Android Surfaceflinger 的使用

    最近在做一个android的新平台，涉及到了SurfaceFlinger的使用。又要在另外一个平台上实现一个抓屏的功能，被折磨的囧啊。最近终于能够闲下来整理一下这块的东西了。网上有很多讲解SurfaceFlinger的文章，但大部分都是原理分析，看的头大。下面是一个测试小例子，测试SurfaceFlinger的使用，并结合skia测试了软合成shotsceen的性能。

/**
 * =====================================================================================
 *       Filename:  surface.cpp
 *        Created:  2012年03月24日 13时39分28秒
 *         Author:  louie (),
 *        Company:  sunniwell.net
 *    Description:  surface test
 * =====================================================================================
 */

#define LOG_TAG "SurfaceTest"

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <dirent.h>
#include <unistd.h>
#include <string.h>
#include <linux/fb.h>

#include <binder/IPCThreadState.h>
#include <binder/ProcessState.h>
#include <binder/IMemory.h>
#include <binder/IPCThreadState.h>
#include <binder/IServiceManager.h>
#include <binder/MemoryHeapBase.h>
#include <binder/MemoryBase.h>
#include <binder/Binder.h>
#include <utils/Log.h>

#include <cutils/atomic.h>
#include <cutils/properties.h>
#include <utils/threads.h>
#include <utils/Atomic.h>
#include <utils/String16.h>
#include <android_runtime/AndroidRuntime.h>
#include <android_runtime/ActivityManager.h>

#include <media/AudioTrack.h>
#include <media/RobotWrapper.h>

#include <surfaceflinger/Surface.h>
#include <surfaceflinger/ISurface.h>
#include <surfaceflinger/ISurfaceComposer.h>
#include <surfaceflinger/SurfaceComposerClient.h>
#include <ui/DisplayInfo.h>

#include <SkTypeface.h>
#include <SkTemplates.h>
#include <SkRegion.h>
#include <SkDevice.h>
#include <SkRect.h>
#include <SkCanvas.h>
#include <SkBitmap.h>
#include <SkStream.h>
#include <SkImageDecoder.h>
#include <SkImageEncoder.h>
#include "hi_unf_disp.h"

using namespace android;

bool SkFileDecoder( SkBitmap* bitmap, const char srcPath[], int bits_per_pixel)
{
    SkFILEStream stream(srcPath);
    if (!stream.isValid()) {
        LOGE("ERROR: bad filename <%s>\n", srcPath);
        return false;
    }

    stream.rewind();
    SkImageDecoder* codec = SkImageDecoder::Factory(&stream);
    if (NULL == codec) {
        LOGE("ERROR: no codec found for <%s>\n", srcPath);
        return false;
    }

    SkBitmap::Config config;
    switch (bits_per_pixel)
    {
        case 32:
            config = SkBitmap::kARGB_8888_Config;
            break;
        case 16:
            config = SkBitmap::kRGB_565_Config;
            break;
        default:
            LOGE ("Warning: drawRect() not implemented for color depth %i\n",bits_per_pixel);
            break;
    }
    SkAutoTDelete<SkImageDecoder> ad(codec);

    stream.rewind();
    if (!codec->decode(&stream, bitmap,  config,
                SkImageDecoder::kDecodePixels_Mode)) {
        LOGE("ERROR: codec failed for <%s>\n", srcPath);
        return false;
    }
    return true;
}

int main( )
{
    sp<SurfaceComposerClient>  surfaceclient;
    sp<SurfaceControl>         surfaceControl;
    sp<Surface>                surface;
    SkBitmap                   bitmap;
    Surface::SurfaceInfo       info;
    DisplayInfo display;

    //surface 的名字以pid开头
    LOGE("[%s %s %d] \n", __FUNCTION__, __FILE__, __LINE__, getpid());
    surfaceclient = new SurfaceComposerClient();
    surfaceclient->getDisplayInfo(0, &display);
    LOGE("display < %d %d>", display.w, display.h);
    surfaceControl = surfaceclient->createSurface(getpid(), 0, display.w, display.h, PIXEL_FORMAT_RGBA_8888);

    //composer parameters必须在一对open/close transaction之间当close调用时，
    //参数被提交给服务端参数值的改变都存放在/frameworks/base/include/private/surfaceflinger/LayerState.h:layer_state_t中，
    //当调用closeTransaction时，结构体才会被传送到服务端。这样可以明显简化C/S接口、加快C/S通信速度。
    surfaceclient->openTransaction();
    surfaceControl->setLayer(1000);
    surfaceControl->setSize(display.w, display.h);
    surfaceControl->setPosition(1, 1);
    surfaceControl->show( );
    surfaceclient->closeTransaction();

    surface = surfaceControl->getSurface();

    surface->lock(&info);
    bitmap.setConfig(SkBitmap::kARGB_8888_Config, fb_w, fb_h);
    bitmap.setIsOpaque(true);
    bitmap.setPixels(info.bits);
    SkCanvas* canvas = new SkCanvas(bitmap);
    surface->unlockAndPost();

    int A = 150, R = 128, G = 128, B = 128 ;
    while( A < 256)
    {
        LOGE("Surface <%d %d %d %d>\n", A, R, G, B);
        surface->lock(&info);
        /*bitmap 的buffer 被重置，surface 为双缓冲，前后buffer被替换 因此每次都要重新设置bitmap的内存*/
        bitmap.setPixels(info.bits);
        bitmap.eraseARGB(A, R, G, B);
        surface->unlockAndPost();
        A += 20;
        sleep(3);
    }

    SkPaint paint;
    int color = 0xff00ff77;
    paint.setARGB(color>>24 & 0xff, color>>16 & 0xff, color>>8 & 0xff, color & 0xff);

    surface->lock(&info);
    bitmap.setPixels(info.bits);
    bitmap.eraseARGB(0, 0, 0, 0);
    canvas->setBitmapDevice(bitmap);
    canvas->drawLine(100, 100, 500, 500, paint);
    surface->unlockAndPost();
    sleep(3);

    surface->lock(&info);
    bitmap.setPixels(info.bits);
    bitmap.eraseARGB(0, 0, 0, 0);
    SkRect rect;
    rect.fLeft = 200;
    rect.fTop  = 200;
    rect.fRight = 400;
    rect.fBottom = 400;
    color = 0xffff0077;
    paint.setARGB(color>>24 & 0xff, color>>16 & 0xff, color>>8 & 0xff, color & 0xff);
    canvas->setBitmapDevice(bitmap);
    canvas->drawRect(rect, paint);
    surface->unlockAndPost();
    sleep(3);

    surface->lock(&info);
    bitmap.setPixels(info.bits);
    bitmap.eraseARGB(0, 0, 0, 0);
    color = 0xff0f00ff;
    paint.setARGB(color>>24 & 0xff, color>>16 & 0xff, color>>8 & 0xff, color & 0xff);
    canvas->setBitmapDevice(bitmap);
    canvas->drawCircle(640, 260, 100, paint);
    surface->unlockAndPost();
    sleep(3);

    surface->lock(&info);
    bitmap.setIsOpaque(false);
    bitmap.setPixels(info.bits);
    bitmap.eraseColor(0);
    canvas->setBitmapDevice(bitmap);
    /* 在这里原来使用的是bitmap，但是没有显示出来，仔细分析了一下，觉得原因在图片解码的时候，
     * bitmap内存被重新分配。可以看一下skia的源码。在这里画出的2.png的位置有点问题，但是jpg的
     * 图片的位置时正确的，没找到原因。
     */
    SkBitmap  Ibitmap;
    SkFileDecoder(&Ibitmap, "/swcommon/1.png", 32);
    SkRect dst{0, 0, bitmap.width(), bitmap.height()};
    SkIRect src{0, 0, Ibitmap.width(), Ibitmap.height()};
    canvas->drawBitmapRect(Ibitmap, &src, dst);
    Ibitmap.eraseColor(0);
    SkFileDecoder(&Ibitmap, "/swcommon/2.png", 32);
    SkRect dst2{200, 200, 700, 500};
    canvas->drawBitmapRect(Ibitmap, &src, dst2);
    surface->unlockAndPost();
    sleep(3);

    surface->lock(&info);
    bitmap.setPixels(info.bits);
    bitmap.eraseColor(0);
    canvas->setBitmapDevice(bitmap);
    Ibitmap.eraseColor(0);
    SkFileDecoder(&Ibitmap, "/swcommon/1.jpg", 32);
    SkIRect srcj{0, 0, Ibitmap.width(), Ibitmap.height()};
    canvas->drawBitmapRect(Ibitmap, &srcj, dst);

    Ibitmap.eraseColor(0);
    SkFileDecoder(&Ibitmap, "/swcommon/2.jpg", 32);
    SkRect dst4{200, 200, 700, 500};
    canvas->drawBitmapRect(Ibitmap, &src, dst4);
    SkImageEncoder::EncodeFile("/swcommon/screenshot.jpg", bitmap, SkImageEncoder::kJPEG_Type, 100);

    surface->unlockAndPost();
    sleep(3);

    LOGE("[%s %s %d]  END !\n", __FUNCTION__, __FILE__, __LINE__);
    return 0;
}