Fixing YAxis format on zoom

Author: brett-estabrook

Sources/Microcharts/Charts/AxisBasedChart.cs

@@ -198,8 +198,9 @@ public override void DrawContent(SKCanvas canvas, int width, int height)
                 float minValue = InternalMinValue.HasValue ? InternalMinValue.Value : MinValue;
 
                 //This function might change the min/max value
+                string yAxisFormat = XForm.Scale == 1.0f ? "G" : "F1";
                 int yMaxTicks = (int)(YAxisMaxTicks * XForm.Scale);
-                var yAxisSize = MeasureHelper.CalculateYAxis(ShowYAxisText, ShowYAxisLines, entries, yMaxTicks, YAxisTextPaint, YAxisPosition, width, fixedRange, ref maxValue, ref minValue, out float yAxisXShift, out List<float> yAxisIntervalLabels);
+                var yAxisSize = MeasureHelper.CalculateYAxis(ShowYAxisText, ShowYAxisLines, yAxisFormat, yMaxTicks, YAxisTextPaint, YAxisPosition, width, fixedRange, ref maxValue, ref minValue, out float yAxisXShift, out List<float> yAxisIntervalLabels);
                 width = (int)yAxisSize.Width;
 
                 float valRange = maxValue - minValue;
@@ -250,7 +251,7 @@ public override void DrawContent(SKCanvas canvas, int width, int height)
 
                 canvas.Save();
                 if(EnableZoom) canvas.ClipRect(yAxisRect);
-                DrawHelper.DrawYAxis(ShowYAxisText, ShowYAxisLines, YAxisPosition, YAxisTextPaint, YAxisLinesPaint, XForm.Offset, XForm.Scale, Margin, AnimationProgress, maxValue, valRange, canvas, width, yAxisXShift, yAxisIntervalLabels, headerHeight, itemSize, origin);
+                DrawHelper.DrawYAxis(ShowYAxisText, ShowYAxisLines, yAxisFormat, YAxisPosition, YAxisTextPaint, YAxisLinesPaint, XForm.Offset, XForm.Scale, Margin, AnimationProgress, maxValue, valRange, canvas, width, yAxisXShift, yAxisIntervalLabels, headerHeight, itemSize, origin);
                 canvas.Restore();
 
 

Sources/Microcharts/Charts/Legacy/LegacyPointChart.cs

@@ -130,8 +130,9 @@ public override void DrawContent(SKCanvas canvas, int width, int height)
             {
                 float maxValue = MaxValue;
                 float minValue = MinValue;
-                var yAxisRect = MeasureHelper.CalculateYAxis(ShowYAxisText, ShowYAxisLines, Entries, YAxisMaxTicks, YAxisTextPaint, YAxisPosition, width, false, ref maxValue, ref minValue, out float yAxisXShift, out List<float> yAxisIntervalLabels);
-                width = (int)yAxisRect.Width;
+                string yAxisFormat = "G";
+                var yAxisSize = MeasureHelper.CalculateYAxis(ShowYAxisText, ShowYAxisLines, yAxisFormat, YAxisMaxTicks, YAxisTextPaint, YAxisPosition, width, false, ref maxValue, ref minValue, out float yAxisXShift, out List<float> yAxisIntervalLabels);
+                width = (int)yAxisSize.Width;
 
                 var labels = Entries.Select(x => x.Label).ToArray();
                 var labelSizes = MeasureHelper.MeasureTexts(labels, LabelTextSize);
@@ -144,7 +145,7 @@ public override void DrawContent(SKCanvas canvas, int width, int height)
                 var itemSize = CalculateItemSize(width, height, footerHeight, headerHeight);
                 var origin = CalculateYOrigin(itemSize.Height, headerHeight);
                 var points = CalculatePoints(itemSize, origin, headerHeight, yAxisXShift);
-                DrawHelper.DrawYAxis(ShowYAxisText, ShowYAxisLines, YAxisPosition, YAxisTextPaint, YAxisLinesPaint, new SKPoint(0,0), 1.0f, Margin, AnimationProgress, MaxValue, ValueRange, canvas, width, yAxisXShift, yAxisIntervalLabels, headerHeight, itemSize, origin);
+                DrawHelper.DrawYAxis(ShowYAxisText, ShowYAxisLines, yAxisFormat, YAxisPosition, YAxisTextPaint, YAxisLinesPaint, new SKPoint(0,0), 1.0f, Margin, AnimationProgress, MaxValue, ValueRange, canvas, width, yAxisXShift, yAxisIntervalLabels, headerHeight, itemSize, origin);
 
                 DrawAreas(canvas, points, itemSize, origin, headerHeight);
                 DrawPoints(canvas, points);

Sources/Microcharts/Helpers/DrawHelper.cs

@@ -92,15 +92,15 @@ internal static void DrawLabel(SKCanvas canvas, Orientation orientation, YPositi
             }
         }
 
-        internal static void DrawYAxis(bool showYAxisText, bool showYAxisLines, Position yAxisPosition, SKPaint yAxisTextPaint, SKPaint yAxisLinesPaint, SKPoint offset, float scale, float margin, float animationProgress, float maxValue, float valueRange, SKCanvas canvas, int width, float yAxisXShift, List<float> yAxisIntervalLabels, float headerHeight, SKSize itemSize, float origin)
+        internal static void DrawYAxis(bool showYAxisText, bool showYAxisLines, string yAxisFormat, Position yAxisPosition, SKPaint yAxisTextPaint, SKPaint yAxisLinesPaint, SKPoint offset, float scale, float margin, float animationProgress, float maxValue, float valueRange, SKCanvas canvas, int width, float yAxisXShift, List<float> yAxisIntervalLabels, float headerHeight, SKSize itemSize, float origin)
         {
             if (showYAxisText || showYAxisLines)
             {
                 int cnt = 0;
                 var intervals = yAxisIntervalLabels
                     .Select(t => new ValueTuple<string, SKPoint>
                     (
-                        t.ToString(),
+                        t.ToString(yAxisFormat),
                         new SKPoint(yAxisPosition == Position.Left ? yAxisXShift : width, offset.Y+(scale * MeasureHelper.CalculatePoint(margin, animationProgress, maxValue, valueRange, t, cnt++, itemSize, origin, headerHeight).Y))
                     ))
                     .ToList();

Sources/Microcharts/Helpers/MeasureHelper.cs

@@ -68,7 +68,7 @@ internal static float CalculateFooterHeaderHeight(float margin, float textSize,
             return result;
         }
 
-        internal static SKSize CalculateYAxis(bool showYAxisText, bool showYAxisLines, IEnumerable<ChartEntry> entries, int yAxisMaxTicks, SKPaint yAxisTextPaint, Position yAxisPosition, int width, bool fixedRange, ref float maxValue, ref float minValue, out float yAxisXShift, out List<float> yAxisIntervalLabels)
+        internal static SKSize CalculateYAxis(bool showYAxisText, bool showYAxisLines, string yAxisFormat, int yAxisMaxTicks, SKPaint yAxisTextPaint, Position yAxisPosition, int width, bool fixedRange, ref float maxValue, ref float minValue, out float yAxisXShift, out List<float> yAxisIntervalLabels)
         {
             float height = 0;
             yAxisXShift = 0.0f;
@@ -106,7 +106,7 @@ internal static SKSize CalculateYAxis(bool showYAxisText, bool showYAxisLines, I
                     .Select(i => (float)(niceMax - (i * tickSpacing)))
                     .ToList();
 
-                var longestYAxisLabel = yAxisIntervalLabels.Aggregate(string.Empty, (max, cur) => max.Length > cur.ToString().Length ? max : cur.ToString());
+                var longestYAxisLabel = yAxisIntervalLabels.Aggregate(string.Empty, (max, cur) => max.Length > cur.ToString(yAxisFormat).Length ? max : cur.ToString(yAxisFormat));
                 var longestYAxisLabelRect = MeasureHelper.MeasureTexts(new string[] { longestYAxisLabel }, yAxisTextPaint).FirstOrDefault();
 
                 yAxisWidth = (int)(width - longestYAxisLabelRect.Width);