BezelImageView.java

/*
 * Original code by Google
 * Modified by Jonathan GERBAUD, Abewy
 * 
 * Copyright 2012 Google Inc.
 * 
 * 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 com.abewy.android.apps.klyph.messenger.widget;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.ColorMatrix;
import android.graphics.ColorMatrixColorFilter;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.drawable.Drawable;
import android.support.v4.view.ViewCompat;
import android.util.AttributeSet;
import com.abewy.android.apps.klyph.messenger.R;

/**
 * An {@link android.widget.ImageView} that draws its contents inside a mask and draws a border
 * drawable on top. This is useful for applying a beveled look to image contents, but is also
 * flexible enough for use with other desired aesthetics.
 */
public class BezelImageView extends KlyphImageView
{
	private Paint					mBlackPaint;
	private Paint					mMaskedPaint;

	private Rect					mBounds;
	private RectF					mBoundsF;

	private Drawable				mBorderDrawable;
	private Drawable				mMaskDrawable;

	private ColorMatrixColorFilter	mDesaturateColorFilter;
	private boolean					mDesaturateOnPress	= false;
	private boolean					mMaskEnabled		= false;

	private boolean					mCacheValid			= false;
	private Bitmap					mCacheBitmap;
	private int						mCachedWidth;
	private int						mCachedHeight;

	public BezelImageView(Context context)
	{
		this(context, null);
	}

	public BezelImageView(Context context, AttributeSet attrs)
	{
		this(context, attrs, 0);
	}

	public BezelImageView(Context context, AttributeSet attrs, int defStyle)
	{
		super(context, attrs, defStyle);

		// Attribute initialization
		final TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.BezelImageView, defStyle, 0);

		setMaskDrawable(a.getDrawable(R.styleable.BezelImageView_maskDrawable));

		setBorderDrawable(a.getDrawable(R.styleable.BezelImageView_borderDrawable));

		mDesaturateOnPress = a.getBoolean(R.styleable.BezelImageView_desaturateOnPress, mDesaturateOnPress);

		a.recycle();

		// Other initialization
		mBlackPaint = new Paint();
		mBlackPaint.setColor(0xff000000);

		mMaskedPaint = new Paint();
		mMaskedPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));

		// Always want a cache allocated.
		mCacheBitmap = Bitmap.createBitmap(1, 1, Bitmap.Config.ARGB_8888);

		if (mDesaturateOnPress)
		{
			// Create a desaturate color filter for pressed state.
			ColorMatrix cm = new ColorMatrix();
			cm.setSaturation(0);
			mDesaturateColorFilter = new ColorMatrixColorFilter(cm);
		}
	}

	protected void setMaskDrawable(Drawable maskDrawable)
	{
		if (mMaskDrawable != null)
		{
			mMaskDrawable.setCallback(null);
		}

		mMaskDrawable = maskDrawable;

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

	protected void setBorderDrawable(Drawable borderDrawable)
	{
		if (mBorderDrawable != null)
		{
			mBorderDrawable.setCallback(null);
		}

		mBorderDrawable = borderDrawable;

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

	protected void setMaskEnabled(boolean enabled)
	{
		mMaskEnabled = enabled;
	}

	@Override
	protected boolean setFrame(int l, int t, int r, int b)
	{
		final boolean changed = super.setFrame(l, t, r, b);
		mBounds = new Rect(0, 0, r - l, b - t);
		mBoundsF = new RectF(mBounds);

		if (mBorderDrawable != null)
		{
			mBorderDrawable.setBounds(mBounds);
		}
		if (mMaskDrawable != null)
		{
			mMaskDrawable.setBounds(mBounds);
		}

		if (changed)
		{
			mCacheValid = false;
		}

		return changed;
	}

	@Override
	protected void onDraw(Canvas canvas)
	{
		if (mBounds == null)
		{
			return;
		}

		int width = mBounds.width();
		int height = mBounds.height();

		if (width == 0 || height == 0)
		{
			return;
		}

		if (!mCacheValid || width != mCachedWidth || height != mCachedHeight)
		{
			// Need to redraw the cache
			if (width == mCachedWidth && height == mCachedHeight)
			{
				// Have a correct-sized bitmap cache already allocated. Just erase it.
				mCacheBitmap.eraseColor(0);
			}
			else
			{
				// Allocate a new bitmap with the correct dimensions.
				mCacheBitmap.recycle();
				// noinspection AndroidLintDrawAllocation
				mCacheBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
				mCachedWidth = width;
				mCachedHeight = height;
			}

			Canvas cacheCanvas = new Canvas(mCacheBitmap);
			if (mMaskDrawable != null && mMaskEnabled == true)
			{
				int sc = cacheCanvas.save();
				mMaskDrawable.draw(cacheCanvas);
				mMaskedPaint.setColorFilter((mDesaturateOnPress && isPressed()) ? mDesaturateColorFilter : null);
				cacheCanvas.saveLayer(mBoundsF, mMaskedPaint, Canvas.HAS_ALPHA_LAYER_SAVE_FLAG | Canvas.FULL_COLOR_LAYER_SAVE_FLAG);
				super.onDraw(cacheCanvas);
				cacheCanvas.restoreToCount(sc);
			}
			else if (mDesaturateOnPress && isPressed())
			{
				int sc = cacheCanvas.save();
				cacheCanvas.drawRect(0, 0, mCachedWidth, mCachedHeight, mBlackPaint);
				mMaskedPaint.setColorFilter(mDesaturateColorFilter);
				cacheCanvas.saveLayer(mBoundsF, mMaskedPaint, Canvas.HAS_ALPHA_LAYER_SAVE_FLAG | Canvas.FULL_COLOR_LAYER_SAVE_FLAG);
				super.onDraw(cacheCanvas);
				cacheCanvas.restoreToCount(sc);
			}
			else
			{
				super.onDraw(cacheCanvas);
			}

			if (mBorderDrawable != null)
			{
				mBorderDrawable.draw(cacheCanvas);
			}
		}

		// Draw from cache
		canvas.drawBitmap(mCacheBitmap, mBounds.left, mBounds.top, null);
	}

	@Override
	protected void drawableStateChanged()
	{
		super.drawableStateChanged();
		if (mBorderDrawable != null && mBorderDrawable.isStateful())
		{
			mBorderDrawable.setState(getDrawableState());
		}
		if (mMaskDrawable != null && mMaskDrawable.isStateful())
		{
			mMaskDrawable.setState(getDrawableState());
		}
		if (isDuplicateParentStateEnabled())
		{
			ViewCompat.postInvalidateOnAnimation(this);
		}
	}

	@Override
	public void invalidateDrawable(Drawable who)
	{
		if (who == mBorderDrawable || who == mMaskDrawable)
		{
			invalidate();
		}
		else
		{
			super.invalidateDrawable(who);
		}
	}

	@Override
	protected boolean verifyDrawable(Drawable who)
	{
		return who == mBorderDrawable || who == mMaskDrawable || super.verifyDrawable(who);
	}
}