Bugfix: custom layer G-code was applied before Z change, and not after like it was documented. #869

MANIFEST

@@ -55,6 +55,7 @@ t/arcs.t
 t/clean_polylines.t
 t/clipper.t
 t/collinear.t
+t/custom_gcode.t
 t/dynamic.t
 t/fill.t
 t/geometry.t

lib/Slic3r/GCode.pm

@@ -7,6 +7,7 @@ use Slic3r::Geometry qw(scale unscale scaled_epsilon points_coincide PI X Y B);
 
 has 'multiple_extruders' => (is => 'ro', default => sub {0} );
 has 'layer'              => (is => 'rw');
+has 'move_z_callback'    => (is => 'rw');
 has 'shift_x'            => (is => 'rw', default => sub {0} );
 has 'shift_y'            => (is => 'rw', default => sub {0} );
 has 'z'                  => (is => 'rw');
@@ -79,6 +80,7 @@ sub move_z {
         $self->speed('travel');
         $gcode .= $self->G0(undef, $z, 0, $comment || ('move to next layer (' . $self->layer->id . ')'))
             unless ($current_z // -1) != ($self->z // -1);
+        $gcode .= $self->move_z_callback->() if defined $self->move_z_callback;
     }
     
     return $gcode;

lib/Slic3r/Print.pm

@@ -738,8 +738,13 @@ sub write_gcode {
         # set new layer, but don't move Z as support material interfaces may need an intermediate one
         $gcodegen->layer($self->objects->[$object_copies->[0][0]]->layers->[$layer_id]);
         $gcodegen->elapsed_time(0);
-        $gcode .= $Slic3r::Config->replace_options($Slic3r::Config->layer_gcode) . "\n"
+        
+        # prepare callback to call as soon as a Z command is generated
+        $gcodegen->move_z_callback(sub {
+            $gcodegen->move_z_callback(undef);  # circular ref or not?
+            return $Slic3r::Config->replace_options($Slic3r::Config->layer_gcode) . "\n"
                 if $Slic3r::Config->layer_gcode;
+        });
         
         # extrude skirt
         if ($skirt_done < $Slic3r::Config->skirt_height) {

t/custom_gcode.t

@@ -0,0 +1,41 @@
+use Test::More tests => 1;
+use strict;
+use warnings;
+
+BEGIN {
+    use FindBin;
+    use lib "$FindBin::Bin/../lib";
+}
+
+use Slic3r;
+use Slic3r::Test;
+
+my $config = Slic3r::Config->new_from_defaults;
+
+my $test = sub {
+    my ($conf) = @_;
+    $conf ||= $config;
+    
+    my $print = Slic3r::Test::init_print('2x20x10', config => $conf);
+    
+    my $last_move_was_z_change = 0;
+    Slic3r::Test::GCodeReader->new(gcode => Slic3r::Test::gcode($print))->parse(sub {
+        my ($self, $cmd, $args, $info) = @_;
+        
+        if ($last_move_was_z_change && $cmd ne $config->layer_gcode) {
+            fail 'custom layer G-code was not applied after Z change';
+        }
+        if (!$last_move_was_z_change && $cmd eq $config->layer_gcode) {
+            fail 'custom layer G-code was not applied after Z change';
+        }
+        
+        $last_move_was_z_change = (defined $info->{dist_Z} && $info->{dist_Z} > 0);
+    });
+    
+    1;
+};
+
+$config->set('layer_gcode', '_MY_CUSTOM_GCODE_');
+ok $test->(), "custom layer G-code is applied after Z move and before other moves";
+
+__END__