Monthly Archives: July 2008

Gumstix / OpenEmbedded Webcam Support

Getting v4l2 webcam support is fairly straight forward once you have the toolchain in place.

First, you need to install the v4l2 modules. You can either follow the build instructions located here or download the binary version below.

The modules should be installed at /lib/modules/2.6.21/kernel/drivers/media/video.

Here is a set of video modules compiled for the 2.6.21 kernel.

Included Kernel Modules

uvcvideo.ko
compat_ioctl32.ko
v4l1-compat.ko
videodev.ko
v4l2-common.ko

Once you have the modules installed issue a “depmod -a” command so the system can find them.

To test your work, download a copy of uvccapture for OpenEmbeeded.

Before you can install the uvccapture package you will need to install a copy of libjpeg.

ipkg install libjpeg62

Once you have libjpeg installed you can install uvccapture.

ipkg install uvccapture_0.4-r5_armv5te.ipk

Here is a quick time lapse photography script

#!/bin/sh
for i in `seq 1 1000`;
do
        fname=`printf "%05d" "$i"`;
        uvccapture -o${fname}.jpg -x800 -y600;
        sync; #make sure image is stored in case of a power loss
        sleep 10;
done

#!/bin/sh

for i in `seq 1 1000`;

fname=`printf "%05d" "$i"`;

uvccapture -o${fname}.jpg -x800 -y600;

sync; #make sure image is stored in case of a power loss

sleep 10;

done

You can create a movie from the images using jpeg2yuv. Under Ubuntu, jpeg2yuv is part of the mjpegtools package.

#!/bin/sh
jpeg2yuv -f 25 -b 1 -I p -j %05d.jpg | mpeg2enc -o time_lapse.m1v

1 2	#!/bin/sh jpeg2yuv -f 25 -b 1 -I p -j %05d.jpg \| mpeg2enc -o time_lapse.m1v

Flex Brainfuck Interpreter

[Full Source Code]

Brainfuck is a minimalist programming language having of only 8 commands.
Operations are performed using a single pointer and an array of bytes to store data.

Command	Description
>	Move the pointer to the right
<	Move the pointer to the left
+	Increment the memory cell under the pointer
-	Decrement the memory cell under the pointer
.	Output the character signified by the cell at the pointer
,	Input a character and store it in the cell at the pointer
[	Jump past the matching ] if the cell under the pointer is 0
]	Jump back to the matching [

SVG Viewer – SVG Title Support and Text Node Fix

Updates

You can now access the title of the SVG via SVGViewer.title
Text now computes proper x and y offset coordinates

[Subversion Repo]
svn co https://iciifs.com/svn/SvgViewer SvgViewer
http://code.google.com/p/svg-viewer/

SVG Viewer – Opacity and Rectangle Fix

Updates

Node opacity (alpha) is now functional
Rounded rectangles are now supported
Rectangles are now properly placed on the x,y coordinate system
The transform argument “rotate” is now supported
Added line cap, joint, and miter limit support

[Subversion Repo]
svn co https://iciifs.com/svn/SvgViewer SvgViewer
http://code.google.com/p/svg-viewer/

SVG Viewer – Code Rewrite and Documentation

Over the last week I’ve completely rewritten the SVG Viewer.
I got rid of a lot of hacks such as the XML preprocessor which was creating multiple copies of the SVG XML.

[Subversion Repo]
svn co https://iciifs.com/svn/SvgViewer SvgViewer
http://code.google.com/p/svg-viewer/

Changes

Use nodes now pull XML from symbol and def nodes. The preprocessor no longer copies XML into the use nodes.
Symbols, Defs, and Clip-Paths now have revision support. When a change is made to any of these nodes other nodes will update their display to reflect the changes.
The text and tspan nodes are included in this update.
All nodes with ids now register with the root node.

Also, there is now documentation for the SVG Viewer library.

Flex SVG Viewer – Text and TSpan Support

This movie requires Flash Player 9

[SVG File] text along a path

I’ve added basic support for Text and TSpan SVG elements to a branch of the SVG Viewer. In the next few days I will add text support to the main library.

In order to support text rotation I am creating a bitmap of the text.

var myText:String = "This is a test...";

//Create TextField
var textField:TextField = new TextField();
textField.autoSize = TextFieldAutoSize.LEFT;
textField.text = myText;

/**
 * Load font styling: textField.setTextFormat(textFormat);
 * Load any transformations: handled in transformNode()
 **/

//Convert TextField to a bitmap so we can rotate the text
var bitmapData:BitmapData = new BitmapData(textField.width, textField.height, true, 0x000000);
bitmapData.draw(textField);

var textBitmap:Bitmap = new Bitmap(bitmapData);
textBitmap.smoothing = true;

this.addChild(textBitmap);

var myText:String = "This is a test...";

//Create TextField

var textField:TextField = new TextField();

textField.autoSize = TextFieldAutoSize.LEFT;

textField.text = myText;

/**

* Load font styling: textField.setTextFormat(textFormat);

* Load any transformations: handled in transformNode()

**/

//Convert TextField to a bitmap so we can rotate the text

var bitmapData:BitmapData = new BitmapData(textField.width, textField.height, true, 0x000000);

bitmapData.draw(textField);

var textBitmap:Bitmap = new Bitmap(bitmapData);

textBitmap.smoothing = true;

this.addChild(textBitmap);

Flex SVG Viewer – Elliptical Arc Support

[Full Source Code]

Path elements now support elliptical arcs.
The conversion code comes from com.degrafa.geometry.utilities.ArcUtils.

Example SVG from w3.org SVG docs.

Flex Svg Viewer – New Subversion Repository

I’ve moved the SVG library to a new repository.
You can find it at: ~~https://iciifs.com/svn/SvgViewer~~
http://code.google.com/p/svg-viewer/

A bug in the placement of ellipses has been fixed and posted to the repo.