function newRect = OffsetRect(oldRect,x,y)
% newRect = OffsetRect(oldRect,x,y)
%
% Offset the passed rect matrix by the horizontal (x)
% and vertical (y) shift given. You can also pass in column vectors x and y
% with e.g., n different "shifts" and the function will return n copies of
% oldRect, each shifted by one of the shift values in x and y.
%
% Alternatively you can give a single scalar x,y shift value, but apply it
% to a whole matrix of rects 'oldRect' --> Apply a common offset to a large
% number of rects simultaneously.
%
% Also see PsychRects.
% 5/16/96 dhb Relented to Pelli's request to change calling order
% from v,h to x,y.
% dhb Index using RectTop etc.
% 7/10/96 dgp Wrote it.
% 8/5/96 dgp Check rect size.
% 5/18/08 mk Vectorized.
% 5/31/09 mk Improved error handling. Add support for offsetting a
% single rect multiple times, ie., pass x,y as vectors, then
% create many offset versions of single input rect.
% 1/17/16 mscain Resolve ambiguity for 4x4 matrix to fix failure.
if nargin~=3
error('Usage: newRect = OffsetRect(oldRect,x,y)');
end
if PsychNumel(oldRect) == 4
% Single rect case:
if size(oldRect,2)~=4
error('Wrong size rect argument. A single rect must be a 1-row 4 element vector!');
end
if length(x)==1 && length(y)==1
% Single rect, offset by a single (x,y) point:
newRect(RectTop) = oldRect(RectTop) + y;
newRect(RectBottom) = oldRect(RectBottom) + y;
newRect(RectLeft) = oldRect(RectLeft) + x;
newRect(RectRight) = oldRect(RectRight) + x;
else
% Single rect, but multiple points:
if ~all(size(x) == size(y)) || size(x,2)~=1
error('Wrong format of x or y in multipoint case: x and y must be 1-column vectors of matching size!');
else
% x and y are one column vectors with size(x,1) rows/elements.
% Replicate oldRect into nrpts identical copies, then add point
% offsets:
newRect = repmat(oldRect, size(x, 1), 1) + [x, y, x, y];
end
end
else
% Multirect case: Offsets (x,y) can be vectors, or a single point:
% A 4x4 matrix is a special case, treated as 4 rects in 4 rows to
% resolve the ambiguity, as proposed by GitHub user mscain.
if size(oldRect, 1)==4 && size(oldRect, 2)~=4
newRect(RectTop, :) = oldRect(RectTop, :) + y;
newRect(RectBottom, :) = oldRect(RectBottom, :) + y;
newRect(RectLeft, :) = oldRect(RectLeft, :) + x;
newRect(RectRight, :) = oldRect(RectRight, :) + x;
else
newRect(:, RectTop) = oldRect(:, RectTop) + y;
newRect(:, RectBottom) = oldRect(:, RectBottom) + y;
newRect(:, RectLeft) = oldRect(:, RectLeft) + x;
newRect(:, RectRight) = oldRect(:, RectRight) + x;
end
end