Bug Report T622136
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TdxCameraControl uses CPU resources for still frame repainting after the State property is set to cssPause

created 7 years ago

I use the VCL TdxCameraControl (Version 17.2.6). The component itself works fine.
However,  the permanent CPU load is very high when the component is activated (14% at 1024x768 component size in my case).
The CPU load goes even higher when the component size is increased.

Setting the dxCameraControl1.state = ccsPaused doesn't help. The cpu load remains the same.
This behaviour is shown with different cameras connected to the PC.

Is there a possibility to influence the CPU load caused by the component? Reduce frame rate, …?

Kind regards,
Johannes

Show previous comments (1)
JH JH
Johannes Huber 7 years ago

    Hello Paulo,

    having a reduced CPU load in ccsPaused state would help allot!

    I have only one TdxCameraControl on the form.

    DevExpress Support Team 7 years ago

      Thanks, Johannes. I have just published the hotfix that should help you decrease the amount of used CPU resources in the ccsPaused state. Please download it from the right side of this page, apply it to v17.2.6 and let me know the result.

      JH JH
      Johannes Huber 7 years ago

        Thanks Paulo for your excellent support!!!

        The provided solution is nearly perfect. There is a small side effect.
        The component behaves different when dxCameraControl1.state = ccsPaused and the method dxCameraControl1.Capture is called.
        Before the change the displayed image was updated.
        Now it doesn't get updated when the component is in ccsPaused state and capture is called.
        I think it would be just a minor change in TdxCustomCameraControl.Capture an the component behaves as before.
        procedure TdxCustomCameraControl.Capture;
        begin
          cxInvalidateRect(Self);     //add
          FCamera.Capture(FCapturedBitmap);
        end;

        Answers approved by DevExpress Support

        created 7 years ago (modified 7 years ago)

        We have fixed the issue described in this ticket and will include the fix in our next maintenance update. To apply this solution before the official update, request a hotfix by clicking the corresponding link for product versions you require.

        Note: Hotfixes may be unavailable for beta versions and updates that are about to be released.

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