"crop" & "set transparent color"

[dbolyard]

Is there a way to crop images in Inspire or set transparent color to part of an image? When your flipchart has numerous colors in the background, an image with it's own solid background sticks out like a sore thumb:(. Even the color picker is limited in this case.

[dbolyard]

No sooner did I hit submit than I realized that the camera tool can be used to crop:rolleyes:, even though it creates another image. I can live with that. However, I haven't discovered a way to get transparent color.

[LisaD]

If you click on the item and open the "property browser" window, you should see the options to set a particular color as "transparent." See screenshot. (Of course some backgrounds "look" like one color but could actually have several shades of that color!)

Lisa

[dbolyard]

Thanks Lisa.

However, just so I know that I'm using it correctly: When selecting the "transparent color" in the property browser, you are actually selecting the color from the image which you want to be transparent, correct? If that's so, you can then use the color picker tool provided to select the exact color you want to be transparent. So it would make any part of the image containing that color, transparent. In addition, it appears that you can select only one color to be transparent in any given image (using this method). Moreover, as you pointed out, an image's background may consist of many shades of one color, rendering the transparent coloring option...useless...better to find another image.

Did I get all that right?:confused:

I hope not...

[LisaD]

Yes, but you could use the camera tool to select the portion of the image you do want. Depending on what it is (its shape), either the "point to point" or the "freehand" camera tool might do the trick.

Lisa

[Nigel Pearce]

It's worth mentioning that ActivInspire can work with PNG files and if they contain an alpha channel it makes for some really impressive effects.

What does 'alpha channel' mean?

The simplest way is to see it in action. Download the attached flipchart. The first page contains 3 alpha channel PNG images.

Try moving them around and watch what happens.

Notice how parts of the image are partially translucent (in differing amounts). You can see through the ice and the toucan casts a true shadow. Alpha blending is amazing and it's how many professional, graphic designers create their artwork.

For a description of PNG, wiki is a good read...

http://en.wikipedia.org/wiki/Portable_Network_Graphics

A great way to create PNG files is using The Gimp image editor...

http://www.gimp.org/

And what's more... it's free! [clap]

[dbolyard]

Thanks again Lisa; I think I will be making heavy use of the camera tool.

Nigel, thanks for pointing out the PNG capabilities. I have a whole database of PNG images that I am happy to be able to use without having to convert to JPG. I am very impressed with the properties of the images on that flipchart. I read the wiki on PNG and read on about alpha channel. However, I am still at a loss for understanding. I was not able to download the Gimp Editor due to network restrictions (something I may be able to work around if it's worthwhile). Moreover, I am a super newb at editing images outside of apps like Microsoft Office or Activ software. Does it take much time to learn how to manipulate images and create effects like those on the flipchart?

(always eager to learn cool stuff)

[Nigel Pearce]

"I am still at a loss for understanding"

I know the feeling. These days my industry (namely software development) seems to re-invent the rules almost weekly. It can be quite frustrating at times.

The best way to think about an alpha channel is that it allows each pixel (or point) in an image to have its own level of translucency, in other words: the amount of 'see-through-ness' (did I just say that? :confused:).

An alpha channel allows an image to 'blend into' whatever is underneath, in the places where it matters. For example a good PNG will have feathered edges, where the alpha channel causes edges to gradually blend with the background. This avoids seeing harsh, antialiased edges. It also allows you to produce images containing realistic clouds, shadows, water and ice, etc.

In terms of what it takes to create good PNG images, like anything else, practise makes perfect. An editor such as The Gimp allows you to create and modify an alpha channel for any image, then to use various tools in applying varying levels of translucency to chosen areas of the image.