gecko-dev/mobile/android/base/LightweightThemeDrawable.java
2013-02-26 21:50:25 -08:00

129 lines
4.1 KiB
Java

/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.gecko;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.ColorFilter;
import android.graphics.ComposeShader;
import android.graphics.LinearGradient;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffColorFilter;
import android.graphics.Rect;
import android.graphics.Shader;
import android.graphics.drawable.Drawable;
/**
* A special drawable used with lightweight themes. This draws a color
* (with an optional color-filter) and a bitmap (with a linear gradient
* to specify the alpha) in order.
*/
public class LightweightThemeDrawable extends Drawable {
private Paint mPaint;
private Paint mColorPaint;
private Bitmap mBitmap;
private Resources mResources;
private int mStartColor;
private int mEndColor;
public LightweightThemeDrawable(Resources resources, Bitmap bitmap) {
mBitmap = bitmap;
mResources = resources;
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setStrokeWidth(0.0f);
}
@Override
protected void onBoundsChange(Rect bounds) {
super.onBoundsChange(bounds);
initializeBitmapShader();
}
@Override
public void draw(Canvas canvas) {
// Draw the colors, if available.
if (mColorPaint != null)
canvas.drawPaint(mColorPaint);
// Draw the bitmap.
canvas.drawPaint(mPaint);
}
@Override
public int getOpacity() {
return PixelFormat.TRANSLUCENT;
}
@Override
public void setAlpha(int alpha) {
// A StateListDrawable will reset the alpha value with 255.
// We cannot use to be the bitmap alpha.
mPaint.setAlpha(alpha);
}
@Override
public void setColorFilter(ColorFilter filter) {
mPaint.setColorFilter(filter);
}
/**
* Creates a paint that paint a particular color.
*
* @param color The color to be painted.
*/
public void setColor(int color) {
mColorPaint = new Paint(mPaint);
mColorPaint.setColor(color);
}
/**
* Creates a paint that paint a particular color, and a filter for the color.
*
* @param color The color to be painted.
* @param filter The filter color to be applied using SRC_OVER mode.
*/
public void setColorWithFilter(int color, int filter) {
mColorPaint = new Paint(mPaint);
mColorPaint.setColor(color);
mColorPaint.setColorFilter(new PorterDuffColorFilter(filter, PorterDuff.Mode.SRC_OVER));
}
/**
* Set the alpha for the linear gradient used with the bitmap's shader.
*
* @param startAlpha The starting alpha (0..255) value to be applied to the LinearGradient.
* @param startAlpha The ending alpha (0..255) value to be applied to the LinearGradient.
*/
public void setAlpha(int startAlpha, int endAlpha) {
mStartColor = startAlpha << 24;
mEndColor = endAlpha << 24;
initializeBitmapShader();
}
private void initializeBitmapShader() {
// A bitmap-shader to draw the bitmap.
// Clamp mode will repeat the last row of pixels.
// Hence its better to have an endAlpha of 0 for the linear-gradient.
BitmapShader bitmapShader = new BitmapShader(mBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
// A linear-gradient to specify the opacity of the bitmap.
LinearGradient gradient = new LinearGradient(0, 0, 0, mBitmap.getHeight(), mStartColor, mEndColor, Shader.TileMode.CLAMP);
// Make a combined shader -- a performance win.
// The linear-gradient is the 'SRC' and the bitmap-shader is the 'DST'.
// Drawing the DST in the SRC will provide the opacity.
mPaint.setShader(new ComposeShader(bitmapShader, gradient, PorterDuff.Mode.DST_IN));
}
}