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fennecslite/matlab/export_fig/crop_borders.m
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crop_borders.m
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function [A, vA, vB, bb_rel] = crop_borders(A, bcol, padding, crop_amounts)
%CROP_BORDERS Crop the borders of an image or stack of images
%
% [B, vA, vB, bb_rel] = crop_borders(A, bcol, [padding])
%
%IN:
% A - HxWxCxN stack of images.
% bcol - Cx1 background colour vector.
% padding - scalar indicating how much padding to have in relation to
% the cropped-image-size (0<=padding<=1). Default: 0
% crop_amounts - 4-element vector of crop amounts: [top,right,bottom,left]
% where NaN/Inf indicate auto-cropping, 0 means no cropping,
% and any other value mean cropping in pixel amounts.
%
%OUT:
% B - JxKxCxN cropped stack of images.
% vA - coordinates in A that contain the cropped image
% vB - coordinates in B where the cropped version of A is placed
% bb_rel - relative bounding box (used for eps-cropping)
%{
% 06/03/15: Improved image cropping thanks to Oscar Hartogensis
% 08/06/15: Fixed issue #76: case of transparent figure bgcolor
% 21/02/16: Enabled specifying non-automated crop amounts
% 04/04/16: Fix per Luiz Carvalho for old Matlab releases
% 23/10/16: Fixed issue #175: there used to be a 1px minimal padding in case of crop, now removed
% 15/05/22: Fixed EPS bounding box (issue #356)
%}
if nargin < 3
padding = 0;
end
if nargin < 4
crop_amounts = nan(1,4); % =auto-cropping
end
crop_amounts(end+1:4) = NaN; % fill missing values with NaN
[h, w, c, n] = size(A);
if isempty(bcol) % case of transparent bgcolor
bcol = A(ceil(end/2),1,:,1);
end
if isscalar(bcol)
bcol = bcol(ones(c, 1));
end
% Crop margin from left
if ~isfinite(crop_amounts(4))
bail = false;
for l = 1:w
for a = 1:c
if ~all(col(A(:,l,a,:)) == bcol(a))
bail = true;
break;
end
end
if bail
break;
end
end
else
l = 1 + abs(crop_amounts(4));
end
% Crop margin from right
if ~isfinite(crop_amounts(2))
bcol = A(ceil(end/2),w,:,1);
bail = false;
for r = w:-1:l
for a = 1:c
if ~all(col(A(:,r,a,:)) == bcol(a))
bail = true;
break;
end
end
if bail
break;
end
end
else
r = w - abs(crop_amounts(2));
end
% Crop margin from top
if ~isfinite(crop_amounts(1))
bcol = A(1,ceil(end/2),:,1);
bail = false;
for t = 1:h
for a = 1:c
if ~all(col(A(t,:,a,:)) == bcol(a))
bail = true;
break;
end
end
if bail
break;
end
end
else
t = 1 + abs(crop_amounts(1));
end
% Crop margin from bottom
bcol = A(h,ceil(end/2),:,1);
if ~isfinite(crop_amounts(3))
bail = false;
for b = h:-1:t
for a = 1:c
if ~all(col(A(b,:,a,:)) == bcol(a))
bail = true;
break;
end
end
if bail
break;
end
end
else
b = h - abs(crop_amounts(3));
end
if padding == 0 % no padding
% Issue #175: there used to be a 1px minimal padding in case of crop, now removed
%{
if ~isequal([t b l r], [1 h 1 w]) % Check if we're actually croppping
padding = 1; % Leave one boundary pixel to avoid bleeding on resize
bcol(:) = nan; % make the 1px padding transparent
end
%}
elseif abs(padding) < 1 % pad value is a relative fraction of image size
padding = sign(padding)*round(mean([b-t r-l])*abs(padding)); % ADJUST PADDING
else % pad value is in units of 1/72" points
padding = round(padding); % fix cases of non-integer pad value
end
if padding > 0 % extra padding
% Create an empty image, containing the background color, that has the
% cropped image size plus the padded border
B = repmat(bcol,[(b-t)+1+padding*2,(r-l)+1+padding*2,1,n]); % Fix per Luiz Carvalho
% vA - coordinates in A that contain the cropped image
vA = [t b l r];
% vB - coordinates in B where the cropped version of A will be placed
vB = [padding+1, (b-t)+1+padding, padding+1, (r-l)+1+padding];
% Place the original image in the empty image
B(vB(1):vB(2), vB(3):vB(4), :, :) = A(vA(1):vA(2), vA(3):vA(4), :, :);
A = B;
else % extra cropping
vA = [t-padding b+padding l-padding r+padding];
A = A(vA(1):vA(2), vA(3):vA(4), :, :);
vB = [NaN NaN NaN NaN];
end
% For EPS cropping, determine the relative BoundingBox - bb_rel
bb_pixels = [l-1 h-b-1 r+1 h-t+1]; %[LowerLeftXY, UpperRightXY]
bb_pixels(bb_pixels<0) = 0;
bb_pixels = min(bb_pixels, [w h w h]);
bb_rel = bb_pixels ./ [w h w h];
end
function A = col(A)
A = A(:);
end
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