Current Timeframe Course Overview

R. Craig Collins > intro to Computer Graphics > Overview 7

Overview 7 © R. Craig Collins, 2005/7

Items that should be accomplished before the beginning of the current time frame:
• Submitted Lab 4
• From On-line book: GIMP Basics

Reminder: Did you check your TC WebMail? Did you check the Quarantine folder?
Did you check the D2L Dropbox, to View feedback? Did you check D2L Grades for feedback? (You may have to scroll down)

Items to accomplish during the current course time frame:

•Read\Review
   • Review GIMP Online Help: First Steps
   • About jpeg and png
   • Comparing jpeg-png
   • From On-line book: GIMP Basics: 1.2 Loading and Saving Images

   • Additional reading: Scanners
   • Additional reading: Digitizing tablets

Additional Notes on jpeg and GIMP

Unlike other programs, a convenient feature of the Save Image dialog in the GIMP is that the file is automatically saved in the format specified by the extension of the typed filename.
As an example, if the filename you wish to use is denmark85.jpg, just type that in, and, the file will be saved in JPEG format.
(Of course you could choose the jpg dropbox box, as with other programs.)
When saving a file as jpg in GIMP, it goes through an export system, as it compressed the file.
Again, the two areas of compressions typically are
repeat or remove colors
remove resolution
Reducing quality to reduce file size
1) When you choose File\Save as... move the save as dialog box to the right, so you can see the original image

A new screen screen opens with jpeg options.
2) Choose the Show preview in image window box

3) Drag the Quality down, you can actually see color depth and resolution changing in the Image window...
typically below 30 is too poor quality to use, even on the web.
4) More on quality issues, and Advanced Options, later

•Activities
        Denmark,.png Actual file is 800 K, and is 1050x740. To save, right click the image, and choose Save Picture As...

   • Open denmark.png, or any png image you may have,
             Zoom in to 800%, and analyze the image, especially the windmill in the lower right corner.
             Use the GIMP to save the file (85 quality) as denmark85.jpg; close the image.
           Check the file size and compare to the original png
             Use then GIMP to open the new file, zoom in to 800%, and analyze the image, especially the windmill in the lower right corner.

   • Open or switch back to denmark.png, or your starting png image ,
             Use the GIMP to save the file (50 quality) as denmark50.jpg; close the image.
           Check the file size and compare to the original png
             Use then GIMP to open the new file, zoom in to 800%, and analyze the image, especially the windmill in the lower right corner.

   • Open or switch back to denmark.png, or your starting png image ,
             Use the GIMP to save the file (30 quality) as denmark30.jpg; close the image.
           Check the file size and compare to the original png
             Use then GIMP to open the new file, zoom in to 800%, and analyze the image, especially the windmill in the lower right corner.

• Spend time using the various selection tools in the GIMP; select by shapes, and using the color selection options.

From here on out:
png is for high quality source originals, and printable versions...
jpg is web quality.

•Submit by 11:59 pm, Friday, of the current week (see due dates)
   • MUD 7 (My Understanding, Details) Respond
      What topics, if any, during this time frame do you feel very comfortable with? Why?
      What topics, if any, during this time frame do you not feel comfortable with?
   • Participation Discussion 7 Respond in the class D2L Discussion forum to the following:
      Name a good point for jpeg. Name a good point for png. Could png completely replace jpeg or gif?
• Using D2L Discussions    • Using D2L dropbox       • Using D2L Quizzes      • Logon

              •You may click on Discussions, Dropbox, or Quizzes below, for more info
D2L navigation

• to Checklist

For the next time frame:
•Read From On-line book: GIMP Basics: selection tools,
•Each test has a review; you may wish to write out pertinent information from the readings and activities
•After completing this overview, you may wish to start on the next Overview material, and preview Lab 5

Checklist
Would you like to see a check list here? Add comments to this week's MUD
to Overview 7