AJYN Graphics Language PLT Project by Group JAYN Jared Kennedy Ananya Das Yaniv Schiller Neel Goyal May 13, 2003

AJYN Features A simple graphics language to model animations. Compilation outputs to swf format and plays using any Flash player. Simple model of computation allows for quick learning and easy use.

Basic Graphics Overview Graphics primitives: Points Lines Rectangles Ellipses Polygons Transformations: Translations Rotations Scales

Language Functionality Additional AJYN features: Grouping: Groups together various graphics primitives to be transformed and animated as a single unit. Hiding objects: By declaring a given object invisible over a set period of frames, it can be hidden temporarily from the scene without needing to instantiate a new object.

AJYN Syntax Initializing a program: Program name = screen width, screen height, total frames; Declaring objects: point id = x coordinate, y coordinate; line id = x1 coord, y1 coord, x2 coord, y2 coord; rect id = upper-left x, upper-left y, rect width, rect height; ellipse id = center x coord, center y coord, x radius, y radius; poly id = x1 coord, y1 coord, x2 coord, y2 coord, …; Grouping: group id = obj1, obj2, …objN, x coord, y coord;

AJYN Syntax cont… Transforming Objects: translate(id, new x pos, new y pos, start frame, stop frame); rotate(id, rotation degrees, start frame, stop frame); scale(id, scale size, start frame, stop frame); Hiding Objects: setInvisible(id, start frame, stop frame); Comments: AJYN only supports commenting of single lines Comments are denoted by //

Compilation Process Source ANTLR IR File Backend Application including Ming API SWF (“SWIFF”) Output

Abstract Syntax Tree The AST for out language is a linked list containing the elements that go into creating the animation. It has the follow structure: Program node Object node Groups node Functions node Visibility node Contains info declared in the Program command Contains a vector holding shapes with an ID number and other object parameters Contains a vector of nodes that contain group ID numbers along with a vector of object IDs Contains a vector of transformation nodes that act on objects referenced through their IDs Contains information about visibility of an object from frame to frame

Intermediate Representation Corresponding IR file: Example Code: Program Clock = 500, 500, 2160; ActiveColor = 0, 0, 255; line L1 = 250, 250, 250, 150; ActiveColor = 255, 255, 255; line L2 = 250, 250, ; ActiveColor = 0, 255, 0; line L3 = 250, 250, 250, 50; ActiveColor =255, 255, 255; line L4 = 250, 250, 250, 450; ActiveColor = 255, 0, 0; ellipse E1 = 250, 250, 200, 200; group hours = L1, L2, ; group minutes = L3, L4, 250, 250; rotate(minutes, 4320, 0, 2160); rotate(hours, 360, 0, 2160);

Backend Compilation Our point was not to reinvent the wheel, it was to make animations easy to use. Ming, an open source project located on Sourceforge, replaced Macromedia in creating an open source API for swf files. Ming, written in C, comes with extensions for Java, PHP and C++. AJYN uses this source to compile the actual animation file. Ming does not handle animations in a simple fashion. Objects must be placed on a frame by frame basis. The backend application accepts a file containing the intermediate representation and produces the animations without the complexities of Ming.

Backend Compilation cont… Basic backend algorithm: For each frame: Show the objects and groups that are visible If animations: Reposition/Resize the affected objects Backend complexities: Swf does not handle ellipses and circles. It only handles Bezier curves. Creating an ellipse requires the conversion from ellipse specifications to a group of curved lines. Issues in making objects disappear, even mid-animation, and then reappear in the correct location.

Sample Source Code //Test Code for a Simple Clock Program Clock = 500, 500, 2160; ActiveColor = 0, 0, 255; line L1 = 250, 250, 250, 150; ActiveColor = 255, 255, 255; line L2 = 250, 250, 250, 350; group hour = L1, L2, 250, 250; ActiveColor = 0, 255, 0; line L3 = 250, 250, 250, 50; //Test Code Continued…. ActiveColor =255, 255, 255; line L4 = 250, 250, 250, 450; group mins = L3, L4, 250, 250; ActiveColor = 255, 0, 0; ellipse E1 = 250, 250, 200, 200; rotate(mins, 4230, 0, 2160); rotate(hour, 360, 30, 2160);

Compiled SWF File The amazing clock