chore(cellbuf): merge pull request #224 from charmbracelet/cellbuf2

Cellbuf: refactor, fix bugs, and tidy

cellbuf/buffer.go

@@ -19,24 +19,24 @@ func (b *Buffer) Height() int {
 	return len(b.cells) / b.width
 }
 
-// At returns the cell at the given x, y position.
-func (b *Buffer) At(x, y int) (Cell, error) {
+// Cell returns the cell at the given x, y position.
+func (b *Buffer) Cell(x, y int) (Cell, bool) {
 	if b.width == 0 {
-		return Cell{}, ErrOutOfBounds
+		return Cell{}, false
 	}
 	height := len(b.cells) / b.width
 	if x < 0 || x >= b.width || y < 0 || y >= height {
-		return Cell{}, ErrOutOfBounds
+		return Cell{}, false
 	}
 	idx := y*b.width + x
 	if idx < 0 || idx >= len(b.cells) {
-		return Cell{}, ErrOutOfBounds
+		return Cell{}, false
 	}
-	return b.cells[idx], nil
+	return b.cells[idx], true
 }
 
-// Set sets the cell at the given x, y position.
-func (b *Buffer) Set(x, y int, c Cell) (v bool) {
+// SetCell sets the cell at the given x, y position.
+func (b *Buffer) SetCell(x, y int, c Cell) (v bool) {
 	if b.width == 0 {
 		return
 	}
@@ -49,7 +49,44 @@ func (b *Buffer) Set(x, y int, c Cell) (v bool) {
 		return
 	}
 
+	// When a wide cell is partially overwritten, we need
+	// to fill the rest of the cell with space cells to
+	// avoid rendering issues.
+	prev := b.cells[idx]
+	if prev.Width > 1 {
+		// Writing to the first wide cell
+		for j := 0; j < prev.Width; j++ {
+			newCell := prev
+			newCell.Content = " "
+			newCell.Width = 1
+			b.cells[idx+j] = newCell
+		}
+	} else if prev.Width == 0 {
+		// Writing to wide cell placeholders
+		for j := 1; j < 4; j++ {
+			wide := b.cells[idx-j]
+			if wide.Width > 1 {
+				for k := 0; k < wide.Width; k++ {
+					newCell := wide
+					newCell.Content = " "
+					newCell.Width = 1
+					b.cells[idx-j+k] = newCell
+				}
+				break
+			}
+		}
+	}
+
 	b.cells[idx] = c
+
+	// Mark wide cells with emptyCell zero width
+	// We set the wide cell down below
+	if c.Width > 1 {
+		for j := 1; j < c.Width; j++ {
+			b.cells[idx+j] = emptyCell
+		}
+	}
+
 	return true
 }
 

cellbuf/cell.go

@@ -29,18 +29,9 @@ type Cell struct {
 
 // Equal returns whether the cell is equal to the other cell.
 func (c Cell) Equal(o Cell) bool {
-	spaceStyleEqual := func(lhs, rhs Style) bool {
-		return colorEqual(lhs.Bg, rhs.Bg) &&
-			colorEqual(lhs.Ul, rhs.Ul) &&
-			lhs.Attrs == rhs.Attrs &&
-			lhs.UlStyle == rhs.UlStyle
-	}
-
-	return c.Content == o.Content &&
-		// OPTIM: If the cell is a space, we don't care about its FG color.
-		((c.Content == " " && spaceStyleEqual(c.Style, o.Style)) ||
-			(c.Style.Equal(o.Style))) &&
-		c.Width == o.Width &&
+	return c.Width == o.Width &&
+		c.Content == o.Content &&
+		c.Style.Equal(o.Style) &&
 		c.Link.Equal(o.Link)
 }
 

cellbuf/go.mod

@@ -3,7 +3,7 @@ module github.com/charmbracelet/x/cellbuf
 go 1.18
 
 require (
-	github.com/charmbracelet/x/ansi v0.3.2
+	github.com/charmbracelet/x/ansi v0.4.0
 	github.com/charmbracelet/x/wcwidth v0.0.0-20241011142426-46044092ad91
 )
 

cellbuf/go.sum

@@ -1,5 +1,5 @@
-github.com/charmbracelet/x/ansi v0.3.2 h1:wsEwgAN+C9U06l9dCVMX0/L3x7ptvY1qmjMwyfE6USY=
-github.com/charmbracelet/x/ansi v0.3.2/go.mod h1:dk73KoMTT5AX5BsX0KrqhsTqAnhZZoCBjs7dGWp4Ktw=
+github.com/charmbracelet/x/ansi v0.4.0 h1:NqwHA4B23VwsDn4H3VcNX1W1tOmgnvY1NDx5tOXdnOU=
+github.com/charmbracelet/x/ansi v0.4.0/go.mod h1:dk73KoMTT5AX5BsX0KrqhsTqAnhZZoCBjs7dGWp4Ktw=
 github.com/charmbracelet/x/wcwidth v0.0.0-20241011142426-46044092ad91 h1:D5OO0lVavz7A+Swdhp62F9gbkibxmz9B2hZ/jVdMPf0=
 github.com/charmbracelet/x/wcwidth v0.0.0-20241011142426-46044092ad91/go.mod h1:Ey8PFmYwH+/td9bpiEx07Fdx9ZVkxfIjWXxBluxF4Nw=
 github.com/rivo/uniseg v0.4.7 h1:WUdvkW8uEhrYfLC4ZzdpI2ztxP1I582+49Oc5Mq64VQ=

cellbuf/method.go

@@ -1,11 +1,11 @@
 package cellbuf
 
-// WidthMethod is a type that represents the how the renderer should calculate
-// the display width of cells.
-type WidthMethod uint8
+// Method is a type that represents the how the renderer should calculate the
+// display width of cells.
+type Method uint8
 
 // Display width modes.
 const (
-	WcWidth WidthMethod = iota
+	WcWidth Method = iota
 	GraphemeWidth
 )