text: [API] remove Text and Advances from Layout

These fields are no longer needed with the new text shaper.
Advances is redundant to the glyph information, and Text
should never be used during layout, as you should
traverse the cluster list instead. This commit also removed
the now-unused string field from the path LRU cache key.

References: https://todo.sr.ht/~eliasnaur/gio/146
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>

text/lru.go

@@ -40,7 +40,6 @@ type layoutKey struct {
 
 type pathKey struct {
 	ppem    fixed.Int26_6
-	str     string
 	gidHash uint64
 }
 

text/lru_test.go

@@ -24,10 +24,10 @@ func TestLayoutLRU(t *testing.T) {
 func TestPathLRU(t *testing.T) {
 	c := new(pathCache)
 	put := func(i int) {
-		c.Put(pathKey{str: strconv.Itoa(i), gidHash: uint64(i)}, Layout{Runes: Range{Count: i}}, clip.PathSpec{})
+		c.Put(pathKey{gidHash: uint64(i)}, Layout{Runes: Range{Count: i}}, clip.PathSpec{})
 	}
 	get := func(i int) bool {
-		_, ok := c.Get(pathKey{str: strconv.Itoa(i), gidHash: uint64(i)}, Layout{Runes: Range{Count: i}})
+		_, ok := c.Get(pathKey{gidHash: uint64(i)}, Layout{Runes: Range{Count: i}})
 		return ok
 	}
 	testLRU(t, put, get)

text/shaper.go

@@ -168,7 +168,6 @@ func (f *faceCache) shape(ppem fixed.Int26_6, layout Layout) clip.PathSpec {
 	}
 	pk := pathKey{
 		ppem:    ppem,
-		str:     layout.Text,
 		gidHash: f.hashGIDs(layout),
 	}
 	if clip, ok := f.pathCache.Get(pk, layout); ok {

text/text.go

@@ -92,8 +92,6 @@ type Layout struct {
 	// so the first cluster will describe the beginning of the text and may
 	// refer to the final glyphs in the Glyphs field if the text is RTL.
 	Clusters []GlyphCluster
-	Text     string
-	Advances []fixed.Int26_6
 	// Runes describes the position of the text data this layout represents
 	// within the overall body of text being shaped.
 	Runes Range