advanced user interfaces with java sd 98 session 3206 l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Advanced User Interfaces with Java SD’98 - Session 3206 PowerPoint Presentation
Download Presentation
Advanced User Interfaces with Java SD’98 - Session 3206

Loading in 2 Seconds...

play fullscreen
1 / 45

Advanced User Interfaces with Java SD’98 - Session 3206 - PowerPoint PPT Presentation


  • 400 Views
  • Uploaded on

Advanced User Interfaces with Java SD’98 - Session 3206 Ted Faison ted.faison@computer.org Faison Computing Inc. www.faisoncomputing.com JDK 1.2 - A Better Graphics Framework JDK 1.1 had little or no support for complex shapes, coordinate transformations or pixel blending

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Advanced User Interfaces with Java SD’98 - Session 3206' - niveditha


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
advanced user interfaces with java sd 98 session 3206
Advanced User Interfaces with JavaSD’98 - Session 3206

Ted Faison

ted.faison@computer.org

Faison Computing Inc.

www.faisoncomputing.com

jdk 1 2 a better graphics framework

JDK 1.2 - A Better Graphics Framework

JDK 1.1 had little or no support for complex shapes, coordinate transformations or pixel blending

The graphics extensions were added as new packages under the AWT as the Java 2D API

the java 2d packages
The Java 2D Packages
  • java.awt.color: Color control
  • java.awt.font: Fonts as complex shapes
  • java.awt.geom: Coordinate transformations and shapes
  • java.awt.print: Advanced printing support
    • Books, Pages and Paper
java 2d api features
Java 2D API Features
  • Support for separate user and device coordinate spaces
  • Coordinates can be integers, floats or doubles

Device Space

User Space

java 2d api features5
Java 2D API Features
  • Support for coordinate transformations, for translation, rotation, scaling and shearing

Device Space

User Space

java 2d api features6
Java 2D API Features
  • Support for complex shapes and hit-testing
  • Support for complex clipping
  • More precise color control
  • Support for variable transparency, allowing color blending
java 2d api features7
Java 2D API Features
  • Better image-processing support, with convolution, color look-up, amplitude scaling.
  • Improved screen updating, with offscreen buffers supporting BufferedImages and transparency
basic drawing
Basic Drawing
  • The old Graphics context is still there
  • All 2D drawing done using Graphics2D
    • Painting: typecasting Graphics into Graphics2D

public void paint(Graphics g) {

Graphics2D g2d = (Graphics2D) g;

g2d.setColor(Color.red);

//…

}

coordinate transformations
Coordinate Transformations
  • Functions that map a point in one space to a point in another space
  • Represented using a 3x3 matrix
  • Transformations require multiplying each pixel by a transformation matrix
  • Positive angles rotate the X+ axis towards the Y+ axis
  • Can be used to invert axes, bend images, distort space arbitrarily
coordinate transformations10
Coordinate Transformations

a11 a12 a13

a21 a22 a23

0 0 1

x

y

1

a11x a12y a13

a21x a22y a23

0 0 1

x’

y’

1

=

=

affine transforms
Affine Transforms
  • Maintain straightness and parallelism
  • Translation
      • setToTranslation(double dx, double, dy);
      • used to support graphics scrolling

Device Space

User Space

affine transforms12
Affine Transforms
  • Rotation
    • Rotating about the origin
      • setToRotation(double theta);

Device Space

User Space

affine transforms13
Affine Transforms
  • Rotation about an arbitrary point
    • SetToRotation(theta, x, y);

(x, y)

(x, y)

Device Space

User Space

affine transforms14
Affine Transforms
  • Shearing
      • setToShear(double sh, double sy)

Device Space

User Space

affine transforms15
Affine Transforms
  • Scaling
      • setToScale(double sx, double sy)
      • anisotropic vs isotropic scaling

Device Space

User Space

using class affinetransform
Using class AffineTransform
  • Commands can be cumulative
    • concatenating transformations
  • Commands are not commutative
    • Matrix multiplication is not commutative
  • Dealing directly with the transformation matrix, to effect combined transformations in one pass
      • g2D.setTransform(myAffineTransform);
affine transforms17
Affine Transforms
  • Handling transformed images with offscreen buffers
    • Examples
      • ScalingImages.java
      • RotatingImages.java
      • ShearingImages.java
drawing with paths
Drawing with Paths
  • All 2D shapes are drawn as paths, including lines and rectangles
  • Class GeneralPath
    • Used to define arbitrary paths
    • The outline can be stroked
    • Graphics2D uses a default stroke:
      • square pen
      • width is 1 pixel
      • continuous drawing - no dashes
bezier curves
Bezier curves
  • Used by the 2D API for cubic curves.
  • Defined by simple control points
drawing a straight line
Drawing a Straight Line

public void paint(Graphics g) {

Graphics2D g2d = (Graphics2D) g;

g2d.setColor(Color.red);

GeneralPath path =

new GeneralPath(GeneralPath.EVEN_ODD);

path.moveTo(50.0f, 50.0f);

path.lineTo(200.0f, 200.0f);

g2d.draw(path);

}

filling a shape
Filling a shape

public void paint(Graphics g) {

Graphics2D g2d = (Graphics2D) g;

g2d.setColor(Color.blue);

GeneralPath path =

new GeneralPath(GeneralPath.EVEN_ODD);

path.moveTo(20.0f, 20.0f);

path.lineTo(100.0f, 20.0f);

path.lineTo(100.0f, 70.0f);

path.lineTo(20.0f, 70.0f);

path.closePath();

g2d.fill(path);

}

filling a shape with a pattern
Filling a Shape with a Pattern

BufferedImage image; // create a buffered image

Rectangle2D.Float rect = new Rectangle2D.Float(0.0f, 0.0f, 100.0f, 200.0f);

TexturePaint pattern =

new TexturePaint(image, rect,

TexturePaint.NEAREST_NEIGHBOR);

g2d.setPaint(pattern);

g2d.drawString(styledString, 10, 10);

filling a shape with an image
Filling a Shape with an Image

Image image = getToolkit().getImage(url);

AffineTransform at = new AffineTransform();

at.setToTranslation(0, 200);

g2d.transform(at);

g2d.setClip(myShape);

at.setToTranslation(0, -200);

g2d.drawImage(image, at, this);

at.setToTranslation(0, 200);

g2d.setClip(null);

g2d.draw(myShape);

filling a shape with a gradient
Filling a Shape with a Gradient

Font myFont = new Font("Helvetica",

Font.PLAIN, 200);

StyledString styledString =

new StyledString("AB", myFont);

Shape myShape = styledString.getStringOutline();

GradientPaint gradient =

new GradientPaint(0.0f, 0.0f, Color.red,

200.0f, 200.0f,

Color.yellow);

g2d.setPaint(gradient);

g2d.drawString(styledString, 10, 200);

custom strokes
Custom Strokes
  • Class BasicStroke
    • simple to use
    • define common stroke properties
      • width
      • end caps
      • line joins
      • dash attributes
defining a custom stroke
Defining a Custom Stroke

g2d.setStroke(

new BasicStroke(penWidth,

BasicStroke.CAP_ROUND,

BasicStroke.JOIN_MITER ) );

path.moveTo(10.0f, 40.0f);

path.lineTo(90.0f, 40.0f);

g2d.draw(path);

2d drawing shortcuts
2D Drawing Shortcuts
  • interface Rectangle2D
    • Rectangle2D.Float
    • Rectangle2D.Double
  • RoundRectangle2D
  • Arc2D
  • Ellipse2D
clipping
Clipping
  • Graphics2D.setClip(Path);
  • Clipping a circle with a rectangle

Ellipse2D.Float circle = new

Ellipse2D.Float(10.0f, 10.0f, 100.0f, 100.0f);

Rectangle2D.Float rect = new Rectangle2D.Float (10.0f, 30.0f, 100.0f, 70.0f);

g2d.setClip(rect);

g2d.setColor(Color.red);

g2d.fill(circle);

g2d.setClip(null);

g2d.setColor(Color.black);

g2d.draw(rect);

clipping with text
Clipping with Text

Font myFont = new Font("Helvetica",Font.PLAIN,200);

StyledString styledString =

new StyledString("ABC", myFont);

Shape myShape = styledString.getStringOutline();

AffineTransform at = new AffineTransform();

at.setToTranslation(0, 200);

g2d.transform(at);

Ellipse2D.Float circle =

new Ellipse2D.Float(10.0f,-150.0f,400.0f,150.0f);

g2d.setClip(myShape);

g2d.setColor(Color.red);

g2d.fill(circle);

blending objects
Blending objects
  • Transparency
  • The Alpha Channel
  • Compositing Operations
    • called Raster Operations (ROP) in Windows
    • Class AlphaComposite
      • Implements a subset of the Porter-Duff rules

Cd = Cs*Fs + Cd*Fd

Ad = As*Fs + Ad*Fd

C = Color d = destination

F = Fraction s = source

A = Alpha

compositing operations
Compositing Operations
  • Alpha=1 indicated total opaqueness
  • Setting the Operation

AlphaComposite c = AlphaComposite.getInstance(

AlphaComposite.SRC_OVER,

0.5f);

g2d.setComposite(c);

porter duff operations supported
Porter-Duff Operations Supported
  • CLEAR: destination cleared
  • SRC: source copied to destination
  • SRC_OVER: source is blended over dest
  • SRC_IN: part of source already in dest replaces dest
  • SRC_OUT: part of source not already in dest replaces dest
  • DST_IN, DST_OUT, DEST_OVER
conclusion
Conclusion
  • The Java 2D API extends the AWT with:
    • advanced geometric shapes
    • coordinate transformations
    • shapes of arbitrary complexity
    • text as a shape
    • arbitrary clipping regions
    • image blending through compositing
    • image processing capabilities
    • precise color control