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| import javafx.beans.property.*;
import javafx.geometry.BoundingBox;
import javafx.geometry.Rectangle2D;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.input.MouseEvent;
import javafx.scene.input.ScrollEvent;
import javafx.scene.layout.Region;
import java.util.List;
import java.util.Objects;
public final class ImagePanView extends Region {
private final ImageView content = new ImageView();
public ImagePanView() {
this(null);
}
public ImagePanView(final Image image) {
super();
setId("imagePanView");
getStyleClass().add("image-pan-view");
content.setId("content");
content.getStyleClass().add("content");
content.setPreserveRatio(true);
content.imageProperty().bind(imageProperty());
content.setMouseTransparent(true);
getChildren().addAll(content);
imageProperty().addListener((observable, oldValue, newValue) -> {
offsetX = (newValue == null) ? 0 : Math.min(offsetX, newValue.getWidth());
offsetY = (newValue == null) ? 0 : Math.min(offsetY, newValue.getHeight());
computeView();
});
widthProperty().addListener((observable, oldValue, newValue) -> computeView());
heightProperty().addListener((observable, oldValue, newValue) -> computeView());
setImage(image);
//
addEventFilter(MouseEvent.MOUSE_PRESSED, this::handleMousePressed);
addEventFilter(MouseEvent.MOUSE_DRAGGED, this::handleMouseDragged);
addEventFilter(ScrollEvent.SCROLL, this::handleZoomByScroll);
}
@Override
protected void layoutChildren() {
super.layoutChildren();
final double width = getWidth();
final double height = getHeight();
final var insets = getInsets();
final double insetsLeft = insets.getLeft();
final double insetsRight = insets.getRight();
final double insetsTop = insets.getTop();
final double insetsBot = insets.getBottom();
final double viewPortX = insetsLeft;
final double viewPortY = insetsTop;
final double viewPortW = Math.max(0, width - (insetsLeft + insetsRight));
final double viewPortH = Math.max(0, height - (insetsTop + insetsBot));
content.setLayoutX(viewPortX);
content.setLayoutY(viewPortY);
content.setFitWidth(viewPortW);
content.setFitHeight(viewPortH);
}
private static final BoundingBox EMPTY_BOUNDS = new BoundingBox(0, 0, 0, 0);
private static final Rectangle2D EMPTY_CONTENT_VIEWPORT = new Rectangle2D(0, 0, 0, 0);
private void computeView() {
System.out.println("computeView()");
final var image = getImage();
if (Objects.isNull(image)) {
viewport.set(EMPTY_BOUNDS);
content.setViewport(EMPTY_CONTENT_VIEWPORT);
return;
}
final double width = getWidth();
final double height = getHeight();
final var insets = getInsets();
final double insetsLeft = insets.getLeft();
final double insetsRight = insets.getRight();
final double insetsTop = insets.getTop();
final double insetsBot = insets.getBottom();
final double viewPortX = insetsLeft;
final double viewPortY = insetsTop;
final double viewPortW = Math.max(0, width - (insetsLeft + insetsRight));
final double viewPortH = Math.max(0, height - (insetsTop + insetsBot));
if (viewPortW == 0 || viewPortH == 0) {
viewport.set(EMPTY_BOUNDS);
content.setViewport(EMPTY_CONTENT_VIEWPORT);
return;
}
final double zoom = getZoom();
final double imageW = image.getWidth();
final double imageH = image.getHeight();
final double viewX = clamp(0, offsetX, image.getWidth());
final double viewY = clamp(0, offsetY, image.getHeight());
final double viewW = Math.min(imageW - viewX, viewPortW / zoom);
final double viewH = Math.min(imageH - viewY, viewPortH / zoom);
final var oldViewport = getViewport();
if (oldViewport.isEmpty() || oldViewport.getMinX() != viewX || oldViewport.getMinY() != viewY || oldViewport.getWidth() != viewW || oldViewport.getHeight() != viewH) {
viewport.set(new BoundingBox(viewX, viewY, viewW, viewH));
content.setViewport(new Rectangle2D(viewX, viewY, viewW, viewH));
}
}
private final ObjectProperty<Image> image = new SimpleObjectProperty<>(this, "image");
public final Image getImage() {
return image.get();
}
public final void setImage(final Image value) {
image.set(value);
}
public final ObjectProperty<Image> imageProperty() {
return image;
}
private final ReadOnlyObjectWrapper<BoundingBox> viewport = new ReadOnlyObjectWrapper<>(this, "viewport", EMPTY_BOUNDS);
public final BoundingBox getViewport() {
return viewport.get();
}
public final ReadOnlyObjectProperty<BoundingBox> viewportProperty() {
return viewport.getReadOnlyProperty();
}
private double clamp(double min, double value, double max) {
double result = Math.max(min, value);
result = Math.min(result, max);
return result;
}
private double offsetX;
private double offsetY;
private final ReadOnlyDoubleWrapper zoom = new ReadOnlyDoubleWrapper(this, "zoom", 1);
public final double getZoom() {
return zoom.get();
}
public final void setZoom(final double value) {
if (value > 0) {
zoom.set(value);
computeView();
}
}
public final ReadOnlyDoubleProperty zoomProperty() {
return zoom.getReadOnlyProperty();
}
private double startX;
private double startY;
private void handleMousePressed(final MouseEvent event) {
startX = event.getX();
startY = event.getX();
}
private void handleMouseDragged(final MouseEvent event) {
final var image = getImage();
if (image == null) {
return;
}
final double zoom = getZoom();
final double rawDragX = startX - event.getX();
final double rawDragY = startY - event.getY();
startX = event.getX();
startY = event.getY();
final double dragX = rawDragX / zoom;
final double dragY = rawDragY / zoom;
System.out.printf("DRAG %f %f%n", dragX, dragY);
final var viewport = getViewport();
final double newOffsetX = clamp(0, offsetX + dragX, image.getWidth() - viewport.getWidth());
final double newOffsetY = clamp(0, offsetY + dragY, image.getHeight() - viewport.getWidth());
System.out.printf("%f -> %f%n", offsetX, newOffsetX);
System.out.printf("%f -> %f%n", offsetY, newOffsetY);
offsetX = newOffsetX;
offsetY = newOffsetY;
computeView();
}
final List<Double> ZOOM_FACTORS = List.of(0.25, 0.5, 1d, 2d, 4d, 8d, 16d);
private void handleZoomByScroll(final ScrollEvent event) {
final double deltaY = event.getDeltaY();
final double oldZoom = getZoom();
int zoomIndex = ZOOM_FACTORS.indexOf(oldZoom);
// User provided zoom.
if (zoomIndex < 0) {
zoomIndex = ZOOM_FACTORS.stream()
.filter(value -> value < oldZoom)
.findFirst()
.map(ZOOM_FACTORS::indexOf)
.orElse(0);
}
int newZoomIndex = zoomIndex + ((deltaY > 0) ? -1 : 1);
newZoomIndex = (int) clamp(0, newZoomIndex, ZOOM_FACTORS.size() - 1);
final double zoom = ZOOM_FACTORS.get(newZoomIndex);
setZoom(zoom);
}
} |
