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Flutter – Expand CameraPreview to fit device width

I am building a custom camera UI. I would like the CameraPreview to be expanded so it fits the device width. This is the implementation and the result:

          return Column(
            mainAxisSize: MainAxisSize.max,
            children: [
              Expanded(
                  child: GestureDetector(
                onTapUp: (details) {
                  focusOnTap(details);
                },
                onScaleStart: (details) {
                  zoom = _scaleFactor;
                },
                onScaleUpdate: (details) {
                  if (currentCamera == widget.normalCamera) {
                    onZoomChange(details.scale);
                  }
                },
                child: Stack(
                  children: [
                    CameraPreview(cameraController),
                    // top banner
                    Positioned.fill(
                      ...
                    ),
                    // bottom banner
                    Positioned.fill(
                      ...
                    ),


                    // zoom selector
                    Positioned.fill(
                      ....
                    ),

                    // top actions
                    SafeArea(
                      ....
                    ),
                  ],
                ),
              )),

              // bottom actions
              GestureDetector(
                onHorizontalDragEnd: (details) {
                  cameraController.dispose();
                  widget.onSwipe(details);
                },
                child: Container(
                  ....
                ),
              ),

enter image description here

As you can see, on the right there is a black empty space. I would like it to be gone and the camera preview expanded to match the full width.

Tags:

2

Answers


  1. Chosen as BEST ANSWER
    0

    Ok was easier than I thought. I was playing with AspectRadio and Transform.scale, but was enough to wrap CameraPreview in a Container

    Container(width: screenSize.width ,child: CameraPreview(cameraController))


  2. 0

    To expand the CameraPreview to match the full width of the device, you can use the LayoutBuilder widget to get the available width and set the appropriate aspect ratio for the CameraPreview. Here’s how you can modify your code:

    return LayoutBuilder(
  builder: (BuildContext context, BoxConstraints constraints) {
    final screenWidth = constraints.maxWidth;
    final screenHeight = constraints.maxHeight;

    return Column(
      mainAxisSize: MainAxisSize.max,
      children: [
        Expanded(
          child: GestureDetector(
            onTapUp: (details) {
              focusOnTap(details);
            },
            onScaleStart: (details) {
              zoom = _scaleFactor;
            },
            onScaleUpdate: (details) {
              if (currentCamera == widget.normalCamera) {
                onZoomChange(details.scale);
              }
            },
            child: Stack(
              children: [
                AspectRatio(
                  aspectRatio: cameraController.value.aspectRatio,
                  child: CameraPreview(cameraController),
                ),
               // top banner
                Positioned.fill(
                  child: Container(
                    color: Colors.black.withOpacity(0.5),
                    // Add your top banner content here
                  ),
                ),
                // bottom banner
                Positioned.fill(
                  child: Align(
                    alignment: Alignment.bottomCenter,
                    child: Container(
                      color: Colors.black.withOpacity(0.5),
                      // Add your bottom banner content here
                    ),
                  ),
                ),
                // zoom selector
                Positioned.fill(
                  child: Align(
                    alignment: Alignment.center,
                    child: Container(
                      // Add your zoom selector content here
                    ),
                  ),
                ),
                // top actions
                SafeArea(
                  child: Container(
                   // Add your top actions content here
                  ),
                ),
              ],
            ),
          ),
        ),
        // bottom actions
        GestureDetector(
          onHorizontalDragEnd: (details) {
            cameraController.dispose();
            widget.onSwipe(details);
          },
          child: Container(
            // Add your bottom actions content here
          ),
        ),
      ],
    );
  },
);

    Here’s what’s changed:

    1. We wrap the entire Column with a LayoutBuilder widget to get the available width and height of the screen.
    2. Inside the LayoutBuilder, we calculate the screenWidth and screenHeight based on the constraints.
    3. We replace the CameraPreview with an AspectRatio widget, which will maintain the aspect ratio of the camera preview while expanding it to the full width of the screen.
    4. We set the aspectRatio of the AspectRatio widget to cameraController.value.aspectRatio, which ensures that the camera preview maintains its original aspect ratio.
    5. We adjust the positioning of the top and bottom banners using Positioned.fill and Align to ensure they cover the entire screen width.
    6. We adjust the positioning of the zoom selector and top actions to maintain their desired positions.
    7. We adjust the positioning of the bottom actions to maintain their desired position.

    By wrapping the CameraPreview with an AspectRatio widget and using LayoutBuilder to get the available width and height, the camera preview will now expand to match the full width of the device while maintaining its aspect ratio.

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