Scratch 2.0 editor and player 
Note: Scratch 2.0 is now in maintenance mode while the team focuses efforts on Scratch 3.0. While critical issues will be addressed please note that any feature requests or minor issues will not be reviewed until the next major release.
This is the open source version of Scratch 2.0 and the core code for the official version found on http://scratch.mit.edu. This code has been released under the GPL version 2 license. Forks can be released under the GPL v2 or any later version of the GPL.
If you're interested in contributing to Scratch, please take a look at the issues on this repository. Two great ways of helping Scratch are by identifying bugs and documenting them as issues, or fixing issues and creating pull requests. When submitting pull requests please be patient -- the Scratch Team is very busy and it can take a while to find time to review them. The organization and class structures can't be radically changed without significant coordination and collaboration from the Scratch Team, so these types of changes should be avoided.
It's been said that the Scratch Team spends about one hour of design discussion for every pixel in Scratch, but some think that estimate is a little low. While we welcome suggestions for new features in our suggestions forum (especially ones that come with mockups), we are unlikely to accept PRs with new features that we haven't deeply thought through. Why? Because we have a strong belief in the value of keeping things simple for new users. To learn more about our design philosophy, see this forum post, or this paper.
Building
The Scratch 2.0 build process now uses Gradle to simplify the process of acquiring dependencies: the necessary Flex SDKs will automatically be downloaded and cached for you. The Gradle wrapper is included in this repository, but you will need a Java Runtime Environment or Java Development Kit in order to run Gradle; you can download either from Oracle's Java download page. That page also contains guidance on whether to download the JRE or JDK.
There are two versions of the Scratch 2.0 editor that can be built from this repository. See the following table to determine the appropriate command for each version. When building on Windows, replace ./gradlew with .\gradlew.
| Required Flash version | Features | Command |
|---|---|---|
| 11.6 or above | 3D-accelerated rendering | ./gradlew build -Ptarget=11.6 |
| 10.2 - 11.5 | Compatibility with older Flash (Linux, older OS X, etc.) | ./gradlew build -Ptarget=10.2 |
A successful build should look something like this (SDK download information omitted):
$ ./gradlew build -Ptarget=11.6
Defining custom 'build' task when using the standard Gradle lifecycle plugins has been deprecated and is scheduled to be removed in Gradle 3.0
Target is: 11.6
Commit ID for scratch-flash is: e6df4f4
:copyresources
:compileFlex
WARNING: The -library-path option is being used internally by GradleFx. Alternative: specify the library as a 'merged' Gradle dependendency
:copytestresources
:test
Skipping tests since no tests exist
:build
BUILD SUCCESSFUL
Total time: 13.293 secsUpon completion, you should find your new SWF in the build subdirectory.
$ ls -R build
build:
10.2 11.6
build/10.2:
ScratchFor10.2.swf
build/11.6:
Scratch.swfPlease note that the Scratch trademarks (including the Scratch name, logo, Scratch Cat, and Gobo) are property of MIT. For use of these Marks, please see the Scratch Trademark Policy.
Debugging
Here are a few integrated development environments available with Flash debugging support:
It may be difficult to configure your IDE to use Gradle's cached version of the Flex SDK. To debug the Scratch 2.0 SWF with your own copy of the SDK you will need the Flex SDK version 4.10+, and playerglobal.swc files for Flash Player versions 10.2 and 11.4 added to the Flex SDK.
After downloading playerglobal11_4.swc and playerglobal10_2.swc, move them to <path to flex>/frameworks/libs/player/<version>/playerglobal.swc. E.g., playerglobal11_4.swc should be located at <path to flex>/frameworks/libs/player/11.4/playerglobal.swc.
Consult your IDE's documentation to configure it for your newly-constructed copy of the Flex SDK.
If the source is building but the resulting .swf is producing runtime errors, your first course of action should be to download version 4.11 of the Flex SDK and try targeting that. The Apache foundation maintains an installer that lets you select a variety of versions.