Intervention/image · error · InvalidArgumentException

You must specify either 3 or 4 points to create a bezier cur

Error message

You must specify either 3 or 4 points to create a bezier curve

What it means

The GD driver's bezier implementation only supports quadratic curves (exactly 3 control points) and cubic curves (exactly 4 control points). apply() runs validatePointCount() before anything is drawn and throws InvalidArgumentException for any other point count. This is pure API input validation - the image is untouched when it fires.

Source

Thrown at src/Drivers/Gd/Modifiers/DrawBezierModifier.php:62

            if ($this->drawable->hasBorder() && $this->drawable->borderSize() > 0) {
                $borderColor = $this->driver()->colorProcessor($image)->export($this->borderColor());
                $this->drawBezierBorder($frame->native(), $polygon, $polygonBorderSegments, $borderColor);
            }
        }

        return $image;
    }

    /**
     * Validate that the drawable has exactly 3 or 4 points.
     *
     * @throws InvalidArgumentException
     */
    private function validatePointCount(): void
    {
        if ($this->drawable->count() !== 3 && $this->drawable->count() !== 4) {
            throw new InvalidArgumentException('You must specify either 3 or 4 points to create a bezier curve');
        }
    }

    /**
     * Draw the bezier polygon with the background color.
     *
     * @param array<mixed> $polygon
     * @throws ModifierException
     */
    private function drawBezierBackground(GdImage $canvas, array $polygon, int $color): void
    {
        imagesetthickness($canvas, 0);
        $this->abortUnless(imagefilledpolygon($canvas, $polygon, $color), 'Unable to draw bezier background');
    }

    /**
     * Draw the bezier border, using thin lines for size 1 or filled polygon segments otherwise
     *

View on GitHub (pinned to 5598b9e397)

Solutions

1. Provide exactly 3 points (quadratic) or exactly 4 points (cubic)
2. Split longer paths into several drawBezier() calls of 3 or 4 points each
3. Use drawPolygon() or drawLine() for arbitrary point chains
4. Check $bezier->count() before calling $image->drawBezier($bezier)

Example fix

// before: two points do not define a curve
$image->drawBezier(fn($b) => $b->point(0, 100)->point(100, 100));

// after: three points define a quadratic bezier
$image->drawBezier(fn($b) => $b
    ->point(0, 100)
    ->point(50, 0)
    ->point(100, 100));

use Intervention\Image\Geometry\Bezier;
use Intervention\Image\Geometry\Point;

$bezier = new Bezier();
$bezier->addPoint(new Point(0, 100));
$bezier->addPoint(new Point(50, 0));
$bezier->addPoint(new Point(100, 100));

if (!in_array($bezier->count(), [3, 4], true)) {
    throw new InvalidArgumentException(
        'Bezier needs exactly 3 or 4 points, got ' . $bezier->count()
    );
}

$image->drawBezier($bezier);

use Intervention\Image\Geometry\Bezier;

function isDrawableBezier(Bezier $bezier): bool
{
    return in_array($bezier->count(), [3, 4], true);
}

use Intervention\Image\Exceptions\InvalidArgumentException;

try {
    $image->drawBezier($bezier);
} catch (InvalidArgumentException $e) {
    // fix the point list, or draw a polygon with the same points instead
    $image->drawPolygon($bezier);
}

When it happens

Trigger: $image->drawBezier() with a closure or Bezier object holding 2 points or 5+ points; data-driven point lists whose length varies at runtime; loops that accidentally append the starting point again as an end point; passing a Bezier built for a different shape.

Common situations: Converting SVG path data or design-tool exports to drawing code; generating diagrams from variable-length coordinate arrays; assuming drawBezier() accepts arbitrary point chains like drawPolygon().

Related errors

• The specified position ({x}, {y}) is not within the image ar
• Invalid image size
• GD driver can only decode colors in integer or array format
• GD driver can only decode array color format array{red: int,
• Unable to decode binary data from empty string

AI-assisted analysis of Intervention/image@5598b9e397 (2026-08-23). Data as JSON: /api/errors/67ecf1a1b7c7c346. Report an issue: GitHub.