lv_obj_scroll.h

Enums

enum lv_scrollbar_mode_t

Scrollbar modes: shows when should the scrollbars be visible

Values:

enumerator LV_SCROLLBAR_MODE_OFF: Never show scrollbars

enumerator LV_SCROLLBAR_MODE_ON: Always show scrollbars

enumerator LV_SCROLLBAR_MODE_ACTIVE: Show scroll bars when Widget is being scrolled

enumerator LV_SCROLLBAR_MODE_AUTO: Show scroll bars when the content is large enough to be scrolled

enum lv_scroll_snap_t

Scroll span align options. Tells where to align the snappable children when scroll stops.

Values:

enumerator LV_SCROLL_SNAP_NONE: Do not align, leave where it is

enumerator LV_SCROLL_SNAP_START: Align to the left/top

enumerator LV_SCROLL_SNAP_END: Align to the right/bottom

enumerator LV_SCROLL_SNAP_CENTER: Align to the center

Functions

void lv_obj_set_scrollbar_mode(lv_obj_t *obj, lv_scrollbar_mode_t mode)

Set how the scrollbars should behave.

Parameters:

obj – pointer to Widget
mode – LV_SCROLL_MODE_ON/OFF/AUTO/ACTIVE

void lv_obj_set_scroll_dir(lv_obj_t *obj, lv_dir_t dir)

Set direction Widget can be scrolled

Parameters:

obj – pointer to Widget
dir – one or more bit-wise OR-ed values of lv_dir_t enumeration

void lv_obj_set_scroll_snap_x(lv_obj_t *obj, lv_scroll_snap_t align)

Set where to snap the children when scrolling ends horizontally

Parameters:

obj – pointer to Widget
align – value from lv_scroll_snap_t enumeration

void lv_obj_set_scroll_snap_y(lv_obj_t *obj, lv_scroll_snap_t align)

Set where to snap the children when scrolling ends vertically

Parameters:

obj – pointer to Widget
align – value from lv_scroll_snap_t enumeration

lv_scrollbar_mode_t lv_obj_get_scrollbar_mode(const lv_obj_t *obj)

Get the current scroll mode (when to hide the scrollbars)

Parameters:: obj – pointer to Widget
Returns:: the current scroll mode from lv_scrollbar_mode_t

lv_dir_t lv_obj_get_scroll_dir(const lv_obj_t *obj)

Get directions Widget can be scrolled (set with lv_obj_set_scroll_dir())

Parameters:: obj – pointer to Widget
Returns:: current scroll direction bit(s)

lv_scroll_snap_t lv_obj_get_scroll_snap_x(const lv_obj_t *obj)

Get where to snap child Widgets when horizontal scrolling ends.

Parameters:: obj – pointer to Widget
Returns:: current snap value from lv_scroll_snap_t

lv_scroll_snap_t lv_obj_get_scroll_snap_y(const lv_obj_t *obj)

Get where to snap child Widgets when vertical scrolling ends.

Parameters:: obj – pointer to Widget
Returns:: current snap value from lv_scroll_snap_t

int32_t lv_obj_get_scroll_x(const lv_obj_t *obj)

Get current X scroll position. Identical to lv_obj_get_scroll_left().

Parameters:

obj – pointer to scrollable container Widget

Returns:

current scroll position from left edge

If Widget is not scrolled return 0.
If scrolled return > 0.
If scrolled inside (elastic scroll) return < 0.

int32_t lv_obj_get_scroll_y(const lv_obj_t *obj)

Get current Y scroll position. Identical to lv_obj_get_scroll_top().

Parameters:

obj – pointer to scrollable container Widget

Returns:

current scroll position from top edge

If Widget is not scrolled return 0.
If scrolled return > 0.
If scrolled inside (elastic scroll) return < 0.

int32_t lv_obj_get_scroll_top(lv_obj_t *obj)

Number of pixels a scrollable container Widget can be scrolled down before its top edge appears. When LV_OBJ_FLAG_SCROLL_ELASTIC flag is set in Widget, this value can go negative while Widget is being dragged below its normal top-edge boundary.

Parameters:: obj – pointer to scrollable container Widget
Returns:: pixels Widget can be scrolled down before its top edge appears

int32_t lv_obj_get_scroll_bottom(lv_obj_t *obj)

Number of pixels a scrollable container Widget can be scrolled up before its bottom edge appears. When LV_OBJ_FLAG_SCROLL_ELASTIC flag is set in Widget, this value can go negative while Widget is being dragged above its normal bottom-edge boundary.

Parameters:: obj – pointer to scrollable container Widget
Returns:: pixels Widget can be scrolled up before its bottom edge appears

int32_t lv_obj_get_scroll_left(lv_obj_t *obj)

Number of pixels a scrollable container Widget can be scrolled right before its left edge appears. When LV_OBJ_FLAG_SCROLL_ELASTIC flag is set in Widget, this value can go negative while Widget is being dragged farther right than its normal left-edge boundary.

Parameters:: obj – pointer to scrollable container Widget
Returns:: pixels Widget can be scrolled right before its left edge appears

int32_t lv_obj_get_scroll_right(lv_obj_t *obj)

Number of pixels a scrollable container Widget can be scrolled left before its right edge appears. When LV_OBJ_FLAG_SCROLL_ELASTIC flag is set in Widget, this value can go negative while Widget is being dragged farther left than its normal right-edge boundary.

Parameters:: obj – pointer to scrollable container Widget
Returns:: pixels Widget can be scrolled left before its right edge appears

void lv_obj_get_scroll_end(lv_obj_t *obj, lv_point_t *end)

Get the X and Y coordinates where the scrolling will end for Widget if a scrolling animation is in progress. If no scrolling animation, give the current x or y scroll position.

Parameters:

obj – pointer to scrollable Widget
end – pointer to lv_point_t object in which to store result

void lv_obj_scroll_by(lv_obj_t *obj, int32_t dx, int32_t dy, lv_anim_enable_t anim_en)

Scroll by given amount of pixels.

Note

> 0 value means scroll right/bottom (show the more content on the right/bottom)

Note

e.g. dy = -20 means scroll down 20 px

Parameters:

obj – pointer to scrollable Widget to scroll
dx – pixels to scroll horizontally
dy – pixels to scroll vertically
anim_en – LV_ANIM_ON: scroll with animation; LV_ANIM_OFF: scroll immediately

void lv_obj_scroll_by_bounded(lv_obj_t *obj, int32_t dx, int32_t dy, lv_anim_enable_t anim_en)

Scroll by given amount of pixels. dx and dy will be limited internally to allow scrolling only on the content area.

Note

e.g. dy = -20 means scroll down 20 px

Parameters:

obj – pointer to scrollable Widget to scroll
dx – pixels to scroll horizontally
dy – pixels to scroll vertically
anim_en – LV_ANIM_ON: scroll with animation; LV_ANIM_OFF: scroll immediately

void lv_obj_scroll_to(lv_obj_t *obj, int32_t x, int32_t y, lv_anim_enable_t anim_en)

Scroll to given coordinate on Widget. x and y will be limited internally to allow scrolling only on the content area.

Parameters:

obj – pointer to scrollable Widget to scroll
x – pixels to scroll horizontally
y – pixels to scroll vertically
anim_en – LV_ANIM_ON: scroll with animation; LV_ANIM_OFF: scroll immediately

void lv_obj_scroll_to_x(lv_obj_t *obj, int32_t x, lv_anim_enable_t anim_en)

Scroll to X coordinate on Widget. x will be limited internally to allow scrolling only on the content area.

Parameters:

obj – pointer to scrollable Widget to scroll
x – pixels to scroll horizontally
anim_en – LV_ANIM_ON: scroll with animation; LV_ANIM_OFF: scroll immediately

void lv_obj_scroll_to_y(lv_obj_t *obj, int32_t y, lv_anim_enable_t anim_en)

Scroll to Y coordinate on Widget. y will be limited internally to allow scrolling only on the content area.

Parameters:

obj – pointer to scrollable Widget to scroll
y – pixels to scroll vertically
anim_en – LV_ANIM_ON: scroll with animation; LV_ANIM_OFF: scroll immediately

void lv_obj_scroll_to_view(lv_obj_t *obj, lv_anim_enable_t anim_en)

Scroll obj's parent Widget until obj becomes visible.

Parameters:

obj – pointer to Widget to scroll into view
anim_en – LV_ANIM_ON: scroll with animation; LV_ANIM_OFF: scroll immediately

void lv_obj_scroll_to_view_recursive(lv_obj_t *obj, lv_anim_enable_t anim_en)

Scroll obj's parent Widgets recursively until obj becomes visible. Widget will be scrolled into view even it has nested scrollable parents.

Parameters:

obj – pointer to Widget to scroll into view
anim_en – LV_ANIM_ON: scroll with animation; LV_ANIM_OFF: scroll immediately

bool lv_obj_is_scrolling(const lv_obj_t *obj)

Tell whether Widget is being scrolled or not at this moment

Parameters:: obj – pointer to Widget
Returns:: true: obj is being scrolled

void lv_obj_update_snap(lv_obj_t *obj, lv_anim_enable_t anim_en)

Check children of obj and scroll obj to fulfill scroll_snap settings.

Parameters:

obj – Widget whose children need to be checked and snapped
anim_en – LV_ANIM_ON/OFF

void lv_obj_get_scrollbar_area(lv_obj_t *obj, lv_area_t *hor, lv_area_t *ver)

Get the area of the scrollbars

Parameters:

obj – pointer to Widget
hor – pointer to store the area of the horizontal scrollbar
ver – pointer to store the area of the vertical scrollbar

void lv_obj_scrollbar_invalidate(lv_obj_t *obj)

Invalidate the area of the scrollbars

Parameters:: obj – pointer to Widget

void lv_obj_readjust_scroll(lv_obj_t *obj, lv_anim_enable_t anim_en)

Checks if the content is scrolled "in" and adjusts it to a normal position.

Parameters:

obj – pointer to Widget
anim_en – LV_ANIM_ON/OFF