cgif_example_video.c

#include <stdlib.h>
#include <stdint.h>
#include <string.h>

#include "cgif.h"

#define WIDTH  100
#define HEIGHT 100

/* Small helper functions to initialize GIF- and frame-configuration */
static void initGIFConfig(CGIF_Config* pConfig, char* path, uint16_t width, uint16_t height, uint8_t* pPalette, uint16_t numColors) {
  memset(pConfig, 0, sizeof(CGIF_Config));
  pConfig->width                   = width;
  pConfig->height                  = height;
  pConfig->pGlobalPalette          = pPalette;
  pConfig->numGlobalPaletteEntries = numColors;
  pConfig->path                    = path;
  pConfig->attrFlags               = CGIF_ATTR_IS_ANIMATED;
}
static void initFrameConfig(CGIF_FrameConfig* pConfig, uint8_t* pImageData, uint16_t delay) {
  memset(pConfig, 0, sizeof(CGIF_FrameConfig));
  pConfig->delay      = delay;
  pConfig->pImageData = pImageData;
}

/* This is an example code that creates a GIF-animation with a moving stripe-pattern. */
int main(void) {
  CGIF*            pGIF;                                                 // struct containing the GIF
  CGIF_Config       gConfig;                                               // global configuration parameters for the GIF
  CGIF_FrameConfig  fConfig;                                               // configuration parameters for a frame
  uint8_t*    pImageData;                                                // image data (an array of color-indices)
  uint8_t aPalette[] = {0xFF, 0x00, 0x00,                                // red
                        0x00, 0xFF, 0x00,                                // green
                        0x00, 0x00, 0xFF};                               // blue
  uint8_t numColors = 3;                                                 // number of colors in aPalette (up to 256 possible)
  int numFrames = 12;                                                    // number of frames in the video

  // initialize the GIF-configuration and create a new GIF
  initGIFConfig(&gConfig, "example_video_cgif.gif", WIDTH, HEIGHT, aPalette, numColors);
  pGIF = cgif_newgif(&gConfig);

  // create image frames and add them to GIF
  pImageData = malloc(WIDTH * HEIGHT);                                   // allocate memory for image data
  for (int f = 0; f < numFrames; ++f) {
    for (int i = 0; i < (WIDTH * HEIGHT); ++i) {
      pImageData[i] = (unsigned char)((f + i % WIDTH ) / 4 % numColors); // moving stripe pattern (4 pixels per stripe)
    }
    initFrameConfig(&fConfig, pImageData, 10);                           // initialize the frame-configuration
    cgif_addframe(pGIF, &fConfig);                                       // append the new frame
  }
  free(pImageData);                                                      // free image data when all frames are added

  // close created GIF-file and free allocated space
  cgif_close(pGIF);
  return 0;
}