Allowed negative values for Line and Area charts

App.js

@@ -548,17 +548,6 @@ const App = () => {
       </View>
     );
   };
-  const barData = [
-    {
-      value: 15,
-      label: 'Mon',
-    },
-    {value: 30, label: 'Tue'},
-    {value: 26, label: 'Wed'},
-    {value: 40, label: 'Thu'},
-    {value: 16, label: 'Wed'},
-    {value: 40, label: 'Thu'},
-  ];
 
   const styleObject = {
     marginLeft: -95,
@@ -600,6 +589,18 @@ const App = () => {
     {value: 190},
   ]);
 
+  const barData = [
+    {
+      value: 15,
+      label: 'Mon',
+    },
+    {value: 30, label: 'Tue'},
+    {value: -23, label: 'Wed'},
+    {value: 40, label: 'Thu'},
+    {value: -16, label: 'Wed'},
+    {value: 40, label: 'Thu'},
+  ];
+
   return (
     <View
       style={{
@@ -607,8 +608,8 @@ const App = () => {
         // marginLeft: 46,
         marginLeft: 20,
       }}>
-      {/* <BarChart backgroundColor={'green'} data={barData} /> */}
+      <BarChart yAxisSide='right' width={260} scrollToEnd curved data={barData} />
-      <BarChart
+      {/* <BarChart
       // isAnimated={true}
       isThreeD={true}
         data={dtt}
@@ -634,7 +635,7 @@ const App = () => {
         // noOfSections={4}
         // innerCircleBorderColor={'gray'}
         // showTextBackground={true}
-      />
+      /> */}
       <TouchableOpacity
       onPress={()=>{dtt[1].value+=20;setDtt([...dtt])}}>
         <Text>Press me</Text>

docs/LineChart/LineChartProps.md

@@ -10,7 +10,9 @@
 | width                         | number         | Width of the Bar chart                                                                             | width of the parent |
 | height                        | number         | Height of the Bar chart (excluding the bottom label)                                               | 200                 |
 | maxValue                      | number         | Maximum value shown in the Y axis                                                                  | 200                 |
+| minValue | number | Minimum negative value shown in the Y axis (to be used only if the data set has negative values too) | \_ |
 | noOfSections                  | number         | Number of sections in the Y axis                                                                   | 10                  |
+| noOfSectionsBelowXAxis | number | Number of sections in the Y axis below X axis (in case the data set has negative values too) | 0 |
 | stepValue                     | number         | Value of 1 step/section in the Y axis                                                              | 20                  |
 | stepHeight                    | number         | Height of 1 step/section in the Y axis                                                             | 20                  |
 | spacing                       | number         | Distance between 2 consecutive bars in the Bar chart                                               | 20                  |

package.json

@@ -1,6 +1,6 @@
 {
   "name": "react-native-gifted-charts",
-  "version": "1.0.5",
+  "version": "1.0.6",
   "description": "The most complete library for Bar, Line, Area, Pie and Donut charts in React Native. Allows 2D, 3D, gradient, animations and live data updates.",
   "main": "src/index.tsx",
   "files": [

src/BarChart/index.tsx

@@ -235,7 +235,8 @@ export const BarChart = (props: PropTypes) => {
   const labelsExtraHeight = props.labelsExtraHeight || 0;
 
   let totalWidth = spacing;
-  let maxItem = 0, minItem = 0;
+  let maxItem = 0,
+    minItem = 0;
   if (props.stackData) {
     props.stackData.forEach(stackItem => {
       // console.log('stackItem', stackItem);
@@ -282,7 +283,7 @@ export const BarChart = (props: PropTypes) => {
   } else {
     maxItem = maxItem + (10 - (maxItem % 10));
     if (minItem !== 0) {
-      minItem = minItem - (10 + (minItem % 10))
+      minItem = minItem - (10 + (minItem % 10));
     }
   }
 
@@ -290,7 +291,8 @@ export const BarChart = (props: PropTypes) => {
   const minValue = props.minValue || minItem;
 
   const stepValue = props.stepValue || maxValue / noOfSections;
-  const noOfSectionsBelowXAxis = props.noOfSectionsBelowXAxis || (-minValue / stepValue);
+  const noOfSectionsBelowXAxis =
+    props.noOfSectionsBelowXAxis || -minValue / stepValue;
   const disableScroll = props.disableScroll || false;
   const showScrollIndicator = props.showScrollIndicator || false;
   const initialSpacing =
@@ -545,9 +547,10 @@ export const BarChart = (props: PropTypes) => {
       }
       horizSectionsBelow.push({
         value: props.yAxisLabelTexts
-        ? props.yAxisLabelTexts[noOfSectionsBelowXAxis - i] ?? value.toString()
+          ? props.yAxisLabelTexts[noOfSectionsBelowXAxis - i] ??
+            value.toString()
           : value.toString(),
-      })
+      });
     }
   }
 
@@ -602,7 +605,7 @@ export const BarChart = (props: PropTypes) => {
                     ? props.width || totalWidth
                     : props.width || totalWidth + 11,
                 },
-                yAxisSide === 'right' && {transform:[{rotateY:'180deg'}]}
+                yAxisSide === 'right' && {transform: [{rotateY: '180deg'}]},
               ]}>
               <View
                 style={[
@@ -628,13 +631,16 @@ export const BarChart = (props: PropTypes) => {
                     style={[
                       yAxisTextStyle,
                       index === noOfSections && {marginBottom: stepHeight / -2},
-                      horizontal ? {
+                      horizontal
+                        ? {
                             transform: [
                               {rotate: '270deg'},
                               {translateY: yAxisAtTop ? 0 : 50},
                             ],
-                      }:
+                          }
-                      yAxisSide === 'right' && {transform:[{rotateY:'180deg'}]}
+                        : yAxisSide === 'right' && {
+                            transform: [{rotateY: '180deg'}],
+                          },
                     ]}>
                     {label}
                   </Text>
@@ -745,7 +751,8 @@ export const BarChart = (props: PropTypes) => {
                     ? props.width || totalWidth
                     : props.width || totalWidth + 11,
                 },
-                index===0&&{marginTop:stepHeight/2}
+                yAxisSide === 'right' && {transform: [{rotateY: '180deg'}]},
+                index === 0 && {marginTop: stepHeight / 2},
               ]}>
               <View
                 style={[
@@ -762,7 +769,7 @@ export const BarChart = (props: PropTypes) => {
                     height: index === 0 ? stepHeight * 1.5 : stepHeight,
                     width: yAxisLabelWidth,
                   },
-                  index===0&&{marginTop:-stepHeight/2}
+                  index === 0 && {marginTop: -stepHeight / 2},
                 ]}>
                 {!hideYAxisText ? (
                   <Text
@@ -777,16 +784,16 @@ export const BarChart = (props: PropTypes) => {
                           {translateY: yAxisAtTop ? 0 : 50},
                         ],
                       },
+                      yAxisSide === 'right' && {
+                        transform: [{rotateY: '180deg'}],
+                      },
                     ]}>
                     {label}
                   </Text>
                 ) : null}
               </View>
               <View
-                style={[
+                style={[styles.leftPart, {backgroundColor: backgroundColor}]}>
-                   styles.leftPart,
-                   {backgroundColor: backgroundColor},
-                ]}>
                 {hideRules ? null : (
                   <Rule
                     config={{
@@ -803,7 +810,7 @@ export const BarChart = (props: PropTypes) => {
                 )}
               </View>
             </View>
-          )
+          );
         })}
       </>
     );
@@ -1116,7 +1123,8 @@ export const BarChart = (props: PropTypes) => {
         }}
         style={[
           {
-            marginLeft: yAxisSide === 'right' ? -yAxisLabelWidth+10 : yAxisLabelWidth,
+            marginLeft:
+              yAxisSide === 'right' ? -yAxisLabelWidth + 10 : yAxisLabelWidth,
             position: 'absolute',
             bottom: stepHeight * -0.5 - 60 + xAxisThickness,
           },
@@ -1127,9 +1135,11 @@ export const BarChart = (props: PropTypes) => {
         contentContainerStyle={[
           {
             // backgroundColor: 'yellow',
-            height: containerHeight + 130 + horizSectionsBelow.length * stepHeight,
+            height:
+              containerHeight + 130 + horizSectionsBelow.length * stepHeight,
             paddingLeft: initialSpacing,
-            paddingBottom:horizSectionsBelow.length * stepHeight + labelsExtraHeight,
+            paddingBottom:
+              horizSectionsBelow.length * stepHeight + labelsExtraHeight,
             alignItems: 'flex-end',
           },
           !props.width && {width: totalWidth},

src/LineChart/index.tsx

@@ -33,6 +33,7 @@ type propTypes = {
   height?: number;
   noOfSections?: number;
   maxValue?: number;
+  minValue?: number;
   stepHeight?: number;
   stepValue?: number;
   spacing?: number;
@@ -192,6 +193,7 @@ type propTypes = {
   yAxisLabelSuffix?: String;
   scrollToEnd?: Boolean;
   scrollAnimation?: Boolean;
+  noOfSectionsBelowXAxis?: number;
 };
 type referenceConfigType = {
   thickness: number;
@@ -280,7 +282,6 @@ export const LineChart = (props: propTypes) => {
   const yAxisLabelSuffix = props.yAxisLabelSuffix || '';
   const yAxisSide = props.yAxisSide || 'left';
 
-
   if (!initialData) {
     initialData = [...data];
     animations = initialData.map(item => new Animated.Value(item.value));
@@ -456,15 +457,39 @@ export const LineChart = (props: propTypes) => {
   const xAxisColor = props.xAxisColor || 'black';
 
   let totalWidth = initialSpacing;
-  let maxItem = 0;
+  let maxItem = 0,
+    minItem = 0;
   data.forEach((item: itemType) => {
     if (item.value > maxItem) {
       maxItem = item.value;
     }
+    if (item.value < minItem) {
+      minItem = item.value;
+    }
     totalWidth += spacing;
   });
 
-  const maxValue = props.maxValue || maxItem || 10;
+  if (props.showFractionalValues || props.roundToDigits) {
+    maxItem *= 10 * (props.roundToDigits || 1);
+    maxItem = maxItem + (10 - (maxItem % 10));
+    maxItem /= 10 * (props.roundToDigits || 1);
+    maxItem = parseFloat(maxItem.toFixed(props.roundToDigits || 1));
+
+    if (minItem !== 0) {
+      minItem *= 10 * (props.roundToDigits || 1);
+      minItem = minItem - (10 + (minItem % 10));
+      minItem /= 10 * (props.roundToDigits || 1);
+      minItem = parseFloat(minItem.toFixed(props.roundToDigits || 1));
+    }
+  } else {
+    maxItem = maxItem + (10 - (maxItem % 10));
+    if (minItem !== 0) {
+      minItem = minItem - (10 + (minItem % 10));
+    }
+  }
+
+  const maxValue = props.maxValue || maxItem;
+  const minValue = props.minValue || minItem;
 
   useEffect(() => {
     // console.log('comes here............')
@@ -767,18 +792,12 @@ export const LineChart = (props: propTypes) => {
     xAxisThickness,
   ]);
 
-  if (props.showFractionalValues || props.roundToDigits) {
-    maxItem *= 10 * (props.roundToDigits || 1);
-    maxItem = maxItem + (10 - (maxItem % 10));
-    maxItem /= 10 * (props.roundToDigits || 1);
-    maxItem = parseFloat(maxItem.toFixed(props.roundToDigits || 1));
-  } else {
-    maxItem = maxItem + (10 - (maxItem % 10));
-  }
-
   const horizSections = [{value: '0'}];
+  const horizSectionsBelow = [];
   const stepHeight = props.stepHeight || containerHeight / noOfSections;
   const stepValue = props.stepValue || maxValue / noOfSections;
+  const noOfSectionsBelowXAxis =
+    props.noOfSectionsBelowXAxis || -minValue / stepValue;
   const thickness1 = props.thickness1;
   const thickness2 = props.thickness2;
   const thickness3 = props.thickness3;
@@ -939,6 +958,20 @@ export const LineChart = (props: propTypes) => {
         : value.toString(),
     });
   }
+  if (noOfSectionsBelowXAxis) {
+    for (let i = 1; i <= noOfSectionsBelowXAxis; i++) {
+      let value = stepValue * -i;
+      if (props.showFractionalValues || props.roundToDigits) {
+        value = parseFloat(value.toFixed(props.roundToDigits || 1));
+      }
+      horizSectionsBelow.push({
+        value: props.yAxisLabelTexts
+          ? props.yAxisLabelTexts[noOfSectionsBelowXAxis - i] ??
+            value.toString()
+          : value.toString(),
+      });
+    }
+  }
 
   const renderLabel = (
     index: number,
@@ -1078,7 +1111,7 @@ export const LineChart = (props: propTypes) => {
                   {
                     width: (props.width ? props.width : totalWidth) + 15,
                   },
-                  yAxisSide === 'right' && {transform:[{rotateY:'180deg'}]}
+                  yAxisSide === 'right' && {transform: [{rotateY: '180deg'}]},
                 ]}>
                 <View
                   style={[
@@ -1095,7 +1128,9 @@ export const LineChart = (props: propTypes) => {
                       ellipsizeMode={'clip'}
                       style={[
                         yAxisTextStyle,
-                        yAxisSide === 'right' && {transform:[{rotateY:'180deg'}]},
+                        yAxisSide === 'right' && {
+                          transform: [{rotateY: '180deg'}],
+                        },
                         index === noOfSections && {
                           marginBottom: stepHeight / -2,
                         },
@@ -1190,6 +1225,70 @@ export const LineChart = (props: propTypes) => {
               </View>
             );
           })}
+
+        {horizSectionsBelow.map((sectionItems, index) => {
+          let label = getLabel(sectionItems.value);
+          if (hideOrigin && index === horizSections.length - 1) {
+            label = '';
+          }
+          return (
+            <View
+              key={index}
+              style={[
+                styles.horizBar,
+                {
+                  width: (props.width ? props.width : totalWidth) + 15,
+                },
+                index === 0 && {marginTop: stepHeight / 2},
+                yAxisSide === 'right' && {transform: [{rotateY: '180deg'}]},
+              ]}>
+              <View
+                style={[
+                  styles.leftLabel,
+                  {
+                    borderRightWidth: yAxisThickness,
+                    borderColor: yAxisColor,
+                    marginLeft: 1,
+                  },
+                  {
+                    height: index === 0 ? stepHeight * 1.5 : stepHeight,
+                    width: yAxisLabelWidth,
+                  },
+                  index === 0 && {marginTop: -stepHeight / 2},
+                ]}>
+                {!hideYAxisText ? (
+                  <Text
+                    numberOfLines={1}
+                    ellipsizeMode={'clip'}
+                    style={[
+                      yAxisTextStyle,
+                      index === 0 && {marginBottom: stepHeight / -2},
+                      yAxisSide === 'right' && {
+                        transform: [{rotateY: '180deg'}],
+                      },
+                    ]}>
+                    {label}
+                  </Text>
+                ) : null}
+              </View>
+              <View
+                style={[styles.leftPart, {backgroundColor: backgroundColor}]}>
+                {hideRules ? null : (
+                  <Rule
+                    config={{
+                      thickness: rulesThickness,
+                      color: rulesColor,
+                      width: (props.width || totalWidth) + 11,
+                      dashWidth: dashWidth,
+                      dashGap: dashGap,
+                      type: rulesType,
+                    }}
+                  />
+                )}
+              </View>
+            </View>
+          );
+        })}
       </>
     );
   };
@@ -1481,11 +1580,11 @@ export const LineChart = (props: propTypes) => {
       <View
         style={{
           position: 'absolute',
-          height: containerHeight + 10,
+          height: containerHeight + 10 + horizSectionsBelow.length * stepHeight,
           bottom: 60, //stepHeight * -0.5 + xAxisThickness,
           width: totalWidth,
           zIndex: -1,
-          // backgroundColor: 'rgba(200,150,150,0.1)'
+          // backgroundColor: 'rgba(200,150,150,0.6)'
         }}>
         <Svg>
           <Path
@@ -1587,7 +1686,7 @@ export const LineChart = (props: propTypes) => {
       <Animated.View
         style={{
           position: 'absolute',
-          height: containerHeight + 10,
+          height: containerHeight + 10 + horizSectionsBelow.length * stepHeight,
           bottom: 60, //stepHeight * -0.5 + xAxisThickness,
           width: animatedWidth,
           zIndex: -1,
@@ -1678,16 +1777,25 @@ export const LineChart = (props: propTypes) => {
     );
   };
 
+  console.log('horizSectionsBelow -- >', horizSectionsBelow);
+
   return (
-    <View style={[styles.container, {height: containerHeight}, yAxisSide === 'right' && {marginLeft: yAxisLabelWidth + yAxisThickness }]}>
+    <View
+      style={[
+        styles.container,
+        {height: containerHeight + horizSectionsBelow.length * stepHeight},
+        yAxisSide === 'right' && {marginLeft: yAxisLabelWidth + yAxisThickness},
+      ]}>
       {props.hideAxesAndRules !== true && renderHorizSections()}
       {/* {sectionsOverlay()} */}
       <ScrollView
         horizontal
         contentContainerStyle={[
           {
-            height: containerHeight + 130,
+            height:
+              containerHeight + 130 + horizSectionsBelow.length * stepHeight,
             width: totalWidth - 20,
+            paddingBottom: horizSectionsBelow.length * stepHeight,
             // backgroundColor: 'yellow'
           },
           !props.width && {width: totalWidth - 20},
@@ -1702,7 +1810,10 @@ export const LineChart = (props: propTypes) => {
         showsHorizontalScrollIndicator={showScrollIndicator}
         style={[
           {
-            marginLeft: yAxisSide === 'right' ? -yAxisLabelWidth - yAxisThickness + 6 : yAxisLabelWidth + yAxisThickness,
+            marginLeft:
+              yAxisSide === 'right'
+                ? -yAxisLabelWidth - yAxisThickness + 6
+                : yAxisLabelWidth + yAxisThickness,
             position: 'absolute',
             bottom: stepHeight * -0.5 - 60, //stepHeight * -0.5 + xAxisThickness,
             paddingRight: 100,