vector graphics

Description of vector graphics. Examples of creation and uses thereof.

Vector graphics, also known as object-oriented graphics, are the second largest group of digital images. They are simpler than bitmap graphics, since in them the images are stored and represented by means of geometric lines controlled by calculations and mathematical formulas, taking some points of the image as reference to build the rest.

Therefore, images in vector graphics are not built pixel by pixel, but rather are formed from vectors, objects made up of a series of points and mathematically defined straight lines or curves.

For example, a line is defined in a bitmap graphic by the properties of each of the pixels that form it, while in a vector graphic it is defined by the position of its start and end points and by a function that describes the path between them. Similarly, a circle is defined vectorially by the position of its center point (x,y coordinates) and by its radius (r).

Each vector in a vector graphic has an outline line, with a given color and thickness, and is filled with a color of your choice. The outline (or fillet) and fill characteristics can be changed at any time.

Vector images are stored as a list describing each of their component vectors, their position, and their properties.

Resolution-wise, vector graphics are resolution-independent in that they do not depend on a given pixel lattice. Therefore, they have the maximum resolution that the format in which it is stored allows.

Bezier curves

The main constituent elements of a vector are the so-called Bézier curves, developed by Pierre Bézier at the request of the Renault company, who was looking for a family of mathematically representable curves (they are third-degree curves) that would make it possible to represent the smooth curvatures they wanted to give to their automobiles.

A Bézier curve is fully defined by four characteristic points, the start and end points of the curve (nodes or anchor points) and two control points (control points, handles or handles), invisible in the final graph, that define its shape. form. To modify its shape, just change the position of one of its nodes or one of its control points.

They are not very complex and very elegant handling curves, with a very smooth development, capable of adapting to almost any imaginable shape, which is why they are widely used to design logos and icons and to copy any figure.

They are also enormously versatile, being able to adopt from very soft curvatures (almost straight lines) to very strong curvatures (complex curves), going through all intermediate values. They can even change from concave to convex around a point.

Advantages and Limitations of Vector Graphics

The main advantages offered by vector graphics, derived from their mathematical nature, are:

• They store the images in very compact files, since only the information (mathematical formulas) necessary to generate each of the vectors is required. since it does not have to store information to define each point of the screen, but a series of mathematical formulas.
• They allow the size of images and their component objects to be modified without loss of information, since all the new relationships and positions of the geometric elements that compose them are updated mathematically. With this, the size changes of the vector images do not affect their quality, always appearing with the same sharpness.
• They are very useful when printing images, since it is not necessary to pass the information of each point to the printer. It is enough to pass the information of the vectors that make up the image.
• Each object is defined by its own mathematical formulas and is managed independently of the rest, being able to scale, distort and change its shape or position without affecting the other elements of the drawing at all.
• It is possible an independent control of the color, both of the outline and of the fill, admitting the application of textures, gradients, transparencies, etc. li>
• You can control with great precision the shape, orientation and ordering of the elements.
• Any effects applied to objects can be rectified at any time, since the drawing is always editable. This is not the case with bitmap images, where once an element has been painted, it can no longer be changed.
• It is easy to reuse a drawing or a part of it in other projects. Just copy and paste it into a new file or an existing one.
• Chart objects can easily be merged with each other, creating a series of intermediate shapes. For example, you can go from a square to a triangle in five interpolated ways.
• It can be related in different ways with the rest of the objects on the graph (group, separate, clip, intersect, etc.).
• Shapes can be arranged in any way if they overlap each other.
• They allow very advanced text handling, since they support TrueType fonts, which are also vector objects. In addition, letters can be turned into editable outlines, decomposing a text into its constituent vector objects. Once the letters have been converted into objects, it will no longer be necessary to have the font installed to continue editing the outlines, because they will no longer be letters, but objects within the vector graphic, and can be modified as such.
• Bitmaps can be included in a vector drawing, either for shape fills, or as separate elements. In the other sense, a vector can be exported to a standard bitmap format, such as GIF or JPG.

Until the appearance of Macromedia Flash and SWF files, the direct inclusion of vector graphics on the web was not possible. Its introduction in web pages represented a considerable advance, since it allows to include graphics of modifiable size without loss of quality, very useful in logos, plans, diagrams, etc. As an example, if you click on the following image with the right mouse button and select “Enlarge” (Zoom In) or “Reduce” (Zoom Out), it will change its size while preserving its visual characteristics.

The main drawback of vector images is that they have a colder look than bitmap graphics, with their too-perfect outline making them sometimes unnatural, although it’s always possible to deliberately create slightly jagged outlines, so that they look better. look more like natural drawing.

Other drawbacks of this type of graphics are its lack of efficiency to represent photographic images, the difficulty it presents in dealing with some effects (shadows, lights, etc…) and that when they are very large or very complex they can become extremely difficult. to handle by graphic programs and by print media.