static void calculate_state()

in src/terminal/scrollbar.c [242:332]

• 54 lines of code
• 9 McCabe index (conditional complexity)

static void calculate_state(guac_terminal_scrollbar* scrollbar,
        guac_terminal_scrollbar_render_state* render_state,
        int* value) {

    /* Use unchanged current value by default */
    *value = scrollbar->value;

    /* Calculate container dimensions */
    render_state->container_width  = GUAC_TERMINAL_SCROLLBAR_WIDTH;
    render_state->container_height = scrollbar->parent_height;

    /* Calculate container position */
    render_state->container_x = scrollbar->parent_width
                              - render_state->container_width;

    render_state->container_y = 0;

    /* Calculate handle dimensions */
    render_state->handle_width  = render_state->container_width
                                - GUAC_TERMINAL_SCROLLBAR_PADDING*2;

    /* Handle can be no bigger than the scrollbar itself */
    int max_handle_height = render_state->container_height
                          - GUAC_TERMINAL_SCROLLBAR_PADDING*2;

    /* Calculate legal delta between scroll values */
    int scroll_delta;
    if (scrollbar->max > scrollbar->min)
        scroll_delta = scrollbar->max - scrollbar->min;
    else
        scroll_delta = 0;

    /* Scale handle relative to visible area vs. scrolling region size */
    int proportional_height = max_handle_height
                            * scrollbar->visible_area
                            / (scroll_delta + scrollbar->visible_area);

    /* Ensure handle is no smaller than minimum height */
    if (proportional_height > GUAC_TERMINAL_SCROLLBAR_MIN_HEIGHT)
        render_state->handle_height = proportional_height;
    else
        render_state->handle_height = GUAC_TERMINAL_SCROLLBAR_MIN_HEIGHT;

    /* Ensure handle is no larger than maximum height */
    if (render_state->handle_height > max_handle_height)
        render_state->handle_height = max_handle_height;

    /* Calculate handle X position */
    render_state->handle_x = GUAC_TERMINAL_SCROLLBAR_PADDING;

    /* Calculate handle Y range */
    int min_handle_y = GUAC_TERMINAL_SCROLLBAR_PADDING;
    int max_handle_y = min_handle_y + max_handle_height
                     - render_state->handle_height;

    /* Position handle relative to mouse if being dragged */
    if (scrollbar->dragging_handle) {

        int dragged_handle_y = scrollbar->drag_current_y
                             - scrollbar->drag_offset_y;

        /* Keep handle within bounds */
        if (dragged_handle_y < min_handle_y)
            dragged_handle_y = min_handle_y;
        else if (dragged_handle_y > max_handle_y)
            dragged_handle_y = max_handle_y;

        render_state->handle_y = dragged_handle_y;

        /* Calculate scrollbar value */
        if (max_handle_y > min_handle_y) {
            *value = scrollbar->min
                   + (dragged_handle_y - min_handle_y)
                      * scroll_delta
                      / (max_handle_y - min_handle_y);
        }

    }

    /* Handle Y position is relative to current scroll value */
    else if (scroll_delta > 0)
        render_state->handle_y = min_handle_y
                               + (max_handle_y - min_handle_y)
                                  * (scrollbar->value - scrollbar->min)
                                  / scroll_delta;

    /* ... unless there is only one possible scroll value */
    else
        render_state->handle_y = GUAC_TERMINAL_SCROLLBAR_PADDING;

}