locations on a two-dimensional plane; it is an alias for the class of the same name in o1.world.

The Pos type represents locations on a two-dimensional plane; it is an alias for the class of the same name in o1.world.

Attributes

Value members

Concrete fields

val Anchor: Anchor.type

The Anchor type represents anchoring points of two-dimensional elements (such as Pics) within other such elements; it is an alias for the type of the same name in o1.world.objects.

The Anchor type represents anchoring points of two-dimensional elements (such as Pics) within other such elements; it is an alias for the type of the same name in o1.world.objects.

Attributes

val Bounds: Bounds.type

The Bounds type represents rectangular boundaries on a two-dimensional plane; it is an alias for the class of the same name in o1.world.

The Bounds type represents rectangular boundaries on a two-dimensional plane; it is an alias for the class of the same name in o1.world.

Attributes

val Key: Key.type

The Key type represents keys on the keyboard; it is an alias for the corresponding type in Scala’s Swing GUI library

The Key type represents keys on the keyboard; it is an alias for the corresponding type in Scala’s Swing GUI library

Attributes

val Pos: Pos.type

The Pos type represents locations on a two-dimensional plane; it is an alias for the class of the same name in o1.world.

The Pos type represents locations on a two-dimensional plane; it is an alias for the class of the same name in o1.world.

Attributes

Generated with
This document is part of the ebook for O1 (aka CS-A1110 Programming 1), a course at Aalto University.
This document is part of the ebook for O1 (aka CS-A1110 Programming 1), a course at Aalto University.