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/*
* Copyright (C) 2011 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.view;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.SurfaceTexture;
import android.util.AttributeSet;
import android.util.Log;
/**
* <p>A TextureView can be used to display a content stream. Such a content
* stream can for instance be a video or an OpenGL scene. The content stream
* can come from the application's process as well as a remote process.</p>
*
* <p>TextureView can only be used in a hardware accelerated window. When
* rendered in software, TextureView will draw nothing.</p>
*
* <p>Unlike {@link SurfaceView}, TextureView does not create a separate
* window but behaves as a regular View. This key difference allows a
* TextureView to be moved, transformed, animated, etc. For instance, you
* can make a TextureView semi-translucent by calling
* <code>myView.setAlpha(0.5f)</code>.</p>
*
* <p>Using a TextureView is simple: all you need to do is get its
* {@link SurfaceTexture}. The {@link SurfaceTexture} can then be used to
* render content. The following example demonstrates how to render the
* camera preview into a TextureView:</p>
*
* <pre>
* public class LiveCameraActivity extends Activity implements TextureView.SurfaceTextureListener {
* private Camera mCamera;
* private TextureView mTextureView;
*
* protected void onCreate(Bundle savedInstanceState) {
* super.onCreate(savedInstanceState);
*
* mTextureView = new TextureView(this);
* mTextureView.setSurfaceTextureListener(this);
*
* setContentView(mTextureView);
* }
*
* public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
* mCamera = Camera.open();
*
* try {
* mCamera.setPreviewTexture(surface);
* mCamera.startPreview();
* } catch (IOException ioe) {
* // Something bad happened
* }
* }
*
* public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {
* // Ignored, Camera does all the work for us
* }
*
* public void onSurfaceTextureDestroyed(SurfaceTexture surface) {
* mCamera.stopPreview();
* mCamera.release();
* }
* }
* </pre>
*
* <p>A TextureView's SurfaceTexture can be obtained either by invoking
* {@link #getSurfaceTexture()} or by using a {@link SurfaceTextureListener}.
* It is important to know that a SurfaceTexture is available only after the
* TextureView is attached to a window (and {@link #onAttachedToWindow()} has
* been invoked.) It is therefore highly recommended you use a listener to
* be notified when the SurfaceTexture becomes available.</p>
*
* @see SurfaceView
* @see SurfaceTexture
*/
public class TextureView extends View {
private static final String LOG_TAG = "TextureView";
private HardwareLayer mLayer;
private SurfaceTexture mSurface;
private SurfaceTextureListener mListener;
private final Runnable mUpdateLayerAction = new Runnable() {
@Override
public void run() {
updateLayer();
}
};
private SurfaceTexture.OnFrameAvailableListener mUpdateListener;
/**
* Creates a new TextureView.
*
* @param context The context to associate this view with.
*/
public TextureView(Context context) {
super(context);
init();
}
/**
* Creates a new TextureView.
*
* @param context The context to associate this view with.
* @param attrs The attributes of the XML tag that is inflating the view.
*/
@SuppressWarnings({"UnusedDeclaration"})
public TextureView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
/**
* Creates a new TextureView.
*
* @param context The context to associate this view with.
* @param attrs The attributes of the XML tag that is inflating the view.
* @param defStyle The default style to apply to this view. If 0, no style
* will be applied (beyond what is included in the theme). This may
* either be an attribute resource, whose value will be retrieved
* from the current theme, or an explicit style resource.
*/
@SuppressWarnings({"UnusedDeclaration"})
public TextureView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
private void init() {
mLayerPaint = new Paint();
}
@Override
protected void onAttachedToWindow() {
super.onAttachedToWindow();
if (!isHardwareAccelerated()) {
Log.w(LOG_TAG, "A TextureView or a subclass can only be "
+ "used with hardware acceleration enabled.");
}
}
@Override
protected void onDetachedFromWindow() {
super.onDetachedFromWindow();
if (isHardwareAccelerated() && mLayer != null) {
if (mListener != null) {
mListener.onSurfaceTextureDestroyed(mSurface);
}
mLayer.destroy();
mSurface = null;
mLayer = null;
}
}
/**
* The layer type of a TextureView is ignored since a TextureView is always
* considered to act as a hardware layer. The optional paint supplied to this
* method will however be taken into account when rendering the content of
* this TextureView.
*
* @param layerType The ype of layer to use with this view, must be one of
* {@link #LAYER_TYPE_NONE}, {@link #LAYER_TYPE_SOFTWARE} or
* {@link #LAYER_TYPE_HARDWARE}
* @param paint The paint used to compose the layer. This argument is optional
* and can be null. It is ignored when the layer type is
* {@link #LAYER_TYPE_NONE}
*/
@Override
public void setLayerType(int layerType, Paint paint) {
if (paint != mLayerPaint) {
mLayerPaint = paint;
invalidate();
}
}
/**
* Always returns {@link #LAYER_TYPE_HARDWARE}.
*/
@Override
public int getLayerType() {
return LAYER_TYPE_HARDWARE;
}
/**
* Calling this method has no effect.
*/
@Override
public void buildLayer() {
}
/**
* Subclasses of TextureView cannot do their own rendering
* with the {@link Canvas} object.
*
* @param canvas The Canvas to which the View is rendered.
*/
@Override
public final void draw(Canvas canvas) {
super.draw(canvas);
}
/**
* Subclasses of TextureView cannot do their own rendering
* with the {@link Canvas} object.
*
* @param canvas The Canvas to which the View is rendered.
*/
@Override
protected final void onDraw(Canvas canvas) {
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
if (mSurface != null) {
nSetDefaultBufferSize(mSurface, getWidth(), getHeight());
if (mListener != null) {
mListener.onSurfaceTextureSizeChanged(mSurface, getWidth(), getHeight());
}
}
}
@Override
HardwareLayer getHardwareLayer() {
if (mAttachInfo == null || mAttachInfo.mHardwareRenderer == null) {
return null;
}
if (mLayer == null) {
mLayer = mAttachInfo.mHardwareRenderer.createHardwareLayer();
mSurface = mAttachInfo.mHardwareRenderer.createSurfaceTexture(mLayer);
nSetDefaultBufferSize(mSurface, getWidth(), getHeight());
mUpdateListener = new SurfaceTexture.OnFrameAvailableListener() {
@Override
public void onFrameAvailable(SurfaceTexture surfaceTexture) {
// Per SurfaceTexture's documentation, the callback may be invoked
// from an arbitrary thread
post(mUpdateLayerAction);
}
};
mSurface.setOnFrameAvailableListener(mUpdateListener);
if (mListener != null) {
mListener.onSurfaceTextureAvailable(mSurface, getWidth(), getHeight());
}
}
return mLayer;
}
@Override
protected void onVisibilityChanged(View changedView, int visibility) {
super.onVisibilityChanged(changedView, visibility);
if (mSurface != null) {
// When the view becomes invisible, stop updating it, it's a waste of CPU
// To cancel updates, the easiest thing to do is simply to remove the
// updates listener
if (visibility == VISIBLE) {
mSurface.setOnFrameAvailableListener(mUpdateListener);
updateLayer();
} else {
mSurface.setOnFrameAvailableListener(null);
}
}
}
private void updateLayer() {
if (mAttachInfo == null || mAttachInfo.mHardwareRenderer == null) {
return;
}
mAttachInfo.mHardwareRenderer.updateTextureLayer(mLayer, getWidth(), getHeight());
invalidate();
}
/**
* <p>Returns a {@link android.graphics.Bitmap} representation of the content
* of the associated surface texture. If the surface texture is not available,
* this method returns null.</p>
*
* <p>The bitmap returned by this method uses the {@link Bitmap.Config#ARGB_8888}
* pixel format and its dimensions are the same as this view's.</p>
*
* <p><strong>Do not</strong> invoke this method from a drawing method
* ({@link #onDraw(android.graphics.Canvas)} for instance).</p>
*
* @return A valid {@link Bitmap.Config#ARGB_8888} bitmap, or null if the surface
* texture is not available or the width <= 0 or the height <= 0
*
* @see #isAvailable()
* @see #getBitmap(android.graphics.Bitmap)
* @see #getBitmap(int, int)
*/
public Bitmap getBitmap() {
return getBitmap(getWidth(), getHeight());
}
/**
* <p>Returns a {@link android.graphics.Bitmap} representation of the content
* of the associated surface texture. If the surface texture is not available,
* this method returns null.</p>
*
* <p>The bitmap returned by this method uses the {@link Bitmap.Config#ARGB_8888}
* pixel format.</p>
*
* <p><strong>Do not</strong> invoke this method from a drawing method
* ({@link #onDraw(android.graphics.Canvas)} for instance).</p>
*
* @param width The width of the bitmap to create
* @param height The height of the bitmap to create
*
* @return A valid {@link Bitmap.Config#ARGB_8888} bitmap, or null if the surface
* texture is not available or width is <= 0 or height is <= 0
*
* @see #isAvailable()
* @see #getBitmap(android.graphics.Bitmap)
* @see #getBitmap()
*/
public Bitmap getBitmap(int width, int height) {
if (isAvailable() && width > 0 && height > 0) {
return getBitmap(Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888));
}
return null;
}
/**
* <p>Copies the content of this view's surface texture into the specified
* bitmap. If the surface texture is not available, the copy is not executed.
* The content of the surface texture will be scaled to fit exactly inside
* the specified bitmap.</p>
*
* <p><strong>Do not</strong> invoke this method from a drawing method
* ({@link #onDraw(android.graphics.Canvas)} for instance).</p>
*
* @param bitmap The bitmap to copy the content of the surface texture into,
* cannot be null, all configurations are supported
*
* @return The bitmap specified as a parameter
*
* @see #isAvailable()
* @see #getBitmap(int, int)
* @see #getBitmap()
*/
public Bitmap getBitmap(Bitmap bitmap) {
if (bitmap != null && isAvailable()) {
mAttachInfo.mHardwareRenderer.copyLayer(mLayer, bitmap);
}
return bitmap;
}
/**
* Returns true if the {@link SurfaceTexture} associated with this
* TextureView is available for rendering. When this method returns
* true, {@link #getSurfaceTexture()} returns a valid surface texture.
*/
public boolean isAvailable() {
return mSurface != null;
}
/**
* Returns the {@link SurfaceTexture} used by this view. This method
* may return null if the view is not attached to a window or if the surface
* texture has not been initialized yet.
*
* @see #isAvailable()
*/
public SurfaceTexture getSurfaceTexture() {
return mSurface;
}
/**
* Returns the {@link SurfaceTextureListener} currently associated with this
* texture view.
*
* @see #setSurfaceTextureListener(android.view.TextureView.SurfaceTextureListener)
* @see SurfaceTextureListener
*/
public SurfaceTextureListener getSurfaceTextureListener() {
return mListener;
}
/**
* Sets the {@link SurfaceTextureListener} used to listen to surface
* texture events.
*
* @see #getSurfaceTextureListener()
* @see SurfaceTextureListener
*/
public void setSurfaceTextureListener(SurfaceTextureListener listener) {
mListener = listener;
}
/**
* This listener can be used to be notified when the surface texture
* associated with this texture view is available.
*/
public static interface SurfaceTextureListener {
/**
* Invoked when a {@link TextureView}'s SurfaceTexture is ready for use.
*
* @param surface The surface returned by
* {@link android.view.TextureView#getSurfaceTexture()}
* @param width The width of the surface
* @param height The height of the surface
*/
public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height);
/**
* Invoked when the {@link SurfaceTexture}'s buffers size changed.
*
* @param surface The surface returned by
* {@link android.view.TextureView#getSurfaceTexture()}
* @param width The new width of the surface
* @param height The new height of the surface
*/
public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height);
/**
* Invoked when the specified {@link SurfaceTexture} is about to be destroyed.
* After this method is invoked, no rendering should happen inside the surface
* texture.
*
* @param surface The surface about to be destroyed
*/
public void onSurfaceTextureDestroyed(SurfaceTexture surface);
}
private static native void nSetDefaultBufferSize(SurfaceTexture surfaceTexture, int width, int height);
}
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