Braille method that sets cell options in an area.

canvas/braille/braille.go

@@ -225,6 +225,23 @@ func (c *Canvas) SetCellOpts(cellPoint image.Point, opts ...cell.Option) error {
 	return nil
 }
 
+// SetAreaCellOpts is like SetCellOpts, but sets the specified options on all
+// the cells within the provided area.
+func (c *Canvas) SetAreaCellOpts(cellArea image.Rectangle, opts ...cell.Option) error {
+	haveArea := c.regular.Area()
+	if !cellArea.In(haveArea) {
+		return fmt.Errorf("unable to set cell options in area %v, it must fit inside the available cell area is %v", cellArea, haveArea)
+	}
+	for col := haveArea.Min.X; col < haveArea.Max.X; col++ {
+		for row := haveArea.Min.Y; row < haveArea.Max.Y; row++ {
+			if err := c.SetCellOpts(image.Point{col, row}, opts...); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
 // Apply applies the canvas to the corresponding area of the terminal.
 // Guarantees to stay within limits of the area the canvas was created with.
 func (c *Canvas) Apply(t terminalapi.Terminal) error {

canvas/braille/braille_test.go

@@ -286,6 +286,43 @@ func TestBraille(t *testing.T) {
 				return ft
 			},
 		},
+		{
+			desc: "SetAreaCellOptions fails on area too large",
+			ar:   image.Rect(0, 0, 1, 1),
+			pixelOps: func(c *Canvas) error {
+				return c.SetAreaCellOpts(image.Rect(0, 0, 2, 2), cell.FgColor(cell.ColorRed), cell.BgColor(cell.ColorBlue))
+			},
+			wantErr: true,
+		},
+		{
+			desc: "SetCellOptions sets the cell options",
+			ar:   image.Rect(0, 0, 3, 3),
+			pixelOps: func(c *Canvas) error {
+				return c.SetAreaCellOpts(image.Rect(0, 0, 2, 2), cell.FgColor(cell.ColorRed), cell.BgColor(cell.ColorBlue))
+			},
+			want: func(size image.Point) *faketerm.Terminal {
+				ft := faketerm.MustNew(size)
+				cvs := testcanvas.MustNew(ft.Area())
+
+				for _, p := range []image.Point{
+					{0, 0},
+					{0, 1},
+					{0, 2},
+					{1, 0},
+					{1, 1},
+					{1, 2},
+					{2, 0},
+					{2, 1},
+					{2, 2},
+				} {
+					c := testcanvas.MustCell(cvs, p)
+					testcanvas.MustSetCell(cvs, p, c.Rune, cell.FgColor(cell.ColorRed), cell.BgColor(cell.ColorBlue))
+				}
+				testcanvas.MustApply(cvs, ft)
+				return ft
+			},
+		},
+
 		{
 			desc: "set pixel 0,0",
 			ar:   image.Rect(0, 0, 1, 1),

canvas/braille/testbraille/testbraille.go

@@ -68,3 +68,10 @@ func MustSetCellOpts(bc *braille.Canvas, cellPoint image.Point, opts ...cell.Opt
 		panic(fmt.Sprintf("bc.SetCellOpts => unexpected error: %v", err))
 	}
 }
+
+// MustSetAreaCellOpts sets the cell options in the area or panics.
+func MustSetAreaCellOpts(bc *braille.Canvas, cellArea image.Rectangle, opts ...cell.Option) {
+	if err := bc.SetAreaCellOpts(cellArea, opts...); err != nil {
+		panic(fmt.Sprintf("bc.SetAreaCellOpts => unexpected error: %v", err))
+	}
+}