From c7a91d914545da52a00534fe20c6379e59178340 Mon Sep 17 00:00:00 2001
From: Kaienss <Kaienss@hotmail.com>
Date: Fri, 1 Oct 2021 18:20:38 -0400
Subject: [PATCH] line chart shadow option

Added one option to dataset
shadowColor: similar to color, if not provided, shadow color for the dataset will be the same as the line color with useShadowColorFromDataset:true,
if useShadowColorFromDataset:false,
shadow color will be chartConfig.color.

shadow color is applied with following priority.
dataset.shadowColor -> dataset.color -> chartConfig.color
---
 src/HelperTypes.ts           |  3 +++
 src/line-chart/LineChart.tsx | 12 ++++++------
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/HelperTypes.ts b/src/HelperTypes.ts
index 6bec6e4d..dd480e0f 100644
--- a/src/HelperTypes.ts
+++ b/src/HelperTypes.ts
@@ -11,6 +11,9 @@ export interface Dataset {
   /** A function returning array of the colors of the stroke given an input opacity value for each data value. */
   colors?: Array<(opacity: number) => string>;
 
+  /** A function returning the color of the shadow given an input opacity value. */
+  shadowColor?:(opacity: number) => string;
+
   /** The width of the stroke. Defaults to 2. */
   strokeWidth?: number;
 
diff --git a/src/line-chart/LineChart.tsx b/src/line-chart/LineChart.tsx
index 3b7a5a90..9383dc9d 100644
--- a/src/line-chart/LineChart.tsx
+++ b/src/line-chart/LineChart.tsx
@@ -231,6 +231,10 @@ class LineChart extends AbstractChart<LineChartProps, LineChartState> {
     return (dataset.color || this.props.chartConfig.color)(opacity);
   };
 
+  getShadowColor = (dataset: Dataset, opacity: number) => {
+    return (dataset.shadowColor || dataset.color || this.props.chartConfig.color)(opacity);
+  };
+
   getStrokeWidth = (dataset: Dataset) => {
     return dataset.strokeWidth || this.props.chartConfig.strokeWidth || 3;
   };
@@ -584,9 +588,7 @@ class LineChart extends AbstractChart<LineChartProps, LineChartState> {
                 (dataset.data.length - 1)},${(height / 4) * 3 +
               paddingTop} ${paddingRight},${(height / 4) * 3 + paddingTop}`
           }
-          fill={`url(#fillShadowGradient${
-            useColorFromDataset ? `_${index}` : ""
-          })`}
+          fill={this.getShadowColor(dataset, 0.2)}
           strokeWidth={0}
         />
       );
@@ -761,9 +763,7 @@ class LineChart extends AbstractChart<LineChartProps, LineChartState> {
         <Path
           key={index}
           d={d}
-          fill={`url(#fillShadowGradient${
-            useColorFromDataset ? `_${index}` : ""
-          })`}
+          fill={this.getShadowColor(dataset, 0.2)}
           strokeWidth={0}
         />
       );