lightning-i2p/app/src/main/java/acr/browser/lightning/DrawerArrowDrawable.java

package acr.browser.lightning;

/*
 * Copyright (C) 2014 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.
 */
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.ColorFilter;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PixelFormat;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v7.appcompat.R;

/**
 * A drawable that can draw a "Drawer hamburger" menu or an Arrow and animate
 * between them.
 */
class DrawerArrowDrawable extends Drawable {
	private final Paint mPaint = new Paint();
	// The angle in degress that the arrow head is inclined at.
	private static final float ARROW_HEAD_ANGLE = (float) Math.toRadians(45);
	private final float mBarThickness;
	// The length of top and bottom bars when they merge into an arrow
	private final float mTopBottomArrowSize;
	// The length of middle bar
	private final float mBarSize;
	// The length of the middle bar when arrow is shaped
	private final float mMiddleArrowSize;
	// The space between bars when they are parallel
	private final float mBarGap;
	// Whether bars should spin or not during progress
	private final boolean mSpin;
	// Use Path instead of canvas operations so that if color has transparency,
	// overlapping sections
	// wont look different
	private final Path mPath = new Path();
	// The reported intrinsic size of the drawable.
	private final int mSize;
	// Whether we should mirror animation when animation is reversed.
	private boolean mVerticalMirror = false;
	// The interpolated version of the original progress
	private float mProgress;

	/**
	 * @param context
	 *            used to get the configuration for the drawable from
	 */
	DrawerArrowDrawable(Context context) {
		final TypedArray typedArray = context.getTheme().obtainStyledAttributes(null,
				R.styleable.DrawerArrowToggle, R.attr.drawerArrowStyle,
				R.style.Base_Widget_AppCompat_DrawerArrowToggle);
		mPaint.setAntiAlias(true);
		mPaint.setColor(typedArray.getColor(R.styleable.DrawerArrowToggle_color, 0));
		mSize = typedArray.getDimensionPixelSize(R.styleable.DrawerArrowToggle_drawableSize, 0);
		mBarSize = typedArray.getDimension(R.styleable.DrawerArrowToggle_barSize, 0);
		mTopBottomArrowSize = typedArray.getDimension(
				R.styleable.DrawerArrowToggle_topBottomBarArrowSize, 0);
		mBarThickness = typedArray.getDimension(R.styleable.DrawerArrowToggle_thickness, 0);
		mBarGap = typedArray.getDimension(R.styleable.DrawerArrowToggle_gapBetweenBars, 0);
		mSpin = typedArray.getBoolean(R.styleable.DrawerArrowToggle_spinBars, true);
		mMiddleArrowSize = typedArray.getDimension(
				R.styleable.DrawerArrowToggle_middleBarArrowSize, 0);
		typedArray.recycle();
		mPaint.setStyle(Paint.Style.STROKE);
		mPaint.setStrokeJoin(Paint.Join.ROUND);
		mPaint.setStrokeCap(Paint.Cap.SQUARE);
		mPaint.setStrokeWidth(mBarThickness);
	}

	protected boolean isLayoutRtl() {
		return false;
	}

	/**
	 * If set, canvas is flipped when progress reached to end and going back to
	 * start.
	 */
	protected void setVerticalMirror(boolean verticalMirror) {
		mVerticalMirror = verticalMirror;
	}

	@Override
	public void draw(Canvas canvas) {
		Rect bounds = getBounds();
		final boolean isRtl = isLayoutRtl();
		// Interpolated widths of arrow bars
		final float arrowSize = lerp(mBarSize, mTopBottomArrowSize, mProgress);
		final float middleBarSize = lerp(mBarSize, mMiddleArrowSize, mProgress);
		// Interpolated size of middle bar
		final float middleBarCut = lerp(0, mBarThickness / 2, mProgress);
		// The rotation of the top and bottom bars (that make the arrow head)
		final float rotation = lerp(0, ARROW_HEAD_ANGLE, mProgress);
		// The whole canvas rotates as the transition happens
		final float canvasRotate = lerp(isRtl ? 0 : -180, isRtl ? 180 : 0, mProgress);
		final float topBottomBarOffset = lerp(mBarGap + mBarThickness, 0, mProgress);
		mPath.rewind();
		final float arrowEdge = -middleBarSize / 2;
		// draw middle bar
		mPath.moveTo(arrowEdge + middleBarCut, 0);
		mPath.rLineTo(middleBarSize - middleBarCut, 0);
		final float arrowWidth = Math.round(arrowSize * Math.cos(rotation));
		final float arrowHeight = Math.round(arrowSize * Math.sin(rotation));
		// top bar
		mPath.moveTo(arrowEdge, topBottomBarOffset);
		mPath.rLineTo(arrowWidth, arrowHeight);
		// bottom bar
		mPath.moveTo(arrowEdge, -topBottomBarOffset);
		mPath.rLineTo(arrowWidth, -arrowHeight);
		mPath.moveTo(0, 0);
		mPath.close();
		canvas.save();
		// Rotate the whole canvas if spinning, if not, rotate it 180 to get
		// the arrow pointing the other way for RTL.
		if (mSpin) {
			canvas.rotate(canvasRotate * ((mVerticalMirror ^ isRtl) ? -1 : 1), bounds.centerX(),
					bounds.centerY());
		} else if (isRtl) {
			canvas.rotate(180, bounds.centerX(), bounds.centerY());
		}
		canvas.translate(bounds.centerX(), bounds.centerY());
		canvas.drawPath(mPath, mPaint);
		canvas.restore();
	}

	@Override
	public void setAlpha(int i) {
		mPaint.setAlpha(i);
	}

	// override
	public boolean isAutoMirrored() {
		// Draws rotated 180 degrees in RTL mode.
		return true;
	}

	@Override
	public void setColorFilter(ColorFilter colorFilter) {
		mPaint.setColorFilter(colorFilter);
	}

	@Override
	public int getIntrinsicHeight() {
		return mSize;
	}

	@Override
	public int getIntrinsicWidth() {
		return mSize;
	}

	@Override
	public int getOpacity() {
		return PixelFormat.TRANSLUCENT;
	}

	public float getProgress() {
		return mProgress;
	}

	public void setProgress(float progress) {
		mProgress = progress;
		invalidateSelf();
	}

	/**
	 * Linear interpolate between a and b with parameter t.
	 */
	private static float lerp(float a, float b, float t) {
		return a + (b - a) * t;
	}
}