images in 3.0

[Travis Bower]

Can someone give a brief run-down on each of the format types?

And if anyone has actually tried them in os3.0, any heads-up would be appreciated.

thanks.

from release notes

Images can be displayed on TI‐Nspire handhelds (running OS 3.0 or later), but they cannot be inserted into documents on the handheld. You must use the desktop software to add images to your documents. TI‐Nspire supports images in bmp, jpeg, jpg, and png formats.

[Eric Findlay]

Bmp: this is a generally uncompressed format, so files will usually be larger.  Recently this format has been enhanced to support compression, but at very low ratios.  It is nice because it no compression = no artifacting.

Jpg/jpeg: jpg and jpeg are the same thing, just with different extensions.  This is the most common type of image these days.  These are compressed images with compression rates that range from very low to heavy.  This means the file size will be the smallest, but it also means that on high-colour images, there will be a lot of artifacting.

Png: designed as a replacement to the gif algorithm, (which requires a licence to use), png is an unlicenced equivalent.  It uses a lossless compression algorithm which means it is compressed (smaller file size) but without artifacting.  Generally this means that files will be smaller than bmps, but not as small (but better looking) than jpgs.  Png also supports transparency (not sure how Nspire handles this).

Hope this helps.

  --Eric

--
To post to this group, send email to tins...@googlegroups.com
To unsubscribe send email to tinspire+u...@googlegroups.com
For more options, visit this group at
http://groups.google.com.au/group/tinspire?hl=en-GB?hl=en-GB
The tns documents shared by group members are archived at
http://lafacroft.com/archive/nspire.php

[Travis Bower]

Thanks Eric.

fyi for others, like me, who do not know what 'artifacting' means.  frm web:

 

A compression artifact (or artefact) is a noticeable distortion of media – an image, audio, or video – due to the application of an overly aggressive or inappropriate lossy data compression algorithm.

[Ellen Browne]

Wow that was really helpful Eric, thanks.

Sent from my iPhone

[Eric Findlay]

Yes, right.  The best example is to take a photograph and save it as a jpg with high compression.  Then you will likely see some blotchy areas or "noise" near colour boundaries.

  --Eric

[lee kucera]

Keep in mind, these photos are being imported onto a tiny screen, not being blown up with a projector.  jpg pictures look just fine on the Nspire screen.

lk

lee kucera

a.p. statistics

leek...@gmail.com

[Sean Bird]

I'm not sure what file type copy/paste from the clipboard is, but that has been my favorite method. I'm not certain if it the method I've used most, but it is quite delightful from grabbing an image from somewhere like
- an image from our text book
- equation editor things I don't want to retype for multiple choice quesitons.

For more tips and images enjoy the recent entry at
http://bird-godlydominion.blogspot.com/

- Sean Bird
Indianapolis, IN

[Eric Findlay]

It would be whatever file type the source is.  If it's from a screen capture, it's likely a bmp.

  --Eric

--

[Travis Bower]

Sean, recent blog:  Thanks for the tips on images.  That is exactly what I need to get started.  All of us can start compiling a list of what works well--best practices for color graphers.  Thanks.

--

[Andy Kemp]

I've just done some testing with how Nspire handles the different file types, and thankfully there is little in it...

I started by taking three identical screenprints and saving them as BMP, PNG and JPEG, the raw file sizes varied from 37KB for the JPEG; 33KB for the PNG and 549KB for the BMP.

I then created a fresh TNS document and made a Geometry page and added the images (I did nothing to adjust them etc).  The TNS files that were produced were JPEG 16KB; PNG 12KB and BMP 12KB.

I then repeated this with a larger photograph (still relatively small) JPEG 242K; PNG 1MB; BMP 4.3 MB.  I again added these to a TNS files which gave the following:

JPEG 90KB; PNG 90KB; BMP 86 KB.

I tried to repeat this with a 2.4MB JPEG but discovered that Nspire will only import images under 10MB (once I converted the JPEG to PNG and BMP both were over 10MB)!

The 2.4MB JPEG file produced a TNS file which was 119KB in size.

In general it appears that BMP files produce a slightly smaller final file size, but more importantly the final file size is significantly effected by the original image file size.  If you are only planning on using the image on a handheld (or in emulator view), then you will save a lot of space by first reducing the file down to something around 320 x 240 pixels, which will be more important on the older B&W handhelds as they have less storage space anyway...

Using the same 2.4MB JPEG, and reducing it down to a 300x225 image, gave the following file sizes: 

BMP 49KB; 

PNG 53KB; 

JPEG (85% quality) 53KB; 

JPEG (100% Quality) 57KB.

In general the Nspire software is doing a very good job of automatically reducing the file size whilst maintaining a reasonable level of quality (for when you view the file in computer view).  Manually reducing large images down to a smaller (handheld size) before importing will save you space (around 50% in my very limited testing), which depending on where you plan to use the the files CX/Touchpad and how you plan on distributing them (and whether you want students to keep them!) there may be times when it will be beneficial to reduce the images down in advance, especially if you are using more than one image in a document...

Cheers

Andy

[Andy Kemp]

Incidentally I also noticed that reusing an image either by copying and pasting or by inserting the same image again, doesn't add to the file size...  So it appears once you insert an image you can use it as many times as you like without any significant change in file size!

[Eric Findlay]

Interesting information.  As I would have expected, PNG is better for smaller pic, and JPG is better for larger pics.

Did you notice any difference in picture  quality when the images were shrunk to the Nspire screen size?

  --Eric

[Nelson Sousa]

I usually go for png on logos, charts and drawings in general, and jpeg for photos.

--

Nelson

[Andy Kemp]

There was no noticeable difference on the screen (in emulator mode), with a little bit of pixelation being observed in 'computer view' with a large window.  

Based on my exploration the smallest TNS files will come from using a BMP file, but ultimately the differences were quite small.