The number of labeled values in the new color legend is determined by how many “nice” labels fit within the span of the legend. Note that if you are not satisfied with the automatic labels in the new color legend, you can exercise total control of the labeled values with the feature described in the next section. In the prior implementation, one could specify a maximum number of labels, but this property was really just a suggestion that did not always work out in a satisfactory way. Instead of having a horizontal orientation that can potentially use up a lot of horizontal and vertical space, the title is rotated to be vertically aligned with the length of the color legend.Īnother key difference with labels in the new color legend is that the number of labels is determined automatically by how many nice numbers fit within the span of the long dimension of the legend. You will also notice that the title placement has changed for vertically oriented color legends. Intermediate tick marks between labels did not aid in interpreting color values, so they have been removed. The new color legend (right) has labeled values that require fewer decimal digits.
The old color legend (left) had labeled values spaced evenly within the numeric range of the scalar bar, but this could lead to label values that were not necessarily human-relatable and requiring potentially numerous decimal digits. In the new color legend we use the same algorithm used by ParaView’s 2D charts to compute “nice” label values that have a more compact representation based on multiples of 2, 5 or 10. Not infrequently, seemingly odd choices of scalar values that required a large number of decimal places would be chosen for labels. These numbers were chosen by subdividing the numeric range assigned to the color legend into evenly spaced intervals. One of the complaints with the previous color legend involved the numbers chosen for labels. The new color legend has some key differences from its older counterpart. For ParaView 5.4, we have added a new color legend implementation that resolves a number of existing bugs and paves the way to make adding features easier in the future. The previous implementation made it challenging to debug when problems arose and difficult to augment when new features were needed. The color legend’s versatility unfortunately came with a somewhat complex implementation. Over the years, ParaView’s color legend features have expanded to cover numerous usage scenarios, including annotating specific values with text, showing the color assigned to NaN values, showing categorical colors, and controlling different elements of the color legend such as font size and style. ParaView’s color legend provides an important link between color and data values, and is a critical component of many visualizations.
Pseudo-coloring of surfaces and volumes is one of ParaView’s primary methods of displaying data.