Photoshop’s shape tools add an important dimension to your drawing and painting capabilities. Whereas many of the tools in the Tools palette are pixel oriented, creating shapes and outlines from swarms of pixels, the Shape tool, like the Pen and Type tools, initially creates scalable outlines by using vectors rather than pixels. Working with vector shapes gives you the freedom to resize your objects at will, and convert them to pixels only when you need to merge them with the rest of your image.
Vectors describe a shape mathematically; pixel images, on the other hand, describe the same shape in terms of a map of pixels. Figure 2-1 shows both types of images. An easy way of understanding this concept is to imagine how each of these graphical measurements measures a square:
- Measured in pixels: A square might be 200 pixels on a side with the corners at particular X and Y coordinates in the image file. The square contains a total of 40,000 different pixels, each of which must be created and stored with the image file.
- Measured in vectors: The same square might be simply defined as four points with equal-length lines connecting each of them at right angles. The scale of the square determines the length of the lines. It isn’t necessary to store information about the area inside the square; the vector image file needs to contain only the position of the four points and the fact that they are each connected by lines at a 90-degree angle.
You can see that to enlarge a square created by vectors, all you need to do is increase the distance between the points. To enlarge a pixel square, you need to create a lot more pixels. The difference between the ways these measurements handle shapes becomes magnified (so to speak) if the shape’s outlines aren’t perfectly straight or if points don’t connect at neat right angles.
Resizing any sort of object made of pixels causes a problem: As you enlarge the pixels, the object takes on a jaggy appearance in lines that aren’t horizontal or vertical. To enlarge a vector object, on the other hand, you only need to rearrange the points that define the lines or curves; the lines and curves themselves don’t grow and become jaggy.
Vectors describe a shape mathematically; pixel images, on the other hand, describe the same shape in terms of a map of pixels. Figure 2-1 shows both types of images. An easy way of understanding this concept is to imagine how each of these graphical measurements measures a square:
- Measured in pixels: A square might be 200 pixels on a side with the corners at particular X and Y coordinates in the image file. The square contains a total of 40,000 different pixels, each of which must be created and stored with the image file.
- Measured in vectors: The same square might be simply defined as four points with equal-length lines connecting each of them at right angles. The scale of the square determines the length of the lines. It isn’t necessary to store information about the area inside the square; the vector image file needs to contain only the position of the four points and the fact that they are each connected by lines at a 90-degree angle.
You can see that to enlarge a square created by vectors, all you need to do is increase the distance between the points. To enlarge a pixel square, you need to create a lot more pixels. The difference between the ways these measurements handle shapes becomes magnified (so to speak) if the shape’s outlines aren’t perfectly straight or if points don’t connect at neat right angles.
Resizing any sort of object made of pixels causes a problem: As you enlarge the pixels, the object takes on a jaggy appearance in lines that aren’t horizontal or vertical. To enlarge a vector object, on the other hand, you only need to rearrange the points that define the lines or curves; the lines and curves themselves don’t grow and become jaggy.
Pixel and Vector in Photoshop
![Pixel and Vector in Photoshop]()
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