feat(ChartPath): implement chart background gradient

Author: ajimae

README.md

@@ -115,16 +115,21 @@ This component is used for showing the path itself.
 | `smoothingWhileTransitioningEnabled` | `number`   | `false`                | Although smoothing is not complex computing, it might impact performance in some low-end devices so while having a big set of data it might be worth disable smoothing while transitioning.   |
 | `height`                             | `number`   | obligatory             | Height od the SVG canvas    |
 | `width`                              | `number`   | obligatory             | Width od the SVG canvas    |
+| `stroke`                             | `string`   | `transparent`          | Color of the path.  |
 | `strokeWidth`                        | `number`   | `1`                    | Width of the path.  |
 | `selectedStrokeWidth`                | `number`   | `1`                    | Width of the path selected.  |
 | `gestureEnabled`                     | `boolean`  | `true`                 | Defines if interaction with the chart should be allowed or not  |
 | `longPressGestureHandlerProps`       | `object`   | `{maxDist: 100000, minDurationMs: 0, shouldCancelWhenOutside: false}`  | Under the hood we're using `LongPressGestureHandler` for handling interactions. It's recommended to not override its props. However, it might be useful while interacting with another GH. |
 | `selectedOpacity`                    | `number`   | `0.7`                  | Target opacity of the path while touching the chart.
-| `hitSlop`                         | `number`   | `0`                    |  While scrubbing the chart touching edges of the screen you may want make points on the edges more accessible. With `hitSlop` it's possible to access points on edges doubling the speed of scrubbing beyond this margin.  |
-| `hapticsEnabled`                      | `boolean`  | `false`                |  On pressing in/out on the chart it might be expected to make haptic feedback. It will happen with `hapticsEnabled` set to `true`.  |
-| `springConfig`                       | object     | `{damping: 15, mass: 1, stiffness: 600}`  | Object [defining the spring animation](https://docs.swmansion.com/react-native-reanimated/docs/next/animations). This spring is used for a dot's scale.
-| `timingFeedbackConfig`               | object     | `{duration: 80}`       | Object [defining the timing animation](https://docs.swmansion.com/react-native-reanimated/docs/next/animations). `timingFeedbackConfig` is used for a path's opacity and width.
-| `timingAnimationConfig`              | object     | `{duration: 300}`      | Object [defining the timing animation](https://docs.swmansion.com/react-native-reanimated/docs/next/animations). `timingAnimationConfig` is used for the transition between chart's data.
+| `hitSlop`                            | `number`   | `0`                    |  While scrubbing the chart touching edges of the screen you may want make points on the edges more accessible. With `hitSlop` it's possible to access points on edges doubling the speed of scrubbing beyond this margin.  |
+| `hapticsEnabled`                     | `boolean`  | `false`                |  On pressing in/out on the chart it might be expected to make haptic feedback. It will happen with `hapticsEnabled` set to `true`.  |
+| `springConfig`                       | object     | `{damping: 15, mass: 1, stiffness: 600}`  | Object [defining the spring animation](https://docs.swmansion.com/react-native-reanimated/docs/next/animations). This spring is used for a dot's scale. |
+| `timingFeedbackConfig`               | object     | `{duration: 80}`       | Object [defining the timing animation](https://docs.swmansion.com/react-native-reanimated/docs/next/animations). `timingFeedbackConfig` is used for a path's opacity and width. |
+| `timingAnimationConfig`              | object     | `{duration: 300}`      | Object [defining the timing animation](https://docs.swmansion.com/react-native-reanimated/docs/next/animations). `timingAnimationConfig` is used for the transition between chart's data. |
+| `gradientEnabled`                    | `boolean`  | `false`                | Specify if background gradient should be enabled for the path under the chart, if not provided it defaults to `false` |
+| `backgroundGradientFrom`             | `string`   | `stroke`               | Start color of the chart path background gradient, if a value is not provided for this prop, it defaults to the stroke color, and if no stroke color is specified, it defaults to `#000000` |
+| `backgroundGradientTo`               | `string`   | `#FFFFFF`              | Stop color of the chart path background gradient, if a value is not provided for this prop, it defaults to `#FFFFFF` |
+| `stopOpacity`                        | `number`   | `0`                    | Opacity of the path background gradient stop color. Defaults to `0` if not provided. |
 | ...rest                              | `object`   | `{}`                   | Props applied to SVG [Path](https://github.com/react-native-community/react-native-svg#path). |
 
 

gifs/gradient.png

@@ -17,7 +17,13 @@ import Animated, {
   withSpring,
   withTiming,
 } from 'react-native-reanimated';
-import { Path, Svg } from 'react-native-svg';
+import {
+  Path,
+  Svg,
+  Defs,
+  Stop,
+  LinearGradient
+} from 'react-native-svg';
 
 import ChartContext, {
   useGenerateValues as generateValues,
@@ -673,6 +679,16 @@ function ChartPath({
     return props;
   }, []);
 
+  const gradientAnimatedProps = useAnimatedStyle(() => {
+    const pathValue = path.value.replace('M', 'L');
+    const gradientD = pathValue.length > 0 ? `M 0,${height} C 0,0 0,0 0,0 ${pathValue} L ${width},${height}` : '';
+    const props = {
+      d: gradientD,
+
+    };
+    return props;
+  }, []);
+
   const animatedStyle = useAnimatedStyle(() => {
     return {
       opacity: pathOpacity.value * (1 - selectedOpacity) + selectedOpacity,
@@ -683,6 +699,7 @@ function ChartPath({
     <InternalContext.Provider
       value={{
         animatedProps,
+        gradientAnimatedProps,
         animatedStyle,
         gestureEnabled,
         height,
@@ -705,6 +722,7 @@ export function SvgComponent() {
     height,
     width,
     animatedProps,
+    gradientAnimatedProps,
     props,
     onLongPressGestureEvent,
     gestureEnabled,
@@ -725,6 +743,23 @@ export function SvgComponent() {
           viewBox={`0 0 ${width} ${height}`}
           width={width}
         >
+          <AnimatedPath
+            animatedProps={gradientAnimatedProps}
+            fill="url(#prefix__paint0_linear)"
+          />
+          {
+            props.gradientEnabled &&
+            <Defs>
+              <LinearGradient id="prefix__paint0_linear" x1="100%" y1="0%" x2="100%" y2="120%">
+                <Stop stopColor={props.backgroundGradientFrom ?? props.stroke} />
+                <Stop
+                  offset="100%"
+                  stopColor={props.backgroundGradientTo ?? '#FFFFFF'}
+                  stopOpacity={props.stopOpacity ?? 0}
+                />
+              </LinearGradient>
+            </Defs>
+          }
           <AnimatedPath
             animatedProps={animatedProps}
             {...props}