Add icon lookup

icon-theme/icon-theme.go

@@ -6,6 +6,7 @@ import "io"
 import "fmt"
 import "log"
 import "image"
+import "strings"
 import "path/filepath"
 import "git.tebibyte.media/tomo/xdg/basedir"
 import "git.tebibyte.media/tomo/xdg/key-value"
@@ -34,6 +35,8 @@ const (
 	// ErrCircularDependency indicates that an icon theme depends on one of
 	// its dependents.
 	ErrCircularDependency = iconThemeError("circular dependency")
+	// ErrIconNotFound indicates that an icon could not be found.
+	ErrIconNotFound = iconThemeError("icon not found")
 )
 
 // ThemeDirs returns the set of directories in which themes should be looked for
@@ -298,6 +301,66 @@ type Theme struct {
 	Example           string
 }
 
+// FindIcon finds the best icon of the given name for the given size and scale.
+// If a list of supported filetypes is not given, { PNG, SVG, XPM } is used
+// instead.
+func (theme Theme) FindIcon (name string, size, scale int, supported ...IconFileType) (Icon, error) {
+	// this method is equivalent to FindIconHelper
+	if len(supported) == 0 { supported = []IconFileType{ PNG, SVG, XPM } }
+
+	// try to find icon in this theme first
+	icon, err := theme.findIconHere(name, size, scale, supported...)
+	if err == nil { return icon, nil }
+
+	// if that didn't work, recurse through parent themes
+	for _, parent := range theme.Inherits {
+		icon, err := parent.FindIcon(name, size, scale, supported...)
+		if err == nil { return icon, nil }
+	}
+
+	return Icon { }, ErrIconNotFound
+}
+
+func (theme Theme) findIconHere (name string, size, scale int, supported ...IconFileType) (Icon, error) {
+	// this method is equivalent to LookupIcon
+
+	// stage 1: attempt to find an exact match
+	for _, directory := range theme.Directories {
+		if directory.Fits(size, scale) {
+			for _, path := range directory.Paths {
+				for _, ty := range supported {
+					icon, err := parseIcon(filepath.Join(path, ty.Extend(name)))
+					if err == nil { return icon, err }
+				}
+			}
+		}
+	}
+
+	// stage 2: find the best icon matching the name
+	minimalDistance := int((^uint(0)) >> 1)
+	closestFilename := ""
+	for _, directory := range theme.Directories {
+		sizeDistance := directory.SizeDistance(size, scale)
+		if sizeDistance < minimalDistance {
+			for _, path := range directory.Paths {
+				for _, ty := range supported {
+					iconFilename := filepath.Join(path, ty.Extend(name))
+					if _, err := os.Stat(iconFilename); err == nil {
+						closestFilename = iconFilename
+						minimalDistance = sizeDistance
+					}
+				}
+			}
+		}
+	}
+	if closestFilename != "" {
+		icon, err := parseIcon(closestFilename)
+		if err == nil { return icon, err }
+	}
+	
+	return Icon { }, ErrIconNotFound
+}
+
 // Directory represents a directory of an icon theme which directly contains
 // icons.
 type Directory struct {
@@ -312,6 +375,79 @@ type Directory struct {
 	Threshold int
 }
 
+// Fits returns whether icons in the directory fit the given size and scale.
+func (directory Directory) Fits (size, scale int) bool {
+	// this method is equivalent to DirectoryMatchesSize
+	if directory.Scale != scale { return false }
+	switch directory.Type {
+	case IconSizeTypeFixed:
+		return directory.Size == size
+	case IconSizeTypeScalable:
+		return directory.MinSize <= size && size <= directory.MaxSize
+	case IconSizeTypeThreshold:
+		return directory.Size - directory.Threshold <=
+			size && size <=
+			directory.Size + directory.Threshold
+	}
+	return false
+}
+
+// SizeDistance returns how close the size of this directory's icons is to the
+// given size. A smaller number is closer.
+func (directory Directory) SizeDistance (size, scale int) int {
+	// this method is equivalent to DirectorySizeDistance
+	// TODO: the pseudocode for DirectorySizeDistance in the spec seems
+	// incredibly wrong, and the code here has been altered to correct for
+	// that. figure out why the spec is the way it is.
+	scaledSize := size * scale
+	scaledDir  := directory.Size    * directory.Scale
+	scaledMin  := directory.MinSize * directory.Scale
+	scaledMax  := directory.MaxSize * directory.Scale
+	threshMin  := (directory.Size - directory.Threshold) * directory.Scale
+	threshMax  := (directory.Size + directory.Threshold) * directory.Scale
+
+	switch directory.Type {
+	case IconSizeTypeFixed:
+		difference := scaledDir - scaledSize
+		if difference > 0 {
+			return difference
+		} else {
+			return -difference
+		}
+		
+	case IconSizeTypeScalable:
+		if scaledSize < scaledMin { return scaledMin  - scaledSize }
+		if scaledSize > scaledMax { return scaledSize - scaledMax  }
+	
+	case IconSizeTypeThreshold:
+		if scaledSize < threshMin { return threshMin  - scaledSize }
+		if scaledSize > threshMax { return scaledSize - threshMin  }
+	}
+	return 0
+}
+
+// IconFileType specifies the file type of an icon.
+type IconFileType uint; const (
+	PNG IconFileType = iota
+	SVG
+	XPM
+)
+
+// String returns a string representation of the file type.
+func (ty IconFileType) String () string {
+	switch ty {
+	case PNG: return ".png"
+	case SVG: return ".svg"
+	case XPM: return ".xpm"
+	default:  return fmt.Sprintf("IconFileType(%d)", ty)
+	}
+}
+
+// Extend applies the file extension to a file name.
+func (ty IconFileType) Extend (name string) string {
+	return name + ty.String()
+}
+
 // IconSizeType specifies how an icon can be scaled. Fixed icons cannot be
 // scaled, scalable icons can be scaled to any size within a min and max range,
 // and threshold icons can be scaled to any size within a certain distance of
@@ -343,9 +479,65 @@ func IconSizeTypeFromString (value string) (IconSizeType, error) {
 	}
 }
 
-// Icon represents data in <icon-name>.icon files
+// Icon represents an icon, and its associated data (if applicable).
 type Icon struct {
-	DisplayName           string
+	Path                  string
+	FileType              IconFileType
+	DisplayName           keyValue.Entry
 	EmbeddedTextRectangle image.Rectangle
 	AttachPoints          []image.Point
 }
+
+func parseIcon (path string) (Icon, error) {
+	_, err := os.Stat(path)
+	if err != nil { return Icon { }, err }
+
+	ext := filepath.Ext(path)
+	dataPath := strings.TrimSuffix(path, ext) + ".icon"
+
+	if data, err := parseIconData(dataPath); err != nil {
+		return data, nil
+	} else {
+		return Icon {
+			Path: path,
+		}, nil
+	}
+}
+
+func parseIconData (path string) (Icon, error) {
+	reader, err := os.Open(path)
+	if err != nil { return Icon { }, err }
+	file, err := keyValue.Parse(reader)
+	if err != nil { return Icon { }, err }
+
+	iconDataGroup, ok := file["Icon Data"]
+	if !ok { return Icon { }, ErrGroupMissing }
+
+	icon := Icon { }
+	
+	// DisplayName (optional)
+	if entry, ok := iconDataGroup["DisplayName"]; ok {
+		icon.DisplayName, err = entry.Unescape()
+		if err != nil { return Icon { }, err }
+	}
+	
+	// EmbeddedTextRectangle (optional)
+	if entry, ok := iconDataGroup["EmbeddedTextRectangle"]; ok {
+		embeddedTextRectangle, err := keyValue.ParseMultipleComma(keyValue.ParseInteger, entry.Value)
+		if len(embeddedTextRectangle) == 4 {
+			icon.EmbeddedTextRectangle = image.Rect (
+				embeddedTextRectangle[0],
+				embeddedTextRectangle[1],
+				embeddedTextRectangle[2],
+				embeddedTextRectangle[3])
+			if err != nil { return Icon { }, err }
+		}
+	}
+
+	// TODO figure out what the actual fuck the spec is talking about with
+	// regard to AttatchPoints. What even the fuck is that supposed to mean.
+	// Ohhhh a list of points separated by |. Mf hoe what do you define as
+	// a point.
+	
+	return icon, nil
+}

key-value/key-value.go

@@ -283,8 +283,6 @@ func (entry Entry) Unescape () (Entry, error) {
 	return localizedValue, nil
 }
 
-// TODO have functions to parse/validate all data types
-
 // ParseString parses a value of type string.
 // Values of type string may contain all ASCII characters except for control
 // characters.