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Summer Challenge [FFH] harmonyos mobile phone remote control Dayu development board camera

2022-06-30 23:26:00 【51CTO】

[ This article is participating in the starlight project 3.0- Summer Challenge ]

The previous blog posts solved HarmonyOS and OpenHarmony Communication problems , Now try to do something with communication . For example, remote control the camera of the development board with a mobile phone , Or the camera of the development board remote control mobile phone , And even send back photos . The way to call the board's camera has been studied , There are two main types , One is camera Components , One is to call API. Start with the simple camera Component start .

0. effect

Interface call successful
Existing problems
The pictures taken are not actually saved to the gallery .

1.Camera Components

1.1 Need authority

Camera permissions , Permission to read and write media files .

     {
        "name": "ohos.permission.CAMERA"
      },
     {
        "name": "ohos.permission.WRITE_MEDIA"
      },
      {
        "name": "ohos.permission.READ_MEDIA"
      }  

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1.2 Supported events

In addition to common events , And support error event , Triggered when the user is not allowed to use the camera .

1.3 Support methods

Support only ,takePhoto(CameraTakePhotoOptions), Photo setting parameters .

CameraTakePhotoOptions
parameter list

Parameters	type	describe
quality	string	Picture quality ：high,normal,low
success	Function	Interface calls the successful callback function
fail	Function	Interface call failed callback function
complete	Function	The callback function at the end of the interface call

2. Case writing

About the mobile phone side , Development board side UDP Please read my previous blog posts for correspondence , Only share here Camera Component invocation of
HarmonyOS And OpenHarmony signal communication

2.1 index.css

Here you can use a camera picture for the overall situation

<camera flash="on" deviceposition="back" @error="cameraError" style="height: 100%;width: 100%;position: absolute;top: 1%;" onclick="takepic" id="c">
  </camera>

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flash Value controls the turn on of the flash
@error That's what I mentioned earlier , Callback function that will be triggered if the user does not authorize
deviceposition The value of indicates the front and rear cameras ,front Indicates the front ,back Indicates post .

2.2 index.js

It is agreed here that , Accept to 0 The information of indicates the operation of taking pictures , The mobile phone side can be written using the previous functions .

takePhoto(options)

   takepic(){
        var options= {
            "quality":"normal",
            "success":this.onSuccess(),
            "fail":this.onFailed(),
            "complete":this.onCompleted()
        }
        this.$element("c").takePhoto(options
        );
    },
    onFailed:async function(){
        prompt.showToast({
            message: " Shooting failed "
        });
    },

    onSuccess:async function(e){
        console.info(this.TAG+JSON.stringify(e))
        prompt.showToast({
            message: " Successful shooting "
        });
    },
    onCompleted:async function(){
        prompt.showToast({
            message: " Shooting complete "
        });
    },
     cameraError(){
        prompt.showToast({
            message: " privilege grant failed ！"
        });
    },

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There will be takpic() Method binding to UDPsocket On the listening function of , When the judgment information is 0 When , Take photos , It can be done by toast The window judges the shooting situation .

stay config.json Add read-write media to , Camera permissions .
Get user authorization

  grantPermission() {
        console.info('Calc[IndexPage] grantPermission')
        let context = featureAbility.getContext()
        context.requestPermissionsFromUser(['ohos.permission.CAMERA', "ohos.permission.WRITE_MEDIA","ohos.permission.READ_MEDIA"], 666, function (result) {
         
        })
    },

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3. Conclusion

so Camera The component can obtain the preview and photographing functions of the camera , Each callback function can enter , But it is not saved to the gallery , It may be that the component is not yet complete . Next time we continue to try calling other api To get the camera preview stream and take photos .

Attachment link ：

Development board side UDP+Camera Case study .zip( https://ost.51cto.com/resource/2108)
HarmonyOS.zip( https://ost.51cto.com/resource/2109)

Want to know more about open source , Please visit ：

51CTO Open source basic software community

https://ost.51cto.com/#bkwz

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