Support defining axis color on slide

Author: ErikBernskiold

src/Components/ChartShape.php

@@ -75,6 +75,10 @@ public function render(): static
             $this->backgroundColor = $this->slide->chartBackgroundColor;
         }
 
+        if($this->slide->chartAxisColor) {
+            $this->axisColor = $this->slide->chartAxisColor;
+        }
+
         if (! empty($this->backgroundColor)) {
             $this->shape->getFill()
                 ->setFillType(Fill::FILL_SOLID)

src/Concerns/Slides/WithChartBackground.php

@@ -6,10 +6,19 @@ trait WithChartBackground
 {
     public ?string $chartBackgroundColor = null;
 
+    public ?string $chartAxisColor = null;
+
     public function chartBackgroundColor(?string $argb): static
     {
         $this->chartBackgroundColor = $argb;
 
         return $this;
     }
+
+    public function chartAxisColor(?string $argb): static
+    {
+        $this->chartAxisColor = $argb;
+
+        return $this;
+    }
 }