> ## Documentation Index
> Fetch the complete documentation index at: https://laravel-qrcode.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Color Methods — RGB, CMYK, Gradients & Grayscale

> Set foreground and background colors in RGB or CMYK mode, apply grayscale tones, and add directional gradients to your Laravel QR codes.

The package supports three color models — RGB (default), CMYK, and grayscale. Switch between them at any point in the builder chain. Every method returns a **cloned** `Generator` so previous state is never mutated.

<Note>
  Alpha values throughout this package use a **0–100 scale** (0 = fully opaque,
  100 = fully transparent). The package converts this internally to the range
  PHP's GD library expects (0–127). You do not need to perform this conversion
  yourself.
</Note>

***

## color()

```php theme={null}
public function color(int $c1, int $c2, int $c3, ?int $c4 = null): static
```

Set the foreground (module) color. The meaning of each channel depends on the active color model.

<ParamField body="c1" type="int" required>
  **RGB mode:** Red channel, 0–255. **CMYK mode:** Cyan channel, 0–100.
</ParamField>

<ParamField body="c2" type="int" required>
  **RGB mode:** Green channel, 0–255. **CMYK mode:** Magenta channel, 0–100.
</ParamField>

<ParamField body="c3" type="int" required>
  **RGB mode:** Blue channel, 0–255. **CMYK mode:** Yellow channel, 0–100.
</ParamField>

<ParamField body="c4" type="int | null">
  **RGB mode:** Alpha channel, 0–100 (0 = fully opaque). **CMYK mode:** Black
  (Key) channel, 0–100. Omit for a fully opaque foreground.
</ParamField>

<CodeGroup>
  ```php RGB foreground theme={null}
  QrCode::color(220, 38, 38)           // solid red
      ->generate('https://example.com');
  ```

  ```php RGB with alpha theme={null}
  QrCode::color(220, 38, 38, 20)       // red at 80% opacity
      ->generate('https://example.com');
  ```

  ```php CMYK foreground theme={null}
  QrCode::cmyk()
      ->color(0, 100, 100, 0)          // CMYK red
      ->generate('https://example.com');
  ```
</CodeGroup>

***

## backgroundColor()

```php theme={null}
public function backgroundColor(int $c1, int $c2, int $c3, ?int $c4 = null): static
```

Set the background color. Accepts the same channel layout as `color()` and respects the active color model.

<ParamField body="c1" type="int" required>
  **RGB mode:** Red, 0–255. **CMYK mode:** Cyan, 0–100.
</ParamField>

<ParamField body="c2" type="int" required>
  **RGB mode:** Green, 0–255. **CMYK mode:** Magenta, 0–100.
</ParamField>

<ParamField body="c3" type="int" required>
  **RGB mode:** Blue, 0–255. **CMYK mode:** Yellow, 0–100.
</ParamField>

<ParamField body="c4" type="int | null">
  **RGB mode:** Alpha, 0–100. **CMYK mode:** Black, 0–100. Omit for a fully
  opaque background.
</ParamField>

<CodeGroup>
  ```php White background (explicit) theme={null}
  QrCode::color(0, 0, 0)
      ->backgroundColor(255, 255, 255)
      ->generate('https://example.com');
  ```

  ```php Transparent background (PNG) theme={null}
  QrCode::format('png')
      ->color(0, 0, 0)
      ->backgroundColor(255, 255, 255, 100) // fully transparent
      ->generate('https://example.com');
  ```
</CodeGroup>

***

## rgb()

```php theme={null}
public function rgb(): static
```

Switch the active color model to **RGB**. This is the default mode — call it explicitly only when you need to revert from CMYK in a chain.

Each channel uses a 0–255 scale. Alpha uses a 0–100 scale.

```php theme={null}
QrCode::rgb()
    ->color(59, 130, 246)
    ->generate('https://example.com');
```

***

## cmyk()

```php theme={null}
public function cmyk(): static
```

Switch the active color model to **CMYK**. All subsequent calls to `color()` and `backgroundColor()` interpret channel values on a **0–100** scale (percentage).

<Warning>
  Gradients (`gradient()`) are only available in RGB mode. Calling `gradient()`
  while in CMYK mode will produce unexpected results. Switch back to `rgb()`
  before using gradients.
</Warning>

```php theme={null}
QrCode::size(300)
    ->cmyk()
    ->color(100, 50, 0, 10)          // deep blue in CMYK
    ->backgroundColor(0, 0, 0, 0)   // white background in CMYK
    ->generate('https://example.com');
```

***

## gray()

```php theme={null}
public function gray(int $gray, ?int $backgroundGray = null): static
```

Switch to **grayscale** mode and set both foreground and background tones in a single call. Internally this sets the color model to `GRAY`.

<ParamField body="gray" type="int" required>
  Foreground luminance: `0` = black, `100` = white.
</ParamField>

<ParamField body="backgroundGray" type="int | null">
  Background luminance on the same 0–100 scale. When `null`, the background
  defaults to white (`100`).
</ParamField>

<CodeGroup>
  ```php Black on white (default grayscale) theme={null}
  QrCode::gray(0)->generate('https://example.com');
  ```

  ```php Dark gray on light gray theme={null}
  QrCode::gray(20, 90)->generate('https://example.com');
  ```
</CodeGroup>

***

## gradient()

```php theme={null}
public function gradient(string|array $start, string|array $end, string|GradientType $type = GradientType::VERTICAL): static
```

Apply a two-stop color gradient to the QR code modules. Gradient operates in **RGB mode only**.

<ParamField body="start" type="string | array" required>
  The gradient start color. Pass a hex string (e.g. `'#3b82f6'`) or an RGB array
  (e.g. `[59, 130, 246]`).
</ParamField>

<ParamField body="end" type="string | array" required>
  The gradient end color. Accepts the same formats as `start`.
</ParamField>

<ParamField body="type" type="string" required>
  The gradient direction. Accepted values:

  | Value              | Description                       |
  | ------------------ | --------------------------------- |
  | `vertical`         | Top-to-bottom (default)           |
  | `horizontal`       | Left-to-right                     |
  | `diagonal`         | Top-left to bottom-right          |
  | `inverse_diagonal` | Top-right to bottom-left          |
  | `radial`           | Radiating from the centre outward |
</ParamField>

<Note>
  `gradient()` takes color values directly rather than using whatever was set by
  a prior `color()` call. The gradient replaces the foreground color entirely.
</Note>

<CodeGroup>
  ```php Vertical gradient (hex strings) theme={null}
  QrCode::size(300)
      ->gradient('#3b82f6', '#8b5cf6', 'vertical')
      ->generate('https://example.com');
  ```

  ```php Horizontal gradient (RGB arrays) theme={null}
  QrCode::size(300)
      ->gradient([59, 130, 246], [139, 92, 246], 'horizontal')
      ->generate('https://example.com');
  ```

  ```php Radial gradient theme={null}
  QrCode::size(350)
      ->gradient('#f59e0b', '#ef4444', 'radial')
      ->generate('https://example.com');
  ```

  ```php Diagonal gradient with white background theme={null}
  QrCode::size(300)
      ->backgroundColor(255, 255, 255)
      ->gradient([0, 200, 100], [0, 50, 200], 'diagonal')
      ->generate('https://example.com');
  ```
</CodeGroup>

***

## Color model comparison

```php theme={null}
use Linkxtr\QrCode\Facades\QrCode;

// Default RGB — channels 0-255, optional alpha 0-100
$rgb = QrCode::color(30, 64, 175)
    ->backgroundColor(239, 246, 255)
    ->generate('https://example.com');

// CMYK — channels 0-100 (percentage)
$cmyk = QrCode::cmyk()
    ->color(83, 64, 0, 31)           // dark blue in CMYK
    ->backgroundColor(0, 0, 0, 0)
    ->generate('https://example.com');

// Grayscale — luminance 0-100
$gray = QrCode::gray(10, 95)->generate('https://example.com');

// Gradient (RGB only)
$gradient = QrCode::gradient('#1e40af', '#7c3aed', 'vertical')
    ->generate('https://example.com');
```