Function screen_to_image

examples/main_video.cpp:210–216

}

static bool screen_to_image(const vapp_state& app, float sx, float sy,
                             float& ix, float& iy) {
    if (app.canvas_w <= 0 || app.canvas_h <= 0) return false;
    ix = (sx - app.canvas_x) / app.canvas_w * app.frame.width;
    iy = (sy - app.canvas_y) / app.canvas_h * app.frame.height;
    return ix >= 0 && iy >= 0 && ix < app.frame.width && iy < app.frame.height;
}

static void create_tracker(vapp_state& app) {
    if (app.visual_only) {