graphics/drawable/RotateDrawable.java

/*
 * Copyright (C) 2007 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.graphics.drawable;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import android.graphics.Canvas;
import android.graphics.ColorFilter;
import android.graphics.Rect;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.util.TypedValue;
import android.util.AttributeSet;
import android.util.Log;

import java.io.IOException;

/**
 * <p>A Drawable that can rotate another Drawable based on the current level
 * value. The start and end angles of rotation can be controlled to map any
 * circular arc to the level values range.</p>
 *
 * <p>It can be defined in an XML file with the <code>&lt;rotate></code> element.</p>
 *
 * @attr ref android.R.styleable#RotateDrawable_visible
 * @attr ref android.R.styleable#RotateDrawable_fromDegrees
 * @attr ref android.R.styleable#RotateDrawable_toDegrees
 * @attr ref android.R.styleable#RotateDrawable_pivotX
 * @attr ref android.R.styleable#RotateDrawable_pivotY
 * @attr ref android.R.styleable#RotateDrawable_drawable
 */
public class RotateDrawable extends Drawable implements Drawable.Callback {
    private static final float MAX_LEVEL = 10000.0f;

    private RotateState mState;
    private boolean mMutated;

    /**
     * <p>Create a new rotating drawable with an empty state.</p>
     */
    public RotateDrawable() {
        this(null);
    }

    /**
     * <p>Create a new rotating drawable with the specified state. A copy of
     * this state is used as the internal state for the newly created
     * drawable.</p>
     *
     * @param rotateState the state for this drawable
     */
    private RotateDrawable(RotateState rotateState) {
        mState = new RotateState(rotateState, this);
    }

    public void draw(Canvas canvas) {
        int saveCount = canvas.save();

        Rect bounds = mState.mDrawable.getBounds();

        int w = bounds.right - bounds.left;
        int h = bounds.bottom - bounds.top;

        final RotateState st = mState;

        float px = st.mPivotXRel ? (w * st.mPivotX) : st.mPivotX;
        float py = st.mPivotYRel ? (h * st.mPivotY) : st.mPivotY;

        canvas.rotate(st.mCurrentDegrees, px, py);

        st.mDrawable.draw(canvas);

        canvas.restoreToCount(saveCount);
    }

    /**
     * Returns the drawable rotated by this RotateDrawable.
     */
    public Drawable getDrawable() {
        return mState.mDrawable;
    }

    @Override
    public int getChangingConfigurations() {
        return super.getChangingConfigurations()
                | mState.mChangingConfigurations
                | mState.mDrawable.getChangingConfigurations();
    }

    public void setAlpha(int alpha) {
        mState.mDrawable.setAlpha(alpha);
    }

    public void setColorFilter(ColorFilter cf) {
        mState.mDrawable.setColorFilter(cf);
    }

    public int getOpacity() {
        return mState.mDrawable.getOpacity();
    }

    public void invalidateDrawable(Drawable who) {
        if (mCallback != null) {
            mCallback.invalidateDrawable(this);
        }
    }

    public void scheduleDrawable(Drawable who, Runnable what, long when) {
        if (mCallback != null) {
            mCallback.scheduleDrawable(this, what, when);
        }
    }

    public void unscheduleDrawable(Drawable who, Runnable what) {
        if (mCallback != null) {
            mCallback.unscheduleDrawable(this, what);
        }
    }

   @Override
    public boolean getPadding(Rect padding) {
        return mState.mDrawable.getPadding(padding);
    }

    @Override
    public boolean setVisible(boolean visible, boolean restart) {
        mState.mDrawable.setVisible(visible, restart);
        return super.setVisible(visible, restart);
    }

    @Override
    public boolean isStateful() {
        return mState.mDrawable.isStateful();
    }

    @Override
    protected boolean onStateChange(int[] state) {
        boolean changed = mState.mDrawable.setState(state);
        onBoundsChange(getBounds());
        return changed;
    }

    @Override
    protected boolean onLevelChange(int level) {
        mState.mDrawable.setLevel(level);
        onBoundsChange(getBounds());

        mState.mCurrentDegrees = mState.mFromDegrees +
                (mState.mToDegrees - mState.mFromDegrees) *
                        ((float) level / MAX_LEVEL);

        invalidateSelf();
        return true;
    }

    @Override
    protected void onBoundsChange(Rect bounds) {
        mState.mDrawable.setBounds(bounds.left, bounds.top,
                bounds.right, bounds.bottom);
    }

    @Override
    public int getIntrinsicWidth() {
        return mState.mDrawable.getIntrinsicWidth();
    }

    @Override
    public int getIntrinsicHeight() {
        return mState.mDrawable.getIntrinsicHeight();
    }

    @Override
    public ConstantState getConstantState() {
        if (mState.canConstantState()) {
            mState.mChangingConfigurations = super.getChangingConfigurations();
            return mState;
        }
        return null;
    }

    @Override
    public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs)
            throws XmlPullParserException, IOException {

        TypedArray a = r.obtainAttributes(attrs,
                com.android.internal.R.styleable.RotateDrawable);

        super.inflateWithAttributes(r, parser, a,
                com.android.internal.R.styleable.RotateDrawable_visible);

        TypedValue tv = a.peekValue(com.android.internal.R.styleable.RotateDrawable_pivotX);
        boolean pivotXRel = tv.type == TypedValue.TYPE_FRACTION;
        float pivotX = pivotXRel ? tv.getFraction(1.0f, 1.0f) : tv.getFloat();

        tv = a.peekValue(com.android.internal.R.styleable.RotateDrawable_pivotY);
        boolean pivotYRel = tv.type == TypedValue.TYPE_FRACTION;
        float pivotY = pivotYRel ? tv.getFraction(1.0f, 1.0f) : tv.getFloat();

        float fromDegrees = a.getFloat(
                com.android.internal.R.styleable.RotateDrawable_fromDegrees, 0.0f);
        float toDegrees = a.getFloat(
                com.android.internal.R.styleable.RotateDrawable_toDegrees, 360.0f);

        toDegrees = Math.max(fromDegrees, toDegrees);

        int res = a.getResourceId(
                com.android.internal.R.styleable.RotateDrawable_drawable, 0);
        Drawable drawable = null;
        if (res > 0) {
            drawable = r.getDrawable(res);
        }

        a.recycle();

        int outerDepth = parser.getDepth();
        int type;
        while ((type = parser.next()) != XmlPullParser.END_DOCUMENT &&
               (type != XmlPullParser.END_TAG || parser.getDepth() > outerDepth)) {

            if (type != XmlPullParser.START_TAG) {
                continue;
            }

            if ((drawable = Drawable.createFromXmlInner(r, parser, attrs)) == null) {
                Log.w("drawable", "Bad element under <rotate>: "
                        + parser .getName());
            }
        }

        if (drawable == null) {
            Log.w("drawable", "No drawable specified for <rotate>");
        }

        mState.mDrawable = drawable;
        mState.mPivotXRel = pivotXRel;
        mState.mPivotX = pivotX;
        mState.mPivotYRel = pivotYRel;
        mState.mPivotY = pivotY;
        mState.mFromDegrees = mState.mCurrentDegrees = fromDegrees;
        mState.mToDegrees = toDegrees;

        if (drawable != null) {
            drawable.setCallback(this);
        }
    }

    @Override
    public Drawable mutate() {
        if (!mMutated && super.mutate() == this) {
            mState.mDrawable.mutate();
            mMutated = true;
        }
        return this;
    }

    /**
     * <p>Represents the state of a rotation for a given drawable. The same
     * rotate drawable can be invoked with different states to drive several
     * rotations at the same time.</p>
     */
    final static class RotateState extends Drawable.ConstantState {
        Drawable mDrawable;

        int mChangingConfigurations;

        boolean mPivotXRel;
        float mPivotX;
        boolean mPivotYRel;
        float mPivotY;

        float mFromDegrees;
        float mToDegrees;

        float mCurrentDegrees;

        private boolean mCanConstantState;
        private boolean mCheckedConstantState;

        public RotateState(RotateState source, RotateDrawable owner) {
            if (source != null) {
                mDrawable = source.mDrawable.getConstantState().newDrawable();
                mDrawable.setCallback(owner);
                mPivotXRel = source.mPivotXRel;
                mPivotX = source.mPivotX;
                mPivotYRel = source.mPivotYRel;
                mPivotY = source.mPivotY;
                mFromDegrees = mCurrentDegrees = source.mFromDegrees;
                mToDegrees = source.mToDegrees;
                mCanConstantState = mCheckedConstantState = true;
            }
        }

        @Override
        public Drawable newDrawable() {
            return new RotateDrawable(this);
        }

        @Override
        public int getChangingConfigurations() {
            return mChangingConfigurations;
        }

        public boolean canConstantState() {
            if (!mCheckedConstantState) {
                mCanConstantState = mDrawable.getConstantState() != null;
                mCheckedConstantState = true;
            }

            return mCanConstantState;
        }
    }
}