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Cambridge IGCSE0417

Images

Information Communication Technology 0417 Chapter Notes

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In this chapter

  1. 1Placing an image with precision
  2. 2Resizing and the aspect ratio
  3. 3Cropping an image
  4. 4Rotating and reflecting
  5. 5Brightness, contrast, grouping and layers
  6. 6Reducing the file size

1. Placing an image with precision

Import the image and place it in the correct paragraph. One mark is for the correct image inserted in the correct paragraph.

The task names an alignment: the left or right column margin, and the top of a paragraph. Set text wrapping so the text flows round the image.

Examiner insight

“The image was occasionally aligned with the left margin instead of to the right of the column.” “Occasionally, the image was too high to align with the top of the paragraph or extended into the left margin.”

Worked example 13 marks

Import the image j2621charger.jpg and place it in the paragraph beginning We have made available in-house …

Rotate the image 90 degrees clockwise with the image size and aspect ratio maintained.

Format the image so that:

• it is aligned to the left column margin and the top of the paragraph We have made available in-house … • the text wraps around the image.

  1. 1

    Correct image inserted in the correct paragraph. [1]

  2. 2

    Image rotated 90 degrees clockwise, size and aspect ratio maintained. [1]

  3. 3

    Text wrapped, aligned to the left of the column and the top of the text. [1]

2. Resizing and the aspect ratio

Resize the image to the exact measurement given, such as a width of 5 centimetres. Use the width or height the question names, not a nearby value.

To maintain the aspect ratio, change width and height by the same factor. The image must not be visibly distorted.

new height = old height × (new width)/(old width)

Examiner insight

“Common errors lay in alignment and resizing with the measurement of 6 cms wide applied instead of the required 6.5 cms wide.” “Some candidates did not maintain the logo size and/or aspect ratio.”

Worked example 12 marks

An image is 8 cm wide and 6 cm high. It is resized to a width of 4 cm with the aspect ratio maintained. Calculate the new height.

  1. 1

    The width is halved, so the height is halved: 6 × 4/8 [1]

  2. 2

    = 3 cm [1]

3. Cropping an image

To crop an image is to cut away its edges: the detail outside the border is removed. Resizing is a different edit. It keeps the whole picture and changes only its size.

A crop must remove everything outside the border and keep all of the image inside it.

Examiner insight

“Most candidates were able to crop the text from the image but did not crop the sides to leave only the whale shark visible.” “Most cropped the bottom of the image correctly although a few cropped too much so the bottom of the anchor was no longer rounded.”

Worked example 14 marks

Import the image j2622enginebay.jpg and place it in the paragraph beginning The new site will …

Crop the image so the red border and everything outside the red border is removed, making sure that all of the image inside the border remains.

Format the image so that:

• it is resized to a width of 5 centimetres with the aspect ratio maintained • it is aligned to the right column margin and the top of the paragraph The new site will… • the text wraps around the image.

  1. 1

    Correct image inserted in the correct paragraph. [1]

  2. 2

    Image cropped: the (red) border and detail outside the border removed. [1]

  3. 3

    Image resized to 5 cm, not visibly distorted. [1]

  4. 4

    Aligned to the top of the text and the right of the column, text wrapped. [1]

4. Rotating and reflecting

Rotate turns the image by the angle given, clockwise or anticlockwise. Reflect (flip) makes a mirror image, horizontally or vertically.

A 180 degree rotation is not a flip. When a task asks for a rotation and then a reflection, the mark scheme credits the image rotated first, then reflected.

Examiner insight

“Rotating the image by 180 degrees was not always done well with many flipping the image horizontally or vertically rather than rotating it.” “Many candidates rotated the image through 90 degrees clockwise, a few were seen rotated anticlockwise, but fewer candidates also reflected this image horizontally, as required by the task.”

Worked example 13 marks

Open the file j26image.png

Rotate this image 90 degrees clockwise.

Reflect (flip) this image horizontally.

Save this image in your skirting folder in .png format with the file name image_ followed by your centre number_candidate number, for example, image_ZZ999_9999.png

  1. 1

    Image rotated 90 degrees clockwise first … [1]

  2. 2

    … then reflected horizontally. [1]

  3. 3

    New image saved in .png format as image_ZZ999_9999.png. [1]

5. Brightness, contrast, grouping and layers

Adjust the brightness and the contrast of an image as the task states.

Images can be layered. Moving an image to the front or back changes which one is seen on top. Grouping joins images so they move as one. Ungrouping separates them again.

Worked example 12 marks

A logo is placed over a photograph in a poster. The logo is hidden behind the photograph. Describe how the user makes the logo visible and then moves both images together.

  1. 1

    Select the logo and move it to the front. [1]

  2. 2

    Select both images and group them, so they move as one. [1]

6. Reducing the file size

File size can be reduced by reducing the image resolution or the colour depth.

A smaller file means the web page downloads faster. The physical size of an image (its dimensions) is not the same as its file size.

Examiner insight

“Many candidates were not specific about the difference between the physical size of the image and its file size.” “Several did not identify that this would affect the download speed of the webpage nor that many browsers will not handle .tif files.”

Worked example 13 marks

A photograph has a very large file size and a web page that contains it is slow to open. Give two ways to reduce the file size of the photograph and state one effect on the web page.

  1. 1

    Reduce the image resolution. [1]

  2. 2

    Reduce the colour depth. [1]

  3. 3

    The web page downloads faster. [1]

Recap

  • Place the image in the correct paragraph, aligned as asked, with text wrapped.
  • Resize to the exact measurement and keep the aspect ratio, so the image is not distorted.
  • Crop removes the detail outside the border. Resize does not.
  • Rotate and reflect are different. Do them in the order the task gives.
  • Layers: move to the front or back. Group so images move as one.
  • File size falls when the image resolution or the colour depth is reduced.

End-of-chapter exercise

Test yourself on the whole chapter. Work through these before moving on.

  1. Reflect (flip) an image horizontally. State what happens to the left and right sides of the image.1 mark
  2. A user must remove a strip of unwanted background from the edge of an image. State which image edit does this.1 mark
  3. An image is 20 cm wide and 15 cm high. It is resized to a height of 6 cm with the aspect ratio maintained. Calculate the new width.2 marks
  4. A user places an image in a paragraph. The image must sit at the right column margin and the top of the paragraph, with the text flowing round it. Describe the settings the user must apply.3 marks
  5. A school puts a photograph on its website and the page is slow to open. A student writes: "Make the photograph smaller." Explain why this answer is not specific enough, and give two ways to reduce the file size of the photograph.3 marks
  6. A logo and a caption in a poster have been grouped. The user must move only the caption to a new position, and then make the logo and the caption move as one again. Describe the steps.3 marks
  7. An image of an arrow pointing up is rotated 90 degrees clockwise and then reflected horizontally. State the direction the arrow points after each step.2 marks
  8. An image of a boat points left and sits upright. State what the boat looks like after (a) a 180 degree rotation and (b) a horizontal reflection.2 marks
  9. A photograph of a diver is 4000 pixels wide and 3000 pixels high. A web designer needs an image that is 1600 pixels wide and 3000 pixels high and shows only the diver, who is in the middle of the photograph. A student resizes the photograph to 1600 pixels wide and 3000 pixels high. (a) Show by calculation that the student's image is distorted. (b) Describe the edit the student should have used. State the orientation of the finished image.4 marks
  10. A photograph is 18 cm wide and 12 cm high. These edits are made in this order: • it is rotated 90 degrees clockwise with the image size and aspect ratio maintained • a 2 cm strip is cropped from the top edge and a 1 cm strip from the left edge • it is resized to a width of 5.5 cm with the aspect ratio maintained • it is reflected vertically. Calculate the final height of the image. State its final width.5 marks

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