BoxPoints, MinAreaRect inconsistent with C++ version of OpenCV, causing precision issues

[TeCHiScy]

Description

In the gocv impl, for example, the MinAreaRect function (https://github.com/covrom/gocv/blob/master/imgproc.cpp#L185), rounds points coordination, center point coordination, and size of a RotatedRect to int, while in OpenCV, they are float. I'm porting Paddle inference code from C++ to Go (which needs gocv), where keeping float precision is essential in sequence of operations, otherwise errors may accumulate. So here's my question:

• Is the round used in BoxPoints and MinAreaRect intentionally (by design)?
• If not, would you accept a PR that provides float precision version, e.g. BoxPoints2f, MinAreaRect2f that consistents with OpenCV?

Steps to Reproduce

No steps needed.

Your Environment

• Operating System and version: Linux docker-desktop 6.6.12-linuxkit # 1 SMP Fri Jan 19 08:53:17 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux
• OpenCV version used: 4.8.1
• How did you install OpenCV? GoCV Makefile
• GoCV version used: v0.35.0
• Go version: go version go1.21.7 linux/amd64
• Did you run the env.sh or env.cmd script before trying to go run or go build? Not related

[deadprogram]

Hello @TeCHiScy

would you accept a PR that provides float precision version, e.g. BoxPoints2f, MinAreaRect2f that consistents with OpenCV?

Yes, please.

The reason for the rounding in BoxPoints() and MinAreaRect() is because most people expect to be able to do something with that Rect such as display it. So your use case is a little different, but seems like a good thing.

[TeCHiScy]

Close as completed in v0.36.0.