Recipe 3 — Trace Colors and the Legend

Trace labels control what appears in the legend, and trace colors make multi-channel plots readable at a glance. This recipe shows both color forms: named colors from the colors:: palette, raw RGB/ARGB literals, and the helper color(...) functions. See Trace Configuration.

Recipe 3 — named traces with RGB and translucent ARGB colors

#include <ViewPoint.h>
using namespace viewpoint;

void setup() {
    view.begin();
    view.setTitle("Two-Channel ADC");
    view.setVerticalRange(0, 1023, 100, 200);
    view.trace("A0").setColor(colors::OrangeRed);
    view.trace("A1").setColor(0x00CCFF);                  // RGB literal
    view.trace("Average").setColor(color(128, 0, 255, 0)); // ARGB helper
}

void loop() {
    float a0 = analogRead(A0);
    float a1 = analogRead(A1);
    view.addData("A0", a0);
    view.addData("A1", a1);
    view.addData("Average", (a0 + a1) * 0.5f);
    view.send();
}

What the functions do

• view.trace("A0") gets or creates a trace by label.
• .setColor(colors::OrangeRed) chooses a named palette color.
• .setColor(0x00CCFF) chooses a raw RGB color in 0xRRGGBB form. Fully opaque alpha is assumed.
• .setColor(color(128, 0, 255, 0)) uses the ARGB helper form: alpha, red, green, blue. Alpha values run from 0 transparent to 255 opaque.
• Trace creation order controls legend order and default automapping to plots.