frameworks_base/graphics/java/android/graphics/drawable/ScaleDrawable.java

/*
 * Copyright (C) 2006 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.content.res.Resources;
import android.content.res.TypedArray;
import android.graphics.*;
import android.view.Gravity;
import android.util.AttributeSet;
import android.view.View;

import java.io.IOException;

/**
 * A Drawable that changes the size of another Drawable based on its current
 * level value.  You can control how much the child Drawable changes in width
 * and height based on the level, as well as a gravity to control where it is
 * placed in its overall container.  Most often used to implement things like
 * progress bars.
 *
 * <p>It can be defined in an XML file with the <code>&lt;scale></code> element. For more
 * information, see the guide to <a
 * href="{@docRoot}guide/topics/resources/drawable-resource.html">Drawable Resources</a>.</p>
 *
 * @attr ref android.R.styleable#ScaleDrawable_scaleWidth
 * @attr ref android.R.styleable#ScaleDrawable_scaleHeight
 * @attr ref android.R.styleable#ScaleDrawable_scaleGravity
 * @attr ref android.R.styleable#ScaleDrawable_drawable
 */
public class ScaleDrawable extends Drawable implements Drawable.Callback {
    private ScaleState mScaleState;
    private boolean mMutated;
    private final Rect mTmpRect = new Rect();

    ScaleDrawable() {
        this(null, null);
    }

    public ScaleDrawable(Drawable drawable, int gravity, float scaleWidth, float scaleHeight) {
        this(null, null);

        mScaleState.mDrawable = drawable;
        mScaleState.mGravity = gravity;
        mScaleState.mScaleWidth = scaleWidth;
        mScaleState.mScaleHeight = scaleHeight;

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

    /**
     * Returns the drawable scaled by this ScaleDrawable.
     */
    public Drawable getDrawable() {
        return mScaleState.mDrawable;
    }

    private static float getPercent(TypedArray a, int name) {
        String s = a.getString(name);
        if (s != null) {
            if (s.endsWith("%")) {
                String f = s.substring(0, s.length() - 1);
                return Float.parseFloat(f) / 100.0f;
            }
        }
        return -1;
    }

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

        int type;

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

        float sw = getPercent(a, com.android.internal.R.styleable.ScaleDrawable_scaleWidth);
        float sh = getPercent(a, com.android.internal.R.styleable.ScaleDrawable_scaleHeight);
        int g = a.getInt(com.android.internal.R.styleable.ScaleDrawable_scaleGravity, Gravity.LEFT);
        boolean min = a.getBoolean(
                com.android.internal.R.styleable.ScaleDrawable_useIntrinsicSizeAsMinimum, false);
        Drawable dr = a.getDrawable(com.android.internal.R.styleable.ScaleDrawable_drawable);

        a.recycle();

        final int outerDepth = parser.getDepth();
        while ((type = parser.next()) != XmlPullParser.END_DOCUMENT
                && (type != XmlPullParser.END_TAG || parser.getDepth() > outerDepth)) {
            if (type != XmlPullParser.START_TAG) {
                continue;
            }
            dr = Drawable.createFromXmlInner(r, parser, attrs);
        }

        if (dr == null) {
            throw new IllegalArgumentException("No drawable specified for <scale>");
        }

        mScaleState.mDrawable = dr;
        mScaleState.mScaleWidth = sw;
        mScaleState.mScaleHeight = sh;
        mScaleState.mGravity = g;
        mScaleState.mUseIntrinsicSizeAsMin = min;
        if (dr != null) {
            dr.setCallback(this);
        }
    }

    // overrides from Drawable.Callback

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

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

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

    // overrides from Drawable

    @Override
    public void draw(Canvas canvas) {
        if (mScaleState.mDrawable.getLevel() != 0)
            mScaleState.mDrawable.draw(canvas);
    }

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

    @Override
    public boolean getPadding(Rect padding) {
        // XXX need to adjust padding!
        return mScaleState.mDrawable.getPadding(padding);
    }

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

    @Override
    public void setAlpha(int alpha) {
        mScaleState.mDrawable.setAlpha(alpha);
    }

    @Override
    public void setColorFilter(ColorFilter cf) {
        mScaleState.mDrawable.setColorFilter(cf);
    }

    @Override
    public int getOpacity() {
        return mScaleState.mDrawable.getOpacity();
    }

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

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

    @Override
    protected boolean onLevelChange(int level) {
        mScaleState.mDrawable.setLevel(level);
        onBoundsChange(getBounds());
        invalidateSelf();
        return true;
    }

    @Override
    protected void onBoundsChange(Rect bounds) {
        final Rect r = mTmpRect;
        final boolean min = mScaleState.mUseIntrinsicSizeAsMin;
        int level = getLevel();
        int w = bounds.width();
        if (mScaleState.mScaleWidth > 0) {
            final int iw = min ? mScaleState.mDrawable.getIntrinsicWidth() : 0;
            w -= (int) ((w - iw) * (10000 - level) * mScaleState.mScaleWidth / 10000);
        }
        int h = bounds.height();
        if (mScaleState.mScaleHeight > 0) {
            final int ih = min ? mScaleState.mDrawable.getIntrinsicHeight() : 0;
            h -= (int) ((h - ih) * (10000 - level) * mScaleState.mScaleHeight / 10000);
        }
        final int layoutDirection = getResolvedLayoutDirectionSelf();
        Gravity.apply(mScaleState.mGravity, w, h, bounds, r, layoutDirection);

        if (w > 0 && h > 0) {
            mScaleState.mDrawable.setBounds(r.left, r.top, r.right, r.bottom);
        }
    }

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

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

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

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

    final static class ScaleState extends ConstantState {
        Drawable mDrawable;
        int mChangingConfigurations;
        float mScaleWidth;
        float mScaleHeight;
        int mGravity;
        boolean mUseIntrinsicSizeAsMin;

        private boolean mCheckedConstantState;
        private boolean mCanConstantState;

        ScaleState(ScaleState orig, ScaleDrawable owner, Resources res) {
            if (orig != null) {
                if (res != null) {
                    mDrawable = orig.mDrawable.getConstantState().newDrawable(res);
                } else {
                    mDrawable = orig.mDrawable.getConstantState().newDrawable();
                }
                mDrawable.setCallback(owner);
                mScaleWidth = orig.mScaleWidth;
                mScaleHeight = orig.mScaleHeight;
                mGravity = orig.mGravity;
                mUseIntrinsicSizeAsMin = orig.mUseIntrinsicSizeAsMin;
                mCheckedConstantState = mCanConstantState = true;
            }
        }

        @Override
        public Drawable newDrawable() {
            return new ScaleDrawable(this, null);
        }

        @Override
        public Drawable newDrawable(Resources res) {
            return new ScaleDrawable(this, res);
        }

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

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

            return mCanConstantState;
        }
    }

    private ScaleDrawable(ScaleState state, Resources res) {
        mScaleState = new ScaleState(state, this, res);
    }
}