Created a block type

src/view/double_buffer.zig

@@ -7,6 +7,7 @@ const Allocator = mem.Allocator;
 const Matrix = grome.container.Matrix;
 const SubMatrix = grome.container.SubMatrix;
 const Point = grome.container.Point;
+const Block = grome.container.Block;
 const Rect = grome.container.Rect;
 const Cell = grome.view.Cell;
 
@@ -40,8 +41,8 @@ pub const DoubleBuffer = struct {
 
     // frame returns a subset of the backbuffer where `loc` is the top left point of the
     // subsection, and `size` is the area or size of the subset.
-    pub fn frame(self: *@This(), loc: Point, size: Rect) SubMatrix(Cell) {
-        return .init(&self.back, loc, size);
+    pub fn frame(self: *@This(), mask: Block) SubMatrix(Cell) {
+        return .init(&self.back, mask);
     }
 
     // swap the front and back. This should be called right before rendering