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License: MIT License
a library for constructing geometric data
License: MIT License
== Welcome to Rails Rails is a web-application framework that includes everything needed to create database-backed web applications according to the Model-View-Control pattern. This pattern splits the view (also called the presentation) into "dumb" templates that are primarily responsible for inserting pre-built data in between HTML tags. The model contains the "smart" domain objects (such as Account, Product, Person, Post) that holds all the business logic and knows how to persist themselves to a database. The controller handles the incoming requests (such as Save New Account, Update Product, Show Post) by manipulating the model and directing data to the view. In Rails, the model is handled by what's called an object-relational mapping layer entitled Active Record. This layer allows you to present the data from database rows as objects and embellish these data objects with business logic methods. You can read more about Active Record in link:files/vendor/rails/activerecord/README.html. The controller and view are handled by the Action Pack, which handles both layers by its two parts: Action View and Action Controller. These two layers are bundled in a single package due to their heavy interdependence. This is unlike the relationship between the Active Record and Action Pack that is much more separate. Each of these packages can be used independently outside of Rails. You can read more about Action Pack in link:files/vendor/rails/actionpack/README.html. == Getting Started 1. At the command prompt, create a new Rails application: <tt>rails new myapp</tt> (where <tt>myapp</tt> is the application name) 2. Change directory to <tt>myapp</tt> and start the web server: <tt>cd myapp; rails server</tt> (run with --help for options) 3. Go to http://localhost:3000/ and you'll see: "Welcome aboard: You're riding Ruby on Rails!" 4. Follow the guidelines to start developing your application. You can find the following resources handy: * The Getting Started Guide: http://guides.rubyonrails.org/getting_started.html * Ruby on Rails Tutorial Book: http://www.railstutorial.org/ == Debugging Rails Sometimes your application goes wrong. Fortunately there are a lot of tools that will help you debug it and get it back on the rails. First area to check is the application log files. Have "tail -f" commands running on the server.log and development.log. Rails will automatically display debugging and runtime information to these files. Debugging info will also be shown in the browser on requests from 127.0.0.1. You can also log your own messages directly into the log file from your code using the Ruby logger class from inside your controllers. Example: class WeblogController < ActionController::Base def destroy @weblog = Weblog.find(params[:id]) @weblog.destroy logger.info("#{Time.now} Destroyed Weblog ID ##{@weblog.id}!") end end The result will be a message in your log file along the lines of: Mon Oct 08 14:22:29 +1000 2007 Destroyed Weblog ID #1! More information on how to use the logger is at http://www.ruby-doc.org/core/ Also, Ruby documentation can be found at http://www.ruby-lang.org/. There are several books available online as well: * Programming Ruby: http://www.ruby-doc.org/docs/ProgrammingRuby/ (Pickaxe) * Learn to Program: http://pine.fm/LearnToProgram/ (a beginners guide) These two books will bring you up to speed on the Ruby language and also on programming in general. == Debugger Debugger support is available through the debugger command when you start your Mongrel or WEBrick server with --debugger. This means that you can break out of execution at any point in the code, investigate and change the model, and then, resume execution! You need to install ruby-debug to run the server in debugging mode. With gems, use <tt>sudo gem install ruby-debug</tt>. Example: class WeblogController < ActionController::Base def index @posts = Post.all debugger end end So the controller will accept the action, run the first line, then present you with a IRB prompt in the server window. Here you can do things like: >> @posts.inspect => "[#<Post:0x14a6be8 @attributes={"title"=>nil, "body"=>nil, "id"=>"1"}>, #<Post:0x14a6620 @attributes={"title"=>"Rails", "body"=>"Only ten..", "id"=>"2"}>]" >> @posts.first.title = "hello from a debugger" => "hello from a debugger" ...and even better, you can examine how your runtime objects actually work: >> f = @posts.first => #<Post:0x13630c4 @attributes={"title"=>nil, "body"=>nil, "id"=>"1"}> >> f. Display all 152 possibilities? (y or n) Finally, when you're ready to resume execution, you can enter "cont". == Console The console is a Ruby shell, which allows you to interact with your application's domain model. Here you'll have all parts of the application configured, just like it is when the application is running. You can inspect domain models, change values, and save to the database. Starting the script without arguments will launch it in the development environment. To start the console, run <tt>rails console</tt> from the application directory. Options: * Passing the <tt>-s, --sandbox</tt> argument will rollback any modifications made to the database. * Passing an environment name as an argument will load the corresponding environment. Example: <tt>rails console production</tt>. To reload your controllers and models after launching the console run <tt>reload!</tt> More information about irb can be found at: link:http://www.rubycentral.org/pickaxe/irb.html == dbconsole You can go to the command line of your database directly through <tt>rails dbconsole</tt>. You would be connected to the database with the credentials defined in database.yml. Starting the script without arguments will connect you to the development database. Passing an argument will connect you to a different database, like <tt>rails dbconsole production</tt>. Currently works for MySQL, PostgreSQL and SQLite 3. == Description of Contents The default directory structure of a generated Ruby on Rails application: |-- app | |-- assets | |-- images | |-- javascripts | `-- stylesheets | |-- controllers | |-- helpers | |-- mailers | |-- models | `-- views | `-- layouts |-- config | |-- environments | |-- initializers | `-- locales |-- db |-- doc |-- lib | `-- tasks |-- log |-- public |-- script |-- test | |-- fixtures | |-- functional | |-- integration | |-- performance | `-- unit |-- tmp | |-- cache | |-- pids | |-- sessions | `-- sockets `-- vendor |-- assets `-- stylesheets `-- plugins app Holds all the code that's specific to this particular application. app/assets Contains subdirectories for images, stylesheets, and JavaScript files. app/controllers Holds controllers that should be named like weblogs_controller.rb for automated URL mapping. All controllers should descend from ApplicationController which itself descends from ActionController::Base. app/models Holds models that should be named like post.rb. Models descend from ActiveRecord::Base by default. app/views Holds the template files for the view that should be named like weblogs/index.html.erb for the WeblogsController#index action. All views use eRuby syntax by default. app/views/layouts Holds the template files for layouts to be used with views. This models the common header/footer method of wrapping views. In your views, define a layout using the <tt>layout :default</tt> and create a file named default.html.erb. Inside default.html.erb, call <% yield %> to render the view using this layout. app/helpers Holds view helpers that should be named like weblogs_helper.rb. These are generated for you automatically when using generators for controllers. Helpers can be used to wrap functionality for your views into methods. config Configuration files for the Rails environment, the routing map, the database, and other dependencies. db Contains the database schema in schema.rb. db/migrate contains all the sequence of Migrations for your schema. doc This directory is where your application documentation will be stored when generated using <tt>rake doc:app</tt> lib Application specific libraries. Basically, any kind of custom code that doesn't belong under controllers, models, or helpers. This directory is in the load path. public The directory available for the web server. Also contains the dispatchers and the default HTML files. This should be set as the DOCUMENT_ROOT of your web server. script Helper scripts for automation and generation. test Unit and functional tests along with fixtures. When using the rails generate command, template test files will be generated for you and placed in this directory. vendor External libraries that the application depends on. Also includes the plugins subdirectory. If the app has frozen rails, those gems also go here, under vendor/rails/. This directory is in the load path.
I found some cases in which intersections between cubic curves are not detected.
As the algorithm is iterative it is harder for me to figure out at which point something goes wrong.
Here a test program that can be dropped into src/io/lacuna/artifex
:
package io.lacuna.artifex;
import io.lacuna.artifex.utils.Intersections;
public class TEST2 {
public static void main(String[] args) {
Vec2 s0 = new Vec2(435.3194971681168, 905.231313655894);
Vec2 a0 = new Vec2(436.60194226635423, 904.5228510213844);
Vec2 b0 = new Vec2(438.3935801257989, 904.1857845636355);
Vec2 e0 = new Vec2(440.3919343740061, 904.1270373708342);
Vec2 s1 = new Vec2(435.198246034818, 896.3191997888123);
Vec2 a1 = new Vec2(436.84762896823827, 898.9951604687135);
Vec2 b1 = new Vec2(438.2241643938649, 902.5923131816958);
Vec2 e1 = new Vec2(439.1164972433261, 906.1884150468093);
// SVG for debugging
System.out.println("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" +
"<svg width=\"420mm\" height=\"297mm\" version=\"1.1\" viewBox=\"0 0 420 297\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:cc=\"http://creativecommons.org/ns#\" xmlns:dc=\"http://purl.org/dc/elements/1.1/\" xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\">\n" +
" <g fill=\"none\" stroke=\"#000\" stroke-width=\".01\">");
System.out.println("<path d=\"M " + s0.x + "," + s0.y +
" L " + a0.x + "," + a0.y +
" L " + b0.x + "," + b0.y +
" L " + e0.x + "," + e0.y + "\" />");
System.out.println("<path d=\"M " + s1.x + "," + s1.y +
" L " + a1.x + "," + a1.y +
" L " + b1.x + "," + b1.y +
" L " + e1.x + "," + e1.y + "\" />");
System.out.println(" </g>\n" + "</svg>\n");
Bezier2.CubicBezier2 curve0 = (Bezier2.CubicBezier2) Bezier2.curve(s0, a0, b0, e0);
Bezier2.CubicBezier2 curve1 = (Bezier2.CubicBezier2) Bezier2.curve(s1, a1, b1, e1);
test2(curve0, curve1);
}
private static void test2(Bezier2.CubicBezier2 curve0, Bezier2.CubicBezier2 curve1) {
System.out.println("\n# Intersections between");
System.out.println("curve 0: " + curve0);
System.out.println("curve 1: " + curve1);
Vec2[] intersections = Intersections.intersections(curve0, curve1);
System.out.println(intersections.length + " intersections");
for (Vec2 intersection : intersections) {
System.out.println(intersection);
}
}
}
The output of the program:
<?xml version="1.0" encoding="UTF-8"?>
<svg width="420mm" height="297mm" version="1.1" viewBox="0 0 420 297" xmlns="http://www.w3.org/2000/svg" xmlns:cc="http://creativecommons.org/ns#" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
<g fill="none" stroke="#000" stroke-width=".01">
<path d="M 435.3194971681168,905.231313655894 L 436.60194226635423,904.5228510213844 L 438.3935801257989,904.1857845636355 L 440.3919343740061,904.1270373708342" />
<path d="M 435.198246034818,896.3191997888123 L 436.84762896823827,898.9951604687135 L 438.2241643938649,902.5923131816958 L 439.1164972433261,906.1884150468093" />
</g>
</svg>
# Intersections between
curve 0: p0=[x=435.3194971681168, y=905.231313655894], p1=[x=436.60194226635423, y=904.5228510213844], p2=[x=438.3935801257989, y=904.1857845636355], p3=[x=440.3919343740061, y=904.1270373708342]
curve 1: p0=[x=435.198246034818, y=896.3191997888123], p1=[x=436.84762896823827, y=898.9951604687135], p2=[x=438.2241643938649, y=902.5923131816958], p3=[x=439.1164972433261, y=906.1884150468093]
0 intersections
And the produced svg (bounding boxes, vertices and colors rendered by Inkscape)
Would it be possible to add difference and intersection operations for open shapes (Path2) versus closes ones (Region2)?
While trying out the Artifex library I run into some clipping artefacts while finding difference and intersections of two circles. I think the problem is best explained by showing a video: https://www.youtube.com/watch?v=HfnP3vG0E-g
Code is a bit hard to share as I have linked Artifex code to a somewhat large codebase. Here is the integration code: openrndr/openrndr@61b4962#diff-6d99a3e2c6edca20aea91f05e5079391
Hi,
I'm working with intersections in OPENRNDR and I have the following design made out of 4 segments (two lines and two curves):
There should be 5 intersections detected but only 4 are found. The original program simplified to only use the two involved segments looks like this:
fun doTest() {
val l = Line2.line(Vec2(512.0, 96.0), Vec2(128.0, 384.0))
val c = Bezier2.curve(Vec2(128.0, 384.0), Vec2(320.0, 168.0), Vec2(512.0, 384.0)) as Bezier2.QuadraticBezier2?
println(l)
println(c)
val i = Intersections.lineQuadratic(l, c)
println(i.size)
i.forEach { println(it) }
}
This is the output of the program:
a=[x=512.0, y=96.0], b=[x=128.0, y=384.0]
p0=[x=128.0, y=384.0], p1=[x=320.0, y=168.0], p2=[x=512.0, y=384.0]
0
Zero intersections are found.
This is a visualization of those vertices using Inkscape. Even if the blue line should be a curve, I think it shows that there should be an intersection:
Any ideas why this happens?
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