PixelShapes

• I - Introduction
• II - Download
• III - Use
• IV - About

---

I - Introduction

This project aims to create usable pixel shapes. A pixel shape is a collection of integer coordinates. Think of it like opening MSPaint and using black on a white background ; the black pixels make up a pixel shape.

---

II - Download

Gradle

In build.gradle :

allprojects {
	repositories {
		/*...*/
		maven { url 'https://jitpack.io' }
	}
}

dependencies {
    implementation 'com.github.MaxBuster380:PixelShapes:alpha-1.5.1'
}

Maven

In pom.xml :

<repositories>
	<repository>
	    <id>jitpack.io</id>
	    <url>https://jitpack.io</url>
	</repository>
</repositories>

<dependency>
    <groupId>com.github.MaxBuster380</groupId>
    <artifactId>PixelShapes</artifactId>
    <version>alpha-1.5.1</version>
</dependency>

---

III - Use

A shape is a set of 2-dimensional integer values. As such, they can all be used as a standard Set<Pair<Int, Int>>.

Interfaces

All pixel shapes implement the PixelShape interface :

interface PixelShape : Set<Pair<Int, Int>>

A pixel shape is, by default, read-only. Read/write pixel shapes implement the MutablePixelShape interface :

interface MutablePixelShape : PixelShape, MutableSet<Pair<Int, Int>>

You can also group shapes together with a CollectionPixelShape :

interface CollectionPixelShape<T : PixelShape> : PixelShape

Implementations

The SetMutablePixelShape is an implementation that uses a regular MutableSet, and thus keeps its time efficient operations. Although very good for most tasks, it requires every value to be inputted one at a time.

val setShape = SetMutablePixelShape()
setShape += Pair(0, 0)
setShape += Pair(1, 0)
setShape += Pair(0, -1)

println(setShape.contains(Pair(1, 0))) // true
println(setShape.contains(Pair(1, 1))) // false
println(setShape.size) // 3

for (point in setShape) {
    print("(${point.first}, ${point.second}), ")
}
// (0,0), (1,0), (0,-1)

The BoxPixelShape is set of points that form a rectangle. While it is restricted to only make such forms, it is more time and space efficient to instanciate than the SetMutablePixelShape, meaning quicker access to its values.

val origin = Pair(0, 0)
val width = 3
val height = 2
val boxShape = BoxPixelShape(origin, width, height)

println(boxShape.size) // 6

for (point in boxShape) {
    print("(${point.first}, ${point.second}), ")
}
// (0,0), (1,0), (2,0), (0,1), (1,1), (2,1),

Now, if you want to group shapes together, there are two options. UnionPixelShape allows you to get the mathematical union between a collection of shapes, meaning all points included in at least 1 of its member shapes is considered " Included".

val union = UnionPixelShape(listOf(setShape, boxShape))

println(union.size) // 7

for (point in boxShape) {
    print("(${point.first}, ${point.second}), ")
}
// (0,-1), (0,0), (1,0), (2,0), (0,1), (1,1), (2,1),

Then there's the IntersectionPixelShape, which holds the points included in all its member shapes.

val intersection = IntersectionPixelShape(listOf(setShape, boxShape))

println(intersection.size) // 2

for (point in boxShape) {
    print("(${point.first}, ${point.second}), ")
}
// (0,0), (1,0), 

To put it simply, UnionPixelShape is an OR operator, while IntersectionPixelShape is an AND operator. For these, note that a CollectionPixelShape does not compile shapes together, meaning you can change them and it'll apply on the collection. This also means that a CollectionPixelShape is less and less efficient the more member shapes it has.

The most basic implementation is the EmptyPixelShape, an efficient and dedicated way to make and use empty sets.

val shape = EmptyPixelShape()
println(shape.size) // 0
println(shape.contains(Pair(1, 0))) // false

IV - About

By MaxBuster380

GitHub Repository