diff --git a/bookletify.py b/bookletify.py
index 9072585..6953485 100755
--- a/bookletify.py
+++ b/bookletify.py
@@ -12,11 +12,7 @@ def main():
         with the size of half a page. Especially useful to print pdfs to A5
         size on A4 paper"""
     
-    parser = argparse.ArgumentParser(
-            prog=PROGRAM_NAME,
-            description=DESCRIPTION
-        )
-    
+    parser = argparse.ArgumentParser(prog=PROGRAM_NAME, description=DESCRIPTION)
     parser.add_argument('filename')
     parser.add_argument('-q', '--quiet',
                         action='store_true',
@@ -28,13 +24,33 @@ def main():
                         metavar='SIZE',
                         help="""set final paper size. Possible values: 'A0',
                             ..., 'A8' or 'C4'. Default value is 'A4'""")
-
     parser.add_argument('-b', '--binding-margin',
                         default=10,
                         type=float,
                         metavar='MARGIN',
                         help="""internal margin for the binding, expressed in
-                            millimeters. Default value is 10""")
+                            millimeters relative to the final paper size (ie:
+                            half of the height of the paper size specified by
+                            --size). Set to 0 to disable. This setting is
+                            independent to the trim setting, ie: increasing or
+                            decreasing this margin does not trim any content on
+                            the final pdf, the content gets scaled down (or up)
+                            to fit to the final width minus the binding margin.
+                            Default value is 10""")
+    parser.add_argument('-t', '--trim',
+                        default=[0,0,0,0],
+                        type=float,
+                        nargs=4,
+                        metavar='T',
+                        help="""margins to trim, expressed in millimeters
+                            relative to the original page size, as: top right
+                            bottom left. This setting is independent to the
+                            binding margin, ie: first the trim is applied, then
+                            the trimmed content gets scaled up (or down) to the
+                            full height and width, minus the binding margin.
+                            Changing the trim does not increase or decrease the
+                            final binding margin. A negative trim adds an empty
+                            border on that side. Default value is 0 0 0 0""")
     
     args = parser.parse_args()
 
@@ -59,8 +75,13 @@ def main():
     smallwidth = fullheight / 2
     smallheight = fullwidth
     # Convert mm to pixels at 72 dpi
-    bindingwidth = args.binding_margin * 72 / float(25.4)
+    bindingwidth = args.binding_margin * 72.0 / 25.4
     smallblank = PageObject.create_blank_page(width=smallwidth - bindingwidth, height=smallheight)
+
+    tt = args.trim[0] * 72.0 / 25.4
+    tr = args.trim[1] * 72.0 / 25.4
+    tb = args.trim[2] * 72.0 / 25.4
+    tl = args.trim[3] * 72.0 / 25.4
     
     # Read the input
     reader = PdfReader(input_name)
@@ -80,24 +101,43 @@ def main():
     output = PdfWriter()
     info("\nRearranging...")
 
-    def merge_srt_page(base, over, angle, tx, ty):
-        sx = float(smallwidth - bindingwidth) / float(over.mediabox.width)
-        sy = float(smallheight) / float(over.mediabox.height)
-        t = Transformation().scale(sx, sy).rotate(angle). translate(tx, ty)
-        over.add_transformation(t)
-        base.merge_page(over)
+    def get_scaling(page):
+        sx = float(smallwidth - bindingwidth) / (float(page.mediabox.width) - tr - tl)
+        sy = float(smallheight) / (float(page.mediabox.height) - tt - tb)
+        return (sx, sy)
 
     m = len(pages)
     for i in range(int(m / 2)):
         prog(i, int(m / 2))
         new_page = PageObject.create_blank_page(width=fullwidth, height=fullheight)
         if i % 2 == 0:
-            merge_srt_page(new_page, pages[m - 1 - i], -90, 0, fullheight)
-            merge_srt_page(new_page, pages[i], - 90, 0, smallwidth - bindingwidth)
-            pass
+            (sx, sy) = get_scaling(pages[m-1-i])
+            t = Transformation().scale(sx, sy).rotate(-90).translate(-tb * sy, fullheight + tl * sx)
+            pages[m-1-i].add_transformation(t)
+            pages[m-1-i].cropbox.upper_right = (smallheight, fullheight)
+            pages[m-1-i].cropbox.lower_left = (0, smallwidth + bindingwidth)
+            new_page.merge_page(pages[m-1-i])
+
+            (sx, sy) = get_scaling(pages[i])
+            t = Transformation().scale(sx, sy).rotate(-90).translate(-tb * sy, smallwidth - bindingwidth + tl * sx)
+            pages[i].add_transformation(t)
+            pages[i].cropbox.upper_right = (smallheight, smallwidth - bindingwidth)
+            pages[i].cropbox.lower_left = (0, 0)
+            new_page.merge_page(pages[i])
         else:
-            merge_srt_page(new_page, pages[m - 1 - i], 90, smallheight, smallwidth + bindingwidth)
-            merge_srt_page(new_page, pages[i], 90, smallheight, 0)
+            (sx, sy) = get_scaling(pages[m-1-i])
+            t = Transformation().scale(sx, sy).rotate(90).translate(smallheight + tb * sy, smallwidth + bindingwidth - tl * sx)
+            pages[m-1-i].add_transformation(t)
+            pages[m-1-i].cropbox.upper_right = (smallheight, fullheight)
+            pages[m-1-i].cropbox.lower_left = (0, smallwidth + bindingwidth)
+            new_page.merge_page(pages[m-1-i])
+
+            (sx, sy) = get_scaling(pages[i])
+            t = Transformation().scale(sx, sy).rotate(90).translate(smallheight + tb * sy, 0 - tl * sx)
+            pages[i].add_transformation(t)
+            pages[i].cropbox.upper_right = (smallheight, smallwidth - bindingwidth)
+            pages[i].cropbox.lower_left = (0, 0)
+            new_page.merge_page(pages[i])
 
         output.add_page(new_page)
     prog(int(m/2), int(m/2))