support semi transparent header colours

clip canvas to prevent events and texts from beeing drawn behind the
header so we can use transparent colours

Author: marunjar

library/src/main/java/com/alamkanak/weekview/WeekView.java

@@ -8,6 +8,7 @@
 import android.graphics.PointF;
 import android.graphics.Rect;
 import android.graphics.RectF;
+import android.graphics.Region;
 import android.graphics.Typeface;
 import android.support.annotation.Nullable;
 import android.support.v4.view.GestureDetectorCompat;
@@ -438,23 +439,23 @@ private void initTextTimeWidth() {
     protected void onDraw(Canvas canvas) {
         super.onDraw(canvas);
 
+        // Hide everything in the first cell (top left corner).
+        canvas.drawRect(0, 0, mTimeTextWidth + mHeaderColumnPadding * 2, mHeaderTextHeight + mHeaderRowPadding * 2, mHeaderBackgroundPaint);
+
         // Draw the header row.
         drawHeaderRowAndEvents(canvas);
 
         // Draw the time column and all the axes/separators.
         drawTimeColumnAndAxes(canvas);
-
-        // Hide everything in the first cell (top left corner).
-        canvas.drawRect(0, 0, mTimeTextWidth + mHeaderColumnPadding * 2, mHeaderTextHeight + mHeaderRowPadding * 2, mHeaderBackgroundPaint);
-
-        // Hide anything that is in the bottom margin of the header row.
-        canvas.drawRect(mHeaderColumnWidth, mHeaderTextHeight + mHeaderRowPadding * 2, getWidth(), mHeaderRowPadding * 2 + mHeaderTextHeight + mHeaderMarginBottom + mTimeTextHeight/2, mHeaderColumnBackgroundPaint);
     }
 
     private void drawTimeColumnAndAxes(Canvas canvas) {
         // Draw the background color for the header column.
         canvas.drawRect(0, mHeaderTextHeight + mHeaderRowPadding * 2, mHeaderColumnWidth, getHeight(), mHeaderColumnBackgroundPaint);
 
+        // Clip to paint in left column only
+        canvas.clipRect(0, mHeaderTextHeight + mHeaderRowPadding * 2, mHeaderColumnWidth, getHeight(), Region.Op.REPLACE);
+
         for (int i = 0; i < 24; i++) {
             float top = mHeaderTextHeight + mHeaderRowPadding * 2 + mCurrentOrigin.y + mHourHeight * i + mHeaderMarginBottom;
 
@@ -544,6 +545,9 @@ else if (mNewHourHeight > mMaxHourHeight)
             }
         }
 
+        // Clip to paint events only
+        canvas.clipRect(mHeaderColumnWidth, mHeaderTextHeight + mHeaderRowPadding * 2 + mHeaderMarginBottom + mTimeTextHeight/2, getWidth(), getHeight(), Region.Op.REPLACE);
+
         // Iterate through each day.
         Calendar oldFirstVisibleDay = mFirstVisibleDay;
         mFirstVisibleDay = (Calendar) today.clone();
@@ -629,6 +633,10 @@ else if (day.before(today)) {
             startPixel += mWidthPerDay + mColumnGap;
         }
 
+
+        // Clip to paint header row only
+        canvas.clipRect(mHeaderColumnWidth, 0, getWidth(), mHeaderTextHeight + mHeaderRowPadding * 2, Region.Op.REPLACE);
+
         // Draw the header background.
         canvas.drawRect(0, 0, getWidth(), mHeaderTextHeight + mHeaderRowPadding * 2, mHeaderBackgroundPaint);