Add gradient

src/Degree.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace Zoomyboy\Gradient;
+
+class Degree
+{
+    public function __construct(public int $value)
+    {
+    }
+
+    public static function from(int $degree): self
+    {
+        if ($degree >= 0 && $degree <= 360) {
+            return new self($degree);
+        }
+
+        throw Exception('Degree must be between 0 and 360');
+    }
+}

src/GradientImage.php

@@ -0,0 +1,50 @@
+<?php
+
+namespace Zoomyboy\Gradient;
+
+use GdImage;
+
+class GradientImage
+{
+    public function generate(int $image_width, int $image_height, string $from, string $to, Degree $degree, Prop $prop = Prop::LINEAR): void
+    {
+        $from = $this->toRgb($from);
+        $to = $this->toRgb($to);
+
+        $image = imagecreatetruecolor($image_width, $image_height);
+        $image = $this->makeGradient($image, $from, $to, $prop->calculatorCallback());
+        $image = imagerotate($image, 360 - $degree->value, 0);
+
+        imagepng($image, 'image.png');
+        imagedestroy($image);
+    }
+
+    public function toRgb(string $hexColor): RgbColor
+    {
+        $hexColor = substr($hexColor, 1);
+
+        $colors = collect(str_split($hexColor, 2))
+            ->map(fn ($hex) => hexdec($hex))
+            ->toArray();
+
+        return new RgbColor(...$colors);
+    }
+
+    private function makeGradient(GdImage $image, RgbColor $from, RgbColor $to, callable $calculator): GdImage
+    {
+        $image_width = imagesx($image);
+        $image_height = imagesy($image);
+
+        for ($i = 0; $i < $image_height; ++$i) {
+            $percent = $calculator($i, $image_height);
+            $color_r = (int) floor(($from->r - $to->r) * $percent) + $to->r;
+            $color_g = (int) floor(($from->g - $to->g) * $percent) + $to->g;
+            $color_b = (int) floor(($from->b - $to->b) * $percent) + $to->b;
+
+            $color = imagecolorallocate($image, $color_r, $color_g, $color_b);
+            imageline($image, 0, $i, $image_width, $i, $color);
+        }
+
+        return $image;
+    }
+}

src/Prop.php

@@ -0,0 +1,17 @@
+<?php
+
+namespace Zoomyboy\Gradient;
+
+enum Prop
+{
+    case LINEAR;
+    case WAVE;
+
+    public function calculatorCallback(): callable
+    {
+        return match ($this) {
+            static::LINEAR => fn ($i, $height) => $i / $height,
+            static::WAVE => fn ($i, $height) => abs(($i / $height) - 0.5),
+        };
+    }
+}

src/RgbColor.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace Zoomyboy\Gradient;
+
+class RgbColor
+{
+    public function __construct(public int $r, public int $g, public int $b)
+    {
+    }
+}