src/com/android/gallery3d/ui/SurfaceTextureScreenNail.java

/*
 * Copyright (C) 2012 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 com.android.gallery3d.ui;

import android.annotation.TargetApi;
import android.graphics.RectF;
import android.graphics.SurfaceTexture;

import com.android.gallery3d.common.ApiHelper;

@TargetApi(ApiHelper.VERSION_CODES.HONEYCOMB)
public abstract class SurfaceTextureScreenNail implements ScreenNail,
        SurfaceTexture.OnFrameAvailableListener {
    @SuppressWarnings("unused")
    private static final String TAG = "SurfaceTextureScreenNail";
    // This constant is not available in API level before 15, but it was just an
    // oversight.
    private static final int GL_TEXTURE_EXTERNAL_OES = 0x8D65;

    protected ExtTexture mExtTexture;
    private SurfaceTexture mSurfaceTexture;
    private int mWidth, mHeight;
    private float[] mTransform = new float[16];
    private boolean mHasTexture = false;

    public SurfaceTextureScreenNail() {
    }

    public void acquireSurfaceTexture() {
        mExtTexture = new ExtTexture(GL_TEXTURE_EXTERNAL_OES);
        mExtTexture.setSize(mWidth, mHeight);
        mSurfaceTexture = new SurfaceTexture(mExtTexture.getId());
        setDefaultBufferSize(mSurfaceTexture, mWidth, mHeight);
        mSurfaceTexture.setOnFrameAvailableListener(this);
        synchronized (this) {
            mHasTexture = true;
        }
    }

    @TargetApi(ApiHelper.VERSION_CODES.ICE_CREAM_SANDWICH_MR1)
    private static void setDefaultBufferSize(SurfaceTexture st, int width, int height) {
        if (ApiHelper.HAS_SET_DEFALT_BUFFER_SIZE) {
            st.setDefaultBufferSize(width, height);
        }
    }

    @TargetApi(ApiHelper.VERSION_CODES.ICE_CREAM_SANDWICH)
    private static void releaseSurfaceTexture(SurfaceTexture st) {
        st.setOnFrameAvailableListener(null);
        if (ApiHelper.HAS_RELEASE_SURFACE_TEXTURE) {
            st.release();
        }
    }

    public SurfaceTexture getSurfaceTexture() {
        return mSurfaceTexture;
    }

    public void releaseSurfaceTexture() {
        synchronized (this) {
            mHasTexture = false;
        }
        mExtTexture.recycle();
        mExtTexture = null;
        releaseSurfaceTexture(mSurfaceTexture);
        mSurfaceTexture = null;
    }

    public void setSize(int width, int height) {
        mWidth = width;
        mHeight = height;
    }

    public void resizeTexture() {
        if (mExtTexture != null) {
            mExtTexture.setSize(mWidth, mHeight);
            setDefaultBufferSize(mSurfaceTexture, mWidth, mHeight);
        }
    }

    @Override
    public int getWidth() {
        return mWidth;
    }

    @Override
    public int getHeight() {
        return mHeight;
    }

    @Override
    public void draw(GLCanvas canvas, int x, int y, int width, int height) {
        synchronized (this) {
            if (!mHasTexture) return;
            mSurfaceTexture.updateTexImage();
            mSurfaceTexture.getTransformMatrix(mTransform);

            // Flip vertically.
            canvas.save(GLCanvas.SAVE_FLAG_MATRIX);
            int cx = x + width / 2;
            int cy = y + height / 2;
            canvas.translate(cx, cy);
            canvas.scale(1, -1, 1);
            canvas.translate(-cx, -cy);
            updateTransformMatrix(mTransform);
            canvas.drawTexture(mExtTexture, mTransform, x, y, width, height);
            canvas.restore();
        }
    }

    @Override
    public void draw(GLCanvas canvas, RectF source, RectF dest) {
        throw new UnsupportedOperationException();
    }

    protected void updateTransformMatrix(float[] matrix) {}

    @Override
    abstract public void noDraw();

    @Override
    abstract public void recycle();

    @Override
    abstract public void onFrameAvailable(SurfaceTexture surfaceTexture);
}