From 0f4fc1d73f3fe4aea14c0bbe215f22b9cbb8f54d Mon Sep 17 00:00:00 2001
From: "osm@osm.rrze" <osm@osm.rrze.uni-erlangen.de>
Date: Fri, 5 Apr 2013 10:58:20 +0200
Subject: [PATCH] script for merging maptiles out of high-zoom non-text and
 lowzoom textlayer-tiles.

---
 scripts/osm-mergemaptiles.pl | 95 ++++++++++++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)
 create mode 100755 scripts/osm-mergemaptiles.pl

diff --git a/scripts/osm-mergemaptiles.pl b/scripts/osm-mergemaptiles.pl
new file mode 100755
index 0000000..e6ed782
--- /dev/null
+++ b/scripts/osm-mergemaptiles.pl
@@ -0,0 +1,95 @@
+#!/usr/bin/perl -w
+
+# WARNING: Doing this for zoom level 0 requires 90 GB of space in $TEMP!
+# That's why layers 0-2 are not generated by default (you need to change
+# a line below)
+
+# URL is:   /zoom/X/Y.png
+$srcpath = '/mnt/tiles/lowzoomtilegen/';
+$dstpath='/mnt/tiles/statictiles/mergedtiles/';
+
+use Graphics::Magick;
+
+# No need to change this usually
+$ZOOMMAX = 9;
+$TILESIZE = 256;
+
+# Par. 0:  Z
+# Par. 1:  X
+# Par. 2:  Y
+sub mergetile($$$) {
+  my $ZS = $_[0];
+  my $XS = $_[1];
+  my $YS = $_[2];
+  my $N = 1;
+  my $dstfilename = sprintf("%s/%d/%d/%d.png", $dstpath, $ZS, $XS, $YS);
+  my $olfilename = sprintf("%s/%d/%d/%d.png", $srcpath, $ZS, $XS, $YS);
+  if ($ZS >= $ZOOMMAX) {
+    print("Sorry - can only merge Z <= $ZOOMMAX\n"); exit(1);
+  }
+  my $z = $ZS;
+  while ($ZS < $ZOOMMAX) {
+    $N = $N * 2;  # Twice as many tiles (per direction)
+    $XS = $XS * 2; # Starting at 2*X
+    $YS = $YS * 2; # and 2*Y.
+    $ZS++;
+  }
+  printf("Combining %d tiles (%d x %d pixels)\n", $N * $N, $N * $TILESIZE, $N * $TILESIZE);
+  # Now load them all and fill them into one big picture.
+  my $dimage = Graphics::Magick->new('size' => sprintf("%dx%d", $N * $TILESIZE, $N * $TILESIZE)); # magick => 'png', 
+  $status = $dimage->Read("xc:white"); # This actually creates the image, the above does NOT - very intuitive!
+  warn "$status" if "$status";
+  my $x; my $y;
+  for ($x = 0; $x < $N; $x++) {
+    for ($y = 0; $y < $N; $y++) {
+      my $fn = sprintf("%s/%d/%d/%d.png", $srcpath, $ZOOMMAX, $XS + $x, $YS + $y);
+      #print("Loading: $fn\n");
+      my $tmpimg = Graphics::Magick->new();
+      $status = $tmpimg->Read($fn);
+      warn "$status" if "$status";
+      $dimage->Composite( 'image' => $tmpimg, 'compose' => 'over',
+                          'x' => ($x * $TILESIZE),
+                          'y' => ($y * $TILESIZE));
+    }
+  }
+  $dimage->Resize('geometry' => sprintf("%dx%d", $TILESIZE, $TILESIZE), 'filter' => 'Lanczos');
+  #print("Loading: $olfilename\n");
+  my $olimg = Graphics::Magick->new();
+  $status = $olimg->Read($olfilename);
+  warn "$status" if "$status";
+  $dimage->Composite( 'image' => $olimg, 'compose' => 'over', 'x' => 0, 'y' => 0 );
+  print("Writing combined image to: $dstfilename\n");
+  $status = $dimage->Write($dstfilename);
+  warn "$status" if "$status";
+}
+
+# "main()"
+
+#mergetile(1, 1, 0);
+#mergetile(2, 2, 1);
+#mergetile(3, 4, 2);
+#mergetile(4, 8, 5);
+#mergetile(5, 16, 10);
+#mergetile(6, 33, 21);
+#mergetile(7, 67, 43);
+#mergetile(8, 135, 87);
+my $rz; my $rx; my $ry;
+for ($rz = 3; $rz <= 8; $rz++) {
+  my $ntilesperdir = 2 ** $rz;  # Allgemein: 2 ^ Zoomlevel
+  for ($rx = 0; $rx < $ntilesperdir; $rx++) {
+    my $targdir = sprintf("%s/%d/%d", $dstpath, $rz, $rx);
+    if (! -e $targdir) {
+      print("Trying to create $targdir...");
+      # FIXME: mkdir -p   - the zoom level dir might not exist either!
+      if (mkdir($targdir)) {
+        print(" OK!\n");
+      } else {
+        print(" FAILED!\n");
+      }
+    }
+    for ($ry = 0; $ry < $ntilesperdir; $ry++) {
+      mergetile($rz, $rx, $ry);
+    }
+  }
+  $ntilesperdir = $ntilesperdir * 2;
+}
-- 
2.25.1