Add color temperature preference to Night Display

Bug: 32463283
Test: make RunSettingsRoboTests
Change-Id: Ibf3cf9af05b44a071603d3d7efa6e90ae00c823a

src/com/android/settings/widget/DefaultIndicatorSeekBar.java

@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.widget;
+
+import android.content.Context;
+import android.graphics.Canvas;
+import android.graphics.drawable.Drawable;
+import android.util.AttributeSet;
+import android.widget.SeekBar;
+
+public class DefaultIndicatorSeekBar extends SeekBar {
+
+    private int mDefaultProgress = -1;
+
+    public DefaultIndicatorSeekBar(Context context) {
+        super(context);
+    }
+
+    public DefaultIndicatorSeekBar(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    public DefaultIndicatorSeekBar(Context context, AttributeSet attrs, int defStyleAttr) {
+        super(context, attrs, defStyleAttr);
+    }
+
+    public DefaultIndicatorSeekBar(Context context, AttributeSet attrs, int defStyleAttr,
+            int defStyleRes) {
+        super(context, attrs, defStyleAttr, defStyleRes);
+    }
+
+    /**
+     * N.B. Only draws the default indicator tick mark, NOT equally spaced tick marks.
+     */
+    @Override
+    protected void drawTickMarks(Canvas canvas) {
+        if (isEnabled() && mDefaultProgress <= getMax() && mDefaultProgress >= getMin()) {
+            final Drawable defaultIndicator = getTickMark();
+
+            // Adjust the drawable's bounds to center it at the point where it's drawn.
+            final int w = defaultIndicator.getIntrinsicWidth();
+            final int h = defaultIndicator.getIntrinsicHeight();
+            final int halfW = w >= 0 ? w / 2 : 1;
+            final int halfH = h >= 0 ? h / 2 : 1;
+            defaultIndicator.setBounds(-halfW, -halfH, halfW, halfH);
+
+            // This mimics the computation of the thumb position, to get the true "default."
+            final int availableWidth = getWidth() - mPaddingLeft - mPaddingRight;
+            final int range = getMax() - getMin();
+            final float scale = range > 0f ? mDefaultProgress / (float) range : 0f;
+            final int offset = (int) ((scale * availableWidth) + 0.5f);
+            final int indicatorPosition = isLayoutRtl() && getMirrorForRtl()
+                    ? availableWidth - offset + mPaddingRight : offset + mPaddingLeft;
+
+            final int saveCount = canvas.save();
+            canvas.translate(indicatorPosition, getHeight() / 2);
+            defaultIndicator.draw(canvas);
+            canvas.restoreToCount(saveCount);
+        }
+    }
+
+    /**
+     * N.B. This sets the default *unadjusted* progress, i.e. in the SeekBar's [0 - max] terms.
+     */
+    public void setDefaultProgress(int defaultProgress) {
+        if (mDefaultProgress != defaultProgress) {
+            mDefaultProgress = defaultProgress;
+            invalidate();
+        }
+    }
+
+    public int getDefaultProgress() {
+        return mDefaultProgress;
+    }
+}