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      1 /*
      2  * Copyright (C) 2010 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include <android/looper.h>
     18 #include <gui/DisplayEventReceiver.h>
     19 #include <utils/Looper.h>
     20 
     21 using namespace android;
     22 
     23 int receiver(int /*fd*/, int /*events*/, void* data)
     24 {
     25     DisplayEventReceiver* q = (DisplayEventReceiver*)data;
     26 
     27     ssize_t n;
     28     DisplayEventReceiver::Event buffer[1];
     29 
     30     static nsecs_t oldTimeStamp = 0;
     31 
     32     while ((n = q->getEvents(buffer, 1)) > 0) {
     33         for (int i=0 ; i<n ; i++) {
     34             if (buffer[i].header.type == DisplayEventReceiver::DISPLAY_EVENT_VSYNC) {
     35                 printf("event vsync: count=%d\t", buffer[i].vsync.count);
     36             }
     37             if (oldTimeStamp) {
     38                 float t = float(buffer[i].header.timestamp - oldTimeStamp) / s2ns(1);
     39                 printf("%f ms (%f Hz)\n", t*1000, 1.0/t);
     40             }
     41             oldTimeStamp = buffer[i].header.timestamp;
     42         }
     43     }
     44     if (n<0) {
     45         printf("error reading events (%s)\n", strerror(-n));
     46     }
     47     return 1;
     48 }
     49 
     50 int main(int /*argc*/, char** /*argv*/)
     51 {
     52     DisplayEventReceiver myDisplayEvent;
     53 
     54 
     55     sp<Looper> loop = new Looper(false);
     56     loop->addFd(myDisplayEvent.getFd(), 0, ALOOPER_EVENT_INPUT, receiver,
     57             &myDisplayEvent);
     58 
     59     myDisplayEvent.setVsyncRate(1);
     60 
     61     do {
     62         //printf("about to poll...\n");
     63         int32_t ret = loop->pollOnce(-1);
     64         switch (ret) {
     65             case ALOOPER_POLL_WAKE:
     66                 //("ALOOPER_POLL_WAKE\n");
     67                 break;
     68             case ALOOPER_POLL_CALLBACK:
     69                 //("ALOOPER_POLL_CALLBACK\n");
     70                 break;
     71             case ALOOPER_POLL_TIMEOUT:
     72                 printf("ALOOPER_POLL_TIMEOUT\n");
     73                 break;
     74             case ALOOPER_POLL_ERROR:
     75                 printf("ALOOPER_POLL_TIMEOUT\n");
     76                 break;
     77             default:
     78                 printf("ugh? poll returned %d\n", ret);
     79                 break;
     80         }
     81     } while (1);
     82 
     83     return 0;
     84 }
     85