Hit Testing

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In NOV Diagram you can use the HitTest methods of the drawing page to detect which shapes are hit (overlapped) by a given rectangle or a point.

Hit testing in NOV Diagram works with shape geometry, not with shape bounds. If a shape or group doesn't have a geometry, it won't be subject to hit testing and will never be considered as hit.

Get all shapes in a rectangle or under a point

To get all shapes in a given rectangle area of the drawing page, use the following piece of code:

Get all shapes in a rectangle	Copy Code
// Hit test the page NList<NDiagramItem> hitItems = drawingView.ActivePage.HitTestItems(rectangle);

Similarly you can pass a point instead of a rectangle to the HitTestItems method to get all shapes under a given point (in page coordinates).

Get top most shape in a rectangle or under a point

To quickly check if a given rectangle or point hits any shape on the drawing page, you can use the GetTopMostHitItem method of the page:

Check if a rectangle contains any shapes	Copy Code
// Hit test the page NDiagramItem hitItem = drawingView.ActivePage.GetTopMostHitItem(rectangle); if (hitItem != null) { // Item hit } else { // Item not hit }

The method returns the top-most item hit by the passed rectangle or point or null if no item was hit.

Get all shapes overlapped by a given shape

To get all diagram items overlapped by a specific shape, use the following piece of code:

Get all shapes overlapped by a given shape	Copy Code
// Get the shape bounds in page coordinates NRectangle rect = shape.GetAlignBoxInPage(); // Hit test the page NList<NDiagramItem> hitItems = drawingView.ActivePage.HitTestItems(rect); // Remove the shape we are hit testing with from the list hitShapes.Remove(shape);

Get all shapes overlapped by a given shape

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// Get the shape bounds in page coordinates
NRectangle rect = shape.GetAlignBoxInPage();
// Hit test the page
NList<NDiagramItem> hitItems = drawingView.ActivePage.HitTestItems(rect);
// Remove the shape we are hit testing with from the list
hitShapes.Remove(shape);

To quickly check if any shape was hit, use the GetTopMostHitItem method instead of the HitTestItems method:

Check if a shape overlaps any shapes	Copy Code
// Get the shape bounds in page coordinates NRectangle rect = shape.GetAlignBoxInPage(); // Hit test the page NDiagramItem hitItem = drawingView.ActivePage.GetTopMostHitItem(rect); if (hitItem != shape) { // The shape overlaps hitItem } else { // The shape doesn't overlap any shapes }

Check if a shape overlaps any shapes

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// Get the shape bounds in page coordinates
NRectangle rect = shape.GetAlignBoxInPage();
// Hit test the page
NDiagramItem hitItem = drawingView.ActivePage.GetTopMostHitItem(rect);

if (hitItem != shape)
{
    // The shape overlaps hitItem
}
else
{
    // The shape doesn't overlap any shapes
}

Get all 2D shapes overlapped by a given shape

You can also use filters. For example, to get all 2D shapes overlapped by a given shape, use the following code:

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// Get the shape bounds in page coordinates NRectangle rect = shape.GetAlignBoxInPage(); // Hit test the page NList<NDiagramItem> hitItems = drawingView.ActivePage.HitTestItems(rect, NDiagramFilters.ShapeType2D); // Remove the shape we are hit testing with from the list hitShapes.Remove(shape);

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// Get the shape bounds in page coordinates
NRectangle rect = shape.GetAlignBoxInPage();
// Hit test the page
NList<NDiagramItem> hitItems = drawingView.ActivePage.HitTestItems(rect, NDiagramFilters.ShapeType2D);
// Remove the shape we are hit testing with from the list
hitShapes.Remove(shape);

To quickly check if any shape was hit, use the GetTopMostHitItem method instead of the HitTestItems method:

Check if a shape overlaps any shapes	Copy Code
// Get the shape bounds in page coordinates NRectangle rect = shape.GetAlignBoxInPage(); // Hit test the page NDiagramItem hitItem = drawingView.ActivePage.GetTopMostHitItem(rect, NDiagramFilters.ShapeType2D); if (hitItem != shape) { // The shape overlaps hitItem } else { // The shape doesn't overlap any shapes }

Check if a shape overlaps any shapes

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// Get the shape bounds in page coordinates
NRectangle rect = shape.GetAlignBoxInPage();
// Hit test the page
NDiagramItem hitItem = drawingView.ActivePage.GetTopMostHitItem(rect, NDiagramFilters.ShapeType2D);

if (hitItem != shape)
{
    // The shape overlaps hitItem
}
else
{
    // The shape doesn't overlap any shapes
}