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# CVV : the API

## Introduction

Namespace for all functions is cvv, i.e. cvv::showImage().

Compilation:

- For development, i.e. for cvv GUI to show up, compile your code using cvv with g++ -DCVVISUAL_DEBUGMODE.
- For release, i.e. cvv calls doing nothing, compile your code without above flag.

See cvv tutorial for a commented example application using cvv.

## API Functions

### showImage

Add a single image to debug GUI (similar to imshow).

C++:`` void `showImage`(InputArray img, const CallMetaData& metaData, const string& description, const string& view)

  Parameters: | img – Image to show in debug GUI. metaData – Properly initialized CallMetaData struct, i.e. information about file, line and function name for GUI. Use CVVISUAL_LOCATION macro. description – Human readable description to provide context to image. view – Preselect view that will be used to visualize this image in GUI. Other views can still be selected in GUI later on.

### debugFilter

Add two images to debug GUI for comparison. Usually the input and output of some filter operation, whose result should be inspected.

C++:`` void `debugFilter`(InputArray original, InputArray result, const CallMetaData& metaData, const string& description, const string& view)

  Parameters: | original – First image for comparison, e.g. filter input. result – Second image for comparison, e.g. filter output. metaData – See `showImage()` description – See `showImage()` view – See `showImage()`

### debugDMatch

Add a filled in DMatch to debug GUI. The matches can are visualized for interactive inspection in different GUI views (one similar to an interactive drawMatches).

C++:`` void `debugDMatch`(InputArray img1, std::vector<cv::KeyPoint> keypoints1, InputArray img2, std::vector<cv::KeyPoint> keypoints2, std::vector<cv::DMatch> matches, const CallMetaData& metaData, const string& description, const string& view, bool useTrainDescriptor)

  Parameters: | img1 – First image used in DMatch. keypoints1 – Keypoints of first image. img2 – Second image used in DMatch. keypoints2 – Keypoints of second image. metaData – See `showImage()` description – See `showImage()` view – See `showImage()` useTrainDescriptor – Use DMatch‘s train descriptor index instead of query descriptor index.

### finalShow

This function must be called once after all cvv calls if any. As an alternative create an instance of FinalShowCaller, which calls finalShow() in its destructor (RAII-style).

C++:`` void `finalShow`()

### setDebugFlag

Enable or disable cvv for current translation unit and thread (disabled this way has higher - but still low - overhead compared to using the compile flags).

C++:`` void `setDebugFlag`(bool active)

  Parameters: | active – See above

## Help and Feedback

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- Ask a question on the Q&A forum.
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### Navigation

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- cvv. GUI for Interactive Visual Debugging of Computer Vision Programs »