subsurface/stats/statscolors.cpp
Dirk Hohndel 7339dc28ae statistics: add color-related functions
Add a source file and a header file, which implement the color
scheme used by the statistics module.

Besides a few color constants, the centerpiece is a
function that returns the color representing a bin and
an appropriate label color. It picks a roughly equi-distant
set of colors out of an already balanced set of 50 candidate
colors. And it also picks white as text color when adding a
label to a segment with a dark color.

The color list was created using a tool by Gregor Aisch that
is available on GitHub as https://github.com/gka/palettes to
create multi-hued, multi-stop color scales that are safe for
color blind people.

This commit contains code from three authors.
Dirk (main author): adaptive color scheme.
Willem: Colors of single-bin charts and lines.
Berthold: Infrastructure.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Signed-off-by: willemferguson <willemferguson@zoology.up.ac.za>
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
2021-01-01 21:10:10 +01:00

36 lines
1.6 KiB
C++

#include "statscolors.h"
// Colors created using the Chroma.js Color Palette Helper
// https://vis4.net/palettes/#/50|d|00108c,3ed8ff,ffffe0|ffffe0,ff005e,743535|1|1
static const QColor binColors[] = {
QRgb(0x00108c), QRgb(0x0f1c92), QRgb(0x1a2798), QRgb(0x23319d), QRgb(0x2a3ba3),
QRgb(0x3144a8), QRgb(0x374eae), QRgb(0x3e58b3), QRgb(0x4461b8), QRgb(0x4b6bbd),
QRgb(0x5274c2), QRgb(0x587ec7), QRgb(0x6088cc), QRgb(0x6791d0), QRgb(0x6f9bd4),
QRgb(0x78a5d8), QRgb(0x81aedb), QRgb(0x8ab8df), QRgb(0x95c2e2), QRgb(0xa0cbe4),
QRgb(0xacd5e6), QRgb(0xb9dee7), QRgb(0xc7e7e7), QRgb(0xd7efe7), QRgb(0xeaf8e4),
QRgb(0xfff5d8), QRgb(0xffead0), QRgb(0xffe0c8), QRgb(0xffd5c0), QRgb(0xffcab8),
QRgb(0xffbfb0), QRgb(0xffb4a8), QRgb(0xffa99f), QRgb(0xfc9e98), QRgb(0xf99490),
QRgb(0xf48b89), QRgb(0xf08182), QRgb(0xea787b), QRgb(0xe46f74), QRgb(0xde666e),
QRgb(0xd75e67), QRgb(0xcf5661), QRgb(0xc64f5b), QRgb(0xbd4855), QRgb(0xb3434f),
QRgb(0xa83e49), QRgb(0x9d3a44), QRgb(0x90383f), QRgb(0x83363a), QRgb(0x743535)
};
// Pick roughly equidistant colors out of the color set above
// if we need more bins than we have colors (what chart is THAT?) simply loop
QColor binColor(int bin, int numBins)
{
if (numBins == 1 || bin < 0 || bin >= numBins)
return fillColor;
if (numBins > (int)std::size(binColors))
return binColors[bin % std::size(binColors)];
// use integer math to spread out the indices
int idx = bin * (std::size(binColors) - 1) / (numBins - 1);
return binColors[idx];
}
// Figure out if we want a light or a dark label
QColor labelColor(int bin, size_t numBins)
{
return (binColor(bin, numBins).lightness() < 150) ? lightLabelColor : darkLabelColor;
}