Make image output dynamic

This adds command-line flags for certain parameters, and uses stdin for
the content to include in the final graphic.

cmd/wfgraphic-cli/main.go

@@ -11,6 +11,8 @@
 package main
 
 import (
+	"flag"
+	"io/ioutil"
 	"os"
 	"time"
 
@@ -18,10 +20,33 @@ import (
 	"github.com/writeas/web-core/log"
 )
 
+var (
+	outputFile = flag.String("o", "out.png", "Image output filename")
+	font       = flag.String("font", "serif", "Post font (options: \"serif\", \"sans\", \"mono\") - NOT IMPLEMENTED YET")
+	instance   = flag.String("i", "write.as", "WriteFreely instance hostname (e.g. pencil.writefree.ly)")
+	author     = flag.String("u", "", "WriteFreely author username")
+)
+
 func main() {
 	log.Info("Starting...")
+	flag.Parse()
+
+	if *author == "" {
+		log.Info("Aborting. -u flag is required")
+		flag.Usage()
+		os.Exit(1)
+	}
+
+	log.Info("Reading input...")
+	in, err := ioutil.ReadAll(os.Stdin)
+	if err != nil {
+		log.Error("read: %s", err)
+		os.Exit(1)
+	}
+
+	log.Info("Generating image...")
 	start := time.Now()
-	err := textpic.Run()
+	err = textpic.GenerateImage(textpic.NewContentOptions(*instance, *author, false, *font, string(in)), *outputFile)
 	if err != nil {
 		log.Error("%s", err)
 		os.Exit(1)

options.go

@@ -0,0 +1,41 @@
+/*
+ * Copyright © 2021 A Bunch Tell LLC.
+ *
+ * This file is part of text-pic.
+ *
+ * text-pic is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, included
+ * in the LICENSE file in this source code package.
+ */
+
+package textpic
+
+type ContentOptions struct {
+	// Author information
+	Instance string
+	Username string
+
+	// Write.as-only option
+	IsSubdomain bool // UNIMPLEMENTED
+
+	// Content
+	Font    string // UNIMPLEMENTED
+	Content string
+}
+
+func NewContentOptions(instance, username string, isSubdomain bool, font, content string) *ContentOptions {
+	opt := &ContentOptions{
+		Instance:    instance,
+		Username:    username,
+		IsSubdomain: isSubdomain,
+		Font:        font,
+		Content:     content,
+	}
+	if opt.Instance == "" {
+		opt.Instance = "write.as"
+	}
+	if opt.Content == "" {
+		opt.Content = "Hello, world!"
+	}
+	return opt
+}

textpic.go

@@ -33,7 +33,7 @@ func loadFont(dc *gg.Context, bold bool, points float64) error {
 	return nil
 }
 
-func Run() error {
+func GenerateImage(opt *ContentOptions, outputFilename string) error {
 	w := 900
 	h := 900
 	wf := float64(w)
@@ -63,7 +63,7 @@ func Run() error {
 	if err != nil {
 		return err
 	}
-	instance := "write.as"
+	instance := opt.Instance
 	baseTextWidth, textHeight := dc.MeasureString(instance)
 
 	// Create user path
@@ -73,7 +73,7 @@ func Run() error {
 	}
 	dc.SetColor(color.Black)
 
-	userPath := "/matt"
+	userPath := "/" + opt.Username
 	userTextWidth, _ := dc.MeasureString(userPath)
 	// x = canvas halfway point - total text width halfway point
 	x = wf/2 - (baseTextWidth+userTextWidth)/2
@@ -98,7 +98,7 @@ func Run() error {
 	if err != nil {
 		return err
 	}
-	s := "The rest of the travelers in our flying bus napped or stared listlessly at a shiny slab in their lap and the staring yellow orb morphed into a full circle out in the blue. As we banked to the right — a nod to its awakening — it seemed to rest in acknowledgement, hanging for a moment on the invisible horizon."
+	s := opt.Content
 	lines := dc.WordWrap(s, contentWidth)
 	linesStr := ""
 	for i, str := range lines {
@@ -112,7 +112,7 @@ func Run() error {
 	y = contentTopMargin - contentBottomMargin + hf/2 - contentTextHeight/2
 	dc.DrawStringWrapped(s, x, y, 0, 0, contentWidth, lineSpacing, gg.AlignLeft)
 
-	err = dc.SavePNG("out.png")
+	err = dc.SavePNG(outputFilename)
 	if err != nil {
 		return fmt.Errorf("save png: %s", err)
 	}