dashed line support for Web

[michael]

Firefox changes by Arpad:
r15113
r15111
r15108
r15109

Chrome/Webkit: looks promising
​http://git.chromium.org/gitweb/?p=external/Webkit.git;a=commitdiff;h=6cabcb625c6282f61f7d704c8798ad47372a9e21

[michael]

Hopefully Chrome-Canary will support webkitLineDash soon :)
​http://www.chromium.org/getting-involved/dev-channel
@Arpad: please add support for webkitLineDash in anticipation

[michael]

Two fixes needed for mozDash:

• "regular" lines are being drawn dashed
• when drawing a polyline, style needs to be ROUNDED not MITRE

(see screenshots)

[michael]

First problem fixed here:
http://www.geogebra.org/trac/changeset/15118

[arpad]

Replying to michael:

Hopefully Chrome-Canary will support webkitLineDash soon :)
​http://www.chromium.org/getting-involved/dev-channel
@Arpad: please add support for webkitLineDash in anticipation

I've done this here, although I couldn't test Canary builds on Ubuntu Linux, so I don't know if it is actually working or not (Dev build is buggy currently, Beta build is like the Stable):

http://www.geogebra.org/trac/changeset/15182/trunk/geogebra

[arpad]

Replying to michael:

• when drawing a polyline, style needs to be ROUNDED not MITRE

Second problem fixed here; now Web looks is similar to Java except inequality:

http://www.geogebra.org/trac/changeset/15184/trunk/geogebra

[michael]

Tested in WebKit build 104795, works really well!!! Screenshot attached.

(Rendering not consistent for different line thicknesses, not our bug)

[michael]

Now we just need to wait for IE9 to implement dashed lines...

[arpad]

As I am getting more experienced with GWT, I could find a better solution for dashed lines which also available for other canvas than the main canvas:

http://www.geogebra.org/trac/changeset/15609/trunk/geogebra

But it should be tested whether it's OK in recent canary build of Chromium/Webkit or not.

[arpad]

Later we could probably avoid the JSNI method when we use GWT's Element.getPropertyJSO and setPropertyJSO (JSO=JavaScriptObject=JsArrayNumber). But new functionality is more important than refactoring.

[michael]

​http://code.google.com/p/chromium/issues/detail?id=112145
Safari: bug id 10784015
​http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2011-November/033744.html

[arpad]

Question: do we need implementing mozDashOffset, webkitLineDashOffset? That could be included in the Stroke object in Graphics2D, however it is not set currently...

[michael]

​https://bugs.webkit.org/show_bug.cgi?id=80674

[michael]

Possible solution here:
​http://davidowens.wordpress.com/2010/09/07/html-5-canvas-and-dashed-lines/

(commented out here)
​https://dev.geogebra.org/trac/changeset/16666

but doesn't work for curves or filled shapes.

[michael]

​http://www.whatwg.org/specs/web-apps/current-work/multipage/the-canvas-element.html#dom-context-2d-setlinedash

[michael]

Dashed emulation re-enabled (for full gui only): r16994

[michael]

Problem shown up by r16994 fixed:
​http://dev.geogebra.org/trac/changeset/17001

Maybe there is still a problem with setClip(Shape) or AwtFactory.prototype.newRectangle(x, y, width, height)