Cannot figure out how the bounds of a Region work - javafx-8

Question

I'm currently writing a CAD-like program for logic circuits (it's my first "graphics intensive" program ever). When I place a component on the schematic, let say an AND gate (which is Region class at its root), I want to be able to interact with it (select it, change its properties, etc). So far, so good. I can click on it and everything go well. However, if I click outside of it, the mouse click event still show the component as it source(!).
Digging a bit further, I put some traces in the mouse click handler and found out that getBoundsInLocal() and getBoundsInParent() return bounds that are around 50% larger than it should be. The getLayoutBounds(), getWidth() and getHeight() do return the correct value.
The pane onto which the components are laid out is a simple Pane object, but it uses setScaleX() and setScaleY() to implement zooming capabilities. I did try to disable them, with no luck.
public abstract class SchematicComponent
extends Region {
private Shape graphicShape = null;
public Shape getGraphicShape() {
if( isShapeDirty() ) {
if( graphicShape != null ) {
getChildren().remove( graphicShape );
}
graphicShape = createShape();
markShapeDirty( false );
if( graphicShape != null ) {
getChildren().add( graphicShape );
}
}
return graphicShape;
}
abstract protected Shape createShape();
}
abstract public class CircuitComponent
extends SchematicComponent {
}
abstract public class LogicGate
extends CircuitComponent {
#Override
protected void layoutChildren() {
super.layoutChildren();
Pin outPin;
final double inputLength = getInputPinsMaxLength();
// Layout the component around its center.
// NOTE: I did try to set the center offset to 0 with no luck.
Point2D centerOffset = getCenterPointOffset().multiply( -1 );
Shape gateShape = getGraphicShape();
if( gateShape != null ) {
gateShape.setLayoutX( centerOffset.getX() + inputLength );
gateShape.setLayoutY( centerOffset.getY() );
}
/* Layout the output pins. */
outPin = getOutputPin();
if( outPin != null ) {
outPin.layout();
outPin.setLayoutX( centerOffset.getX() + getWidth() );
outPin.setLayoutY( centerOffset.getY() + getHeight() / 2 );
}
/* Compute the first input pin location and the gap between each
pins */
double pinGap = 2;
double y;
if( getInputPins().size() == 2 ) {
y = centerOffset.getY() + getHeight() / 2 - 2;
pinGap = 4;
}
else {
y = centerOffset.getY() + ( getHeight() / 2 ) - getInputPins().size() + 1;
}
/* Layout the input pins */
for( Pin inPin : getInputPins() ) {
inPin.layout();
inPin.layoutXProperty().set( centerOffset.getX() );
inPin.layoutYProperty().set( y );
y += pinGap;
}
}
}
// The actual object placed on the schematic
public class AndGate
extends LogicGate {
#Override
protected double computePrefWidth( double height ) {
// NOTE: computeMin/MaxWidth methods call this one
double width = getSymbolWidth() + getInputPinsMaxLength();
double length = 0;
width += length;
if( getOutputPin().getLength() > 0 ) {
width += getOutputPin().getLength();
}
return width; // Always 16
}
#Override
protected double computePrefHeight( double width ) {
// NOTE: computeMin/MaxHeight methods call this one
return getSymbolHeight() + getExtraHeight(); // Always 10
}
#Override
protected Shape createShape() {
Path shape;
final double extraHeight = getExtraHeight();
final double inputLength = getInputPinsMaxLength();
final double outputLength = getOutputPin().getLength();
/* Width and Height of the symbol itself (i,e, excluding the
input/output pins */
final double width = getWidth() - inputLength - outputLength;
final double height = getHeight() - extraHeight;
/* Starting point */
double startX = 0;
double startY = extraHeight / 2;
ArrayList<PathElement> elements = new ArrayList<>();
elements.add( new MoveTo( startX, startY ) );
elements.add( new HLineTo( startX + ( width / 2 ) ) );
elements.add( new ArcTo( ( width / 2 ), // X radius
height / 2, // Y radius
180, // Angle 180°
startX + ( width / 2 ), // X position
startY + height, // Y position
false, // large arc
true ) ); // sweep
elements.add( new HLineTo( startX ) );
if( extraHeight > 0 ) {
/* The height of the input pins is larger than the height of
the shape so we need to add extra bar on top and bottom of
the shape.
*/
elements.add( new MoveTo( startX, 0 ) );
elements.add( new VLineTo( extraHeight + height ) );
}
else {
elements.add( new VLineTo( startY ) );
}
shape = new Path( elements );
shape.setStroke( getPenColor() );
shape.setStrokeWidth( getPenSize() );
shape.setStrokeLineJoin( StrokeLineJoin.ROUND );
shape.setStrokeLineCap( StrokeLineCap.ROUND );
shape.setFillRule( FillRule.NON_ZERO );
shape.setFill( getFillColor() );
return shape;
}
} // End: LogiGate
// SchematicView is the ScrollPane container that handles the events
public class SchematicView
extends ScrollPane {
/* Mouse handler inner class */
private class MouseEventHandler
implements EventHandler<MouseEvent> {
#Override
public void handle( MouseEvent event ) {
if( event.getEventType() == MouseEvent.MOUSE_CLICKED ) {
processMouseClicked( event );
}
else { /* ... more stuff ... */ }
}
private void processMouseClicked( MouseEvent event ) {
Object node = event.getSource();
SchematicSheet sheet = getSheet();
Bounds local = ( (Node) node ).getLayoutBounds();
Bounds local1 = ( (Node) node ).getBoundsInLocal();
Bounds parent = ( (Node) node ).getBoundsInParent();
// At this point, here is what I get:
// node.getHeight() = 10 -> Good
// local.getHeight() = 10 -> Good
// local1.getHeight() = 15.6499996... -> Not expected!
// parent.getHeight() = 15.6500015... -> Not expected!
/*... More stuff ... */
}
}
So at this point, I'm running of clues of what is going on. Where do these getBoundsInXXX() values come from? They doesn't match with the parent's scale values either. The same goes with getWidth(): I get 24.825000... instead of 16.
Looking at this, I understand why clicking outside the component works as if I clicked on it. Its bounds are about 50% bigger than what it should be.
I googled the damn thing and search some doc for almost 2 days now and I'm still baffled. I think I understand that getBoundsInXXX() methods do their own computation but could it be off by that much? I don't thing so. My best guess is that it is something inside the createShape() method but I just can't figure what it is.
Anyone has a clue of what is going on?
Many thanks for your help.
P.S.: This is my first post here, so hopefully I did it right ;)

Answer 1

I think I finally found the problem :)
Basically, the Pin custom shape was drawn in the negative part of X axis (wrong calculations, my bad!). My best guess is that somehow, Java notices that I drew outside the standard bounds and then added the extra space used to the bounds, hence, adding 50% to width, which matches the length of the Pin. Drawing it in the positive region seem to have fixed the problem.
I'm not 100% sure if that is the right answer, but it make sense and it is now working has expected.