Package org.tinfour.utils.rendering

Class RenderingSurfaceAid

java.lang.Object

org.tinfour.utils.rendering.RenderingSurfaceAid

public class RenderingSurfaceAid
extends Object

Creates data elements suitable for rendering 2D graphics based on a Cartesian coordinate system. This class establishes a BufferedImage and associated Graphics2D object, as well as the appropriate coordinate transforms. Applications that require only the transform data may use the companion utility RenderingTransformAid.

Constructor Summary

Constructors

Constructor	Description
RenderingSurfaceAid(int width, int height, int pad, double x0, double y0, double x1, double y1)	Constructs a graphics surface (BufferedImage) and resources for a coordinate system appropriate for the presentation of a rectangular region defined by the specified coordinates.
RenderingSurfaceAid(int width, int height, int pad, double x0, double y0, double x1, double y1, boolean alpha)	Constructs a graphics surface (BufferedImage) and resources for a coordinate system appropriate for the presentation of a rectangular region defined by the specified coordinates.

Method Summary

Modifier and Type	Method	Description
void	drawFrame(Color c)	Draws a 1-pixel rectangular frame around the outer boundaries of the rendering surface in the specified color.
void	fillBackground(Color c)	Fills the overall image with the specified color
BufferedImage	getBufferedImage()	Gets the buffered image associated with this drawing surface
AffineTransform	getCartesianToPixelTransform()	Gets the affine transform for mapping Cartesian coordinates to pixel coordinates.
Rectangle2D	getDomainRectangle()	Gets the rectangle for the drawing area corresponding to the coordinate domain that was specified for the constructor.
Graphics2D	getGraphics2D()	Get the Graphics2D object associated with this drawing surface.
double	getPixelsPerUnit()	Gets the distance in pixels across one unit of distance in the Cartesian coordinate system.
AffineTransform	getPixelToCartesianTransform()	Gets the affine transform for mapping pixel coordinates to Cartesian coordinates.
double	getUnitsPerPixel()	Gets the distance across a pixel in the corresponding Cartesian coordinate system.

Methods inherited from class java.lang.Object

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

Constructor Detail

RenderingSurfaceAid

public RenderingSurfaceAid(int width,
                           int height,
                           int pad,
                           double x0,
                           double y0,
                           double x1,
                           double y1)

Constructs a graphics surface (BufferedImage) and resources for a coordinate system appropriate for the presentation of a rectangular region defined by the specified coordinates. The transforms created by this class will be appropriate for drawing graphs within the coordinate domain as large as possible within the bounds of the specified size of the graphics surface based on width, height, and padding allowance.

Some implementations of the of Java API's ImageIO do not support creating JPEG image files from a BufferedImage with an alpha channel When using this class with Java ImageIO to write JPEG images, the associated BufferedImage should be created without an alpha channel. An alternate constructor is provided for this purpose.

Parameters:

width - the width of the drawing surface, in pixels

height - the height of the drawing surface, in pixels

pad - an arbitrary padding to be added to each side of the rectangle, in pixels

x0 - Cartesian x coordinate for the lower-left corner of the domain

y0 - Cartesian y coordinate for the lower-left corner of the domain

x1 - Cartesian x coordinate for the upper-right corner of the domain

y1 - Cartesian y coordinate for the upper-right corner of the domain

RenderingSurfaceAid

public RenderingSurfaceAid(int width,
                           int height,
                           int pad,
                           double x0,
                           double y0,
                           double x1,
                           double y1,
                           boolean alpha)

Constructs a graphics surface (BufferedImage) and resources for a coordinate system appropriate for the presentation of a rectangular region defined by the specified coordinates. The transforms created by this class will be appropriate for drawing graphs within the coordinate domain as large as possible within the bounds of the specified size of the graphics surface based on width, height, and padding allowance.

When using this class with Java ImageIO to write JPEG images, the associated BufferedImage should be created without an alpha channel. Some implementations of the of Java API's ImageIO do not support creating JPEG image files from a BufferedImage with an alpha channel.

Parameters:

width - the width of the drawing surface, in pixels

height - the height of the drawing surface, in pixels

pad - an arbitrary padding to be added to each side of the rectangle, in pixels

x0 - Cartesian x coordinate for the lower-left corner of the domain

y0 - Cartesian y coordinate for the lower-left corner of the domain

x1 - Cartesian x coordinate for the upper-right corner of the domain

y1 - Cartesian y coordinate for the upper-right corner of the domain

alpha - indicates if the associated image should be created using an alpha channel.

Method Detail

getCartesianToPixelTransform

public AffineTransform getCartesianToPixelTransform()

Gets the affine transform for mapping Cartesian coordinates to pixel coordinates. The transform was established by the constructor for this class.

Returns:

a valid instance of an affine transform

getPixelToCartesianTransform

public AffineTransform getPixelToCartesianTransform()

Gets the affine transform for mapping pixel coordinates to Cartesian coordinates. The transform was established by the constructor for this class.

Returns:

a valid instance of an affine transform

getDomainRectangle

public Rectangle2D getDomainRectangle()

Gets the rectangle for the drawing area corresponding to the coordinate domain that was specified for the constructor. This rectangle is suitable for use as a clipping rectangle when creating images.

Returns:

a valid instance of a rectangle, in pixel coordinates.

getBufferedImage

public BufferedImage getBufferedImage()

Gets the buffered image associated with this drawing surface

Returns:

a valid instance of a buffered image

getGraphics2D

public Graphics2D getGraphics2D()

Get the Graphics2D object associated with this drawing surface.

Returns:

a valid instance of a graphics object.

getUnitsPerPixel

public double getUnitsPerPixel()

Gets the distance across a pixel in the corresponding Cartesian coordinate system.

Returns:

a non-zero floating point value

getPixelsPerUnit

public double getPixelsPerUnit()

Gets the distance in pixels across one unit of distance in the Cartesian coordinate system.

Returns:

a non-zero floating point value

fillBackground

public void fillBackground(Color c)

Fills the overall image with the specified color

Parameters:

c - a valid instance.

drawFrame

public void drawFrame(Color c)

Draws a 1-pixel rectangular frame around the outer boundaries of the rendering surface in the specified color.

Parameters:

c - a valid instance.