Adding canvas function that sets area of cells.

canvas/canvas.go

@@ -21,6 +21,7 @@ import (
 
 	"github.com/mum4k/termdash/area"
 	"github.com/mum4k/termdash/cell"
+	"github.com/mum4k/termdash/cell/runewidth"
 	"github.com/mum4k/termdash/terminalapi"
 )
 
@@ -117,6 +118,32 @@ func (c *Canvas) SetCellOpts(p image.Point, opts ...cell.Option) error {
 	return nil
 }
 
+// SetAreaCells is like SetCell, but sets the specified rune and options on all
+// the cells within the provided area.
+// This method is idempotent.
+func (c *Canvas) SetAreaCells(cellArea image.Rectangle, r rune, opts ...cell.Option) error {
+	haveArea := c.Area()
+	if !cellArea.In(haveArea) {
+		return fmt.Errorf("unable to set cell runes in area %v, it must fit inside the available cell area is %v", cellArea, haveArea)
+	}
+
+	rw := runewidth.RuneWidth(r)
+	for row := cellArea.Min.Y; row < cellArea.Max.Y; row++ {
+		for col := cellArea.Min.X; col < cellArea.Max.X; {
+			p := image.Point{col, row}
+			if col+rw > cellArea.Max.X {
+				break
+			}
+			cells, err := c.SetCell(p, r, opts...)
+			if err != nil {
+				return err
+			}
+			col += cells
+		}
+	}
+	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 {

canvas/canvas_test.go

@@ -317,6 +317,173 @@ func TestCanvas(t *testing.T) {
 					}
 				}
 
+				if err := cvs.Apply(ft); err != nil {
+					return nil, err
+				}
+				return ft, nil
+			},
+		},
+		{
+			desc:   "SetAreaCells sets cells in the full canvas",
+			canvas: image.Rect(0, 0, 1, 1),
+			ops: func(cvs *Canvas) error {
+				return cvs.SetAreaCells(image.Rect(0, 0, 1, 1), 'r')
+			},
+			want: func(size image.Point) (*faketerm.Terminal, error) {
+				ft := faketerm.MustNew(size)
+				cvs, err := New(ft.Area())
+				if err != nil {
+					return nil, err
+				}
+
+				if _, err := cvs.SetCell(image.Point{0, 0}, 'r'); err != nil {
+					return nil, err
+				}
+
+				if err := cvs.Apply(ft); err != nil {
+					return nil, err
+				}
+				return ft, nil
+			},
+		},
+		{
+			desc:   "SetAreaCells is idempotent",
+			canvas: image.Rect(0, 0, 1, 1),
+			ops: func(cvs *Canvas) error {
+				if err := cvs.SetAreaCells(image.Rect(0, 0, 1, 1), 'r'); err != nil {
+					return err
+				}
+				return cvs.SetAreaCells(image.Rect(0, 0, 1, 1), 'r')
+			},
+			want: func(size image.Point) (*faketerm.Terminal, error) {
+				ft := faketerm.MustNew(size)
+				cvs, err := New(ft.Area())
+				if err != nil {
+					return nil, err
+				}
+
+				if _, err := cvs.SetCell(image.Point{0, 0}, 'r'); err != nil {
+					return nil, err
+				}
+
+				if err := cvs.Apply(ft); err != nil {
+					return nil, err
+				}
+				return ft, nil
+			},
+		},
+		{
+			desc:   "SetAreaCells fails on area too large",
+			canvas: image.Rect(0, 0, 1, 1),
+			ops: func(cvs *Canvas) error {
+				return cvs.SetAreaCells(image.Rect(0, 0, 2, 2), 'r', cell.FgColor(cell.ColorRed), cell.BgColor(cell.ColorBlue))
+			},
+			wantErr: true,
+		},
+		{
+			desc:   "SetAreaCells sets cell options",
+			canvas: image.Rect(0, 0, 1, 1),
+			ops: func(cvs *Canvas) error {
+				return cvs.SetAreaCells(image.Rect(0, 0, 1, 1), 'r', cell.FgColor(cell.ColorRed), cell.BgColor(cell.ColorBlue))
+			},
+			want: func(size image.Point) (*faketerm.Terminal, error) {
+				ft := faketerm.MustNew(size)
+				cvs, err := New(ft.Area())
+				if err != nil {
+					return nil, err
+				}
+
+				if _, err := cvs.SetCell(image.Point{0, 0}, 'r', cell.FgColor(cell.ColorRed), cell.BgColor(cell.ColorBlue)); err != nil {
+					return nil, err
+				}
+
+				if err := cvs.Apply(ft); err != nil {
+					return nil, err
+				}
+				return ft, nil
+			},
+		},
+		{
+			desc:   "SetAreaCells sets cell in a sub-area",
+			canvas: image.Rect(0, 0, 3, 3),
+			ops: func(cvs *Canvas) error {
+				return cvs.SetAreaCells(image.Rect(0, 0, 2, 2), 'p')
+			},
+			want: func(size image.Point) (*faketerm.Terminal, error) {
+				ft := faketerm.MustNew(size)
+				cvs, err := New(ft.Area())
+				if err != nil {
+					return nil, err
+				}
+
+				for _, p := range []image.Point{
+					{0, 0},
+					{0, 1},
+					{1, 0},
+					{1, 1},
+				} {
+					if _, err := cvs.SetCell(p, 'p'); err != nil {
+						return nil, err
+					}
+				}
+
+				if err := cvs.Apply(ft); err != nil {
+					return nil, err
+				}
+				return ft, nil
+			},
+		},
+		{
+			desc:   "SetAreaCells sets full-width runes that fit",
+			canvas: image.Rect(0, 0, 3, 3),
+			ops: func(cvs *Canvas) error {
+				return cvs.SetAreaCells(image.Rect(0, 0, 2, 2), '世')
+			},
+			want: func(size image.Point) (*faketerm.Terminal, error) {
+				ft := faketerm.MustNew(size)
+				cvs, err := New(ft.Area())
+				if err != nil {
+					return nil, err
+				}
+
+				for _, p := range []image.Point{
+					{0, 0},
+					{0, 1},
+				} {
+					if _, err := cvs.SetCell(p, '世'); err != nil {
+						return nil, err
+					}
+				}
+
+				if err := cvs.Apply(ft); err != nil {
+					return nil, err
+				}
+				return ft, nil
+			},
+		},
+		{
+			desc:   "SetAreaCells sets full-width runes that will leave a gap at the end of each row",
+			canvas: image.Rect(0, 0, 3, 3),
+			ops: func(cvs *Canvas) error {
+				return cvs.SetAreaCells(image.Rect(0, 0, 3, 3), '世')
+			},
+			want: func(size image.Point) (*faketerm.Terminal, error) {
+				ft := faketerm.MustNew(size)
+				cvs, err := New(ft.Area())
+				if err != nil {
+					return nil, err
+				}
+
+				for _, p := range []image.Point{
+					{0, 0},
+					{0, 1},
+					{0, 2},
+				} {
+					if _, err := cvs.SetCell(p, '世'); err != nil {
+						return nil, err
+					}
+				}
+
 				if err := cvs.Apply(ft); err != nil {
 					return nil, err
 				}