java - 如何在JavaFX中有效地滚动和缩放大图像？

Question

作为图像处理应用程序的一部分，我需要创建具有缩放、滚动和 vector 叠加功能的简单查看器模块。图像相当大:~40000x20000，这使得 ImageView 上的操作变慢、缓冲等。在 JavaFX 中处理巨大图像时，改善用户体验的最佳选项是什么？

Answer 1

我有一个 8k x 4k 图像，通过缓存我放置的滚动 Pane 并使用此代码进行缩放，可以很好地缩放。滚动 Pane 和大图像的唯一问题是平移非常糟糕且缓慢，我正在尝试在当前的应用程序中找到解决方案。

final double SCALE_DELTA = 1.175;
private double SCALE_TOTAL = 1;

.

    //Adds functionality to scrolling
    mapScroll.addEventFilter(ScrollEvent.ANY, e ->{
        //Consumes the event
        e.consume();
        if(e.getDeltaY() == 0)
        {
            return;
        }
        double scaleFactor =
                  (e.getDeltaY() > 0)
                    ? SCALE_DELTA
                    : 1/SCALE_DELTA;
        //Ensures that you do not exceed the limits of the map
        if(scaleFactor * SCALE_TOTAL >= 1)
        {
            Bounds viewPort = mapScroll.getViewportBounds();
            Bounds contentSize = mapGrid.getBoundsInParent();

            double centerPosX = (contentSize.getWidth() - viewPort.getWidth()) * mapScroll.getHvalue() + viewPort.getWidth() / 2;
            double centerPosY = (contentSize.getHeight() - viewPort.getHeight()) * mapScroll.getVvalue() + viewPort.getHeight() / 2;

            mapGrid.setScaleX(mapGrid.getScaleX() * scaleFactor);
            mapGrid.setScaleY(mapGrid.getScaleY() * scaleFactor);
            SCALE_TOTAL *= scaleFactor;

            double newCenterX = centerPosX * scaleFactor;
            double newCenterY = centerPosY * scaleFactor;

            mapScroll.setHvalue((newCenterX - viewPort.getWidth()/2) / (contentSize.getWidth() * scaleFactor - viewPort.getWidth()));
            mapScroll.setVvalue((newCenterY - viewPort.getHeight()/2) / (contentSize.getHeight() * scaleFactor  -viewPort.getHeight()));
        }
    });