Adapt GoSlice struct to be fully exported. This allows easy usage as …

…lib.

README.md

@@ -4,9 +4,9 @@
 
 # GoSlice
 
-This is a very experimental slicer for 3d printing. It is currently in a very early stage but it can already slice models:
+This is a very experimental slicer for 3d printing. It is currently in a very early stage, but it can already slice models:
 
-Supported features:
+__Supported features:__
 * perimeters
 * simple linear infill
 * rotated infill
@@ -18,11 +18,18 @@ Supported features:
 * simple support generation
 * brim and skirt
 
+__For users - Use CLI:__  
+Provides a basic command line interface. Just run with `--help` and see the description bellow.
+
+__For developers - Use as Go library:__  
+You can use GoSlice as slicing lib, with support to inject custom slicing logic at any stage.
+See __"Use as lib"__ bellow.
+
 Example:  
 <img width="200" alt="sliced Gopher logo" src="https://raw.githubusercontent.com/aligator/GoSlice/master/docs/GoSlice-print.png">
 
 ## Try it out - for users
-Download latest release matching your platform from here:
+Download the latest release matching your platform from here:
 https://github.com/aligator/GoSlice/releases
 
 Unpack the executable and run it in the commandline.  
@@ -41,6 +48,9 @@ If you need the usage of all possible flags, run it with the `--help` flag:
 ./goslice --help
 ```
 
+Note that some flags exist as --initial-... also which applies to the first layer only.
+The non-initial apply to all other layers, but not the first one.
+
 ## Try it out - for developers
 Just running GoSlice:
 ```
@@ -65,6 +75,54 @@ go build -ldflags "-X=main.Version=$(git describe --tags) -X=main.Build=$(git re
 ## How does it work
 [see here](docs/README.md)
 
+## Use as lib
+You want to
+* Create a slicer but do not want to do everything of it?
+* Extend GoSlice functionality? (Please consider Pull Requests if you created a nice addition :-)
+* Create a new, user-friendly frontend?
+
+-> Then you can do it with GoSlice!  
+
+To do this you can copy the `goslice/slicer.go/NewGoSlice` function and just pass to GoSlice what you want.  
+You can add new logic by implementing one of the various handler interfaces used by it.  
+If you need even more control, you can even copy and modify the whole `goslice/slicer.go` file which allows you to
+control how the steps are called after each other.
+
+### Handler Interfaces
+Here some brief explanation of the interfaces. For more detailed information just look into the code...  
+(And take a look at [the docs](docs/README.md) where I explained some aspects a bit deeper.)
+* Reader    handler.ModelReader
+  Is used to read a mesh file. GoSlice provides an implementation for stl files.
+
+* Optimizer handler.ModelOptimizer
+  Is responsible for 
+  1. checking the model 
+  2. optimizing it by e.g. removing doubles 
+  3. calculating some additional information, 
+     like the touching vertices etc. which is needed for the next step.
+  The implementation of GoSlice is very currently basic and may have problems with some models.
+
+* Slicer    handler.ModelSlicer
+  Creates the slices (e.g. layers) out of the model. 
+  It then tries to combine all lines to several polygons per each layer.
+  The implementation of GoSlice is again very basic, but it works.
+
+* Modifiers []handler.LayerModifier
+  This is the most interesting part: Modifiers are called after each other and 
+  Calculate things like perimeters, infill, support, ...
+  They add this information as "Attributes" which is basically just a map of interface{}.
+  GoSlice already provides several basic modifiers.
+
+* Generator handler.GCodeGenerator
+  The generator then generates the final gcode based on the data the modifiers added.
+  The implementation of GoSlice is basically a collection of `Renderer` which often just match one modifier.
+  You can provide your own, additional Renderers or even replace existing ones.
+
+* Writer    handler.GCodeWriter
+  This is the last part, and it basically just writes the gcode to somewhere.
+  You could for example provide a writer which directly sends the gcode to OctoPrint.
+  The default implementation just writes it to a gcode file.
+
 ## Contribution
 You are welcome to help.  
 [Just look for open issues](https://github.com/aligator/GoSlice/issues) and pick one, create new issues or create new pull requests.

cmd/goslice/main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"GoSlice/data"
+	"GoSlice/goslice"
 	"fmt"
 	"io"
 	"os"
@@ -25,7 +26,7 @@ func main() {
 		os.Exit(1)
 	}
 
-	p := NewGoSlice(o)
+	p := goslice.NewGoSlice(o)
 	err := p.Process()
 
 	if err != nil {