Here is a link to an excellent wiki that explains how to put greek symbols in ggplot2. In summary, here is what you do to obtain greek symbols Text Labels: Use parse = T inside geom_text or annotate. Axis Labels: Use expression(alpha) to get greek alpha. Facet Labels: Use labeller = label_parsed inside facet. Legend … Read more
To detect whether two balls collide, just check whether the distance between their centers is less than two times the radius. To do a perfectly elastic collision between the balls, you only need to worry about the component of the velocity that is in the direction of the collision. The other component (tangent to the … Read more
Graphics rendering: I am used to win32 and Borland C++ environments, so I stick to it, but the differences on other environments are mostly only in class names. First some approaches: console/text modes You can use text graphics (ASCII art I think in English). Where point is represented by character. Intensity is made by more … Read more
It may be easier to draw lines using the following approach: click to mark the first endpoint drag to show the line in progress release to mark the second endpoint This related example may offer some additional guidance. Addendum The example below implements the outline above. I’ve update the example to show how to use … Read more
From ggplot 2.2.0 labels can easily be stacked by using position = position_stack(vjust = 0.5) in geom_text. ggplot(Data, aes(x = Year, y = Frequency, fill = Category, label = Frequency)) + geom_bar(stat = “identity”) + geom_text(size = 3, position = position_stack(vjust = 0.5)) Also note that “position_stack() and position_fill() now stack values in the reverse … Read more
How can I determine whether a 2D Point is within a Polygon?