GoogleMaps v2.1 finished (including user docs and bug fixes)

Finally I've updated the documentation for the end user regarding the new features available in the Google Maps plugin version 2.1, but I've fixed also some little details that did appear after the initial testing period.

All the current customers of the v2 will receive shortly a mail with the new zip.

Some clarifications regarding the plugin:

If you want to use the plugin for free, then you must use the v1 code. It's free to use wherever you want, you can test it in that page and then download it and install it in your server to use with FCKeditor.

If you appreciate the work involved to make that version work, or if you want to use all the new features and want to use the v2 plugin, then you must contact me (until I setup an automatic system), the license for a single site is 15€, if you are any kind of OEM or company that want to use it for several sites, you can get a general license for 50€.

Of course, you should really test the free version before trying to use the v2, as the requirements and setup procedure are just the same. If you have the v1 working, to upgrade to the v2 you just need to replace the plugin folder and that's all, no extra job. There's no online demo or download trial of the v2 plugin, this is all javascript, so it's not worth for me trying to implement any kind of security to avoid the people that want to get everything for free.


Text markers and static maps with GoogleMaps plugin

I've finished the coding of the new 2.1 version of the GoogleMaps plugin, the main highlights for this new version are:

Text markers.

You can add your text on the map, aimed at providing an always visible caption for the details that you want to remark.

The title field of normal markers now it's shown as a text besides the marker, and you can add any other text in the map using the Text tool.

This feature is based on the ELabels script provided by Mike Williams, I have simplify it a little to remove unwanted features and decrease its size.

Static images generation.

Ok, the previous version did generate a static image and then loaded the map, but this version does provide an option to not generate any script at all, and most important: it's able to edit again those images.

In the previous versions you were able to copy the image around or manually remove the script from source code, but if you tried to edit it again, it didn't recognize any of its data, so it wasn't very useful. Now it can generate the image without any scripts and then recover all the data that it's used on that image (I mean: data as text labels, areas, kml overlays... won't be recovered because they aren't used in the static maps).

This can be useful if you want to provide the option in a kind of forum where anybody can create data, but you don't want them to use any script due to obvious security reasons.

The scripts now are precompressed using YUICompressor in order to improve loading time, if you want to use the original files in order to make any adjustment or debug anything you just have to rename the files.

Now I need to update the docs and then it will be send to the current users. If you want the script and until I set up an automated system you can mail me at amla70 at gmail dot com and I'll provide you the PayPal info.


Optimizing the generation of gifs in .Net

While debugging some problems that a client had with CKFinder I found out that the thumbnails that were generated using the asp.net code of gif files were in reality png files, just a little oversight and should be easy to fix. Previously the code did test only for jpg files in order to adjust the quality, and the rest of extensions did were saved with

oResampled.Save( targetFile );

But as I said, the .Net framework doesn't check the extension of the file that you want to generate, instead it uses the png format.

So the new code just needed to do a switch:

switch ( extension )
    case ".gif":
        oResampled.Save( targetFile, System.Drawing.Imaging.ImageFormat.Gif );
        break ;
    case ".png":
        oResampled.Save( targetFile, System.Drawing.Imaging.ImageFormat.Png );
        break ;
    case ".bmp":
        oResampled.Save( targetFile, System.Drawing.Imaging.ImageFormat.Bmp );
        break ;
easy fix, isn't it?

You're wrong, for some strange design decision at MS, decreasing the palette from full color to 256 colors uses the infamous "web safe" palette, so your page will look again like those done at the start of the times, back when Nestcape was synonymous to Internet.

Why has the .Net team gone that way at this time and age?. I don't care, I didn't want to know why it's done that way, I just wanted to know how to do it the right way, how to specify a proper palette for the new file.

So searching a little you can find this very interesting article at MSDN that explains everything that you want to know about gifs and colors, it has links to other resources that try to explain the miracle that is a web safe palette, but it has been years since I saw a system that wasn't able to work with 24 bit-images.

That article does even include a sample that shows exactly how to do the quantization of images and provides also an implementation of an Octree palette generator. Too good to be true :-)

So there we go, add the class and quickly I see that there are some strange attributes on the classes. "unsafe", uh?

Let's recap: the article was written for the .Net Framework 1.1, and nowadays the servers in hosted providers are using mostly (AFAIK) Asp.net 2.0 in medium trust, so that code won't work at all.

Fortunately there was another nice blog by Brendan Tompkins that did found this same problem and does provide an explanation of the required changes in order to run properly. So I tested and now I didn't get the same compilation problems that I had with the original code, the unsafeness seemed to have gone away.

But when I tested really with medium trust, oh no!, a System.Security.SecurityException! Did I make something wrong?

I reviewed the changes and used directly the modified classes, nops, no way, it fails. Reading the comments I found that other people also reported the same problem but no one answered them. Could it be that initially the code did work in .Net 2.0 but some patch later the behavior was changed and now the calls to Marshal aren't allowed?

Searching to find the solution to this problem hasn't been successful, no one seems to know a solution and I spent one or two days reading everything that seemed interesting trying different combinations of search terms. Even trying to find another method to do the quantization hasn't been fruitful, there are questions posted in different places but no one has provided a positive answer.

Obviously I don't need to read the raw memory of the picture, using GetPixel seems that should be enough to create the palette, but this isn't the final solution because to generate the new picture with the specially created palette I need to specify the color/index of each pixel, and when you try to use SetPixel, you get:

"SetPixel is not supported for images with indexed pixel formats"

And again the solutions to this problem suggest to use the LockBits and then writing directly to memory, but that will fail in Medium Trust.

To recap:

  • If you're running in High Trust, CKFinder 1.3 the asp.net or asp version (with asp.net handling) will create gif thumbnails correctly
  • If you're in Medium Trust the call to create the 256-colors image will fail, and so far we haven't been able to find any solution. The GetPixel method is useful only for half of the process, it does still require direct memory access to create the new image so it hasn't been implemented. In this situation the "gif" image is really a 24-bit color png, not optimal and if someday the browsers stop sniffing the content of images they won't be shown, but hopefully before we reach that day MS would have released .Net v8 with some api to control the color-reduction method and/or SetPixel method expanded to handle indexed images.