1 files changed, 72 insertions, 0 deletions
diff --git a/makeDither.py b/makeDither.py
new file mode 100644
index 0000000..d0eb16c
--- /dev/null
+++ b/makeDither.py
@@ -0,0 +1,72 @@
+#!/usr/bin/python
+
+import cgi
+import pbutils
+from os import getpid, path
+from subprocess import call
+
+MAIN_DIRECTORY = ""
+BIN_CONVERT = "convert"
+BIN_IDENTIFY = "identify"
+BIN_COMPOSITE = "composite"
+
+class Dither:
+  def __init__(self, 
+      input_file_path, 
+      dither_file="1.png", 
+      username="",
+    ):
+
+    self.nametag = "imDither";
+    if username:
+      self.username = username
+    else:
+      self.username = "";
+    
+    self.pid = str(getpid())
+    self.dither_file = dither_file;
+    self.original_file = input_file_path;
+    self.MAX_NAME_LENGTH = 10;
+
+    self.image_format = self.original_file.split(".")[-1]
+    try:
+      self.dimensions = pbutils.image_dimensions_and_test(self.original_file);
+    except Exception as E:
+      pbutils.error("Corrupt image")
+    self.canvas_file = self.pid+"blank_canvas.png";
+    self.makeCanvas();
+    self.mask_file = self.pid+"mask_file"+"."+self.image_format;
+    self.makeMask();
+    self.result_file = self.makeResultFilename();
+    self.fuseMask();
+
+  def makeResultFilename(self):
+    file_base, extension = path.splitext(self.original_file)
+    if len(file_base) > self.MAX_NAME_LENGTH:
+      file_base = file_base[0:self.MAX_NAME_LENGTH]
+    return "%s_%s_%s%s%s" % (file_base, self.username, self.nametag, pbutils.now(), extension)
+
+  #first step
+  def makeCanvas(self):
+    call([BIN_CONVERT,"-size",self.dimensions[0]+"x"+self.dimensions[1],"canvas:transparent", self.canvas_file])
+
+  #second step use the Canvas as a background
+  def makeMask(self):
+    #tile the dither pattern on the canvas
+    call([BIN_COMPOSITE,"-tile", self.dither_file, self.canvas_file, self.mask_file])
+    
+    #fuse the tiled file to create a mask
+    #convert thebg.gif -compose Dst_In null: thefile.gif -matte -layers composite new.gif
+    call([BIN_CONVERT, self.mask_file, "-compose", "Dst_In", "null:", self.original_file, "-matte", "-layers", "composite", self.mask_file])
+    
+    #cleanup
+    call(["rm", self.canvas_file])
+  
+  #third step
+  def fuseMask(self, fuse_mode="Pin_Light"):
+    call([BIN_CONVERT, self.mask_file, "null:", self.original_file, "-matte", "-compose", fuse_mode, "-layers", "composite", self.result_file])
+    call(["rm", self.mask_file])
+  
+
+if __name__ == "__main__":
+  dither = Dither("./test.gif");