michael@0: /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: package org.mozilla.gecko;
michael@0: 
michael@0: import org.mozilla.gecko.gfx.BitmapUtils;
michael@0: import org.mozilla.gecko.util.GeckoEventListener;
michael@0: import org.mozilla.gecko.util.ThreadUtils;
michael@0: 
michael@0: import org.json.JSONObject;
michael@0: 
michael@0: import android.app.Application;
michael@0: import android.graphics.Bitmap;
michael@0: import android.graphics.Canvas;
michael@0: import android.graphics.Paint;
michael@0: import android.graphics.Rect;
michael@0: import android.graphics.Shader;
michael@0: import android.graphics.drawable.BitmapDrawable;
michael@0: import android.graphics.drawable.Drawable;
michael@0: import android.os.Build;
michael@0: import android.os.Handler;
michael@0: import android.os.Looper;
michael@0: import android.util.DisplayMetrics;
michael@0: import android.util.Log;
michael@0: import android.view.Gravity;
michael@0: import android.view.View;
michael@0: import android.view.ViewParent;
michael@0: 
michael@0: import java.util.ArrayList;
michael@0: import java.util.List;
michael@0: 
michael@0: public class LightweightTheme implements GeckoEventListener {
michael@0:     private static final String LOGTAG = "GeckoLightweightTheme";
michael@0: 
michael@0:     private Application mApplication;
michael@0:     private Handler mHandler;
michael@0: 
michael@0:     private Bitmap mBitmap;
michael@0:     private int mColor;
michael@0:     private boolean mIsLight;
michael@0: 
michael@0:     public static interface OnChangeListener {
michael@0:         // The View should change its background/text color. 
michael@0:         public void onLightweightThemeChanged();
michael@0: 
michael@0:         // The View should reset to its default background/text color.
michael@0:         public void onLightweightThemeReset();
michael@0:     }
michael@0: 
michael@0:     private List<OnChangeListener> mListeners;
michael@0:     
michael@0:     public LightweightTheme(Application application) {
michael@0:         mApplication = application;
michael@0:         mHandler = new Handler(Looper.getMainLooper());
michael@0:         mListeners = new ArrayList<OnChangeListener>();
michael@0: 
michael@0:         // unregister isn't needed as the lifetime is same as the application.
michael@0:         GeckoAppShell.getEventDispatcher().registerEventListener("LightweightTheme:Update", this);
michael@0:         GeckoAppShell.getEventDispatcher().registerEventListener("LightweightTheme:Disable", this);
michael@0:     }
michael@0: 
michael@0:     public void addListener(final OnChangeListener listener) {
michael@0:         // Don't inform the listeners that attached late.
michael@0:         // Their onLayout() will take care of them before their onDraw();
michael@0:         mListeners.add(listener);
michael@0:     }
michael@0: 
michael@0:     public void removeListener(OnChangeListener listener) {
michael@0:         mListeners.remove(listener);
michael@0:     }
michael@0: 
michael@0:     @Override
michael@0:     public void handleMessage(String event, JSONObject message) {
michael@0:         try {
michael@0:             if (event.equals("LightweightTheme:Update")) {
michael@0:                 JSONObject lightweightTheme = message.getJSONObject("data");
michael@0:                 final String headerURL = lightweightTheme.getString("headerURL"); 
michael@0: 
michael@0:                 // Move any heavy lifting off the Gecko thread
michael@0:                 ThreadUtils.postToBackgroundThread(new Runnable() {
michael@0:                     @Override
michael@0:                     public void run() {
michael@0:                         String croppedURL = headerURL;
michael@0:                         int mark = croppedURL.indexOf('?');
michael@0:                         if (mark != -1)
michael@0:                             croppedURL = croppedURL.substring(0, mark);
michael@0: 
michael@0:                         // Get the image and convert it to a bitmap.
michael@0:                         final Bitmap bitmap = BitmapUtils.decodeUrl(croppedURL);
michael@0:                         mHandler.post(new Runnable() {
michael@0:                             @Override
michael@0:                             public void run() {
michael@0:                                 setLightweightTheme(bitmap);
michael@0:                             }
michael@0:                         });
michael@0:                     }
michael@0:                 });
michael@0:             } else if (event.equals("LightweightTheme:Disable")) {
michael@0:                 mHandler.post(new Runnable() {
michael@0:                     @Override
michael@0:                     public void run() {
michael@0:                         resetLightweightTheme();
michael@0:                     }
michael@0:                 });
michael@0:             }
michael@0:         } catch (Exception e) {
michael@0:             Log.e(LOGTAG, "Exception handling message \"" + event + "\":", e);
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Set a new lightweight theme with the given bitmap.
michael@0:      * Note: This should be called on the UI thread to restrict accessing the
michael@0:      * bitmap to a single thread.
michael@0:      *
michael@0:      * @param bitmap The bitmap used for the lightweight theme.
michael@0:      */
michael@0:     private void setLightweightTheme(Bitmap bitmap) {
michael@0:         if (bitmap == null || bitmap.getWidth() == 0 || bitmap.getHeight() == 0) {
michael@0:             mBitmap = null;
michael@0:             return;
michael@0:         }
michael@0: 
michael@0:         // To find the dominant color only once, take the bottom 25% of pixels.
michael@0:         DisplayMetrics dm = mApplication.getResources().getDisplayMetrics();
michael@0:         int maxWidth = Math.max(dm.widthPixels, dm.heightPixels);
michael@0:         int height = (int) (bitmap.getHeight() * 0.25);
michael@0: 
michael@0:         // The lightweight theme image's width and height.
michael@0:         int bitmapWidth = bitmap.getWidth();
michael@0:         int bitmapHeight = bitmap.getHeight();
michael@0: 
michael@0:         // A cropped bitmap of the bottom 25% of pixels.
michael@0:         Bitmap cropped = Bitmap.createBitmap(bitmap,
michael@0:                                              bitmapWidth > maxWidth ? bitmapWidth - maxWidth : 0,
michael@0:                                              bitmapHeight - height, 
michael@0:                                              bitmapWidth > maxWidth ? maxWidth : bitmapWidth,
michael@0:                                              height);
michael@0: 
michael@0:         // Dominant color based on the cropped bitmap.
michael@0:         mColor = BitmapUtils.getDominantColor(cropped, false);
michael@0: 
michael@0:         // Calculate the luminance to determine if it's a light or a dark theme.
michael@0:         double luminance = (0.2125 * ((mColor & 0x00FF0000) >> 16)) + 
michael@0:                            (0.7154 * ((mColor & 0x0000FF00) >> 8)) + 
michael@0:                            (0.0721 * (mColor &0x000000FF));
michael@0:         mIsLight = (luminance > 110) ? true : false;
michael@0: 
michael@0:         // The bitmap image might be smaller than the device's width.
michael@0:         // If it's smaller, fill the extra space on the left with the dominant color.
michael@0:         if (bitmap.getWidth() >= maxWidth) {
michael@0:             mBitmap = bitmap;
michael@0:         } else {
michael@0:             Paint paint = new Paint();
michael@0:             paint.setAntiAlias(true);
michael@0: 
michael@0:             // Create a bigger image that can fill the device width.
michael@0:             // By creating a canvas for the bitmap, anything drawn on the canvas
michael@0:             // will be drawn on the bitmap.
michael@0:             mBitmap = Bitmap.createBitmap(maxWidth, bitmapHeight, Bitmap.Config.ARGB_8888);
michael@0:             Canvas canvas = new Canvas(mBitmap);
michael@0: 
michael@0:             // Fill the canvas with dominant color.
michael@0:             canvas.drawColor(mColor);
michael@0: 
michael@0:             // The image should be top-right aligned.
michael@0:             Rect rect = new Rect();
michael@0:             Gravity.apply(Gravity.TOP | Gravity.RIGHT,
michael@0:                           bitmapWidth,
michael@0:                           bitmapHeight,
michael@0:                           new Rect(0, 0, maxWidth, bitmapHeight),
michael@0:                           rect);
michael@0: 
michael@0:             // Draw the bitmap.
michael@0:             canvas.drawBitmap(bitmap, null, rect, paint);
michael@0:         }
michael@0: 
michael@0:         for (OnChangeListener listener : mListeners)
michael@0:             listener.onLightweightThemeChanged();
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Reset the lightweight theme.
michael@0:      * Note: This should be called on the UI thread to restrict accessing the
michael@0:      * bitmap to a single thread.
michael@0:      */
michael@0:     private void resetLightweightTheme() {
michael@0:         if (mBitmap != null) {
michael@0:             // Reset the bitmap.
michael@0:             mBitmap = null;
michael@0: 
michael@0:             for (OnChangeListener listener : mListeners)
michael@0:                 listener.onLightweightThemeReset();
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * A lightweight theme is enabled only if there is an active bitmap.
michael@0:      *
michael@0:      * @return True if the theme is enabled.
michael@0:      */
michael@0:     public boolean isEnabled() {
michael@0:         return (mBitmap != null);
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Based on the luminance of the domanint color, a theme is classified as light or dark.
michael@0:      *
michael@0:      * @return True if the theme is light.
michael@0:      */
michael@0:     public boolean isLightTheme() {
michael@0:         return mIsLight;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Crop the image based on the position of the view on the window.
michael@0:      * Either the View or one of its ancestors might have scrolled or translated.
michael@0:      * This value should be taken into account while mapping the View to the Bitmap.
michael@0:      *
michael@0:      * @param view The view requesting a cropped bitmap.
michael@0:      */
michael@0:     private Bitmap getCroppedBitmap(View view) {
michael@0:         if (mBitmap == null || view == null)
michael@0:             return null;
michael@0: 
michael@0:         // Get the global position of the view on the entire screen.
michael@0:         Rect rect = new Rect();
michael@0:         view.getGlobalVisibleRect(rect);
michael@0: 
michael@0:         // Get the activity's window position. This does an IPC call, may be expensive.
michael@0:         Rect window = new Rect();
michael@0:         view.getWindowVisibleDisplayFrame(window);
michael@0: 
michael@0:         // Calculate the coordinates for the cropped bitmap.
michael@0:         int screenWidth = view.getContext().getResources().getDisplayMetrics().widthPixels;
michael@0:         int left = mBitmap.getWidth() - screenWidth + rect.left;
michael@0:         int right = mBitmap.getWidth() - screenWidth + rect.right;
michael@0:         int top = rect.top - window.top;
michael@0:         int bottom = rect.bottom - window.top;
michael@0: 
michael@0:         int offsetX = 0;
michael@0:         int offsetY = 0;
michael@0: 
michael@0:         // Find if this view or any of its ancestors has been translated or scrolled.
michael@0:         ViewParent parent;
michael@0:         View curView = view;
michael@0:         do {
michael@0:             if (Build.VERSION.SDK_INT >= 11) {
michael@0:                 offsetX += (int) curView.getTranslationX() - curView.getScrollX();
michael@0:                 offsetY += (int) curView.getTranslationY() - curView.getScrollY();
michael@0:             } else {
michael@0:                 offsetX -= curView.getScrollX();
michael@0:                 offsetY -= curView.getScrollY();
michael@0:             }
michael@0: 
michael@0:             parent = curView.getParent();
michael@0: 
michael@0:             if (parent instanceof View)
michael@0:                 curView = (View) parent;
michael@0: 
michael@0:         } while(parent instanceof View && parent != null);
michael@0: 
michael@0:         // Adjust the coordinates for the offset.
michael@0:         left -= offsetX;
michael@0:         right -= offsetX;
michael@0:         top -= offsetY;
michael@0:         bottom -= offsetY;
michael@0: 
michael@0:         // The either the required height may be less than the available image height or more than it.
michael@0:         // If the height required is more, crop only the available portion on the image.
michael@0:         int width = right - left;
michael@0:         int height = (bottom > mBitmap.getHeight() ? mBitmap.getHeight() - top : bottom - top);
michael@0: 
michael@0:         // There is a chance that the view is not visible or doesn't fall within the phone's size.
michael@0:         // In this case, 'rect' will have all values as '0'. Hence 'top' and 'bottom' may be negative,
michael@0:         // and createBitmap() will fail.
michael@0:         // The view will get a background in its next layout pass.
michael@0:         try {
michael@0:             return Bitmap.createBitmap(mBitmap, left, top, width, height);
michael@0:         } catch (Exception e) {
michael@0:             return null;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Converts the cropped bitmap to a BitmapDrawable and returns the same.
michael@0:      *
michael@0:      * @param view The view for which a background drawable is required.
michael@0:      * @return Either the cropped bitmap as a Drawable or null.
michael@0:      */
michael@0:     public Drawable getDrawable(View view) {
michael@0:         Bitmap bitmap = getCroppedBitmap(view);
michael@0:         if (bitmap == null)
michael@0:             return null;
michael@0: 
michael@0:         BitmapDrawable drawable = new BitmapDrawable(view.getContext().getResources(), bitmap);
michael@0:         drawable.setGravity(Gravity.TOP|Gravity.RIGHT);
michael@0:         drawable.setTileModeXY(Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
michael@0:         return drawable;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Converts the cropped bitmap to a LightweightThemeDrawable, placing it over the dominant color.
michael@0:      *
michael@0:      * @param view The view for which a background drawable is required.
michael@0:      * @return Either the cropped bitmap as a Drawable or null.
michael@0:      */
michael@0:      public LightweightThemeDrawable getColorDrawable(View view) {
michael@0:          return getColorDrawable(view, mColor, false);
michael@0:      }
michael@0: 
michael@0:     /**
michael@0:      * Converts the cropped bitmap to a LightweightThemeDrawable, placing it over the required color.
michael@0:      *
michael@0:      * @param view The view for which a background drawable is required.
michael@0:      * @param color The color over which the drawable should be drawn.
michael@0:      * @return Either the cropped bitmap as a Drawable or null.
michael@0:      */
michael@0:     public LightweightThemeDrawable getColorDrawable(View view, int color) {
michael@0:         return getColorDrawable(view, color, false);
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Converts the cropped bitmap to a LightweightThemeDrawable, placing it over the required color.
michael@0:      *
michael@0:      * @param view The view for which a background drawable is required.
michael@0:      * @param color The color over which the drawable should be drawn.
michael@0:      * @param needsDominantColor A layer of dominant color is needed or not.
michael@0:      * @return Either the cropped bitmap as a Drawable or null.
michael@0:      */
michael@0:     public LightweightThemeDrawable getColorDrawable(View view, int color, boolean needsDominantColor) {
michael@0:         Bitmap bitmap = getCroppedBitmap(view);
michael@0:         if (bitmap == null)
michael@0:             return null;
michael@0: 
michael@0:         LightweightThemeDrawable drawable = new LightweightThemeDrawable(view.getContext().getResources(), bitmap);
michael@0:         if (needsDominantColor)
michael@0:             drawable.setColorWithFilter(color, (mColor & 0x22FFFFFF));
michael@0:         else
michael@0:             drawable.setColor(color);
michael@0: 
michael@0:         return drawable;
michael@0:     }
michael@0: }