CSE2325/3325 : Ex. 4, Image Manipulation

Early scribbles

Run your paint program (Corel Draw, Paint Shop Pro, Photoshop) and open up a new picture with dimensions in pixels of 300 high x 240 wide.

Is this program for manipulating bitmap images or object/vector type images? How do you know?

Draw a black squiggly line on a white background using the pencil tool.

Draw a black squiggly line on a white background using the brush tool.

Use the zoom tool to get a closer view of the lines. Are they smooth along the edges? How is the brushed line different to the pencilled line? Which looks nicer at normal zoom levels?

Scale down the image size to 150x120 pixels. (Don't just zoom the image, you must alter the file size.)

Now zoom into the image and look at the lines again. Do they look the same as they did when you zoomed in before?

GIF and JPEG graphic file format saving

Use the gradient tool to make a gradient from blue to mid-grey across a whole page.

  • Save a copy of this file as a JPEG file of 25% quality.

  • Save a copy of this file as a GIF file.

  • Which file takes the least amount of space?

  • Which file looks the best?

Repeat the above steps with a picture of a blue square in which is written in large mid-grey lettering the word 'THINK'. Rest the whole square on a mid-grey background of the same size as the previously used image.

Are the results the same as for the gradient image?

Transparent GIF's

Use a text editor to create an HTML document with a light-brown background color.

  • Incorporate the GIF image of the blue square into the brown web page using the <IMG> tag.

  • Open the new HTML document in your web browser locally (ie. leave it on your hard drive and open it within the browser from there) to check the page works as expected.

  • Return to the image editing software and make the mid-grey background of the image of the square transparent. (You'll need to save the image as a GIF89a if it has a transparent colour in its palette.)

  • Check that the HTML document now shows a blue square, brown lettering, on a brown background with no mid-grey border.

Animated GIF's

Use the tools available to create a simple animated GIF file of a bird flying across the image.

Depending on the capabilities of the image editing software you are using, you might need to bring your individual animation frames into the uni labs and use Adobe Premiere to export the animated GIF file.

The GIF Construction Kit is an animated GIF construction tool for Windo$e PC's which you can download from the net.

Some questions for you to ask (and answer)

CSE2325/3325 lecture notes

©Copyright Alan Dorin & Jon McCormack 1999,2000