Import Android SDK Platform PI [4335822]

/google/data/ro/projects/android/fetch_artifact \
    --bid 4335822 \
    --target sdk_phone_armv7-win_sdk \
    sdk-repo-linux-sources-4335822.zip

AndroidVersion.ApiLevel has been modified to appear as 28

Change-Id: Ic8f04be005a71c2b9abeaac754d8da8d6f9a2c32

1 files changed, 194 insertions, 0 deletions

diff --git a/android/view/RectShadowPainter.java b/android/view/RectShadowPainter.java
new file mode 100644
index 00000000..5665d4f3
--- /dev/null
+++ b/android/view/RectShadowPainter.java
@@ -0,0 +1,194 @@
+/*
+ * Copyright (C) 2015 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 android.view;
+
+import com.android.layoutlib.bridge.impl.GcSnapshot;
+import com.android.layoutlib.bridge.impl.ResourceHelper;
+
+import android.graphics.Canvas;
+import android.graphics.Canvas_Delegate;
+import android.graphics.LinearGradient;
+import android.graphics.Outline;
+import android.graphics.Paint;
+import android.graphics.Paint.Style;
+import android.graphics.Path;
+import android.graphics.Path.FillType;
+import android.graphics.RadialGradient;
+import android.graphics.Rect;
+import android.graphics.RectF;
+import android.graphics.Region.Op;
+import android.graphics.Shader.TileMode;
+
+import java.awt.Rectangle;
+
+/**
+ * Paints shadow for rounded rectangles. Inspiration from CardView. Couldn't use that directly,
+ * since it modifies the size of the content, that we can't do.
+ */
+public class RectShadowPainter {
+
+
+    private static final int START_COLOR = ResourceHelper.getColor("#37000000");
+    private static final int END_COLOR = ResourceHelper.getColor("#03000000");
+    private static final float PERPENDICULAR_ANGLE = 90f;
+
+    public static void paintShadow(Outline viewOutline, float elevation, Canvas canvas) {
+        Rect outline = new Rect();
+        if (!viewOutline.getRect(outline)) {
+            assert false : "Outline is not a rect shadow";
+            return;
+        }
+
+        // TODO replacing the algorithm here to create better shadow
+
+        float shadowSize = elevationToShadow(elevation);
+        int saved = modifyCanvas(canvas, shadowSize);
+        if (saved == -1) {
+            return;
+        }
+
+        float radius = viewOutline.getRadius();
+        if (radius <= 0) {
+            // We can not paint a shadow with radius 0
+            return;
+        }
+
+        try {
+            Paint cornerPaint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.DITHER_FLAG);
+            cornerPaint.setStyle(Style.FILL);
+            Paint edgePaint = new Paint(cornerPaint);
+            edgePaint.setAntiAlias(false);
+            float outerArcRadius = radius + shadowSize;
+            int[] colors = {START_COLOR, START_COLOR, END_COLOR};
+            cornerPaint.setShader(new RadialGradient(0, 0, outerArcRadius, colors,
+                    new float[]{0f, radius / outerArcRadius, 1f}, TileMode.CLAMP));
+            edgePaint.setShader(new LinearGradient(0, 0, -shadowSize, 0, START_COLOR, END_COLOR,
+                    TileMode.CLAMP));
+            Path path = new Path();
+            path.setFillType(FillType.EVEN_ODD);
+            // A rectangle bounding the complete shadow.
+            RectF shadowRect = new RectF(outline);
+            shadowRect.inset(-shadowSize, -shadowSize);
+            // A rectangle with edges corresponding to the straight edges of the outline.
+            RectF inset = new RectF(outline);
+            inset.inset(radius, radius);
+            // A rectangle used to represent the edge shadow.
+            RectF edgeShadowRect = new RectF();
+
+
+            // left and right sides.
+            edgeShadowRect.set(-shadowSize, 0f, 0f, inset.height());
+            // Left shadow
+            sideShadow(canvas, edgePaint, edgeShadowRect, outline.left, inset.top, 0);
+            // Right shadow
+            sideShadow(canvas, edgePaint, edgeShadowRect, outline.right, inset.bottom, 2);
+            // Top shadow
+            edgeShadowRect.set(-shadowSize, 0, 0, inset.width());
+            sideShadow(canvas, edgePaint, edgeShadowRect, inset.right, outline.top, 1);
+            // bottom shadow. This needs an inset so that blank doesn't appear when the content is
+            // moved up.
+            edgeShadowRect.set(-shadowSize, 0, shadowSize / 2f, inset.width());
+            edgePaint.setShader(new LinearGradient(edgeShadowRect.right, 0, edgeShadowRect.left, 0,
+                    colors, new float[]{0f, 1 / 3f, 1f}, TileMode.CLAMP));
+            sideShadow(canvas, edgePaint, edgeShadowRect, inset.left, outline.bottom, 3);
+
+            // Draw corners.
+            drawCorner(canvas, cornerPaint, path, inset.right, inset.bottom, outerArcRadius, 0);
+            drawCorner(canvas, cornerPaint, path, inset.left, inset.bottom, outerArcRadius, 1);
+            drawCorner(canvas, cornerPaint, path, inset.left, inset.top, outerArcRadius, 2);
+            drawCorner(canvas, cornerPaint, path, inset.right, inset.top, outerArcRadius, 3);
+        } finally {
+            canvas.restoreToCount(saved);
+        }
+    }
+
+    private static float elevationToShadow(float elevation) {
+        // The factor is chosen by eyeballing the shadow size on device and preview.
+        return elevation * 0.5f;
+    }
+
+    /**
+     * Translate canvas by half of shadow size up, so that it appears that light is coming
+     * slightly from above. Also, remove clipping, so that shadow is not clipped.
+     */
+    private static int modifyCanvas(Canvas canvas, float shadowSize) {
+        Rect clipBounds = canvas.getClipBounds();
+        if (clipBounds.isEmpty()) {
+            return -1;
+        }
+        int saved = canvas.save();
+        // Usually canvas has been translated to the top left corner of the view when this is
+        // called. So, setting a clip rect at 0,0 will clip the top left part of the shadow.
+        // Thus, we just expand in each direction by width and height of the canvas, while staying
+        // inside the original drawing region.
+        GcSnapshot snapshot = Canvas_Delegate.getDelegate(canvas).getSnapshot();
+        Rectangle originalClip = snapshot.getOriginalClip();
+        if (originalClip != null) {
+            canvas.clipRect(originalClip.x, originalClip.y, originalClip.x + originalClip.width,
+              originalClip.y + originalClip.height, Op.REPLACE);
+            canvas.clipRect(-canvas.getWidth(), -canvas.getHeight(), canvas.getWidth(),
+              canvas.getHeight(), Op.INTERSECT);
+        }
+        canvas.translate(0, shadowSize / 2f);
+        return saved;
+    }
+
+    private static void sideShadow(Canvas canvas, Paint edgePaint,
+            RectF edgeShadowRect, float dx, float dy, int rotations) {
+        if (isRectEmpty(edgeShadowRect)) {
+            return;
+        }
+        int saved = canvas.save();
+        canvas.translate(dx, dy);
+        canvas.rotate(rotations * PERPENDICULAR_ANGLE);
+        canvas.drawRect(edgeShadowRect, edgePaint);
+        canvas.restoreToCount(saved);
+    }
+
+    /**
+     * @param canvas Canvas to draw the rectangle on.
+     * @param paint Paint to use when drawing the corner.
+     * @param path A path to reuse. Prevents allocating memory for each path.
+     * @param x Center of circle, which this corner is a part of.
+     * @param y Center of circle, which this corner is a part of.
+     * @param radius radius of the arc
+     * @param rotations number of quarter rotations before starting to paint the arc.
+     */
+    private static void drawCorner(Canvas canvas, Paint paint, Path path, float x, float y,
+            float radius, int rotations) {
+        int saved = canvas.save();
+        canvas.translate(x, y);
+        path.reset();
+        path.arcTo(-radius, -radius, radius, radius, rotations * PERPENDICULAR_ANGLE,
+                PERPENDICULAR_ANGLE, false);
+        path.lineTo(0, 0);
+        path.close();
+        canvas.drawPath(path, paint);
+        canvas.restoreToCount(saved);
+    }
+
+    /**
+     * Differs from {@link RectF#isEmpty()} as this first converts the rect to int and then checks.
+     * <p/>
+     * This is required because {@link Canvas_Delegate#native_drawRect(long, float, float, float,
+     * float, long)} casts the co-ordinates to int and we want to ensure that it doesn't end up
+     * drawing empty rectangles, which results in IllegalArgumentException.
+     */
+    private static boolean isRectEmpty(RectF rect) {
+        return (int) rect.left >= (int) rect.right || (int) rect.top >= (int) rect.bottom;
+    }
+}