Use the library with Qt Creator on Pi 3 Jessie

[johann74270]

we have everyone, I'm having trouble including feature libraries in my Qt program. I'm a beginner in programming, if you could help me I have the impression that there is a problem in the library I get sort of wrong:

/home/pi/rpi-rgb-led-matrix/lib/led-matrix.cc:361: error: undefined reference to `rgb_matrix::internal::PixelMapper::get(int, int)'

with this simple code :

OBJECTS += /home/pi/rpi-rgb-led-matrix/lib/led-matrix.o INCLUDEPATH += /home/pi/rpi-rgb-led-matrix/include LIBS += -L/home/pi/rpi-rgb-led-matrix/lib

include

include "led-matrix.h"

include

include

include

include

using rgb_matrix::GPIO; using rgb_matrix::RGBMatrix; using rgb_matrix::Canvas;

volatile bool interrupt_received = false; static void InterruptHandler(int signo) { interrupt_received = true; }

static void DrawOnCanvas(Canvas canvas) { /

• Let's create a simple animation. We use the canvas to draw

• pixels. We wait between each step to have a slower animation. */ canvas->Fill(0, 0, 255);

  int center_x = canvas->width() / 2; int center_y = canvas->height() / 2; float radius_max = canvas->width() / 2; float angle_step = 1.0 / 360; for (float a = 0, r = 0; r < radius_max; a += angle_step, r += angle_step) { if (interrupt_received) return; float dot_x = cos(a 2 M_PI) r; float dot_y = sin(a 2 M_PI) r; canvas->SetPixel(center_x + dot_x, center_y + dot_y, 255, 0, 0); usleep(1 * 1000); // wait a little to slow down things. } }

int main(int argc, char *argv[]) { QCoreApplication a(argc, argv);

RGBMatrix::Options defaults;
defaults.hardware_mapping = "regular";  // or e.g. "adafruit-hat"
defaults.rows = 32;
defaults.chain_length = 1;
defaults.parallel = 1;
defaults.show_refresh_rate = true;
Canvas *canvas = rgb_matrix::CreateMatrixFromFlags(&argc, &argv, &defaults);
if (canvas == NULL)
  return 1;

// It is always good to set up a signal handler to cleanly exit when we
// receive a CTRL-C for instance. The DrawOnCanvas() routine is looking
// for that.
signal(SIGTERM, InterruptHandler);
signal(SIGINT, InterruptHandler);

DrawOnCanvas(canvas);    // Using the canvas.

// Animation finished. Shut down the RGB matrix.
canvas->Clear();
delete canvas;

return a.exec();

}

[hzeller]

You need to link the full library lib/librgbmatrix.a not only led-matrix.o in your build system. So

OBJECTS += /home/pi/rpi-rgb-led-matrix/lib/led-matrix.o

won't do it, you rather want something like

LIBS += -L/home/pi/rpi-rgb-led-matrix/lib -lrgbmatrix

This is described in the api integration section.