1 files changed, 140 insertions, 0 deletions
diff --git a/src/com/android/launcher3/graphics/GradientView.java b/src/com/android/launcher3/graphics/GradientView.java
new file mode 100644
index 000000000..c5b769366
--- /dev/null
+++ b/src/com/android/launcher3/graphics/GradientView.java
@@ -0,0 +1,140 @@
+/*
+ * 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.launcher3.graphics;
+
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.graphics.Canvas;
+import android.graphics.Color;
+import android.graphics.Paint;
+import android.graphics.RadialGradient;
+import android.graphics.RectF;
+import android.graphics.Shader;
+import android.util.AttributeSet;
+import android.view.View;
+import android.view.animation.AccelerateInterpolator;
+import android.view.animation.Interpolator;
+
+import com.android.launcher3.R;
+import com.android.launcher3.Utilities;
+
+/**
+ * Draws a translucent radial gradient background from an initial state with progress 0.0 to a
+ * final state with progress 1.0;
+ */
+public class GradientView extends View {
+
+    private static final int DEFAULT_COLOR = Color.WHITE;
+    private static final float GRADIENT_ALPHA_MASK_LENGTH_DP = 300;
+    private static final float FINAL_GRADIENT_ALPHA = 0.75f;
+    private static final boolean DEBUG = false;
+
+    private static Bitmap sFinalGradientMask;
+    private static Bitmap sAlphaGradientMask;
+
+    private int mColor1 = DEFAULT_COLOR;
+    private int mColor2 = DEFAULT_COLOR;
+    private int mWidth;
+    private int mHeight;
+    private final RectF mAlphaMaskRect = new RectF();
+    private final RectF mFinalMaskRect = new RectF();
+    private final Paint mPaint = new Paint();
+    private float mProgress;
+    private final int mMaskHeight;
+    private final Context mAppContext;
+    private final Paint mDebugPaint = DEBUG ? new Paint() : null;
+    private final Interpolator mAccelerator = new AccelerateInterpolator();
+
+    public GradientView(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        this.mAppContext = context.getApplicationContext();
+        this.mMaskHeight = Utilities.pxFromDp(GRADIENT_ALPHA_MASK_LENGTH_DP,
+                mAppContext.getResources().getDisplayMetrics());
+
+        if (sFinalGradientMask == null) {
+            sFinalGradientMask = Utilities.convertToAlphaMask(
+                    Utilities.createOnePixBitmap(), FINAL_GRADIENT_ALPHA);
+        }
+        if (sAlphaGradientMask == null) {
+            Bitmap alphaMaskFromResource = BitmapFactory.decodeResource(context.getResources(),
+                    R.drawable.all_apps_alpha_mask);
+            sAlphaGradientMask = Utilities.convertToAlphaMask(
+                    alphaMaskFromResource, FINAL_GRADIENT_ALPHA);
+        }
+    }
+
+    public void onExtractedColorsChanged(int color1, int color2) {
+        this.mColor1 = color1;
+        this.mColor2 = color2;
+        if (mWidth + mHeight > 0) {
+            createRadialShader();
+        }
+    }
+
+    @Override
+    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
+        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
+        this.mWidth = getMeasuredWidth();
+        this.mHeight = getMeasuredHeight();
+        if (mWidth + mHeight > 0) {
+            createRadialShader();
+        }
+    }
+
+    // only being called when colors change
+    private void createRadialShader() {
+        final float gradientCenterY = 1.05f;
+        float radius = Math.max(mHeight, mWidth) * gradientCenterY;
+
+        float posScreenBottom = (radius - mHeight) / radius; // center lives below screen
+        RadialGradient shader = new RadialGradient(
+                mWidth * 0.5f,
+                mHeight * gradientCenterY,
+                radius,
+                new int[] {mColor1, mColor1, mColor2},
+                new float[] {0f, posScreenBottom, 1f},
+                Shader.TileMode.CLAMP);
+        mPaint.setShader(shader);
+    }
+
+    public void setProgress(float progress) {
+        this.mProgress = progress;
+        invalidate();
+    }
+
+    @Override
+    protected void onDraw(Canvas canvas) {
+        float head = 0.29f;
+        float linearProgress = head + (mProgress * (1f - head));
+        float startMaskY = (1f - linearProgress) * mHeight - mMaskHeight * linearProgress;
+        float startAlpha = 100;
+        float interpolatedAlpha = (255 - startAlpha) * mAccelerator.getInterpolation(mProgress);
+        mPaint.setAlpha((int) (startAlpha + interpolatedAlpha));
+        mAlphaMaskRect.set(0, startMaskY, mWidth, startMaskY + mMaskHeight);
+        mFinalMaskRect.set(0, startMaskY + mMaskHeight, mWidth, mHeight);
+        canvas.drawBitmap(sAlphaGradientMask, null, mAlphaMaskRect, mPaint);
+        canvas.drawBitmap(sFinalGradientMask, null, mFinalMaskRect, mPaint);
+
+        if (DEBUG) {
+            mDebugPaint.setColor(0xFF00FF00);
+            canvas.drawLine(0, startMaskY, mWidth, startMaskY, mDebugPaint);
+            canvas.drawLine(0, startMaskY + mMaskHeight, mWidth, startMaskY + mMaskHeight, mDebugPaint);
+        }
+    }
+
+}
+\ No newline at end of file