获取事件的节点坐标并从 BufferedImage Javafx 读取 RGB

Question

您好，我正在尝试在显示 5 个图像视图的滚动窗格中获取单击坐标的 rgb。 ImageViews 适合屏幕尺寸，而原始图像约为 8k x 4k 像素。下面是我寻找 rgb 的尝试，但是我一直收到 Can't read input file 异常，尽管我之前使用过这个图像。还可能需要注意的是，我有一个缩放机制，用SCALE_TOTAL表示的缩放总数实现了

点击代码

        mapScroll.addEventFilter(MouseEvent.MOUSE_CLICKED, e -> {
        File mapFile = new File("WorldProvincialMap-v1.01.png");
        commandOutput.setText(commandOutput.getText() + " \n" + e.getSceneX() + " " + e.getSceneY());
        try {
            BufferedImage mapBuffered = ImageIO.read(mapFile);
            int rgb = 0;
            if(mapScroll.getHvalue() < 0.2)
            {
                rgb = mapBuffered.getRGB((int) ( e.getSceneX() / SCALE_TOTAL), (int)(e.getSceneY() / SCALE_TOTAL));
            }
            else if(mapScroll.getHvalue() >= 0.2 && mapScroll.getHvalue() < 0.4)
            {
                rgb = mapBuffered.getRGB((int) (e.getSceneX() / (2/SCALE_TOTAL)), (int) (e.getSceneY() / (2/SCALE_TOTAL)));
            }
            else if(mapScroll.getHvalue() >= 0.4 && mapScroll.getHvalue() < 0.6)
            {
                rgb = mapBuffered.getRGB((int) (e.getSceneX() / (3/SCALE_TOTAL)), (int) (e.getSceneY() / (3/SCALE_TOTAL)));
            }
            else if(mapScroll.getHvalue() >= 0.6 && mapScroll.getHvalue() < 0.8)
            {
                rgb = mapBuffered.getRGB((int) (e.getSceneX() / (4/SCALE_TOTAL)), (int) (e.getSceneY() / (4/SCALE_TOTAL)));
            }
            else if(mapScroll.getHvalue() >= 0.8 && mapScroll.getHvalue() < 1);
            {
                rgb = mapBuffered.getRGB((int) (e.getSceneX() / (5/SCALE_TOTAL)), (int) (e.getSceneY() / (5/SCALE_TOTAL)));
            }
            commandOutput.setText(commandOutput.getText() + " \n" + Integer.toString(rgb));
        } catch (IOException e1) {
            e1.printStackTrace();
            commandOutput.setText(commandOutput.getText() + " \n" + e1.getMessage());
        }
    });

堆栈跟踪

javax.imageio.IIOException: Can't read input file!
at javax.imageio.ImageIO.read(Unknown Source)
at gameaspects.SourceCodeVersion9.lambda$5(SourceCodeVersion9.java:208)
at com.sun.javafx.event.CompositeEventHandler$NormalEventFilterRecord.handleCapturingEvent(CompositeEventHandler.java:282)
at com.sun.javafx.event.CompositeEventHandler.dispatchCapturingEvent(CompositeEventHandler.java:98)
at com.sun.javafx.event.EventHandlerManager.dispatchCapturingEvent(EventHandlerManager.java:223)
at com.sun.javafx.event.EventHandlerManager.dispatchCapturingEvent(EventHandlerManager.java:180)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchCapturingEvent(CompositeEventDispatcher.java:43)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:52)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Scene$ClickGenerator.postProcess(Scene.java:3470)
at javafx.scene.Scene$ClickGenerator.access$8100(Scene.java:3398)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3766)
at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3485)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2494)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:380)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:294)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$354(GlassViewEventHandler.java:416)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:415)
at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
at com.sun.glass.ui.View.notifyMouse(View.java:937)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
at java.lang.Thread.run(Unknown Source)

滚动窗格

        Image mapImage = new Image("WorldProvincialMap-v1.01.png");
    //Sets the map to full screen
    GraphicsDevice gd = GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice();
    int width = gd.getDisplayMode().getWidth();
    int height = gd.getDisplayMode().getHeight();
    //Creating the gridPane
    GridPane mapGrid = new GridPane();
    //Creating the image views
    ImageView mapView1 = new ImageView(mapImage);
    ImageView mapView2 = new ImageView(mapImage);
    ImageView mapView3 = new ImageView(mapImage);
    ImageView mapView4 = new ImageView(mapImage);
    ImageView mapView5 = new ImageView(mapImage);
    //Fitting the image views to the screen size.
    mapView1.setFitHeight(height);
    mapView1.setFitWidth(width);
    mapView2.setFitHeight(height);
    mapView2.setFitWidth(width);
    mapView3.setFitHeight(height);
    mapView3.setFitWidth(width);
    mapView4.setFitHeight(height);
    mapView4.setFitWidth(width);
    mapView5.setFitHeight(height);
    mapView5.setFitWidth(width);
    //Adding the imageViews to the girdPane
    mapGrid.add(mapView1,0,0);
    mapGrid.add(mapView2, 1, 0);
    mapGrid.add(mapView3, 2, 0);
    mapGrid.add(mapView4, 3, 0);
    mapGrid.add(mapView5, 4, 0);
    mapGrid.setManaged(false);
    mapScroll.setContent(new Group(mapGrid));
    mapScroll.setPannable(true);
    //Removes the ScrollBars
    mapScroll.setVbarPolicy(ScrollBarPolicy.NEVER);
    mapScroll.setHbarPolicy(ScrollBarPolicy.NEVER);

Answer 1

您应该使用PixelReader 代替javafx.scene.Image 来获取数据，而不是将数据加载到BufferedImage：

Image image = ...
int rgb = image.getPixelReader().getArgb(x, y);

// remove alpha; is this necessary???
rgb = rgb & 0xffffff;

这样可以避免多次将图像加载到内存中。