Share and Enjoy!Alexander Nyßen

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GEF 3.x / Zest 1.x• Mature project with quite long history

• Base technology with lot's of users (direct & indirect through GMF/Graphiti)

• Stable API, no breaking API changes since 2004 (GEF 3.0)• Ready for CBI (migration to Git, Maven/Tycho completed)

• But API is organically evolved and there are ~400 bugzillas, out of which several require to break it

Some Topics for a Renewal• Re-thinking current componentization

• Support for the E4 application model

• Support for rotation and other transformations

• Support for curved connections

• Support for other rendering platforms than SWT• Multi-touch gestures support• Revision of the command framework

• Revision of connection handling (clipping container)• Various renamings and restructurings on the detail level...

Zest 2 (since 2010)• A provisional Zest 2 component was initiated in 2010, to

develop the next generation Zest API.• Goal was to develop a new version of Zest in parallel to the

maintenance of Zest 1.x., with an - up to the final graduation - provisional API

• Sources were intended to be placed in its own Zest2 Git repository, results were published separately via Eclipse Marketplace.

GEF4 (since 2011)• GEF4 was initiated - in analogy to Zest 2 - to develop the next

generation Draw2d and GEF (MVC) API.• Similar to Zest2, development was intended to take place in

parallel to maintenance of Draw2d / GEF (MVC) 3.x

• Initial plans (prior to 3.8): • Create new double-precision Geometry API before Juno

release. • Start to migrate the Draw2d and GEF (MVC) code base on a

step-by-step basis afterwards.

GEF4 + Zest 2 = GEF4

Modified plan: Unification of both approaches after Juno!

GEF4 - A Unified Approach• A unified approach with a shared code base and a

common namespace (org.eclipse.gef4) for all plug-ins.

• Advantages:

• Clear distinction between GEF proper as the production component and GEF4 as the provisional one

• Chance to not only refactor GEF components but the componentization itself, which is only "historically" justified.

GEF4 - Status Quo• GEF4 Geometry component was initiated in 2011, work has been

finalized with the Juno release:• Functionally complete (at least for now)• 344 JUnit tests, ~77% instruction coverage

• GEF4 Graphics component was initiated directly after Juno and is currently under work:• Functionally nearly complete for SWT/AWT, intended JavaFX adoption

about to start• Still limited tests and quite a bit of adjustment needed w.r.t. "platform-

specific" issues of SWT

GEF4 - Status Quo (continued)• GEF4 Zest was transferred to Git repository (and update-

site) but not yet adopted:• Zest2 plug-ins were renamed to org.eclipse.gef4.zest.*• Dependencies on Draw2d 3.x still have to be factored out

GEF4 Geometry• No distinction in low and high precision, but just a single double-precision

API (with built-in imprecision for comparisons).

• Different geometric abstractions for different purposes:• Euclidean (Vector, Straight, Angle)• Projective (Vector3D, Straight3D)• Planar (Point, Dimension, Line, QuadraticCurve, CubicCurve,

BezierCurve, Polyline, PolyBezier, Ellipse, Rectangle, Pie, Arc, Polygon, CurvedPolygon, RoundedRectangle, Ring, Region, Path)

• Conversions to/from AWT and SWT (and between them)

GEF4 Planar Geometry - Features• Support for "non-standard" geometries:

• Arbitrary Bezier curves, curved polygons• Approximation via BezierCurves & Interpolation via PolyBeziers

• Characteristics-related core abstractions (IGeometry, ICurve, IShape, IMultiShape)

• Construction-related base-classes (AbstractRectangleBased-Geometry, AbstractPointListBasedGeometry,...)

• Direct support for affine transformations (ITranslatable, IScalable, IRotatable)

• No direct SWT dependencies (SWT-related conversions bundled in optional plug-in)

GEF4 Planar Geometry - Overview

GEF4 Planar Geometry - Abstractions

GEF4 Planar Geometry - Base Classes

GEF4 Geometry - Examples

GEF4 Geometry - Sample Code

// Bezier approximation of curvesBezierCurve[] fromCurve = curve.toBezier();BezierCurve[] fromShape = shape.getOutline().toBezier();ICurve[] fromPolyShape = polyShape.getOutlineSegments();List<BezierCurve> beziers = new ArrayList<BezierCurve>();for (ICurve c : fromPolyShape) beziers.addAll(Arrays.asList(c.toBezier()));

// PolyBezier interpolationPolyBezier interpolation = PolyBezier.interpolateCubic(p0, p1, p2, p3, ...);

// support for affine transformationsPolygon rhomb = new Rectangle(10, 10, 10, 10).getRotatedCCW(Angle.fromDeg(45));PolyBezier slanted = new Ellipse(100, 100, 100, 50).getRotatedCCW(Angle.fromDeg(30));Ring rotatedClippingArea = region.getRotatedCCW(Angle.fromDeg(300));

GEF4 Graphics• Support for rendering (planar) geometries, images, and text

on an underlying Canvas/Graphics• Key abstractions (Font, Image, Color) and transparent

support for multiple widget toolkits (SWT, AWT, JavaFX*)• Save push/pop/restore and get/set of graphics state

• Combinations of advanced graphics features like xor-mode, patterns (color, gradient, image), affine transformations, etc.

• Extensible image processing support (Pixel-Filter, Channel-Filter, Convolution-Filter)

*) Graphics based on JavaFX Canvas API already prototyped by Tom Schindl

GEF4 Graphics - Features

GEF4 Graphics - Overview

GEF4 Graphics - Examples

GEF4 Graphics - Sample Code

// prepare geometriesfinal Ellipse ellipse = new Ellipse(50, 50, 350, 200);final Rectangle rectangle = new Rectangle(100, 160, 125, 220);final Polygon triangle = new Polygon(260, 170, 190, 300, 330, 300);

// prepare colorsfinal Color red = new Color(255, 0, 0);final Color darkRed = new Color(128, 0, 0);final Color blue = new Color(0, 0, 255);final Color green = new Color(0, 255, 0);final Color darkGreen = new Color(0, 128, 0);

g.setLineWidth(4);g.pushState(); // save the current set of properties on the stack

g.setFill(red).setDraw(darkRed).setDashArray(25, 10);g.fill(ellipse).draw(ellipse.getOutline());

g.restoreState(); // restore the previously saved properties

g.setFill(blue).setLineJoin(LineJoin.ROUND).setLineCap(LineCap.ROUND);g.fill(rectangle).draw(rectangle.getOutline());

g.popState(); // removes the previously saved properties from the stack// and enables the properties that were set in advance

g.setFill(green).setDraw(darkGreen).setLineJoin(LineJoin.MITER);g.fill(triangle).draw(triangle.getOutline());

GEF4 Graphics - More Sample Code• Java2D:

• GEF4 Graphics (Java2D & SWT):

g2d.translate(50, 50);g2d.setPaint(new RadialGradientPaint(new Point(50, 50), 50, new Point(

40, 40), new float[] { 0, .5f, 1 }, new Color[] {new Color(255, 255, 255), new Color(255, 0, 0),new Color(0, 0, 0) }, CycleMethod.REFLECT));

g2d.fill(new Rectangle(0, 0, 200, 200));

g.translate(50, 50);Ellipse ellipse = new Ellipse(0, 0, 100, 100);g.setFill(new Gradient.Radial(ellipse, ellipse

.getCenter().translate(-10, -10), CycleMode.REFLECT)

.addStop(0.0, new Color(255, 255, 255))

.addStop(0.5, new Color(255, 0, 0))

.addStop(1.0, new Color(0, 0, 0)));g.fill(new Rectangle(0, 0, 200, 200));

GEF4 - Outlook (Mid-Term)• GEF4 Layouts is planned:

• Data model for layout computations (based on Draw2d/Zest DirectedGraphLayout)

• Set of layout algorithms based on it (Draw2d & Zest)

• GEF4 'Glyphs' is planned:• Figures/Shapes abstractions inspired by Draw2d, SVG, and

JavaFX (SceneGraph)• Intended as replacement of Draw2d 'core'

GEF4 - Outlook (Long-Term)• Adoption of migrated Zest components to new GEF4

Geometry, Graphics, Canvas, Layouts components

• Migration of remaining Draw2d/GEF (MVC) code base, including re-modularization and adoption

Share & Enjoy - Please get involved!• Evaluate and Provide Feedback!

• Try out early snapshots!• Report bugs, report enhancement requests!

• Contribute!

• Participate in discussions (bugzilla, mailing list)• Supply patches

Thank You! Questions?

http://wiki.eclipse.org/GEF/GEF4