Package tripleplay.ui.util

Class Scale9

java.lang.Object

tripleplay.ui.util.Scale9

public class Scale9
extends Object

Facilitates the rendering of "scale-9" images, that is, images that are designed as a 3x3 grid such that each of the 9 pieces is fixed or stretched in one or both directions to fit a designated area. The corners are drawn without scaling, the top and bottom center pieces are scaled horizontally, the left and right center pieces are scaled vertically, and the center piece is scaled both horizontally and vertically.

By default, the cells are assumed to be of equal size (hence scale-9 image dimensions are normally a multiple of 3). By using xaxis and yaxis, this partitioning can be controlled directly.

Here's a diagram showing the stretching and axes, H = horizontally stretched, V = vertically stretched, U = unstretched.

                         xaxis

                0          1          2
           ---------------------------------
           |          |          |          |
        0  |    U     |    H     |    U     |
           |          |          |          |
           ---------------------------------
           |          |          |          |
 yaxis  1  |    V     |   H&V    |    V     |
           |          |          |          |
           ---------------------------------
           |          |          |          |
        2  |    U     |    H     |    U     |
           |          |          |          |
           ---------------------------------
 

Example 1: the horizontal middle of an image is a single pixel. This code will do that and automatically grow the left and right columns:

     Scale9 s9 = ...;
     s9.xaxis.resize(1, 1);

Example 2: there are no top and bottom rows. This code will stretch all of the image vertically, but keep the left and right third of the image fixed horizontally:

     Scale9 s9 = ...;
     s9.yaxis.resize(0, 0).resize(2, 0);

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Scale9.Axis	A horizontal or vertical axis, broken up into 3 chunks.

Field Summary

Fields

Modifier and Type	Field	Description
final Scale9.Axis	xaxis	The axes of the 3x3 grid.
final Scale9.Axis	yaxis	The axes of the 3x3 grid.

Constructor Summary

Constructors

Constructor	Description
Scale9(float width, float height)	Creates a new scale to match the given width and height.
Scale9(float width, float height, Scale9 source)	Creates a new scale to render the given scale onto a target of the given width and height.

Method Summary

Modifier and Type	Method	Description
static Scale9.Axis	clamp(Scale9.Axis axis, float length)	Ensures that the Axis passed in does not exceed the length given.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

xaxis

public final Scale9.Axis xaxis

The axes of the 3x3 grid.

yaxis

public final Scale9.Axis yaxis

The axes of the 3x3 grid.

Constructor Details

Scale9

public Scale9(float width,
 float height)

Creates a new scale to match the given width and height. Each horizontal and vertical sequence is divided equally between the given values.

Scale9

public Scale9(float width,
 float height,
 Scale9 source)

Creates a new scale to render the given scale onto a target of the given width and height.

Method Details

clamp

public static Scale9.Axis clamp(Scale9.Axis axis,
 float length)

Ensures that the Axis passed in does not exceed the length given. An equal chunk will be removed from the outer chunks if it is too long. The given axis is modified and returned.