Improve readability of history and streak charts

Fixes #432

Co-authored-by: Alinson S. Xavier <git@axavier.org>

android/uhabits-android/src/main/java/org/isoron/uhabits/activities/common/views/HistoryChart.java

@@ -75,14 +75,14 @@ public class HistoryChart extends ScrollableChart
 
     private int colors[];
 
+    private int textColors[];
+
     private RectF baseLocation;
 
     private int primaryColor;
 
     private boolean isBackgroundTransparent;
 
-    private int textColor;
-
     private int reverseTextColor;
 
     private boolean isEditable;
@@ -232,6 +232,7 @@ public class HistoryChart extends ScrollableChart
         pTextHeader.setAntiAlias(true);
 
         pSquareBg = new Paint();
+        pSquareBg.setAntiAlias(true);
 
         pSquareFg = new Paint();
         pSquareFg.setAntiAlias(true);
@@ -250,7 +251,7 @@ public class HistoryChart extends ScrollableChart
         headerOverflow = 0;
         previousMonth = "";
         previousYear = "";
-        pTextHeader.setColor(textColor);
+        pTextHeader.setColor(textColors[1]);
 
         updateDate();
         GregorianCalendar currentDate = (GregorianCalendar) baseDate.clone();
@@ -367,27 +368,41 @@ public class HistoryChart extends ScrollableChart
                             GregorianCalendar date,
                             int checkmarkOffset)
     {
+
         int checkmark = 0;
-        if (checkmarkOffset >= checkmarks.length) pSquareBg.setColor(colors[0]);
+        if (checkmarkOffset >= checkmarks.length)
+        {
+            pSquareBg.setColor(colors[0]);
+            pSquareFg.setColor(textColors[1]);
+        }
         else
         {
             checkmark = checkmarks[checkmarkOffset];
             if(checkmark == 0)
+            {
                 pSquareBg.setColor(colors[0]);
+                pSquareFg.setColor(textColors[1]);
+            }
             else if(checkmark < target)
+            {
                 pSquareBg.setColor(colors[1]);
+                pSquareFg.setColor(textColors[2]);
+            }
             else
+            {
                 pSquareBg.setColor(colors[2]);
+                pSquareFg.setColor(textColors[2]);
+            }
         }
 
-        pSquareFg.setColor(reverseTextColor);
-        pSquareFg.setStrokeWidth(columnWidth * 0.025f);
-
         float round = dpToPixels(getContext(), 2);
         canvas.drawRoundRect(location, round, round, pSquareBg);
 
         if (!isNumerical && checkmark == SKIPPED)
         {
+            pSquareBg.setColor(colors[0]);
+            pSquareBg.setStrokeWidth(columnWidth * 0.025f);
+
             canvas.save();
             canvas.clipRect(location);
             float offset = - columnWidth;
@@ -398,7 +413,7 @@ public class HistoryChart extends ScrollableChart
                                 location.bottom,
                                 location.right + offset,
                                 location.top,
-                                pSquareFg);
+                                pSquareBg);
             }
             canvas.restore();
         }
@@ -448,7 +463,11 @@ public class HistoryChart extends ScrollableChart
             colors[0] = Color.argb(16, 255, 255, 255);
             colors[1] = Color.argb(128, red, green, blue);
             colors[2] = primaryColor;
-            textColor = Color.WHITE;
+
+            textColors = new int[3];
+            textColors[0] = Color.WHITE;
+            textColors[1] = Color.WHITE;
+            textColors[2] = Color.WHITE;
             reverseTextColor = Color.WHITE;
         }
         else
@@ -457,9 +476,12 @@ public class HistoryChart extends ScrollableChart
             colors[0] = res.getColor(R.attr.lowContrastTextColor);
             colors[1] = Color.argb(127, red, green, blue);
             colors[2] = primaryColor;
-            textColor = res.getColor(R.attr.mediumContrastTextColor);
+
-            reverseTextColor =
+            textColors = new int[3];
-                res.getColor(R.attr.highContrastReverseTextColor);
+            textColors[0] = res.getColor(R.attr.lowContrastReverseTextColor);
+            textColors[1] = res.getColor(R.attr.mediumContrastTextColor);
+            textColors[2] = res.getColor(R.attr.highContrastReverseTextColor);
+            reverseTextColor = res.getColor(R.attr.highContrastReverseTextColor);
         }
     }
 

android/uhabits-android/src/main/java/org/isoron/uhabits/activities/common/views/StreakChart.java

@@ -46,6 +46,8 @@ public class StreakChart extends View
 
     private int[] colors;
 
+    private int[] textColors;
+
     private RectF rect;
 
     private int baseSize;
@@ -70,8 +72,6 @@ public class StreakChart extends View
 
     private int textColor;
 
-    private int reverseTextColor;
-
     public StreakChart(Context context)
     {
         super(context);
@@ -213,7 +213,7 @@ public class StreakChart extends View
 
         float yOffset = rect.centerY() + 0.3f * em;
 
-        paint.setColor(reverseTextColor);
+        paint.setColor(percentageToTextColor(percentage));
         paint.setTextAlign(Paint.Align.CENTER);
         canvas.drawText(Long.toString(streak.getLength()), rect.centerX(),
             yOffset, paint);
@@ -223,7 +223,7 @@ public class StreakChart extends View
             String startLabel = dateFormat.format(streak.getStart().toJavaDate());
             String endLabel = dateFormat.format(streak.getEnd().toJavaDate());
 
-            paint.setColor(textColor);
+            paint.setColor(textColors[1]);
             paint.setTextAlign(Paint.Align.RIGHT);
             canvas.drawText(startLabel, gap - textMargin, yOffset, paint);
 
@@ -258,8 +258,11 @@ public class StreakChart extends View
         colors[2] = Color.argb(192, red, green, blue);
         colors[1] = Color.argb(96, red, green, blue);
         colors[0] = res.getColor(R.attr.lowContrastTextColor);
-        textColor = res.getColor(R.attr.mediumContrastTextColor);
+
-        reverseTextColor = res.getColor(R.attr.highContrastReverseTextColor);
+        textColors = new int[3];
+        textColors[2] = res.getColor(R.attr.highContrastReverseTextColor);
+        textColors[1] = res.getColor(R.attr.mediumContrastTextColor);
+        textColors[0] = res.getColor(R.attr.lowContrastReverseTextColor);
     }
 
     private void initPaints()
@@ -277,6 +280,12 @@ public class StreakChart extends View
         return colors[0];
     }
 
+    private int percentageToTextColor(float percentage)
+    {
+        if (percentage >= 0.5f) return textColors[2];
+        return textColors[1];
+    }
+
     private void updateMaxMinLengths()
     {
         maxLength = 0;