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 com.android.internal.R;

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

import android.annotation.NonNull;
import android.annotation.Nullable;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.content.res.Resources.Theme;
import android.util.MathUtils;
import android.util.TypedValue;
import android.util.AttributeSet;

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>
 * It can be defined in an XML file with the <code>&lt;rotate&gt;</code> element.
 * For more information, see the guide to
 * <a href="{@docRoot}guide/topics/resources/animation-resource.html">Animation Resources</a>.
 *
 * @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 DrawableWrapper {
    private static final int MAX_LEVEL = 10000;

    private RotateState mState;

    /**
     * Creates a new rotating drawable with no wrapped drawable.
     */
    public RotateDrawable() {
        this(new RotateState(null, null), null);
    }

    @Override
    public void inflate(@NonNull Resources r, @NonNull XmlPullParser parser,
            @NonNull AttributeSet attrs, @Nullable Theme theme)
            throws XmlPullParserException, IOException {
        final TypedArray a = obtainAttributes(r, theme, attrs, R.styleable.RotateDrawable);

        // Inflation will advance the XmlPullParser and AttributeSet.
        super.inflate(r, parser, attrs, theme);

        updateStateFromTypedArray(a);
        verifyRequiredAttributes(a);
        a.recycle();
    }

    @Override
    public void applyTheme(@NonNull Theme t) {
        super.applyTheme(t);

        final RotateState state = mState;
        if (state == null) {
            return;
        }

        if (state.mThemeAttrs != null) {
            final TypedArray a = t.resolveAttributes(state.mThemeAttrs, R.styleable.RotateDrawable);
            try {
                updateStateFromTypedArray(a);
                verifyRequiredAttributes(a);
            } catch (XmlPullParserException e) {
                rethrowAsRuntimeException(e);
            } finally {
                a.recycle();
            }
        }
    }

    private void verifyRequiredAttributes(@NonNull TypedArray a) throws XmlPullParserException {
        // If we're not waiting on a theme, verify required attributes.
        if (getDrawable() == null && (mState.mThemeAttrs == null
                || mState.mThemeAttrs[R.styleable.RotateDrawable_drawable] == 0)) {
            throw new XmlPullParserException(a.getPositionDescription()
                    + ": <rotate> tag requires a 'drawable' attribute or "
                    + "child tag defining a drawable");
        }
    }

    private void updateStateFromTypedArray(@NonNull TypedArray a) {
        final RotateState state = mState;
        if (state == null) {
            return;
        }

        // Account for any configuration changes.
        state.mChangingConfigurations |= a.getChangingConfigurations();

        // Extract the theme attributes, if any.
        state.mThemeAttrs = a.extractThemeAttrs();

        if (a.hasValue(R.styleable.RotateDrawable_pivotX)) {
            final TypedValue tv = a.peekValue(R.styleable.RotateDrawable_pivotX);
            state.mPivotXRel = tv.type == TypedValue.TYPE_FRACTION;
            state.mPivotX = state.mPivotXRel ? tv.getFraction(1.0f, 1.0f) : tv.getFloat();
        }

        if (a.hasValue(R.styleable.RotateDrawable_pivotY)) {
            final TypedValue tv = a.peekValue(R.styleable.RotateDrawable_pivotY);
            state.mPivotYRel = tv.type == TypedValue.TYPE_FRACTION;
            state.mPivotY = state.mPivotYRel ? tv.getFraction(1.0f, 1.0f) : tv.getFloat();
        }

        state.mFromDegrees = a.getFloat(
                R.styleable.RotateDrawable_fromDegrees, state.mFromDegrees);
        state.mToDegrees = a.getFloat(
                R.styleable.RotateDrawable_toDegrees, state.mToDegrees);
        state.mCurrentDegrees = state.mFromDegrees;
    }

    @Override
    public void draw(Canvas canvas) {
        final Drawable d = getDrawable();
        final Rect bounds = d.getBounds();
        final int w = bounds.right - bounds.left;
        final int h = bounds.bottom - bounds.top;
        final RotateState st = mState;
        final float px = st.mPivotXRel ? (w * st.mPivotX) : st.mPivotX;
        final float py = st.mPivotYRel ? (h * st.mPivotY) : st.mPivotY;

        final int saveCount = canvas.save();
        canvas.rotate(st.mCurrentDegrees, px + bounds.left, py + bounds.top);
        d.draw(canvas);
        canvas.restoreToCount(saveCount);
    }

    /**
     * Sets the start angle for rotation.
     *
     * @param fromDegrees starting angle in degrees
     * @see #getFromDegrees()
     * @attr ref android.R.styleable#RotateDrawable_fromDegrees
     */
    public void setFromDegrees(float fromDegrees) {
        if (mState.mFromDegrees != fromDegrees) {
            mState.mFromDegrees = fromDegrees;
            invalidateSelf();
        }
    }

    /**
     * @return starting angle for rotation in degrees
     * @see #setFromDegrees(float)
     * @attr ref android.R.styleable#RotateDrawable_fromDegrees
     */
    public float getFromDegrees() {
        return mState.mFromDegrees;
    }

    /**
     * Sets the end angle for rotation.
     *
     * @param toDegrees ending angle in degrees
     * @see #getToDegrees()
     * @attr ref android.R.styleable#RotateDrawable_toDegrees
     */
    public void setToDegrees(float toDegrees) {
        if (mState.mToDegrees != toDegrees) {
            mState.mToDegrees = toDegrees;
            invalidateSelf();
        }
    }

    /**
     * @return ending angle for rotation in degrees
     * @see #setToDegrees(float)
     * @attr ref android.R.styleable#RotateDrawable_toDegrees
     */
    public float getToDegrees() {
        return mState.mToDegrees;
    }

    /**
     * Sets the X position around which the drawable is rotated.
     * <p>
     * If the X pivot is relative (as specified by
     * {@link #setPivotXRelative(boolean)}), then the position represents a
     * fraction of the drawable width. Otherwise, the position represents an
     * absolute value in pixels.
     *
     * @param pivotX X position around which to rotate
     * @see #setPivotXRelative(boolean)
     * @attr ref android.R.styleable#RotateDrawable_pivotX
     */
    public void setPivotX(float pivotX) {
        if (mState.mPivotX != pivotX) {
            mState.mPivotX = pivotX;
            invalidateSelf();
        }
    }

    /**
     * @return X position around which to rotate
     * @see #setPivotX(float)
     * @attr ref android.R.styleable#RotateDrawable_pivotX
     */
    public float getPivotX() {
        return mState.mPivotX;
    }

    /**
     * Sets whether the X pivot value represents a fraction of the drawable
     * width or an absolute value in pixels.
     *
     * @param relative true if the X pivot represents a fraction of the drawable
     *            width, or false if it represents an absolute value in pixels
     * @see #isPivotXRelative()
     */
    public void setPivotXRelative(boolean relative) {
        if (mState.mPivotXRel != relative) {
            mState.mPivotXRel = relative;
            invalidateSelf();
        }
    }

    /**
     * @return true if the X pivot represents a fraction of the drawable width,
     *         or false if it represents an absolute value in pixels
     * @see #setPivotXRelative(boolean)
     */
    public boolean isPivotXRelative() {
        return mState.mPivotXRel;
    }

    /**
     * Sets the Y position around which the drawable is rotated.
     * <p>
     * If the Y pivot is relative (as specified by
     * {@link #setPivotYRelative(boolean)}), then the position represents a
     * fraction of the drawable height. Otherwise, the position represents an
     * absolute value in pixels.
     *
     * @param pivotY Y position around which to rotate
     * @see #getPivotY()
     * @attr ref android.R.styleable#RotateDrawable_pivotY
     */
    public void setPivotY(float pivotY) {
        if (mState.mPivotY != pivotY) {
            mState.mPivotY = pivotY;
            invalidateSelf();
        }
    }

    /**
     * @return Y position around which to rotate
     * @see #setPivotY(float)
     * @attr ref android.R.styleable#RotateDrawable_pivotY
     */
    public float getPivotY() {
        return mState.mPivotY;
    }

    /**
     * Sets whether the Y pivot value represents a fraction of the drawable
     * height or an absolute value in pixels.
     *
     * @param relative True if the Y pivot represents a fraction of the drawable
     *            height, or false if it represents an absolute value in pixels
     * @see #isPivotYRelative()
     */
    public void setPivotYRelative(boolean relative) {
        if (mState.mPivotYRel != relative) {
            mState.mPivotYRel = relative;
            invalidateSelf();
        }
    }

    /**
     * @return true if the Y pivot represents a fraction of the drawable height,
     *         or false if it represents an absolute value in pixels
     * @see #setPivotYRelative(boolean)
     */
    public boolean isPivotYRelative() {
        return mState.mPivotYRel;
    }

    @Override
    protected boolean onLevelChange(int level) {
        super.onLevelChange(level);

        final float value = level / (float) MAX_LEVEL;
        final float degrees = MathUtils.lerp(mState.mFromDegrees, mState.mToDegrees, value);
        mState.mCurrentDegrees = degrees;

        invalidateSelf();
        return true;
    }

    @Override
    DrawableWrapperState mutateConstantState() {
        mState = new RotateState(mState, null);
        return mState;
    }

    static final class RotateState extends DrawableWrapper.DrawableWrapperState {
        private int[] mThemeAttrs;

        boolean mPivotXRel = true;
        float mPivotX = 0.5f;
        boolean mPivotYRel = true;
        float mPivotY = 0.5f;
        float mFromDegrees = 0.0f;
        float mToDegrees = 360.0f;
        float mCurrentDegrees = 0.0f;

        RotateState(RotateState orig, Resources res) {
            super(orig, res);

            if (orig != null) {
                mPivotXRel = orig.mPivotXRel;
                mPivotX = orig.mPivotX;
                mPivotYRel = orig.mPivotYRel;
                mPivotY = orig.mPivotY;
                mFromDegrees = orig.mFromDegrees;
                mToDegrees = orig.mToDegrees;
                mCurrentDegrees = orig.mCurrentDegrees;
            }
        }

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

    private RotateDrawable(RotateState state, Resources res) {
        super(state, res);

        mState = state;
    }
}