103 lines
4.2 KiB
Text
103 lines
4.2 KiB
Text
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dojox.gfx
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Version 1.100
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Release date: 08/01/2006
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Project state:
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beta
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HTMLCanvas renderer: experimental
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Credits
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Eugene Lazutkin (eugene.lazutkin@gmail.com)
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Kun Xi (bookstack@gmail.com)
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Chris Mitchell (ccmitchellusa@gmail.com) HTML Canvas
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Project description
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Implementation of simple portable 2D graphics library.
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Dependencies:
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Dojo Core
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Documentation
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Currently it can be found here: http://docs.google.com/Doc?id=d764479_1hnb2tn
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HTMLCanvas Renderer Status
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To use canvas rendering, insert 'canvas' at the beginning of the gfxRenderers list in your
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djConfig, for example:
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<script type="text/javascript" src="../../../dojo/dojo.js"
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djConfig="parseOnLoad: true, gfxRenderer: 'canvas,svg,silverlight,vml'"></script>
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canvas currently will only render on non-IE browsers (see dojox/gfx.js for where the renderer is loaded);
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although it should be possible to use an IE canvas implementation (like Google's); however, it will be very slow.
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The following tests can be made to work with HTML Canvas with minor testcase modification:
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dojox/gfx/tests
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test_gfx.html-Bugs #1
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test_arc.html
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test_bezier.html
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test_pattern.html
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test_gradient.html
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test_linearGradient.html
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test_image1.html - Limitation #3
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test_transform.html - Bug #1
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test_poly.html - Bug #1
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dojox/gfx/demos
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butterfly.html - Bug #1
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lion.html - Bug #1
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tiger.html - Bug #1
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circles.html - No event processing yet :(
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creator.html
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dojox/chart
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test_pie2d.html - Dojo Charts on iPhone anyone? :)
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test_chart2d.html -
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// To make charts work, the following line needs to be added to the end of the
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// Chart2D.js render() method (prior to return)
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if(this.surface.render){this.surface.render()};
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Known Limitations:
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1) event handling- plan is to capture all events at canvas, perform intersect/hit
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tests (not implemented) against scene graph, then propogate event to top-most
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intersected shape. HtmlCanvas shape need intersectsStroke and intersectsBounds,
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and intersects (region).
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2) SVG and VML are "live" scene graphs; eg. any state change to objects in the
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scene automatically get rendered in next engine render pass. For canvas, it's
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procedural, and current implementation requires application to call surface.render()
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whenever scene needs to be updated. Plan is to do dirty region checking based
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on bounding boxes (currently not properly computed), and track dirty areas anytime
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state changes (invalidate) separate from render phase.
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Add the following call where changes to the scene graph are complete and you want to
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render:
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if (surface.render){surface.render();}
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4) Text/Text Paths - Text shape is implemented using DIV overlays. Many text styles are not
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applied, and outline/fills are not possible. This is due to limitations in Canvas spec.
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Firefox 3.0 has proprietary text functions that we could test for and use once FF3 is out.
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No luck on Safari.
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3) No Image skewing - Limitation of Canvas
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Known Bugs:
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1) Matrix xformations (applied from root to shape leaf nodes) not quite right--but very close.
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Canvas does not have a built in transformation function that allows skewing. Need to
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track skew matrix with Shape, and perform other trans/rot/scale transformations without
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using canvas transform functions.
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-------------------------------------------------------------------------------
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Installation instructions
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Grab the following from the Dojo SVN Repository:
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http://svn.dojotoolkit.org/var/src/dojo/dojox/trunk/gfx.js
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http://svn.dojotoolkit.org/var/src/dojo/dojox/trunk/gfx/*
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Install into the following directory structure:
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/dojox/gfx/
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...which should be at the same level as your Dojo checkout.
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