Bugfix - correctly determine area on a braille canvas.

canvas/braille/braille.go

@@ -115,7 +115,7 @@ func (c *Canvas) Size() image.Point {
 // than the area used to create the braille canvas.
 func (c *Canvas) Area() image.Rectangle {
 	ar := c.regular.Area()
-	return image.Rect(0, 0, ar.Dx()*ColMult, ar.Dx()*RowMult)
+	return image.Rect(0, 0, ar.Dx()*ColMult, ar.Dy()*RowMult)
 }
 
 // Clear clears all the content on the canvas.

canvas/braille/braille_test.go

@@ -109,6 +109,12 @@ func TestNew(t *testing.T) {
 			wantSize: image.Point{6, 12},
 			wantArea: image.Rect(0, 0, 6, 12),
 		},
+		{
+			desc:     "braille from non-zero-based multi-cell rectangular area",
+			ar:       image.Rect(6, 6, 9, 10),
+			wantSize: image.Point{6, 16},
+			wantArea: image.Rect(0, 0, 6, 16),
+		},
 	}
 
 	for _, tc := range tests {