Added example c script

rpi2/c-example.c

@@ -0,0 +1,61 @@
+/* -*- mode: c; c-basic-offset: 2; indent-tabs-mode: nil; -*-
+ *
+ * Using the C-API of this library.
+ *
+ */
+#include "led-matrix-c.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+int main(int argc, char **argv) {
+  struct RGBLedMatrixOptions options;
+  struct RGBLedMatrix *matrix;
+  struct LedCanvas *offscreen_canvas;
+  int width, height;
+  int x, y, i;
+
+  memset(&options, 0, sizeof(options));
+  options.rows = 64;
+  options.chain_length = 2;
+
+  /* This supports all the led commandline options. Try --led-help */
+  matrix = led_matrix_create_from_options(&options, &argc, &argv);
+  if (matrix == NULL)
+    return 1;
+
+  /* Let's do an example with double-buffering. We create one extra
+   * buffer onto which we draw, which is then swapped on each refresh.
+   * This is typically a good aproach for animations and such.
+   */
+  offscreen_canvas = led_matrix_create_offscreen_canvas(matrix);
+
+  led_canvas_get_size(offscreen_canvas, &width, &height);
+
+  fprintf(stderr, "Size: %dx%d. Hardware gpio mapping: %s\n",
+          width, height, options.hardware_mapping);
+
+  for (i = 0; i < 1000; ++i) {
+    for (y = 0; y < height; ++y) {
+      for (x = 0; x < width; ++x) {
+        led_canvas_set_pixel(offscreen_canvas, x, y, i & 0xff, x, y);
+      }
+    }
+
+    /* Now, we swap the canvas. We give swap_on_vsync the buffer we
+     * just have drawn into, and wait until the next vsync happens.
+     * we get back the unused buffer to which we'll draw in the next
+     * iteration.
+     */
+    offscreen_canvas = led_matrix_swap_on_vsync(matrix, offscreen_canvas);
+  }
+
+  /*
+   * Make sure to always call led_matrix_delete() in the end to reset the
+   * display. Installing signal handlers for defined exit is a good idea.
+   */
+  led_matrix_delete(matrix);
+
+  return 0;
+}