If all fields for a specific value are set, mark it.

* In this case, the value is drawn a bit less intense than incomplete values.
* Make the keyboard focus background color depend on the actual background
  color.
* No longer allow to drag remove random hint values after removing a value
  from a field.

src/apps/sudoku/SudokuField.cpp

@@ -251,6 +251,21 @@ SudokuField::IsEmpty() const
 }
 
 
+bool
+SudokuField::IsValueCompleted(uint32 value) const
+{
+	uint32 count = 0;
+	for (uint32 y = 0; y < fSize; y++) {
+		for (uint32 x = 0; x < fSize; x++) {
+			if (ValueAt(x, y) == value)
+				count++;
+		}
+	}
+
+	return count == Size();
+}
+
+
 void
 SudokuField::SetHintMaskAt(uint32 x, uint32 y, uint32 hintMask)
 {

src/apps/sudoku/SudokuField.h

@@ -33,6 +33,7 @@ public:
 
 			bool				IsSolved() const;
 			bool				IsEmpty() const;
+			bool				IsValueCompleted(uint32 value) const;
 
 			uint32				Size() const { return fSize; }
 			uint32				BlockSize() const { return fBlockSize; }

src/apps/sudoku/SudokuView.cpp

@@ -814,21 +814,30 @@ SudokuView::MouseDown(BPoint where)
 				| B_TERTIARY_MOUSE_BUTTON)) != 0) {
 		// double click or other buttons set a value
 		if ((fField->FlagsAt(x, y) & kInitialValue) == 0) {
+			bool wasCompleted;
 			if (fField->ValueAt(x, y) > 0) {
+				value = fField->ValueAt(x, y) - 1;
+				wasCompleted = fField->IsValueCompleted(value + 1);
+
 				fField->SetValueAt(x, y, 0);
 				fShowHintX = x;
 				fShowHintY = y;
 			} else {
+				wasCompleted = fField->IsValueCompleted(value + 1);
+
 				fField->SetValueAt(x, y, value + 1);
 				BMessenger(this).SendMessage(kMsgCheckSolved);
+
+				// allow dragging to remove the hint from other fields
+				fLastHintValueSet = false;
+				fLastHintValue = value;
+				fLastField = field;
 			}
 
-			_InvalidateField(x, y);
+			if (wasCompleted != fField->IsValueCompleted(value + 1))
-
+				Invalidate();
-			// allow dragging to remove the hint from other fields
+			else
-			fLastHintValueSet = false;
+				_InvalidateField(x, y);
-			fLastHintValue = value;
-			fLastField = field;
 		}
 		return;
 	}
@@ -1204,8 +1213,8 @@ SudokuView::Draw(BRect /*updateRect*/)
 					|| (fShowKeyboardFocus && x == fKeyboardX
 						&& y == fKeyboardY))
 				&& (fField->FlagsAt(x, y) & kInitialValue) == 0) {
-				//SetLowColor(tint_color(ViewColor(), B_DARKEN_1_TINT));
+				// TODO: make color more intense
-				SetLowColor(255, 255, 210);
+				SetLowColor(tint_color(fBackgroundColor, B_DARKEN_2_TINT));
 				FillRect(_Frame(x, y), B_SOLID_LOW);
 			} else {
 				SetLowColor(fBackgroundColor);
@@ -1222,13 +1231,16 @@ SudokuView::Draw(BRect /*updateRect*/)
 			}
 
 			SetFont(&fFieldFont);
-			if (fField->FlagsAt(x, y) & kInitialValue)
+			if ((fField->FlagsAt(x, y) & kInitialValue) != 0)
 				SetHighColor(0, 0, 0);
 			else {
 				if ((fHintFlags & kMarkInvalid) == 0
-					|| fField->ValidMaskAt(x, y) & (1UL << (value - 1)))
+					|| fField->ValidMaskAt(x, y) & (1UL << (value - 1))) {
-					SetHighColor(0, 0, 200);
+					if (fField->IsValueCompleted(value))
-				else
+						SetHighColor(60, 60, 150);
+					else
+						SetHighColor(0, 0, 220);
+				} else
 					SetHighColor(200, 0, 0);
 			}