The example application I’ll explain here is a utility to combine multiple images into one in one click directly from a Picasa folder view. However, it is very easy to modify this to perform various other batch image processing tasks directly from Picasa.

Part 1: The Picasa button

First of all, we will need a button in our Picasa to start our ImageMagick script. To create the button using Picasa Button API, we follow these steps:

1. Write a PBF file.
   A PBF is basically a simple XML file, that describes our button to Picasa. Here is the PBF file I wrote for my application:

   <?xml version="1.0" encoding="utf-8" ?>
   <buttons format="1" version="1">
     <button id="{ca234ae3-6340-40c3-a46b-51a126bb887c}" type="dynamic">
       <label>Combine</label>
       <tooltip>Combine images vertically and save as a new image</tooltip>
       <action verb="trayexec">
         <param name="exe_name" value="stitch.cmd" />
         <param name="exe_path" value="S:\Tools\" />
       </action>
     </button>
   </buttons>
   

   Although the whole code is contained within a buttons element, the file can currently only describe one button.

   Note the GUID in the button/id attribute. You’ll need a new GUID for every button you make. The PBF must be named using this GUID, {ca234ae3-6340-40c3-a46b-51a126bb887c}.pbf in my case.

   The label and tooltip elements shouldn’t need much explanation. The next important element is action; this describes what the button will actually do when pressed. There are a few actions described in the Button API; the one I use here is a simple executable launch, that starts a batch script stitch.cmd, located in S:\Tools\ (in our environment, S:\ is a shared network drive on the office server). The script will be detailed further on.

2. (optional) Draw an icon.
   You can include a custom icon for your button. The icon has to be an Adobe Photoshop PSD file called using your GUID ({ca234ae3-6340-40c3-a46b-51a126bb887c}.psd for me), in a single layer. If you use an icon, you have to include an additional element in your PBF, inside the button element:

   <icon name="{ca234ae3-6340-40c3-a46b-51a126bb887c}.psd/layer" src="pbz"/>

3. Package your button into a PBZ file.
   A PBZ file is nothing different than a ZIP archive containing your PBF (and the icon, if you want to use one), with its extension changed to .pbz. This file is basically your distribution package, so name it appropriately, since Picasa differentiates its buttons by their PBZ file names. One PBZ can also contain multiple PBF files for multiple buttons at once.

Part 2: The ImageMagick batch script

Since the ImageMagick package provides command-line utilities, the simplest way to automate them in Windows is a batch file. Here is my stitch.cmd script for merging multiple images together vertically, resizing them all to match the first one’s width:

@echo off
cd /D "C:\Program Files\ImageMagick-6.7.1-Q16"

rem --- Output filename
set OUTFOLDER=%~dp1
set OUTFILENAME="%OUTFOLDER%Collage.jpg"

rem --- Imagemagick
for /f "delims=" %%a in ('identify -format "%%[fx:w]" %1') do @set WIDTH=%%a
montage -mode concatenate -resize %WIDTH% -tile 1x %* %OUTFILENAME%

When called from the Picasa button, the script will get filenames of all currently selected images in Picasa as arguments, including full paths.

First, we change directory to where ImageMagick is installed, to avoid possible problems with PATH. Then we generate a filename for our montage, taking the folder path from the first argument (first selected image from Picasa) and adding our own filename.

After that, we apply a batch hack, using a for loop to save a command output (ImageMagick’s identify) into a variable. This gives us the width of the first image. Next, we call the ImageMagick’s montage tool, that will combine all our images in one, additionally providing it with the output filename as a last argument.

Part 3: Installation

The installation is a bit tricky. Picasa doesn’t support importing the buttons directly, it can only be done using a browser and a specially formed link to the file. You’ll need to place your PBZ at some location reachable via an http:// link; since I have a local development server running on my PC, I used that. Here is an the HTML file I used to install my script in Picasa:

<html>
 <body>
  <a href="picasa://importbutton/?url=http://localhost/olex-stitcher.pbz">Install</a>
 </body>
</html>

Just open the file in a browser of your choice and click the link. Picasa will open and prompt you to select the button you want to install (only one option here, unless your PBZ contains multiple buttons), and where to place it in the button bar. Do that, and you’re all done.

A solution came suddenly, when I saw some CCFLs on sale in an online hardware store for €4,99. One trip to the shops and 7€ spent later I’m sitting here in the dark, typing this text and having my eyes not stressed at all

The CCFLs I bought were from Sharkoon, and came with a switch, transformator and a Y-cable to connect to the PC’s power supply, obviuosly aimed at the casemodding scene:

“That’s all very nice”, I thought, “but firstly, how do I power it (my PC is under the table, and the monitor sits above it), and secondly, where do I put the switch so I can turn it on and off?”. I decided to elongate the power cable by 5-6 feet and to put the switch (together with the transformator and the cables) on the back of my screen, where the CCFLs themselves would go. After thinking that, I went to a hardware store and got the following stuff for a total of 7€:

My plan required: a plastic box to put the switch and cables in, cable binders and connectors (because I do not have the tools for soldering), isolating tape and some cable.

I cut the Y-cable after the split from the Molex connector, and reconnected it with 6 feet of my cable using the connectors. Then I put th switch in the side of the plastic box, and put the cable and connectors inside.

After that I connected the transformator and the CCFLs, connected the Y-cable inside my PC, and turned it on. It worked!

A little detail remained – the whole thing had to be put onto the screen. I put the box with the switch on using double-sided tape near the bottom of the screen, so the switch can be easily reached and cannot be seen. For the rest (transformator and lamps) a set of stick-on pads was included in the package, so I used that.

Result: a nice working backlight for 12,99€, that anyone can build.