chore: add a little code documentations

draw_funcs.go

@@ -11,6 +11,7 @@ import (
 	"golang.org/x/image/vector"
 )
 
+// drawingState holds the essential information of drawing glyphs.
 type drawingState struct {
 	vec *vector.Rasterizer
 
@@ -21,6 +22,8 @@ type drawingState struct {
 	topY, bottomY float32
 }
 
+// processY sets the highest and the lowest Y values passed to the draw methods
+// to the current drawingState.
 func (ds *drawingState) processY(ys ...float32) {
 	for _, y := range ys {
 		if y > ds.bottomY {
@@ -33,7 +36,8 @@ func (ds *drawingState) processY(ys ...float32) {
 	}
 }
 
-// drawFuncs
+// drawFuncs contains the internal drawing methods used to pass to the harfbuzz
+// hb_font_draw method for drawing the glyphs.
 var drawFuncs = hb.DrawFuncsCreate()
 
 // This methods adds all drawing methods to drawFuncs variable.

face.go

@@ -6,18 +6,25 @@ import (
 	"github.com/haashemi/go-harfbuzz/hb"
 )
 
+// Just to make sure if [Face] implements [io.Closer].
+var _ io.Closer = &Face{}
+
+// Face holds a harfbuzz Face object.
 type Face struct {
 	io.Closer
 
 	blob hb.Blob
 	face hb.Face
 }
 
-func (f *Face) Close() {
+// Close destroys the harfbuzz Blob and Face objects and frees the memory.
+func (f *Face) Close() error {
 	hb.FaceDestroy(f.face)
 	hb.BlobDestroy(f.blob)
+	return nil
 }
 
+// NewFace returns a newly initialized harfbuzz Face object from “data” bytes.
 func NewFace(data []byte) *Face {
 	blob := hb.BlobCreate(data, hb.MemoryModeDuplicate, nil, nil)
 	face := hb.FaceCreate(blob, 0)
@@ -28,6 +35,7 @@ func NewFace(data []byte) *Face {
 	}
 }
 
+// NewFaceFromFile returns a newly initialized harfbuzz Face object from “filename” file.
 func NewFaceFromFile(filename string) *Face {
 	blob := hb.BlobCreateFromFile(filename)
 	face := hb.FaceCreate(blob, 0)

features.go

@@ -70,7 +70,7 @@ func JustificationAlternatives() Feature {
 	return Feature{Tag: tag("jalt"), Value: 1, Start: 0, End: 4294967295}
 }
 
-// tag converts str to a Tag
+// tag converts “str” to a Tag
 func tag(str string) hb.Tag {
 	if len(str) < 4 {
 		return hb.Tag{}

font.go

@@ -7,35 +7,48 @@ import (
 	"github.com/haashemi/go-harfbuzz/hb"
 )
 
+// FontExtents is just an alias to harfbuzz's FontExtents type.
 type FontExtents = hb.FontExtents
 
+// Just to make sure if [Font] implements [io.Closer].
+var _ io.Closer = &Font{}
+
+// Font holds a harfbuzz Font object.
 type Font struct {
 	io.Closer
 
 	font hb.Font
 }
 
+// NewFont returns a new Font from the “face” with size of “size”.
 func NewFont(face *Face, size int32) *Font {
 	font := &Font{font: hb.FontCreate(face.face)}
 	font.SetSize(size)
 	return font
 }
 
+// Extents returns the FontExtents of the Font.
 func (f *Font) Extents() (FontExtents, bool) {
 	return hb.FontGetHExtents(f.font)
 }
 
+// Size returns the font size.
+//
+// TODO: It may not be accurate if scaled manually. A better way should be found.
 func (f *Font) Size() int32 {
 	_, h := hb.FontGetScale(f.font)
 	return h / 64
 }
 
+// SetSize updates the font size.
 func (f *Font) SetSize(size int32) {
 	hb.FontSetScale(f.font, size*64, size*64)
 }
 
-func (f *Font) Close() {
+// Close destroys the font and frees the memory.
+func (f *Font) Close() error {
 	hb.FontDestroy(f.font)
+	return nil
 }
 
 func (f *Font) draw(glyph uint32, dfuncs hb.DrawFuncs, drawData unsafe.Pointer) {

writer.go

@@ -107,6 +107,7 @@ func (w *Writer) Write(img draw.Image, at image.Point, color image.Image) {
 	state.vec.Draw(img, bounds.Add(at), color, image.Point{})
 }
 
+// Close destroys the writer's buffer and frees the memory.
 func (w *Writer) Close() error {
 	hb.BufferDestroy(w.buf)
 	return nil