init

.gitignore

@@ -0,0 +1,4 @@
+config.json
+release.sh
+.idea
+dist

.goreleaser.yml

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+builds:
+  -
+    env:
+      - CGO_ENABLED=0
+    binary: rescreen
+    goos:
+      - linux
+    goarch:
+      - amd64
+      - i386
+    main: ./cmd/rescreen/main.go
+before:
+  hooks:
+    - go mod download
+archive:
+  replacements:
+    linux: Linux
+    386: i386
+    amd64: x86_64
+checksum:
+  name_template: 'checksums.txt'
+snapshot:
+  name_template: "{{ .Tag }}-next"
+changelog:
+  sort: asc
+  filters:
+    exclude:
+      - '^docs:'
+      - '^test:'

.travis.yml

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+language: go
+env:
+  - GO111MODULE=on
+go:
+  - 1.11.x
+before_install:
+  - go get github.com/mattn/goveralls
+script:
+  - $GOPATH/bin/goveralls -service=travis-ci

README.md

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+# rescreen [![Build Status](https://travis-ci.com/vcraescu/grandr.svg?branch=master)](https://travis-ci.com/vcraescu/grandr) [![Coverage Status](https://coveralls.io/repos/github/vcraescu/rescreen/badge.svg?branch=master)](https://coveralls.io/github/vcraescu/rescreen?branch=master)
+
+Configure screen layout
+
+**config.json**
+```json
+{
+  "layout": [
+    "HDMI-0", "eDP-1-1", 0, 0,
+    0, 0, 0, 0
+  ],
+  "monitors": {
+    "HDMI-0": {
+      "scale": 1.333,
+      "primary": true
+    }
+  }
+}
+```
+
+## Command
+
+`rescreen /path/to/config.json`
+
+If no config file path is given, it will look up for a config.json inside current folder.
+
+#### Dry run
+
+`rescreen --dry-run /path/to/config.json`
+
+It will just display the commands which will be run under the hood.

cmd/rescreen/main.go

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+package main
+
+import (
+	"errors"
+	"fmt"
+	"github.com/logrusorgru/aurora"
+	"github.com/vcraescu/go-xrandr"
+	"github.com/vcraescu/rescreen/config"
+	"github.com/vcraescu/rescreen/layout"
+	"gopkg.in/urfave/cli.v1"
+	"os"
+	"strings"
+)
+
+const version = "0.0.1"
+
+var dryRun bool
+
+func main() {
+	app := cli.NewApp()
+	app.Name = "rescreen"
+	app.Usage = "Configure screen layout"
+	app.UsageText = "rescreen [command options] config-file"
+	app.ArgsUsage = "Config file"
+	app.Version = version
+	app.Flags = []cli.Flag{
+		cli.BoolFlag{
+			Name:        "dry-run",
+			Usage:       "Just print the xrandr commands",
+			Destination: &dryRun,
+		},
+	}
+	app.Action = doAction
+
+	err := app.Run(os.Args)
+	if err != nil {
+		fmt.Println(aurora.Red(err))
+		os.Exit(1)
+	}
+}
+
+func doAction(c *cli.Context) error {
+	var configPath string
+	if c.NArg() == 0 {
+		return errors.New("config file path is mandatory")
+	}
+
+	configPath = c.Args().First()
+	cfg, err := config.LoadFile(configPath)
+	if err != nil {
+		return err
+	}
+
+	screens, err := xrandr.GetScreens()
+	if err != nil {
+		return err
+	}
+
+	lt, err := layout.New(cfg, screens)
+	if err != nil {
+		return err
+	}
+
+	cmd := xrandr.
+		Command().
+		DPI(lt.DPI).
+		ScreenSize(lt.Resolution)
+
+	for _, node := range lt.Nodes {
+		ocmd := cmd.
+			Output(node.Monitor).
+			Scale(node.Scale).
+			SetPrimary(node.Primary).
+			Position(node.Position)
+
+		if node.Right != nil {
+			ocmd = ocmd.LeftOf(node.Right.Monitor)
+		}
+
+		cmd = ocmd.EndOutput()
+	}
+
+	if !dryRun {
+		if err := cmd.Run(); err != nil {
+			return err
+		}
+
+		return nil
+	}
+
+	return execDryRun(cmd)
+}
+
+func execDryRun(cmd xrandr.CommandBuilder) error {
+	fmt.Println(aurora.Bold(aurora.Black(aurora.BgGreen(" DRY RUN "))))
+	cmds, err := cmd.RunnableCommands()
+	if err != nil {
+		return err
+	}
+
+	for _, cmd := range cmds {
+		fmt.Println(aurora.Green(strings.Join(cmd.Args, " ")))
+	}
+
+	return nil
+}

config/config.go

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+package config
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+)
+
+const layoutCols = 4
+const layoutRows = 4
+
+type Config struct {
+	Layout   LayoutConfig
+	Monitors MonitorsConfig `json:"monitors"`
+}
+
+type MonitorConfig struct {
+	Scale   float32 `json:"scale"`
+	Primary bool    `json:"primary"`
+}
+
+type MonitorsConfig map[string]MonitorConfig
+
+type LayoutConfig []string
+
+func (c Config) validate() error {
+	err := c.Layout.validate()
+	if err != nil {
+		return fmt.Errorf("invalid layout config: %s", err)
+	}
+
+	return nil
+}
+
+func (l LayoutConfig) Size() (int, int) {
+	return layoutRows, layoutCols
+}
+
+func (l LayoutConfig) validate() error {
+	u := make(map[string]bool)
+	for _, ID := range l {
+		if ID == "" {
+			continue
+		}
+
+		_, ok := u[ID]
+		if ok {
+			return fmt.Errorf(`"%s" appears twice`, ID)
+		}
+
+		u[ID] = true
+	}
+
+	if len(u) == 0 {
+		return fmt.Errorf("empty layout")
+	}
+
+	return nil
+}
+
+func (l LayoutConfig) Row(index int) ([]string, error) {
+	rowsCount, colsCount := l.Size()
+
+	if index >= rowsCount || index < 0 {
+		return nil, fmt.Errorf("index must be between 0 and %d", rowsCount-1)
+	}
+
+	var rc int
+	row := make([]string, colsCount)
+	for i, v := range l {
+		ci := i % colsCount
+		row[ci] = v
+		if ci != colsCount-1 {
+			continue
+		}
+
+		if rc == index {
+			return row, nil
+		}
+
+		rc++
+		row = make([]string, colsCount)
+	}
+
+	return row, nil
+}
+
+func (l LayoutConfig) RowsCount() int {
+	c := len(l)
+	if c == 0 {
+		return 0
+	}
+
+	return c / layoutCols
+}
+
+func (l LayoutConfig) Matrix() [][]string {
+	matrix := make([][]string, l.RowsCount())
+	for i := 0; i < l.RowsCount(); i++ {
+		row, err := l.Row(i)
+		if err != nil {
+			panic(err)
+		}
+
+		matrix[i] = row
+	}
+
+	return matrix
+}
+
+func (mc MonitorConfig) IsScaled() bool {
+	return mc.Scale > 0
+}
+
+func (mc MonitorConfig) Scaling() float32 {
+	if !mc.IsScaled() {
+		return 1
+	}
+
+	return mc.Scale
+}
+
+func LoadFile(filename string) (Config, error) {
+	var cfg Config
+	b, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return cfg, err
+	}
+
+	json.Unmarshal(b, &cfg)
+
+	err = cfg.validate()
+	if err != nil {
+		return cfg, err
+	}
+
+	return cfg, nil
+}
+

go.mod

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+module github.com/vcraescu/rescreen
+
+require (
+	github.com/logrusorgru/aurora v0.0.0-20181002194514-a7b3b318ed4e
+	github.com/stretchr/testify v1.2.2
+	github.com/vcraescu/go-xrandr v0.0.0-20181229110639-d274803e375e
+	gopkg.in/urfave/cli.v1 v1.20.0
+)

go.sum

@@ -0,0 +1,12 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/logrusorgru/aurora v0.0.0-20181002194514-a7b3b318ed4e h1:9MlwzLdW7QSDrhDjFlsEYmxpFyIoXmYRon3dt0io31k=
+github.com/logrusorgru/aurora v0.0.0-20181002194514-a7b3b318ed4e/go.mod h1:7rIyQOR62GCctdiQpZ/zOJlFyk6y+94wXzv6RNZgaR4=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.2.2 h1:bSDNvY7ZPG5RlJ8otE/7V6gMiyenm9RtJ7IUVIAoJ1w=
+github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+github.com/vcraescu/go-xrandr v0.0.0-20181229110639-d274803e375e h1:UOCgsYTSQbl5SOxRDUWPwDimEhBg0F2zeBlYIKfjVEs=
+github.com/vcraescu/go-xrandr v0.0.0-20181229110639-d274803e375e/go.mod h1:LVPmVEv6GKVAswrHXu0Fuhsg7YZwcKQS78uqLLdvHEA=
+gopkg.in/urfave/cli.v1 v1.20.0 h1:NdAVW6RYxDif9DhDHaAortIu956m2c0v+09AZBPTbE0=
+gopkg.in/urfave/cli.v1 v1.20.0/go.mod h1:vuBzUtMdQeixQj8LVd+/98pzhxNGQoyuPBlsXHOQNO0=

layout/export_test.go

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+package layout
+
+var (
+	FindLayoutNodeById              = findLayoutNodeByID
+	CalculateRescaledNodeResolution = calculateRescaledNodeResolution
+	CalculateNodeResolution         = calculateNodeResolution
+	CalculateNodePosition           = calculateNodePosition
+	CalculateLayoutResolution       = calculateLayoutResolution
+	CalculateDPI                    = calculateDPI
+)