## -*- mode: tcl ; fill-column: 90 -*-
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## Transformers -- Structural changes (data re-arrangements)
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## Highlevel operations implemented on top of the C core
#
## - Cropping
operator op::crop {
section transform structure
example {
aktive op sdf 2image smooth [aktive op sdf ring [aktive image sdf triangle width 128 height 128 a {10 10} b {50 80} c {80 30}] thickness 4]
@1 left 10 right 20 top 30 bottom 50
}
note Returns image containing a rectangular subset of input, \
specified by the amount of rows and columns to remove \
from the four borders.
uint? 0 left Number of columns to remove from the left input border
uint? 0 right Number of columns to remove from the right input border
uint? 0 top Number of rows to remove from the top input border
uint? 0 bottom Number of rows to remove from the bottom input border
input
body {
lassign [aktive query geometry $src] x y w h d
if {($left == 0) &&
($right == 0) &&
($top == 0) &&
($bottom == 0)} { return $src }
if {($left < 0) ||
($right < 0) ||
($top < 0) ||
($bottom < 0)} {
aktive error "Unable to extend image with crop" CROP
}
if {(($top + $bottom) >= $h) ||
(($left + $right) >= $w)} {
aktive error "Unable to crop to empty image" CROP
}
set bottom [expr {$h - 1 - $bottom}]
set right [expr {$w - 1 - $right}]
# TODO ?? optimization
# - 1 - if the src is a select x or (or y) choose the matching orientation as the
# first to place around the source, take advantage of select chain reduction.
#
# - 2 - see if the stack is two select ops indicating a previous crop. If so, reorder
# the stack to reduce both x and y selections.
return [aktive op select y [aktive op select x $src from $left to $right] from $top to $bottom]
}
}
##
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::return