JavaFX学习之Image

  ImageView and Image

ImageView iv = new ImageView(image);
		iv.setFitWidth(200);
		iv.setPreserveRatio(true);
		iv.setSmooth(true);
		
		ImageView iv2 = new ImageView(image);
		iv2.setViewport(new Rectangle2D(192, 256, 300, 300));

setFitHeight(double value)
setFitWidth(double value) 设置ImageView的大小
setPreserveRatio(boolean value) setPreserveRatio(boolean)设置比率，按比率去缩小放大。当你只设置了宽度时，宽度会缩小，但是高度仍然不变，图像就畸形了。若设置为true，则高度也会按比率缩小。
setSmooth(boolean value) 若为true，则用较好的过滤算法花时间，若为false，则快速
setViewport(Rectangle2D value) 设置可视口，因为图片的大小经常大于你ImageViw的设置的大小，而你不想按比率缩放，只想显示图像的一部分，看一下Rectangle2D的参数Rectangle2D(double minX, double minY, double width, double height) minX，Y图片左上的位置，width，height宽度高度，这样就可以从图片上截取一块区域，然后显示出来。

   WritableImage  可编辑的image
   PixelReader  获取image像素数据
  PixelWriter  写入image像素数据

Image image = new Image("http://docs.oracle.com/javafx/"
        + "javafx/images/javafx-documentation.png");
        ImageView imageView = new ImageView();
        imageView.setImage(image);
        // Obtain PixelReader
        PixelReader pixelReader = image.getPixelReader();
        System.out.println("Image Width: "+image.getWidth());
        System.out.println("Image Height: "+image.getHeight());
        System.out.println("Pixel Format: "+pixelReader.getPixelFormat());
        
        // Create WritableImage
         WritableImage wImage = new WritableImage(
                 (int)image.getWidth(),
                 (int)image.getHeight());
         PixelWriter pixelWriter = wImage.getPixelWriter();
       
        // Determine the color of each pixel in a specified row
        for(int readY=0;readY<image.getHeight();readY++){
            for(int readX=0; readX<image.getWidth();readX++){
                Color color = pixelReader.getColor(readX,readY);
                System.out.println("\nPixel color at coordinates ("+
                        readX+","+readY+") "
                        +color.toString());
                System.out.println("R = "+color.getRed());
                System.out.println("G = "+color.getGreen());
                System.out.println("B = "+color.getBlue());
                System.out.println("Opacity = "+color.getOpacity());
                System.out.println("Saturation = "+color.getSaturation());
                
                // Now write a brighter color to the PixelWriter.
                color = color.brighter();
                pixelWriter.setColor(readX,readY,color);
            }
        }
        
        // Display image on screen
        //imageView.setImage(wImage);
        StackPane root = new StackPane();
        root.getChildren().add(imageView);
        Scene scene = new Scene(root, 300, 250);
        primaryStage.setTitle("Image Write Test");
        primaryStage.setScene(scene);
        primaryStage.show();

   PixelFormat   定义图像像素数据的格式
   WritablePixelFormat  可编辑图像像素格式

PixelFormat<ByteBuffer> pixelFormat = PixelFormat.getByteRgbInstance();
pixelWriter.setPixels(int x, int y, int w, int h, PixelFormat<ByteBuffer> pixelformat, byte[] buffer, int offset, int scanlineStride)