Difference between Zooming, Panning and Scaling

Key Difference: Zooming provides an option to the user to change the view of a document or image. It is applicable in two ways – Zooming in and Zooming out. It usually involves shrinking or stretching of pixels. Panning is another way of looking at the desired view. It is achieved by grabbing the document and then moving it around to focus on the desired or target area. Scaling resizes the image or text. There are numerous techniques which are used for scaling. Sometimes, scaling and zooming are used interchangeably.

Zooming, panning and scaling are related to each other, as all three of them are used in context to a certain view on the screen. Zooming provides an option to the user to change the view of a document or image. It is applicable in two ways – Zooming in and Zooming out.

Zooming in allows the user to get the closer look of the particular area of interest on the screen. On the other hand, zooming out allows the user to have a larger view. Zooming in feature is often accompanied by scroll bars which appear when the screen is not wide enough to hold all of the content of the page. It is generally represented by showing a magnifying glass icon. A + sign depicts zoomed in, whereas – sign depicts zoomed out. In modern brwosers, zooming is achieved by just stretching pixels. Generally, it involes the techniques in which pixel stretches widthwise and heightwise both.

Panning is another way of looking at the desired view. It is achieved by grabbing the document and then moving it around to focus on the desired or target area. It makes accessibility to those areas which otherwise may remain hidden from the user.

Panning helps to quickly move around the area at the same magnification set by the user. It is usually represented by an icon showing a hand.

Scaling is a process which aids a user to view a certain text or image. Scaling resizes the image or text. There are numerous techniques which are used for scaling. For example, in scaling method of nearest neighbor interpolation, every pixel is simply replaced by four pixels of the same size. Scaling is also used for performing zooming in and zooming out operation on digital images.

Zooming affects all the portions of the display image or text in a uniform manner. However, in scaling a coder can also use techniques like - resizing can be done by keeping the original height and altering the width or just vice versa. An image (or regions of an image) can be zoomed either through pixel replication or interpolation.

Scaling is used in context to the increase of decrease the physical size of the items. Unlike just stretching the pixels, it uses techniques like nearest neighbor interpolation for resizing. It is important to mention that the term scaling is also used for resizing of the image that occurs on the paper on which it needs to be printed, specifically without any type of pixel resampling. It just stretches the image on the paper and do not change or alter actual pixels.

Comparison between Zooming, Panning and Scaling:

	Zooming	Panning	Scaling
Definition	Zooming provides an option to the user to change the view of a document or image. It is applicable in two ways – Zooming in and Zooming out.	Panning is another way of looking at the desired view. It is achieved by grabbing the document and then moving it around to focus on the desired or target area.	Scaling resizes the image or text. There are numerous techniques which are used for scaling.
Common method	Stretching the pixels	Using the hand tool	Using techniques like nearest neighbor interpolation for resizing
In other contexts	Just the focus of camera is moved further or near the object. No change in the object’s length, width and depth	-A photography technique for capturing an object in motion	Modifies the width, length and depth of the object to make it smaller or larger