Hi K.W.
"K. W. Landry" <[EMAIL PROTECTED]> wrote on 12/11/2006 09:51:34 PM:
> What techniques would you use for limiting the drag of an element to
> within the bounds of another element?
> if(grab) {
> // DOMMouseEvent elementEvent = (DOMMouseEvent) event;
> int dragMoveX = dm.getClientX();
> int dragMoveY = dm.getClientY();
> SVGOMPoint point = new SVGOMPoint(dragMoveX, dragMoveY);
Don't do this. Use the SVGSVGElement as a factory for points:
http://xmlgraphics.apache.org/batik/javadoc/org/w3c/dom/svg/SVGSVGElement.html
SVGPoint point = svgDoc.getRootElement().createPoint;
point.setX(dragMoveX);
point.setY(dragMoveY);
> Node node = ((Node) evt.getTarget()).getParentNode();
> SVGMatrix Drag_M = ((SVGLocatable) node).getScreenCTM();
> Drag_M = Drag_M.inverse();
> SVGOMPoint dp = (SVGOMPoint) point.matrixTransform(Drag_M);
This gives you dp in the local coordinate system of 'node'.
I would suggest that you want 'dp' to be in the local coordinate
system of 'Base':
> Node Base =
(Node)ae.getOwnerDocument().getElementById("rateSlideBase");
> SVGLocatable Base_L = (SVGLocatable)Base;
SVGMatrix Drag_M = Base_L.getScreenCTM();
Drag_M = Drag_M.inverse();
SVGPoint dp = point.matrixTransform(Drag_M);
SVGRect bbox = Base_L.getBBox;
// Limit dp's Y to the bbox.
if (dp.getY() < bbox.getY())
dp.setY(bbox.getY());
if (dp.getY() > bbox.getY() + bbox.getHeight())
dp.setY(bbox.getY() + bbox.getHeight());
// Now map dp to the rateButton's coordinate system:
node =
ae.getOwnerDocument().getElementById("rateButton");
SVGLocatable rb = (SVGLocatable)node;
SVGMatrix elemMat = Base_L.getTransformToElement(rb);
dp = dp.matrixTransform(elemMat);
// Set both in case of rotation...
rb.setAttributeNS(null, "cx", ""+dp.getX())
rb.setAttributeNS(null, "cy", ""+dp.getY())
> top = Base_L.getScreenCTM().getB();
> hgt = Base_L.getScreenCTM().getD();
> rad = Base_L.getScreenCTM().getF();
> bot = hgt+top;
> top = top+(2*rad);
> bot = bot-(2*rad);
>
> newY = dp.getY();
> if(newY < top) newY = top;
> if(newY > bot) newY = bot;
> String cy = String.valueOf(newY);
> String setCY = String.valueOf(dp.getY());
> ae.getOwnerDocument().getElementById("rateButton").
> setAttributeNS(null, "cy",setCY);
>
>
> I've played around with BBox ( have deleted those attempts out of
> this version of the code) but am obviously getting lost in trying to
> determine how to get the topmost Y and bottom-most Y of the
> rectangle to test against.
>
> Thanks for any suggestions,
>
> KWL
