Table of Contents

• Introduction
• Installation
• Usage
• Development
• CI Workflows
• Limitations

I love my grand'ma, she makes the best Belgian waffles in the world.

In order to remain her favorite grand-son, I decided to help her enjoying her favorite hobby: rotating pictures of her dearest memories.

To help her out, I wrote the i-luv-grandma program which takes pbm files and rotates the pictures to a given angle.

• from release assets
  • download assets for your architecture from latest release
  • extract tarball: tar xzf i-luv-grandma_1.0.0_linux_amd64.tar.gz
• from go install: go install gihub.com/psycofdj/i-luv-grandma
• from source: CGO_ENABLED=0 go build -o i-luv-grandma -ldflags='-s -w' .

usage: i-luv-grandma [options]

Rotate pbm image by given angle. Result is written to output file.

  -angle float
        rotation of given decimal angle (positive or negative) (default 90)
  -help
        print usage
  -input string
        process given input file path, '-' for stdin (default "input.pbm")
  -output string
        write to given output file path, '-' for stdout (default "output.pbm")
  -profile string
        generate pprof profile output
  -version
        outputs version and revision informations

Example:

$ ./i-luv-grandma --angle 180 --input dataset/valid_j.pbm --output -

P1
6 10
000000
000000
001110
010001
010000
010000
010000
010000
010000
010000

• original file:
• with 45° rotation:
• with 90° rotation:
• with 180° rotation:

• unit-tests

  • run: go test ./...

• unit-tests coverage report

  • run: go test -cover -coverprofile cover.out -v ./... && go tool cover -func=cover.out

• static check analysis:

  • install: https://golangci-lint.run/usage/install/#local-installation
  • run: golangci-lint run --config .golangci.yml

• performance analysis

  • generate profile trace: ./i-luv-grandma -profile output.pprof -input dataset/4320p.pbm -output /dev/null -angle 180
  • inspect profile: go tool pprof -top i-luv-grandma output.pprof

• view documentation locally

  • install pkgsite: go install golang.org/x/pkgsite/cmd/pkgsite@latest
  • run pkgsite: pkgsite
  • open browser: sensible-browser http://localhost:8080

• the release workflow:

  • triggers on new semver tags like v1.2.3 or v1.2.3-rc4
  • checks that unit-tests are passing and that code is free from linter warnings
  • run goreleaser which:
    • generates tarballs for linux and darwin arch
    • creates new github release
    • upload tarballs to releases

• the tests workflow:

  • triggers on new commits
  • run unit-tests

• the linter workflow:

  • triggers on new commits
  • run golangci-lint
  • creates github annotations for each issues found by the linter

• the reports workflow:

  • triggers on new commit for main branch
  • creates coverage report
    • runs unit-tests and extract coverage informations
    • creates badge file with overall total result (displayed on top of this README.md)
  • creates documentation report
    • generate static documentation websiteusing godoc-static
    • creates badge (displayed on top of this README.md)
  • pushes gh-pages branch which is served by Github Pages

The current rotate implementation guaranty to preserve source image size at the cost of possible pixel loss for those projected outside boundaries.

This could be a problem for my beloved grandma cause she clearly lakes basic photograph skills and the main subject is in the bottom right corner most of the time.

A possible improvement would we to implement a --resize option that allows a different size in result image. It could work as follow:

• create a bigger working space ensuring all points can be projected for any given angles
  • required space size can be computed by rotating all 4 corner pixels
• translate source image in new space matching center of rotation
• operate pixel rotations