feat: Add the ability to add a line at the zero point

library/src/main/java/com/dzeio/charts/axis/YAxis.kt

@@ -40,7 +40,7 @@ class YAxis(
     private var min: Float? = 0f
     private var max: Float? = null
 
-    var drawZeroLine: Boolean = true
+    override var drawZeroLine: Boolean = true
 
     override var scrollEnabled: Boolean = false
 
@@ -99,11 +99,10 @@ class YAxis(
 
         val min = getYMin()
         val max = getYMax() - min
-        val top = space.top
         val bottom = space.bottom
         var maxWidth = 0f
 
-        val increment = (bottom - top) / labelCount
+        val increment = space.height() / labelCount
         val valueIncrement = max / labelCount
         for (index in 0 until labelCount) {
             val text = onValueFormat(min + (valueIncrement * (index + 1)))
@@ -135,6 +134,11 @@ class YAxis(
             )
         }
 
+        if (this.drawZeroLine) {
+            val pos = ((1 - -min / (getYMax() - min)) * space.height() + space.top)
+            canvas.drawLine(0f, pos, space.right - maxWidth - 32f, pos, linePaint)
+        }
+
         return maxWidth + 32f
     }
 

library/src/main/java/com/dzeio/charts/axis/YAxisInterface.kt

@@ -38,6 +38,11 @@ sealed interface YAxisInterface {
      */
     var scrollEnabled: Boolean
 
+    /**
+     * do the Zero line gets drawn?
+     */
+    var drawZeroLine: Boolean
+
     /**
      * run when manually refreshing the system
      *