Add code from our freetype fork

emoji.go

@@ -0,0 +1,155 @@
+package freetype
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"unicode/utf8"
+)
+
+// Emoji is a node of an EmojiTable
+type Emoji struct {
+	Codepoint []rune
+	IsEmoji   bool
+	Path      string
+	Sub       EmojiTable
+}
+
+func (e Emoji) String() (str string) {
+	str = "Emoji("
+	for _, cprune := range e.Codepoint {
+		str += fmt.Sprintf("%U ", cprune)
+	}
+	str = strings.TrimRight(str, " ") + ")"
+	if e.Sub != nil {
+		str += "+"
+	}
+	if e.IsEmoji {
+		str += fmt.Sprintf("\n  └ Path: %s", e.Path)
+	}
+	return str + "\n"
+}
+
+// Length returns the lenght of the emoji in bytes
+func (e Emoji) Length() int {
+	total := 0
+	for _, r := range e.Codepoint {
+		total += utf8.RuneLen(r)
+	}
+	return total
+}
+
+// EmojiTable is a table of detected Unicode codepoints sequences for which an emoticon is available
+type EmojiTable map[rune]Emoji
+
+// Find checks if a given strings begins with an emoji made by one or more sequential runes
+func (em EmojiTable) Find(str string) *Emoji {
+	for i, r := range str {
+		e, ok := em[r]
+		if !ok {
+			break
+		}
+		// Check if there are more bytes to check
+		if len(str) > i && e.Sub != nil {
+			rlen := utf8.RuneLen(r)
+			newemj := e.Sub.Find(str[i+rlen:])
+			if newemj != nil {
+				return newemj
+			}
+		}
+		if e.IsEmoji {
+			return &e
+		}
+	}
+	return nil
+}
+
+// IsEmoji checks whether the given rune is an emoji
+func (em EmojiTable) IsEmoji(cp rune) bool {
+	_, ok := em[cp]
+	return ok
+}
+
+func (em EmojiTable) tostring(indent string, nomarker bool) (str string) {
+	counter := len(em)
+	marker := "│ "
+	if nomarker {
+		marker = "  "
+	}
+	for r, emo := range em {
+		listr := "├"
+		if counter == 1 {
+			listr = "└"
+		}
+		str += fmt.Sprintf(indent+"%s%s %U", marker, listr, r)
+		if emo.IsEmoji {
+			str += fmt.Sprintf(": %s", emo.Path)
+		}
+		str += "\n"
+		if emo.Sub != nil {
+			str += emo.Sub.tostring(indent+marker, counter == 1)
+		}
+		counter--
+	}
+	return
+}
+
+func (em EmojiTable) String() string {
+	return "Emoji table\n" + em.tostring("", true)
+}
+
+// ScanEmojiDirectory scans a directory for images to use as icons
+// Pictures must be named in this format:
+//    emoji_uXXXX_XXXX.png
+// where XXXX are Unicode codepoints
+// See <https://github.com/googlei18n/noto-emoji/tree/master/png/128>
+func ScanEmojiDirectory(emojipath string) (tab EmojiTable, err error) {
+	tab = make(EmojiTable)
+	filepath.Walk(emojipath, func(path string, info os.FileInfo, err error) error {
+		// Ignore non-images
+		if !strings.HasSuffix(strings.ToLower(path), ".png") {
+			return nil
+		}
+
+		// Get icon filename
+		emojiname := filepath.Base(path)
+
+		// Strip prefix and suffix
+		extsep := strings.LastIndexByte(emojiname, '.')
+		basesep := strings.IndexByte(emojiname, '_')
+		codepointstr := emojiname[basesep+2 : extsep]
+
+		// Split codepoints by separator (_)
+		codepointlist := strings.Split(codepointstr, "_")
+
+		// Parse codepoints to runes
+		curtab := &tab
+		codepoints := []rune{}
+		for cpi, cpstr := range codepointlist {
+			num, err := strconv.ParseInt(cpstr, 16, 32)
+			if err != nil {
+				return fmt.Errorf("malformed icon filename: %s (codepoints are not valid int32)", emojiname)
+			}
+			cprune := rune(num)
+			newemo := (*curtab)[cprune]
+			codepoints = append(codepoints, cprune)
+			newemo.Codepoint = codepoints[:]
+			if len(codepointlist) < cpi+2 {
+				// Set as emoji
+				newemo.IsEmoji = true
+				newemo.Path = path
+			} else {
+				// Add sub-entry if not existant
+				if newemo.Sub == nil {
+					newemo.Sub = make(EmojiTable)
+				}
+			}
+			(*curtab)[cprune] = newemo
+			curtab = &newemo.Sub
+		}
+		return nil
+	})
+	return tab, err
+}