icns

Easily create .icns files (Mac Icons) with this Go library or the included CLI.
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slot.go (1978B)

      1 package icns
      2 
      3 import (
      4 	"fmt"
      5 	"regexp"
      6 	"strconv"
      7 )
      8 
      9 // Slot identifies an icon by the size it is drawn at and the display scale it
     10 // is drawn for, the way an iconset names its files. Artwork for 16x16@2x and
     11 // for 32x32 is 32 pixels either way, but the two fill different slots and
     12 // need not be the same drawing.
     13 type Slot struct {
     14 	// Points is the size the icon is drawn at.
     15 	Points uint
     16 	// Scale is the display scale, 1 for a plain display and 2 for retina.
     17 	Scale uint
     18 }
     19 
     20 // Pixels returns the dimensions artwork for this slot has.
     21 func (s Slot) Pixels() uint {
     22 	return s.Points * s.Scale
     23 }
     24 
     25 // String renders the slot the way an iconset names it, such as "16x16@2x".
     26 func (s Slot) String() string {
     27 	if s.Scale > 1 {
     28 		return fmt.Sprintf("%dx%d@%dx", s.Points, s.Points, s.Scale)
     29 	}
     30 	return fmt.Sprintf("%dx%d", s.Points, s.Points)
     31 }
     32 
     33 // Slots returns the slots an encoded icns holds, largest artwork first.
     34 func Slots() []Slot {
     35 	var slots []Slot
     36 	for _, size := range sizes {
     37 		types, ok := getTypesFromSize(size)
     38 		if !ok {
     39 			continue
     40 		}
     41 		for _, t := range types {
     42 			slots = append(slots, t.slot)
     43 		}
     44 	}
     45 	return slots
     46 }
     47 
     48 // iconsetName matches the file names iconutil accepts in an iconset.
     49 var iconsetName = regexp.MustCompile(`^icon_(\d+)x(\d+)(?:@(\d+)x)?\.png$`)
     50 
     51 // ParseSlot reads an iconset file name, such as "icon_16x16@2x.png". The
     52 // boolean reports whether the name is one.
     53 func ParseSlot(name string) (Slot, bool) {
     54 	match := iconsetName.FindStringSubmatch(name)
     55 	if match == nil {
     56 		return Slot{}, false
     57 	}
     58 	width, err := strconv.ParseUint(match[1], 10, 32)
     59 	if err != nil {
     60 		return Slot{}, false
     61 	}
     62 	height, err := strconv.ParseUint(match[2], 10, 32)
     63 	if err != nil || width != height || width == 0 {
     64 		return Slot{}, false
     65 	}
     66 	scale := uint64(1)
     67 	if match[3] != "" {
     68 		if scale, err = strconv.ParseUint(match[3], 10, 32); err != nil || scale == 0 {
     69 			return Slot{}, false
     70 		}
     71 	}
     72 	return Slot{Points: uint(width), Scale: uint(scale)}, true
     73 }