Line Intersection Detection and Splitting

This post demonstrates efficient line intersection detection using SVG-optimized techniques, with automatic circle placement and visual line splitting effects.

Intersection Demos:

SVG Optimization Techniques

1. Bounding Box Pre-filtering

function bboxIntersect(bbox1, bbox2) {
    return !(bbox1.x + bbox1.width < bbox2.x || 
             bbox2.x + bbox2.width < bbox1.x || 
             bbox1.y + bbox1.height < bbox2.y || 
             bbox2.y + bbox2.height < bbox1.y);
}

// Quick elimination before expensive intersection math
if (bboxIntersect(line1.getBBox(), line2.getBBox())) {
    // Only then do precise intersection calculation
}

2. SVG Coordinate Extraction

function getLineFromElement(line) {
    return {
        x1: parseFloat(line.getAttribute('x1')),
        y1: parseFloat(line.getAttribute('y1')),
        x2: parseFloat(line.getAttribute('x2')),
        y2: parseFloat(line.getAttribute('y2'))
    };
}

3. Visual Line Splitting

function getLineSplitSegments(line, intersections) {
    // Creates visual gaps at intersection points
    // More efficient than creating separate path elements
    const segments = [];
    intersections.forEach(intersection => {
        // Add gap around intersection point
        const gapSize = 0.02; // 2% of line length
        // Split line into segments with gaps
    });
    return segments;
}

4. Efficient Intersection Algorithm

function lineIntersection(line1, line2) {
    // Parametric line intersection
    // Returns null for parallel lines (early exit)
    // Checks if intersection is within line segments
    // Returns intersection point with parameter values
}

Performance Features

Optimization Strategies:

1. Bounding Box Testing: Quick elimination of non-intersecting line pairs
2. SVG Native Coordinates: Direct attribute access without transformations
3. Parametric Intersection: Mathematical precision with early exits
4. Visual Effects: Line splitting and gap rendering
5. Real-time Updates: Efficient redraw strategies

Interactive Features:

• Draggable Endpoints: Move line endpoints to see live intersection updates
• Visual Splitting: Lines break at intersection points with dashed gaps
• Real-time Counting: Dynamic intersection count display
• Smooth Animation: Moving lines with continuous intersection detection

SVG-Specific Benefits:

• Direct Coordinate Access: getAttribute() for line positions
• Built-in Bounding Boxes: getBBox() for quick spatial queries
• Native Rendering: Hardware-accelerated line and circle drawing
• Event Integration: Mouse events directly on SVG elements

This system demonstrates how SVG’s built-in features can optimize geometric calculations and provide smooth interactive experiences!