font.go

package main

import (
	"log"

	"github.com/hajimehoshi/ebiten/v2/text"
	"golang.org/x/image/font"
	"golang.org/x/image/font/opentype"
)

const fpx = 120.0

var (
	fontDPI float64 = fpx
	uiScale         = 1.0

	// Fonts
	toolTipFont      font.Face
	monoFont         font.Face
	generalFont      font.Face
	largeGeneralFont font.Face
	generalFontH     int
)

func updateFonts() {
	defer reportPanic("updateFonts")

	newVal := fpx * uiScale
	if newVal < 1 {
		newVal = 1
	}
	fontDPI = newVal

	var mono, tt *opentype.Font
	var err error

	fontData := getFont("Ubuntu-Mono.ttf")
	collection, err := opentype.ParseCollection(fontData)
	if err != nil {
		log.Fatal(err)
	}

	tt, err = collection.Font(0)
	if err != nil {
		log.Fatal(err)
	}

	// Mono font
	fontData = getFont("Ubuntu.ttf")
	collection, err = opentype.ParseCollection(fontData)
	if err != nil {
		log.Fatal(err)
	}

	mono, err = collection.Font(0)
	if err != nil {
		log.Fatal(err)
	}

	/*
	 * Font DPI
	 * Changes how large the font is for a given point value
	 */

	// General font
	generalFont, err = opentype.NewFace(tt, &opentype.FaceOptions{
		Size:    10,
		DPI:     fontDPI,
		Hinting: font.HintingFull,
	})
	if err != nil {
		log.Fatal(err)
	}
	generalFontH = getFontHeight(generalFont)

	// Large General font
	largeGeneralFont, err = opentype.NewFace(tt, &opentype.FaceOptions{
		Size:    20,
		DPI:     fontDPI,
		Hinting: font.HintingFull,
	})
	if err != nil {
		log.Fatal(err)
	}

	// Tooltip font
	toolTipFont, err = opentype.NewFace(tt, &opentype.FaceOptions{
		Size:    8,
		DPI:     fontDPI,
		Hinting: font.HintingFull,
	})
	if err != nil {
		log.Fatal(err)
	}

	// Mono font
	monoFont, err = opentype.NewFace(mono, &opentype.FaceOptions{
		Size:    10,
		DPI:     fontDPI,
		Hinting: font.HintingFull,
	})
	if err != nil {
		log.Fatal(err)
	}

}

const sizingText = "!@#$%^&*()_+-=[]{}|;':,.<>?`~qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM"

func getFontHeight(font font.Face) int {
	defer reportPanic("getFontHeight")
	tRect := text.BoundString(font, sizingText)
	return tRect.Dy()
}