Updated UI.

- Removed unnecessary UI elements from QML file;
- Added the ColorScale class and implemented glyph color mapping from class
  labels;
- Mark geometry nodes of individual glyphs as dirty when updating the scene
  graph.

1 files changed, 72 insertions, 0 deletions

diff --git a/colorscale.cpp b/colorscale.cpp
new file mode 100644
index 0000000..50fedae
--- /dev/null
+++ b/colorscale.cpp
@@ -0,0 +1,72 @@
+#include "colorscale.h"
+
+ColorScale::ColorScale(const QColor &firstColor, const QColor &lastColor)
+    : m_colors{firstColor, lastColor}
+{
+    setExtents(0, 1);
+}
+
+ColorScale::ColorScale(std::initializer_list<QColor> colors)
+    : m_colors(colors)
+{
+    setExtents(0, 1);
+}
+
+ColorScale::ColorScale(const QList<QColor> &colors)
+    : m_colors(colors)
+{
+    setExtents(0, 1);
+}
+
+ColorScale::~ColorScale()
+{
+}
+
+void ColorScale::setExtents(qreal min, qreal max)
+{
+    if (min >= max)
+        return;
+
+    m_min = min;
+    m_max = max;
+}
+
+static QColor lerp(const QColor &c1, const QColor &c2, qreal t)
+{
+    qreal r1, g1, b1, a1;
+    qreal r2, g2, b2, a2;
+
+    c1.getRgbF(&r1, &g1, &b1, &a1);
+    c2.getRgbF(&r2, &g2, &b2, &a2);
+    QColor color;
+    color.setRgbF(r1 * (1 - t) + r2 * t,
+                  g1 * (1 - t) + g2 * t,
+                  b1 * (1 - t) + b2 * t,
+                  a1 * (1 - t) + a2 * t);
+    return color;
+}
+
+QColor ColorScale::color(qreal t) const
+{
+    if (t < m_min || t > m_max)
+        return QColor();
+
+    // normalize t
+    t = (t - m_min) / (m_max - m_min);
+
+    // two colors, use a simpler solution
+    if (m_colors.size() == 2)
+        return lerp(m_colors.first(), m_colors.last(), t);
+
+    // find which colors in the scale are adjacent to ours
+    qreal step = 1.0 / m_colors.size();
+    int i = (int) (t / step);
+    int j = i + 1;
+
+    if (i >= m_colors.size() - 1)
+        return QColor(m_colors.last());
+
+    // normalize t between the two colors
+    t = (t - i*step) / (j*step - i*step);
+    return lerp(m_colors[i], m_colors[j], t);
+}