Update README w/ subtraction script example

2 files changed, 22 insertions, 17 deletions

diff --git a/README.rst b/README.rst
index 0324166..0e467b9 100644
--- a/README.rst
+++ b/README.rst
@@ -305,6 +305,8 @@ Options:
 Subtraction scripts
 *******************
 
+.. image:: pics/subtract_example.png
+
 Subtraction scripts tell ``gerbolyze paste`` which layers to remove from other layers. When a source layer is given in
 the subtraction script, gerbolyze will dilate everything on this source layer and remove it from the target layer. By
 default, Gerbolyze subtracts the mask layer from the silk layer to make sure there are no silk primitives that overlap
@@ -330,6 +332,9 @@ The default subtraction script is:
 .. code-block::
 
     out.silk -= in.mask
+    out.silk -= in.silk+0.5
+    out.mask -= in.mask+0.5
+    out.copper -= in.copper+0.5
 
 ``gerbolyze vectorize``
 ~~~~~~~~~~~~~~~~~~~~~~~
@@ -486,7 +491,7 @@ gerbolyze using ``--vectorizer binary-contours``.
 board, which is about the smallest detail most manufacturers can resolve on the silkscreen layer. You can control this
 setting using the ``--fab-resolution`` and ``--oversampling`` options. Refer to ``gerbolyze --help`` for details.
 
-.. image:: https://raw.githubusercontent.com/jaseg/gerbolyze/master/screenshots/01import01.png
+.. image:: screenshots/01import01.png
 
 2 Import your desired artwork
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -495,28 +500,28 @@ Though anime or manga pictures are highly recommended, you can use any image inc
 a picture with comparatively low detail that remains recognizable at very low resolution. While working on a screen this
 is hard to vizualize, but the grain resulting from the low resolution of a PCB's silkscreen is quite coarse.
 
-.. image:: https://raw.githubusercontent.com/jaseg/gerbolyze/master/screenshots/02import02.png
+.. image:: screenshots/02import02.png
 
 3 Paste the artwork onto the render as a new layer
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. image:: https://raw.githubusercontent.com/jaseg/gerbolyze/master/screenshots/03paste.png
+.. image:: screenshots/03paste.png
 
 4 Scale, rotate and position the artwork to the desired size
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. image:: https://raw.githubusercontent.com/jaseg/gerbolyze/master/screenshots/04scale_cut.png
+.. image:: screenshots/04scale_cut.png
 
 For alignment it may help to set the artwork layer's mode in the layers dialog to ``overlay``, which makes the PCB
 render layer below shine through more. If you can't set the layer's mode, make sure you have actually made a new layer
 from the floating selection you get when pasting one image into another in the GIMP.
 
-.. image:: https://raw.githubusercontent.com/jaseg/gerbolyze/master/screenshots/05position.png
+.. image:: screenshots/05position.png
 
 5 Convert the image to grayscale
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. image:: https://raw.githubusercontent.com/jaseg/gerbolyze/master/screenshots/06grayscale.png
+.. image:: screenshots/06grayscale.png
 
 6 Fine-tune the image's contrast
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -529,7 +534,7 @@ dots that might be beyond your PCB manufacturer's maximum resolution. To control
 of the grayscale value curve as shown (exaggerated) in the picture below. These steps saturate very bright grays to
 white and very dark grays to black while preserving the values in the middle.
 
-.. image:: https://raw.githubusercontent.com/jaseg/gerbolyze/master/screenshots/08curve_cut.png
+.. image:: screenshots/08curve_cut.png
 
 7 Retouch details
 ~~~~~~~~~~~~~~~~~
@@ -542,12 +547,12 @@ If you don't want the image's background to show up on the final PCB at all, jus
 Particularly on low-resolution source images it may make sense to apply a blur with a radius similar to the following
 newsprint filter's cell size (10px) to smooth out the dot pattern generated by the newsprint filter.
 
-.. image:: https://raw.githubusercontent.com/jaseg/gerbolyze/master/screenshots/09retouch.png
+.. image:: screenshots/09retouch.png
 
 In the following example, I retouched the highlights in the hair of the character in the picture to make them completely
 white instead of light-gray, so they still stand out nicely in the finished picture.
 
-.. image:: https://raw.githubusercontent.com/jaseg/gerbolyze/master/screenshots/10retouched.png
+.. image:: screenshots/10retouched.png
 
 8 Run the newsprint filter
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -560,15 +565,15 @@ with ``gerbolyze render`` default settings for good-quality silkscreen). In gene
 The second important setting is oversampling, which should be set to four or slightly higher. This improves the result
 of the edge reconstruction of ``gerbolyze vectorize``.
 
-.. image:: https://raw.githubusercontent.com/jaseg/gerbolyze/master/screenshots/11newsprint.png
+.. image:: screenshots/11newsprint.png
 
 The following are examples on the detail resulting from the newsprint filter.
 
-.. image:: https://raw.githubusercontent.com/jaseg/gerbolyze/master/screenshots/12newsprint.png
+.. image:: screenshots/12newsprint.png
 
-.. image:: https://raw.githubusercontent.com/jaseg/gerbolyze/master/screenshots/13newsprint.png
+.. image:: screenshots/13newsprint.png
 
-.. image:: https://raw.githubusercontent.com/jaseg/gerbolyze/master/screenshots/14newsprint.png
+.. image:: screenshots/14newsprint.png
 
 9 Export the image for use with ``gerbolyze vectorize``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -576,16 +581,16 @@ The following are examples on the detail resulting from the newsprint filter.
 Simply export the image as a PNG file. Below are some pictures of the output ``gerbolyze vectorize`` produced for this
 example.
 
-.. image:: https://raw.githubusercontent.com/jaseg/gerbolyze/master/screenshots/14result_cut.png
+.. image:: screenshots/14result_cut.png
 
-.. image:: https://raw.githubusercontent.com/jaseg/gerbolyze/master/screenshots/15result_cut.png
+.. image:: screenshots/15result_cut.png
 
-.. image:: https://raw.githubusercontent.com/jaseg/gerbolyze/master/screenshots/16result_cut.png
+.. image:: screenshots/16result_cut.png
 
 Gallery
 -------
 
-.. image:: https://raw.githubusercontent.com/jaseg/gerbolyze/master/sample3.jpg
+.. image:: pics/sample3.jpg
 
 Limitations
 -----------
diff --git a/pics/subtract_example.png b/pics/subtract_example.png
new file mode 100644
index 0000000..13305af
--- /dev/null
+++ b/pics/subtract_example.png