Table of Contents

Introduction

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.

Installation

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

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:

Development

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

CI Workflows

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

Limitations

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: