Predefined brush shapes
You can see 19 predefined brushes, ranging from quite small to large. You can choose a single pixel brush; block brushes of sizes from 2x1 to 6x6 pixels; vertical and horizontal 8-pixel long line brushes as well as 4 and 8 pixel long oblique lines in either direction; and a circular brush with a diameter of 6 pixels.
Each brush produces a different effect, as you can see below:
By varying the magnification of the page you can effectively influence the brush size: As the brush size always remains constant on the screen, the real line width increases when you reduce the image magification. That may sound a little confusing, but we can make the effect clear with an example: If you make a dot with a ball-point pen on a map of a city, the size of the dot may correspond to the size of a telephone kiosk. If you make a similar dot on a country-wide map, it may correspond to the size of a house or even a football field. On a globe the dot may cover at least a large city. The same effect forms the basis of the Calamus Brush module.
The important thing is that the effective size of the brush is enlarged and reduced with changes of magnification. This means in particular that the circular and slanted line brushes produce circles and slanted lines at the resolution of the image – and not only in the screen resolution.