解析android截屏问题

/*
  * Copyright (C) 2010 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.
  */

 #include <utils/Log.h>

 #include <binder/IPCThreadState.h>
 #include <binder/ProcessState.h>
 #include <binder/IServiceManager.h>

 #include <binder/IMemory.h>
 #include <surfaceflinger/ISurfaceComposer.h>

 #include <SkImageEncoder.h>
 #include <SkBitmap.h>

 using namespace android;

 int main(int argc, char** argv)
 {
     if (argc != 2) {
         printf("usage: %s path\n", argv[0]);
         exit(0);
     }

     const String16 name("SurfaceFlinger");
     sp<ISurfaceComposer> composer;
     getService(name, &composer);

     sp<IMemoryHeap> heap;
     uint32_t w, h;
     PixelFormat f;
     status_t err = composer->captureScreen(0, &heap, &w, &h, &f, 0, 0);
     if (err != NO_ERROR) {
         fprintf(stderr, "screen capture failed: %s\n", strerror(-err));
         exit(0);
     }

     printf("screen capture success: w=%u, h=%u, pixels=%p\n",
             w, h, heap->getBase());

     printf("saving file as PNG in %s ...\n", argv[1]);

     SkBitmap b;
     b.setConfig(SkBitmap::kARGB_8888_Config, w, h);
     b.setPixels(heap->getBase());
     SkImageEncoder::EncodeFile(argv[1], b,
             SkImageEncoder::kPNG_Type, SkImageEncoder::kDefaultQuality);

     return 0;
 }

status_t SurfaceFlinger::captureScreenImplLocked(DisplayID dpy,
         sp<IMemoryHeap>* heap,
         uint32_t* w, uint32_t* h, PixelFormat* f,
         uint32_t sw, uint32_t sh)
 {
    LOGI("captureScreenImplLocked");
     status_t result = PERMISSION_DENIED;

     // only one display supported for now
     if (UNLIKELY(uint32_t(dpy) >= DISPLAY_COUNT))
         return BAD_VALUE;

     if (!GLExtensions::getInstance().haveFramebufferObject())
         return INVALID_OPERATION;

     // get screen geometry
     const DisplayHardware& hw(graphicPlane(dpy).displayHardware());
     const uint32_t hw_w = hw.getWidth();
     const uint32_t hw_h = hw.getHeight();

     if ((sw > hw_w) || (sh > hw_h))
         return BAD_VALUE;

     sw = (!sw) ? hw_w : sw;
     sh = (!sh) ? hw_h : sh;
     const size_t size = sw * sh * 4;

     // make sure to clear all GL error flags
     while ( glGetError() != GL_NO_ERROR ) ;

     // create a FBO
     GLuint name, tname;
     glGenRenderbuffersOES(1, &tname);
     glBindRenderbufferOES(GL_RENDERBUFFER_OES, tname);
     glRenderbufferStorageOES(GL_RENDERBUFFER_OES, GL_RGBA8_OES, sw, sh);
     glGenFramebuffersOES(1, &name);
     glBindFramebufferOES(GL_FRAMEBUFFER_OES, name);
     glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES,
             GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, tname);

     GLenum status = glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES);
     if (status == GL_FRAMEBUFFER_COMPLETE_OES) {

         // invert everything, b/c glReadPixel() below will invert the FB
         glViewport(0, 0, sw, sh);
         glScissor(0, 0, sw, sh);
         glMatrixMode(GL_PROJECTION);
         glPushMatrix();
         glLoadIdentity();
         glOrthof(0, hw_w, 0, hw_h, 0, 1);
         glMatrixMode(GL_MODELVIEW);

         // redraw the screen entirely...
         glClearColor(0,0,0,1);
         glClear(GL_COLOR_BUFFER_BIT);

         const Vector< sp<LayerBase> >& layers(mVisibleLayersSortedByZ);
         const size_t count = layers.size();
         for (size_t i=0 ; i<count ; ++i) {
             const sp<LayerBase>& layer(layers[i]);
             layer->drawForSreenShot();
         }

         // XXX: this is needed on tegra
         glScissor(0, 0, sw, sh);

         // check for errors and return screen capture
         if (glGetError() != GL_NO_ERROR) {
             // error while rendering
             result = INVALID_OPERATION;
         } else {
             // allocate shared memory large enough to hold the
             // screen capture
             sp<MemoryHeapBase> base(
                     new MemoryHeapBase(size, 0, "screen-capture") );
             void* const ptr = base->getBase();
             if (ptr) {
                 // capture the screen with glReadPixels()
                 glReadPixels(0, 0, sw, sh, GL_RGBA, GL_UNSIGNED_BYTE, ptr);
                 if (glGetError() == GL_NO_ERROR) {
                     *heap = base;
                     *w = sw;
                     *h = sh;
                     *f = PIXEL_FORMAT_RGBA_8888;
                     result = NO_ERROR;
                 }
             } else {
                 result = NO_MEMORY;
             }
         }
         glEnable(GL_SCISSOR_TEST);
         glViewport(0, 0, hw_w, hw_h);
         glMatrixMode(GL_PROJECTION);
         glPopMatrix();
         glMatrixMode(GL_MODELVIEW);

  
     } else {
         result = BAD_VALUE;
     }

     // release FBO resources
     glBindFramebufferOES(GL_FRAMEBUFFER_OES, 0);
     glDeleteRenderbuffersOES(1, &tname);
     glDeleteFramebuffersOES(1, &name);

     hw.compositionComplete();

     return result;
 }

  
 status_t SurfaceFlinger::captureScreen(DisplayID dpy,
         sp<IMemoryHeap>* heap,
         uint32_t* width, uint32_t* height, PixelFormat* format,
         uint32_t sw, uint32_t sh)
 {
            LOGI("into captureScreen");          
     // only one display supported for now
     if (UNLIKELY(uint32_t(dpy) >= DISPLAY_COUNT))
         return BAD_VALUE;

     if (!GLExtensions::getInstance().haveFramebufferObject())
         return INVALID_OPERATION;

     class MessageCaptureScreen : public MessageBase {
         SurfaceFlinger* flinger;
         DisplayID dpy;
         sp<IMemoryHeap>* heap;
         uint32_t* w;
         uint32_t* h;
         PixelFormat* f;
         uint32_t sw;
         uint32_t sh;
         status_t result;
     public:
         MessageCaptureScreen(SurfaceFlinger* flinger, DisplayID dpy,
                 sp<IMemoryHeap>* heap, uint32_t* w, uint32_t* h, PixelFormat* f,
                 uint32_t sw, uint32_t sh)
             : flinger(flinger), dpy(dpy),
               heap(heap), w(w), h(h), f(f), sw(sw), sh(sh), result(PERMISSION_DENIED)
         {

         }
         status_t getResult() const {
            LOGI("getResult()");          
          return result;
         }
         virtual bool handler() {

  
    LOGI("handler()");
             Mutex::Autolock _l(flinger->mStateLock);

             // if we have secure windows, never allow the screen capture
             if (flinger->mSecureFrameBuffer)
                 return true;

             result = flinger->captureScreenImplLocked(dpy,
                     heap, w, h, f, sw, sh);

             return true;
         }
     };
    LOGI("before messagecapturescreen");
     sp<MessageBase> msg = new MessageCaptureScreen(this,
             dpy, heap, width, height, format, sw, sh);
     status_t res = postMessageSync(msg);
     if (res == NO_ERROR) {
         res = static_cast<MessageCaptureScreen*>( msg.get() )->getResult();
     }
     return res;
 }

status_t SurfaceFlinger::onTransact(
     uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
 {

     switch (code) {
         case CREATE_CONNECTION:
         case OPEN_GLOBAL_TRANSACTION:
         case CLOSE_GLOBAL_TRANSACTION:
         case SET_ORIENTATION:
         case FREEZE_DISPLAY:
         case UNFREEZE_DISPLAY:
         case BOOT_FINISHED:
         case TURN_ELECTRON_BEAM_OFF:
         case TURN_ELECTRON_BEAM_ON:
         {
             // codes that require permission check
             IPCThreadState* ipc = IPCThreadState::self();
             const int pid = ipc->getCallingPid();
             const int uid = ipc->getCallingUid();
             if ((uid != AID_GRAPHICS) && !mAccessSurfaceFlinger.check(pid, uid)) {
                 LOGE("Permission Denial: "
                         "can't access SurfaceFlinger pid=%d, uid=%d", pid, uid);
                 return PERMISSION_DENIED;
             }
             break;
         }
         case CAPTURE_SCREEN:
         {
             // codes that require permission check
             IPCThreadState* ipc = IPCThreadState::self();
             const int pid = ipc->getCallingPid();
             const int uid = ipc->getCallingUid();
             if ((uid != AID_GRAPHICS) && !mReadFramebuffer.check(pid, uid)) {

                 LOGE("Permission Denial: "
                         "can't read framebuffer pid=%d, uid=%d", pid, uid);
                 return PERMISSION_DENIED;
             }

             break;
         }
     }

     status_t err = BnSurfaceComposer::onTransact(code, data, reply, flags);
     if (err == UNKNOWN_TRANSACTION || err == PERMISSION_DENIED) {
         CHECK_INTERFACE(ISurfaceComposer, data, reply);
         if (UNLIKELY(!mHardwareTest.checkCalling())) {
             IPCThreadState* ipc = IPCThreadState::self();
             const int pid = ipc->getCallingPid();
             const int uid = ipc->getCallingUid();

    LOGI("err");
             LOGE("Permission Denial: "
                     "can't access SurfaceFlinger pid=%d, uid=%d", pid, uid);
             return PERMISSION_DENIED;
         }
         int n;
         switch (code) {
             case 1000: // SHOW_CPU, NOT SUPPORTED ANYMORE
             case 1001: // SHOW_FPS, NOT SUPPORTED ANYMORE
                 return NO_ERROR;
             case 1002:  // SHOW_UPDATES
                 n = data.readInt32();
                 mDebugRegion = n ? n : (mDebugRegion ? 0 : 1);
                 return NO_ERROR;
             case 1003:  // SHOW_BACKGROUND
                 n = data.readInt32();
                 mDebugBackground = n ? 1 : 0;
                 return NO_ERROR;
             case 1004:{ // repaint everything
                 Mutex::Autolock _l(mStateLock);
                 const DisplayHardware& hw(graphicPlane(0).displayHardware());
                 mDirtyRegion.set(hw.bounds()); // careful that's not thread-safe
                 signalEvent();
                 return NO_ERROR;
             }
             case 1005:{ // force transaction
                 setTransactionFlags(eTransactionNeeded|eTraversalNeeded);
                 return NO_ERROR;
             }
             case 1006:{ // enable/disable GraphicLog
                 int enabled = data.readInt32();
                 GraphicLog::getInstance().setEnabled(enabled);
                 return NO_ERROR;
             }
             case 1007: // set mFreezeCount
                 mFreezeCount = data.readInt32();
                 mFreezeDisplayTime = 0;
                 return NO_ERROR;
             case 1010:  // interrogate.
                 reply->writeInt32(0);
                 reply->writeInt32(0);
                 reply->writeInt32(mDebugRegion);
                 reply->writeInt32(mDebugBackground);
                 return NO_ERROR;
             case 1013: {
                 Mutex::Autolock _l(mStateLock);
                 const DisplayHardware& hw(graphicPlane(0).displayHardware());
                 reply->writeInt32(hw.getPageFlipCount());
             }
             return NO_ERROR;
         }
     }
     return err;
 }

 int checkSignaturesLP(Signature[] s1, Signature[] s2) {
        if (s1 == null) {
            return s2 == null
                    ? PackageManager.SIGNATURE_NEITHER_SIGNED
                    : PackageManager.SIGNATURE_FIRST_NOT_SIGNED;
        }
        if (s2 == null) {
            return PackageManager.SIGNATURE_SECOND_NOT_SIGNED;
        }
        HashSet<Signature> set1 = new HashSet<Signature>();
        for (Signature sig : s1) {
            set1.add(sig);
        }
        HashSet<Signature> set2 = new HashSet<Signature>();
        for (Signature sig : s2) {
            set2.add(sig);
        }
        // Make sure s2 contains all signatures in s1.
        if (set1.equals(set2)) {
            return PackageManager.SIGNATURE_MATCH;
        }
        return PackageManager.SIGNATURE_NO_MATCH;
    }

  

 // Check for shared user signatures
        if (pkgSetting.sharedUser != null && pkgSetting.sharedUser.signatures.mSignatures != null) {
            if (checkSignaturesLP(pkgSetting.sharedUser.signatures.mSignatures,
                    pkg.mSignatures) != PackageManager.SIGNATURE_MATCH) {
                Slog.e(TAG, "Package " + pkg.packageName
                        + " has no signatures that match those in shared user "
                        + pkgSetting.sharedUser.name + "; ignoring!");
                mLastScanError = PackageManager.INSTALL_FAILED_SHARED_USER_INCOMPATIBLE;
                return false;
            }
        }
        return true;

  
    private boolean verifySignaturesLP(PackageSetting pkgSetting,
            PackageParser.Package pkg) {

        // Check for shared user signatures
        if (pkgSetting.sharedUser != null && pkgSetting.sharedUser.signatures.mSignatures != null) {

        if (checkSignaturesLP(pkgSetting.sharedUser.signatures.mSignatures,
                    pkg.mSignatures) != PackageManager.SIGNATURE_MATCH) {

            Slog.e(TAG, "Package " + pkg.packageName
                        + " has no signatures that match those in shared user "
                        + pkgSetting.sharedUser.name + "; ignoring!");
                mLastScanError = PackageManager.INSTALL_FAILED_SHARED_USER_INCOMPATIBLE;
                return false;

            }
        }
        return true;
    }

View view = getWindow().getDecorView();  
       Display display = this.getWindowManager().getDefaultDisplay();  
       view.layout(0, 0, display.getWidth(), display.getHeight());  
       view.setDrawingCacheEnabled(true);//允许当前窗口保存缓存信息，这样  getDrawingCache()方法才会返回一个Bitmap  
       Bitmap bmp = Bitmap.createBitmap(view.getDrawingCache());