rendering everything with nice script and language detection and font-picking.

image_utils.go

@@ -0,0 +1,256 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"image"
+	"image/color"
+	"image/draw"
+	"math"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/fogleman/gg"
+	"github.com/go-text/typesetting/di"
+	"github.com/go-text/typesetting/font"
+	"github.com/go-text/typesetting/language"
+	"github.com/pemistahl/lingua-go"
+)
+
+const nSupportedScripts = 11
+
+var (
+	supportedScripts = [nSupportedScripts]language.Script{
+		language.Unknown,
+		language.Hiragana,
+		language.Katakana,
+		language.Hebrew,
+		language.Thai,
+		language.Arabic,
+		language.Devanagari,
+		language.Bengali,
+		language.Javanese,
+		language.Han,
+		language.Hangul,
+	}
+
+	detector     lingua.LanguageDetector
+	scriptRanges []ScriptRange
+	fontMap      [nSupportedScripts]font.Face
+	emojiFont    font.Face
+)
+
+type ScriptRange struct {
+	Start  rune
+	End    rune
+	Pos    int
+	Script language.Script
+}
+
+func initializeImageDrawingStuff() error {
+	// language detector
+	detector = lingua.NewLanguageDetectorBuilder().FromLanguages(
+		lingua.Japanese,
+		lingua.Persian,
+		lingua.Chinese,
+		lingua.Thai,
+		lingua.Hebrew,
+		lingua.Arabic,
+		lingua.Bengali,
+		lingua.Korean,
+	).WithLowAccuracyMode().Build()
+
+	// script detector material
+	for ssi, script := range supportedScripts {
+		for _, srange := range language.ScriptRanges {
+			if srange.Script == script {
+				scriptRanges = append(scriptRanges, ScriptRange{
+					Start:  srange.Start,
+					End:    srange.End,
+					Script: srange.Script,
+					Pos:    ssi,
+				})
+			}
+		}
+	}
+
+	// fonts
+	loadFont := func(filepath string) font.Face {
+		fontData, err := fonts.ReadFile(filepath)
+		face, err := font.ParseTTF(bytes.NewReader(fontData))
+		if err != nil {
+			log.Fatal().Err(err).Str("path", filepath).Msg("error loading font on startup")
+			return nil
+		}
+		return face
+	}
+	fontMap[0] = loadFont("fonts/NotoSans.ttf")
+	fontMap[1] = loadFont("fonts/NotoSansJP.ttf")
+	fontMap[2] = fontMap[1]
+	fontMap[3] = loadFont("fonts/NotoSansHebrew.ttf")
+	fontMap[4] = loadFont("fonts/NotoSansThai.ttf")
+	fontMap[5] = loadFont("fonts/NotoSansArabic.ttf")
+	fontMap[6] = loadFont("fonts/NotoSansDevanagari.ttf")
+	fontMap[7] = loadFont("fonts/NotoSansBengali.ttf")
+	fontMap[8] = loadFont("fonts/NotoSansJavanese.ttf")
+	fontMap[9] = loadFont("fonts/NotoSansSC.ttf")
+	fontMap[10] = loadFont("fonts/NotoSansKR.ttf")
+	emojiFont = loadFont("fonts/NotoEmoji.ttf")
+
+	return nil
+}
+
+// quotesAsBlockPrefixedText replaces nostr:nevent1... and note with their text, as an extra line
+// prefixed by BLOCK this returns a slice of lines
+func quotesAsBlockPrefixedText(ctx context.Context, lines []string) []string {
+	ctx, cancel := context.WithTimeout(ctx, time.Second*3)
+	defer cancel()
+
+	blocks := make([]string, 0, len(lines)+7)
+
+	for _, line := range lines {
+		matches := nostrNoteNeventMatcher.FindAllStringSubmatchIndex(line, -1)
+
+		if len(matches) == 0 {
+			// no matches, just return text as it is
+			blocks = append(blocks, line)
+			continue
+		}
+
+		// one or more matches, return multiple lines
+		blocks = append(blocks, line[0:matches[0][0]])
+		i := -1 // matches iteration counter
+		b := 0  // current block index
+		for _, match := range matches {
+			i++
+
+			matchText := line[match[0]:match[1]]
+			submatch := nostrNoteNeventMatcher.FindStringSubmatch(matchText)
+			nip19 := submatch[0][6:]
+
+			event, _, err := getEvent(ctx, nip19, nil)
+			if err != nil {
+				// error case concat this to previous block
+				blocks[b] += matchText
+				continue
+			}
+
+			// add a new block with the quoted text
+			blocks = append(blocks, BLOCK+" "+event.Content)
+
+			// increase block count
+			b++
+		}
+		// add remaining text after the last match
+		remainingText := line[matches[i][1]:]
+		if strings.TrimSpace(remainingText) != "" {
+			blocks = append(blocks, remainingText)
+		}
+	}
+
+	return blocks
+}
+
+func getLanguageAndScriptAndDirectionAndFont(paragraph []rune) (
+	language.Language,
+	language.Script,
+	di.Direction,
+	font.Face,
+) {
+	var ranking [nSupportedScripts]int
+	nLetters := len(paragraph)
+	threshold := nLetters / 2
+	var script language.Script
+	var face font.Face
+	var idx int
+	for l := 0; l < nLetters; l++ {
+		idx := lookupScript(paragraph[l])
+		ranking[idx]++
+		if l > threshold && ranking[idx] > threshold {
+			script = supportedScripts[idx]
+			face = fontMap[idx]
+			goto gotScript
+		}
+	}
+	idx = maxIndex(ranking[:])
+	script = supportedScripts[idx]
+	face = fontMap[idx]
+
+gotScript:
+	direction := di.DirectionLTR
+	if script == language.Arabic {
+		direction = di.DirectionRTL
+	}
+
+	lng := language.Language("en-us")
+	lang, ok := detector.DetectLanguageOf(string(paragraph))
+	if ok {
+		lng = language.Language(lang.IsoCode639_1().String())
+	}
+
+	return lng, script, direction, face
+}
+
+func fetchImageFromURL(url string) (image.Image, error) {
+	response, err := http.Get(url)
+	if err != nil {
+		return nil, err
+	}
+	defer response.Body.Close()
+
+	img, _, err := image.Decode(response.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	return img, nil
+}
+
+func roundImage(img image.Image) image.Image {
+	bounds := img.Bounds()
+	diameter := math.Min(float64(bounds.Dx()), float64(bounds.Dy()))
+	radius := diameter / 2
+
+	// Create a new context for the mask
+	mask := gg.NewContext(bounds.Dx(), bounds.Dy())
+	mask.SetColor(color.Black) // Set the mask color to fully opaque
+	mask.DrawCircle(float64(bounds.Dx())/2, float64(bounds.Dy())/2, radius)
+	mask.ClosePath()
+	mask.Fill()
+
+	// Apply the circular mask to the original image
+	result := image.NewRGBA(bounds)
+	maskImg := mask.Image()
+	draw.DrawMask(result, bounds, img, image.Point{}, maskImg, image.Point{}, draw.Over)
+
+	return result
+}
+
+func cropToSquare(img image.Image) image.Image {
+	bounds := img.Bounds()
+	size := int(math.Min(float64(bounds.Dx()), float64(bounds.Dy())))
+	squareImg := image.NewRGBA(image.Rect(0, 0, size, size))
+	for x := 0; x < size; x++ {
+		for y := 0; y < size; y++ {
+			squareImg.Set(x, y, img.At(x+(bounds.Dx()-size)/2, y+(bounds.Dy()-size)/2))
+		}
+	}
+	return squareImg
+}
+
+func lookupScript(r rune) int {
+	// binary search
+	for i, j := 0, len(scriptRanges); i < j; {
+		h := i + (j-i)/2
+		entry := scriptRanges[h]
+		if r < entry.Start {
+			j = h
+		} else if entry.End < r {
+			i = h + 1
+		} else {
+			return h // position in supportedScripts
+		}
+	}
+	return 0 // unknown
+}

render_image.go

@@ -14,16 +14,10 @@ import (
 
 	"github.com/fogleman/gg"
 	"github.com/go-text/render"
-	"github.com/go-text/typesetting/di"
-	"github.com/go-text/typesetting/font"
-	"github.com/go-text/typesetting/fontscan"
-	"github.com/go-text/typesetting/language"
-	"github.com/go-text/typesetting/opentype/api/metadata"
 	"github.com/go-text/typesetting/shaping"
 	"github.com/golang/freetype/truetype"
 	sdk "github.com/nbd-wtf/nostr-sdk"
 	"github.com/nfnt/resize"
-	"github.com/pemistahl/lingua-go"
 	xfont "golang.org/x/image/font"
 	"golang.org/x/image/math/fixed"
 )
@@ -36,53 +30,11 @@ var (
 	BACKGROUND     = color.RGBA{23, 23, 23, 255}
 	BAR_BACKGROUND = color.RGBA{10, 10, 10, 255}
 	FOREGROUND     = color.RGBA{255, 230, 238, 255}
-
-	fontmap  *fontscan.FontMap
-	detector lingua.LanguageDetector
 )
 
 //go:embed fonts/*
 var fonts embed.FS
 
-func initializeImageDrawingStuff() error {
-	// language detector
-	detector = lingua.NewLanguageDetectorBuilder().FromLanguages(
-		lingua.Japanese,
-		lingua.Persian,
-		lingua.Chinese,
-		lingua.Thai,
-		lingua.Hebrew,
-	).WithLowAccuracyMode().Build()
-
-	// fonts
-	dir, err := fonts.ReadDir("fonts")
-	if err != nil {
-		return fmt.Errorf("error reading fonts/ dir: %w", err)
-	}
-	fontmap = fontscan.NewFontMap(nil)
-	for _, entry := range dir {
-		filepath := "fonts/" + entry.Name()
-		fontData, err := fonts.ReadFile(filepath)
-		face, err := font.ParseTTF(bytes.NewReader(fontData))
-		if err != nil {
-			return fmt.Errorf("error loading font %s: %w", filepath, err)
-		}
-		fontmap.AddFace(face,
-			fontscan.Location{File: filepath},
-			metadata.Description{
-				Family: "Noto",
-				Aspect: metadata.Aspect{
-					Style:   metadata.StyleNormal,
-					Weight:  metadata.WeightNormal,
-					Stretch: metadata.StretchNormal,
-				},
-				IsMonospace: false,
-			},
-		)
-	}
-	return nil
-}
-
 func renderImage(w http.ResponseWriter, r *http.Request) {
 	fmt.Println(r.URL.Path, ":~", r.Header.Get("user-agent"))
 
@@ -104,7 +56,7 @@ func renderImage(w http.ResponseWriter, r *http.Request) {
 	// this turns the raw event.Content into a series of lines ready to drawn
 	paragraphs := replaceUserReferencesWithNames(r.Context(),
 		quotesAsBlockPrefixedText(r.Context(),
-			content,
+			strings.Split(content, "\n"),
 		),
 	)
 
@@ -145,8 +97,8 @@ func drawImage(paragraphs []string, style Style, metadata sdk.ProfileMetadata, d
 	img.SetColor(FOREGROUND)
 
 	// main content text
-	textImg := drawText(paragraphs, width-4*2, height-2*2)
-	img.DrawImage(textImg, 4, 2)
+	textImg := drawText(paragraphs, width-25*2, height-20)
+	img.DrawImage(textImg, 25, 20)
 
 	// font for writing the bottom bar stuff
 	fontData, _ := fonts.ReadFile("fonts/NotoSans.ttf")
@@ -219,12 +171,12 @@ func drawImage(paragraphs []string, style Style, metadata sdk.ProfileMetadata, d
 }
 
 func drawText(paragraphs []string, width, height int) image.Image {
-	const FONT_SIZE = 26
+	const FONT_SIZE = 25
 
 	r := &render.Renderer{
 		PixScale: 1,
 		FontSize: FONT_SIZE,
-		Color:    color.White,
+		Color:    color.RGBA{R: 255, G: 230, B: 238, A: 255},
 	}
 
 	img := image.NewNRGBA(image.Rect(0, 0, width, height))
@@ -233,24 +185,18 @@ func drawText(paragraphs []string, width, height int) image.Image {
 	for _, paragraph := range paragraphs {
 		text := []rune(paragraph)
 
-		detectedLanguage, ok := detector.DetectLanguageOf(paragraph)
-		var lang language.Language
-		if ok {
-			lang = language.NewLanguage(detectedLanguage.IsoCode639_1().String())
-		}
-
+		lang, script, dir, face := getLanguageAndScriptAndDirectionAndFont(text)
 		shaper := &shaping.HarfbuzzShaper{}
 
-		face := fontmap.ResolveFace(text[0])
 		shapedRunes := shaper.Shape(shaping.Input{
-			Text:      []rune(text),
+			Text:      text,
 			RunStart:  0,
-			RunEnd:    len([]rune(text)),
+			RunEnd:    len(text),
 			Face:      face,
 			Size:      fixed.I(int(r.FontSize)),
-			Script:    language.LookupScript([]rune(text)[0]),
+			Script:    script,
 			Language:  lang,
-			Direction: di.DirectionRTL,
+			Direction: dir,
 		})
 
 		var wrapper shaping.LineWrapper
@@ -258,7 +204,7 @@ func drawText(paragraphs []string, width, height int) image.Image {
 
 		for _, line := range lines {
 			for _, out := range line {
-				r.DrawShapedRunAt(out, img, 0, FONT_SIZE*i)
+				r.DrawShapedRunAt(out, img, 0, FONT_SIZE*i*12/10)
 				i++
 			}
 		}

utils.go

@@ -7,17 +7,12 @@ import (
 	"fmt"
 	"html"
 	"html/template"
-	"image"
-	"image/color"
-	"image/draw"
-	"math"
 	"math/rand"
 	"net/http"
 	"regexp"
 	"strings"
 	"time"
 
-	"github.com/fogleman/gg"
 	"github.com/microcosm-cc/bluemonday"
 	"golang.org/x/exp/slices"
 	"mvdan.cc/xurls/v2"
@@ -510,97 +505,14 @@ func isntRealRelay(url string) bool {
 	return bytes.IndexByte(substr, '/') != -1
 }
 
-// quotesAsBlockPrefixedText replaces nostr:nevent1... and note with their text, as an extra line
-// prefixed by BLOCK this returns a slice of lines
-func quotesAsBlockPrefixedText(ctx context.Context, input string) []string {
-	ctx, cancel := context.WithTimeout(ctx, time.Second*3)
-	defer cancel()
-
-	blocks := make([]string, 0, 8)
-	matches := nostrNoteNeventMatcher.FindAllStringSubmatchIndex(input, -1)
-
-	if len(matches) == 0 {
-		// no matches, just return text as it is
-		blocks = append(blocks, input)
-		return blocks
-	}
-
-	// one or more matches, return multiple lines
-	blocks = append(blocks, input[0:matches[0][0]])
-	i := -1 // matches iteration counter
-	b := 0  // current block index
-	for _, match := range matches {
-		i++
-
-		matchText := input[match[0]:match[1]]
-		submatch := nostrNoteNeventMatcher.FindStringSubmatch(matchText)
-		nip19 := submatch[0][6:]
-
-		event, _, err := getEvent(ctx, nip19, nil)
-		if err != nil {
-			// error case concat this to previous block
-			blocks[b] += matchText
-			continue
-		}
-
-		// add a new block with the quoted text
-		blocks = append(blocks, BLOCK+" "+event.Content)
-
-		// increase block count
-		b++
-	}
-	// add remaining text after the last match
-	remainingText := input[matches[i][1]:]
-	if strings.TrimSpace(remainingText) != "" {
-		blocks = append(blocks, remainingText)
-	}
-
-	return blocks
-}
-
-func fetchImageFromURL(url string) (image.Image, error) {
-	response, err := http.Get(url)
-	if err != nil {
-		return nil, err
-	}
-	defer response.Body.Close()
-
-	img, _, err := image.Decode(response.Body)
-	if err != nil {
-		return nil, err
-	}
-
-	return img, nil
-}
-
-func roundImage(img image.Image) image.Image {
-	bounds := img.Bounds()
-	diameter := math.Min(float64(bounds.Dx()), float64(bounds.Dy()))
-	radius := diameter / 2
-
-	// Create a new context for the mask
-	mask := gg.NewContext(bounds.Dx(), bounds.Dy())
-	mask.SetColor(color.Black) // Set the mask color to fully opaque
-	mask.DrawCircle(float64(bounds.Dx())/2, float64(bounds.Dy())/2, radius)
-	mask.ClosePath()
-	mask.Fill()
-
-	// Apply the circular mask to the original image
-	result := image.NewRGBA(bounds)
-	maskImg := mask.Image()
-	draw.DrawMask(result, bounds, img, image.Point{}, maskImg, image.Point{}, draw.Over)
-
-	return result
-}
-
-func cropToSquare(img image.Image) image.Image {
-	bounds := img.Bounds()
-	size := int(math.Min(float64(bounds.Dx()), float64(bounds.Dy())))
-	squareImg := image.NewRGBA(image.Rect(0, 0, size, size))
-	for x := 0; x < size; x++ {
-		for y := 0; y < size; y++ {
-			squareImg.Set(x, y, img.At(x+(bounds.Dx()-size)/2, y+(bounds.Dy()-size)/2))
+func maxIndex(slice []int) int {
+	maxIndex := 0
+	maxVal := 0
+	for i, val := range slice {
+		if val > maxVal {
+			maxVal = val
+			maxIndex = i
 		}
 	}
-	return squareImg
+	return maxIndex
 }