Understanding Vectors and Bitmaps

Vector and Bitmap objects will comprise the majority of the artwork you create. This article is designed to explain the difference between the two so you understand better how to handle these objects, whether you are creating them or receiving them from a customer.

Vectors

Vector Artwork consists of two major parts: Paths and Fill.

 

Paths

A piece of vector artwork contains a series of lines called paths. Paths operate between a series of points that shape where the paths go. These paths can be open or closed. An open Path is just a line, but a closed path makes a complete shape, and there is no opening along the entire perimeter. This article will deal closed paths specifically.

 

Example: A vector sign with its points, a closed path.

mceclip1.png

 

The idea behind Vectors is that the program can see the data that the paths consist of, and thus can manipulate the lines and their fill. As a result, a vector object can be scaled or distorted to any size and not lose the quality of the image. If you were to zoom in on a Vector object, it would continue to zoom and zoom and always look sharp.

 

Fill

When you apply color to a closed vector, it is considered Filled, and the entire shape will be filled with the same color or pattern. Vectors can have 3 types of fills: Solid, Pattern, or Gradient. They can also lack a fill completely, just being Paths as shown above. (These are edited in the Fill/Stroke Editor)

mceclip0.png mceclip4.png mceclip5.png
Solid Fill with Black. Pattern Fill, with blue negative space and repeating yellow stars Gradient Fill, changing from white to black

 

You can further manipulate Vectors by changing, adding, or removing points. (see: Paths Overview). We won't be going over each of the features mentioned in this article, as this is intended to explain what the objects are.

One thing to note about Vectors is that they will never have photograph quality graphics in them. If you are looking at an image that appears to be a photograph, whether real or computer generated, it is extremely likely it is a Bitmap image instead of a Vector.

 

Bitmap

Unlike a vector image, a Bitmap image is much more straight forward. Think of a bitmap image this way. Instead of containing data about lines and points, a bitmap is just rows of colored pixels without any regard with what is in them. Lacking data about lines, points, and fill, a bitmap is not as easily manipulated as a vector image, but it can have much higher quality graphics than a Vector can.

For example, the picture of these daffodils below is a bitmap image. There is no information about the lines or the shapes, so you couldn't easily pick out one of those flowers, blow it up 200%, and change it to blue.

Daffodils.png

To illustrate the point better, lets zoom in on the top left flower there. You can really see the pixels now. They are square and quite obvious, especially along the edges of the flower.

mceclip6.png

 

Resolution

The only real metric to contained in bitmaps then is how many pixels does the object contain, running from left to right, and then top to bottom? For example, the full picture of daffodils is 746 pixels wide by 494 pixels tall, or 746x494.

Now, that number is actually not indicative of the quality of the image, but it's easy to assume that more pixels means higher quality. When you create a bitmap, it is usually 72x72, 150x150, 300x300, or 600x600. This number does not actually tell you how many pixels are in an image, but instead how many pixels per square inch or PPI. That is the resolution of an image. The daffodil picture is 72x72 resolution, which is really low. This is why when you zoom in on that flower it appears blocky. If this picture was originally captured at 600x600, the full picture would look the same or maybe slightly better, but if you zoomed in on any one of those flowers, it would still look sharp and crisp as the pixels would be far smaller. The downside there is that the file size would be many times larger.

Downsampling

The hard part about bitmaps is that you can only go down in quality, not up. If you were to re-rasterize the full daffodil picture at 600x600, it wouldn't actually improve the picture. There's no data for it to extrapolate the space between the big pixels. The existing pixels would instead be split, but the image ultimately would not change. However, you can reduce the number of pixels in a picture. This is called downsampling. The image is taken, broken down into bigger pixels, and the file size is much, much smaller, but there is a loss in quality as a result, depending on how far you downsampled the image.

 

How can I tell the difference?

The tricky part about bitmap images is that there is no limit to what they can look like, which means they can look exactly like a vector image.  If the above sections don't help you figure out whether an image is a bitmap or a vector, then there are a few ways to determine if an image is a Bitmap or a Vector within Flexi.

File Types

Vectors are contained only in a selection of very specific file types, and there are some file types that contains a single bitmap. If the file is one of the following, it is strictly a bitmap, and nothing else:

Bitmap files:

.jpg

.png

.bmp

.tga

.tiff

.gif (Flexi can handle non-animated gifs, but nothing else)

 

The following file types can contain Vectors, however they can also contain bitmaps:

.pdf

.ai

.eps

 

DesignCentral

If the file type is not a bitmap file, and you're unsure, you can load it into flexi and you can figure it out there. Click on the image and look at Design Central. If a tab that looks like a tree in a field shows up in Design Central, then you know that you have a bitmap image. If you click on it, you will have some statistics about it. This means it is a bitmap image. mceclip11.pngIf clicking on the image yields this tab, then you know it's a vector. Those tabs are for adjusting and editing points, which are a vector feature.

mceclip12.png

 

If, however, you get something like this, and it is missing a tab like above, chances are Design Central is looking at a group of objects with design elements applied to them.

mceclip13.png

In this case, right click the image, and look at the second bottom option. Usually it will say "Ungroup", or "Unmask", or "Clear outline".

mceclip14.png

Click that option and select the image again and see if you have those tabs. If not, repeat the process until you do. If you clear a mask, you may need to remove a black shape.

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