我使用DisplayJAI突出显示图像的特定部分。
申请类
import java.awt.BasicStroke;
import java.awt.Graphics2D;
import java.awt.Graphics;
import java.awt.image.RenderedImage;
import java.util.ArrayList;
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Stroke;
public class DisplayIImages {
final static float dash1[] = { 2.0f };
final static BasicStroke dashed = new BasicStroke(1.0f,
BasicStroke.CAP_BUTT, BasicStroke.JOIN_MITER, 10.0f, dash1, 0.0f);
public static void main(String[] args) throws IOException
{
//PlanarImage image=JAI.create("scan", args[0]);
File f= new File("profile.jpeg");
RenderedImage image2=ImageIO.read(f);
DisplayJAIWithAnnotations display = new DisplayJAIWithAnnotations(image2);
// Create a circle annotation.
RectangleAnnotation ca = new RectangleAnnotation(20,100,60,110);
ca.setColor(Color.BLUE);
ca.setStroke(dashed);
// Add the annotation to the instance of DisplayJAIWithAnnotations.
display.addAnnotation(ca);
// Create a new Frame and set the DisplayJAIWithAnnotations.
JFrame frame = new JFrame();
frame.setTitle("Annotations over an image");
frame.getContentPane().add(new JScrollPane(display));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(500,200); // Set the frame size so we can scroll over large images.
frame.setVisible(true);
}
}
DisplayJAI的子类
class DisplayJAIWithAnnotations extends DisplayJAI
{
protected ArrayList<DrawableAnnotation> annotations; // List of annotations that will be
// (non-interactively) drawn over the image.
// Constructor for the class.
public DisplayJAIWithAnnotations(RenderedImage image)
{
super(image); // Calls the constructor for DisplayJAI
annotations = new ArrayList<DrawableAnnotation>(); // List that will held the drawings.
}
// This method paints the component and all its annotations.
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2d = (Graphics2D)g;
for (DrawableAnnotation d:annotations)
{
d.paint(g2d);
}
}
// Add an annotation (instance of any class that inherits from DrawableAnnotation) to the list
// of annotations which will be drawn.
public void addAnnotation(DrawableAnnotation a)
{
annotations.add(a);
}
}
用于突出显示图像矩形部分的注记类
class RectangleAnnotation extends DrawableAnnotation
{
private int x1,y1,x2,y2; // the corners of the rectangle.
// Constructor for this class.
public RectangleAnnotation(int x1,int y1,int x2,int y2)
{
this.x1 = x1; this.y1 = y1;
this.x2 = x2; this.y2 = y2;
}
// Concrete implementation of the paint method.
public void paint(Graphics2D g2d)
{
float[] dash = new float[]{4.0f, 4.0f};
BasicStroke dashStroke = new BasicStroke(1.0f,
BasicStroke.CAP_BUTT,
BasicStroke.JOIN_BEVEL,
0.0f,
dash, 0);
g2d.setColor(getColor());
g2d.setStroke(getStroke());
g2d.drawRect(x1,y1,x2-x1,y2-y1);
}
}
绘制矩形的抽象类
abstract class DrawableAnnotation {
// The annotation color.
private Color color = Color.BLACK;
// The annotation stroke.
private Stroke stroke = new BasicStroke(1f);
// This method will draw the annotation, and must be implemented by
// non-abstract classes.
public abstract void paint(Graphics2D g2d);
// Setter for the color.
public void setColor(Color color) {
this.color = color;
}
// Getter for the color.
public Color getColor() {
return color;
}
// Setter for the stroke.
public void setStroke(Stroke stroke) {
this.stroke = stroke;
}
// Getter for the stroke.
public Stroke getStroke() {
return stroke;
}
}
这是我的代码及其工作正常。但我想使用Graphics2D绘制dispalyJAI而不是直接添加到frame.Is这可能吗？
答案 0 :(得分：1)
问题是如果你正在使用......
ImageIO.read(f);
加载图片，为什么你没有使用BufferedImage，Graphics#drawImage能够画画？
相反，只是使用像...这样的东西。
public class RectangleAnnotation extends JPanel {
private BufferedImage img;
private ArrayList<DrawableAnnotation> annotations
// Constructor for this class.
public RectangleAnnotation(BufferedImage img) {
this.img = img;
annotations = new ArrayList<DrawableAnnotation>();
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
g2d.drawImage(img, 0, 0, this);
for (DrawableAnnotation d : annotations) {
d.paint(g2d);
}
}
public void addAnnotation(DrawableAnnotation a) {
annotations.add(a);
}
}
您将使用类似......
之类的东西申请 File f = new File("profile.jpeg");
BufferedImage image2 = ImageIO.read(f);
RectangleAnnotation display = new RectangleAnnotation(image2);
// Create a circle annotation.
RectangleAnnotation ca = new RectangleAnnotation(20, 100, 60, 110);
ca.setColor(Color.BLUE);
ca.setStroke(dashed);
// Add the annotation to the instance of DisplayJAIWithAnnotations.
display.addAnnotation(ca);
当然，如果您仍然不知所措，可以查看DisplayJAI的源代码
@Override
protected void paintComponent(Graphics g) {
Graphics2D g2d = (Graphics2D)g;
// empty component (no image)
if ( source == null ) {
g2d.setColor(getBackground());
g2d.fillRect(0, 0, getWidth(), getHeight());
return;
}
// account for borders
Insets insets = getInsets();
int tx = insets.left + originX;
int ty = insets.top + originY;
// clear damaged component area
Rectangle clipBounds = g2d.getClipBounds();
g2d.setColor(getBackground());
g2d.fillRect(clipBounds.x,
clipBounds.y,
clipBounds.width,
clipBounds.height);
/**
Translation moves the entire image within the container
*/
affineTrans = new AffineTransform();
affineTrans.setTransform( AffineTransform.getTranslateInstance(tx, ty) );
if ( (sx != 0) && (sy != 0) )
affineTrans.scale(sx, sy);
g2d.drawRenderedImage(source, affineTrans);
}
你不能（或者更重要的是你不应该）尝试获取组件的渲染内容，这很复杂，只要相信我。
相反，你可以使用BufferedImage，它允许你获得图像的Graphics上下文，然后你可以直接绘制到...
List<DrawableAnnotation> annotations = new ArrayList<>(25);
RectangleAnnotation ca = new RectangleAnnotation(20, 100, 60, 110);
ca.setColor(Color.BLUE);
ca.setStroke(dashed);
// Any other annotations...
File f = new File("profile.jpeg");
BufferedImage image2 = ImageIO.read(f);
Graphics2D g2d = image2.createGraphics();
g2d.drawImage(image2, x, y, null);
for (DrawableAnnotation d : annotations) {
d.paint(g2d);
}
g2d.dispose();
从这里开始，您可以使用JPanel及其paintComponent来渲染它，或者如果您感到懒惰，可以使用JLabel ...