ordoor/internal/assetstore/font.go

package assetstore

import (
	"fmt"
	"image"
	"log"

	"code.ur.gs/lupine/ordoor/internal/fonts"
)

type Font struct {
	Name    string
	mapping map[rune]*Sprite
}

func (a *AssetStore) Font(name string) (*Font, error) {
	name = canonical(name)

	// FIXME: these fonts don't exist. For now, point at one that does.
	switch name {
	case "imfnt13", "imfnt14":
		name = "wh40k_12"
	}

	if font, ok := a.fonts[name]; ok {
		return font, nil
	}
	log.Printf("Loading font %v", name)

	filename, err := a.lookup(name, "fnt", "Fonts")
	if err != nil {
		return nil, err
	}

	raw, err := fonts.LoadFont(filename)
	if err != nil {
		return nil, err
	}

	objFile, err := a.lookup(raw.ObjectFile, "", "Fonts")
	if err != nil {
		return nil, err
	}

	obj, err := a.ObjectByPath(objFile)
	if err != nil {
		return nil, err
	}

	out := &Font{
		Name:    name,
		mapping: make(map[rune]*Sprite, len(raw.Mapping)),
	}

	for r, offset := range raw.Mapping {
		spr, err := obj.Sprite(offset)
		if err != nil {
			return nil, err
		}

		out.mapping[r] = spr
	}

	a.fonts[name] = out

	return out, nil
}

// CalculateBounds tries to work out what sort of size the string will be when
// rendered
func (f *Font) CalculateBounds(text string) image.Rectangle {
	width := 0
	height := 0

	for _, r := range text {
		spr, ok := f.mapping[r]
		if !ok {
			continue // FIXME: we could add the space character or something?
		}

		width += spr.Rect.Dx()
		if y := spr.Rect.Dy(); y > height {
			height = y
		}
	}

	return image.Rect(0, 0, width, height)
}

func (f *Font) Glyph(r rune) (*Sprite, error) {
	glyph, ok := f.mapping[r]
	if !ok {
		return nil, fmt.Errorf("Font %v does not specify rune %v", f.Name, r)
	}

	return glyph, nil
}