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lvgl_cpp/lvgl/core/lv_indev_scroll.c

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/**
* @file lv_indev_scroll.c
*
*/
/*********************
* INCLUDES
*********************/
#include "lv_indev.h"
#include "lv_indev_scroll.h"
/*********************
* DEFINES
*********************/
#define ELASTIC_SLOWNESS_FACTOR 4 /*Scrolling on elastic parts are slower by this factor*/
/**********************
* TYPEDEFS
**********************/
/**********************
* STATIC PROTOTYPES
**********************/
static lv_obj_t * find_scroll_obj(_lv_indev_proc_t * proc);
static void init_scroll_limits(_lv_indev_proc_t * proc);
static lv_coord_t find_snap_point_x(const lv_obj_t * obj, lv_coord_t min, lv_coord_t max, lv_coord_t ofs);
static lv_coord_t find_snap_point_y(const lv_obj_t * obj, lv_coord_t min, lv_coord_t max, lv_coord_t ofs);
static void scroll_limit_diff(_lv_indev_proc_t * proc, lv_coord_t * diff_x, lv_coord_t * diff_y);
static lv_coord_t scroll_throw_predict_y(_lv_indev_proc_t * proc);
static lv_coord_t scroll_throw_predict_x(_lv_indev_proc_t * proc);
static lv_coord_t elastic_diff(lv_obj_t * scroll_obj, lv_coord_t diff, lv_coord_t scroll_start, lv_coord_t scroll_end,
lv_dir_t dir);
/**********************
* STATIC VARIABLES
**********************/
/**********************
* MACROS
**********************/
/**********************
* GLOBAL FUNCTIONS
**********************/
void _lv_indev_scroll_handler(_lv_indev_proc_t * proc)
{
lv_obj_t * scroll_obj = proc->types.pointer.scroll_obj;
/*If there is no scroll object yet try to find one*/
if(scroll_obj == NULL) {
proc->types.pointer.scroll_sum.x += proc->types.pointer.vect.x;
proc->types.pointer.scroll_sum.y += proc->types.pointer.vect.y;
scroll_obj = find_scroll_obj(proc);
if(scroll_obj == NULL) return;
init_scroll_limits(proc);
lv_event_send(scroll_obj, LV_EVENT_SCROLL_BEGIN, NULL);
if(proc->reset_query) return;
}
/*Set new position or scroll if the vector is not zero*/
if(proc->types.pointer.vect.x != 0 || proc->types.pointer.vect.y != 0) {
lv_coord_t diff_x = 0;
lv_coord_t diff_y = 0;
if(proc->types.pointer.scroll_dir == LV_DIR_HOR) {
lv_coord_t sr = lv_obj_get_scroll_right(scroll_obj);
lv_coord_t sl = lv_obj_get_scroll_left(scroll_obj);
diff_x = elastic_diff(scroll_obj, proc->types.pointer.vect.x, sl, sr, LV_DIR_HOR);
}
else {
lv_coord_t st = lv_obj_get_scroll_top(scroll_obj);
lv_coord_t sb = lv_obj_get_scroll_bottom(scroll_obj);
diff_y = elastic_diff(scroll_obj, proc->types.pointer.vect.y, st, sb, LV_DIR_VER);
}
lv_dir_t scroll_dir = lv_obj_get_scroll_dir(scroll_obj);
if((scroll_dir & LV_DIR_LEFT) == 0 && diff_x > 0) diff_x = 0;
if((scroll_dir & LV_DIR_RIGHT) == 0 && diff_x < 0) diff_x = 0;
if((scroll_dir & LV_DIR_TOP) == 0 && diff_y > 0) diff_y = 0;
if((scroll_dir & LV_DIR_BOTTOM) == 0 && diff_y < 0) diff_y = 0;
/*Respect the scroll limit area*/
scroll_limit_diff(proc, &diff_x, &diff_y);
lv_obj_scroll_by(scroll_obj, diff_x, diff_y, LV_ANIM_OFF);
proc->types.pointer.scroll_sum.x += diff_x;
proc->types.pointer.scroll_sum.y += diff_y;
}
}
void _lv_indev_scroll_throw_handler(_lv_indev_proc_t * proc)
{
lv_obj_t * scroll_obj = proc->types.pointer.scroll_obj;
if(scroll_obj == NULL) return;
if(proc->types.pointer.scroll_dir == LV_DIR_NONE) return;
lv_indev_t * indev_act = lv_indev_get_act();
lv_coord_t scroll_throw = indev_act->driver->scroll_throw;
if(lv_obj_has_flag(scroll_obj, LV_OBJ_FLAG_SCROLL_MOMENTUM) == false) {
proc->types.pointer.scroll_throw_vect.y = 0;
proc->types.pointer.scroll_throw_vect.x = 0;
}
lv_scroll_snap_t align_x = lv_obj_get_scroll_snap_x(scroll_obj);
lv_scroll_snap_t align_y = lv_obj_get_scroll_snap_y(scroll_obj);
if(proc->types.pointer.scroll_dir == LV_DIR_VER) {
proc->types.pointer.scroll_throw_vect.x = 0;
/*If no snapping "throw"*/
if(align_y == LV_SCROLL_SNAP_NONE) {
proc->types.pointer.scroll_throw_vect.y =
proc->types.pointer.scroll_throw_vect.y * (100 - scroll_throw) / 100;
lv_coord_t sb = lv_obj_get_scroll_bottom(scroll_obj);
lv_coord_t st = lv_obj_get_scroll_top(scroll_obj);
proc->types.pointer.scroll_throw_vect.y = elastic_diff(scroll_obj, proc->types.pointer.scroll_throw_vect.y, st, sb,
LV_DIR_VER);
lv_obj_scroll_by(scroll_obj, 0, proc->types.pointer.scroll_throw_vect.y, LV_ANIM_OFF);
}
/*With snapping find the nearest snap point and scroll there*/
else {
lv_coord_t diff_y = scroll_throw_predict_y(proc);
proc->types.pointer.scroll_throw_vect.y = 0;
scroll_limit_diff(proc, NULL, &diff_y);
lv_coord_t y = find_snap_point_y(scroll_obj, LV_COORD_MIN, LV_COORD_MAX, diff_y);
lv_obj_scroll_by(scroll_obj, 0, diff_y + y, LV_ANIM_ON);
}
}
else if(proc->types.pointer.scroll_dir == LV_DIR_HOR) {
proc->types.pointer.scroll_throw_vect.y = 0;
/*If no snapping "throw"*/
if(align_x == LV_SCROLL_SNAP_NONE) {
proc->types.pointer.scroll_throw_vect.x =
proc->types.pointer.scroll_throw_vect.x * (100 - scroll_throw) / 100;
lv_coord_t sl = lv_obj_get_scroll_left(scroll_obj);
lv_coord_t sr = lv_obj_get_scroll_right(scroll_obj);
proc->types.pointer.scroll_throw_vect.x = elastic_diff(scroll_obj, proc->types.pointer.scroll_throw_vect.x, sl, sr,
LV_DIR_HOR);
lv_obj_scroll_by(scroll_obj, proc->types.pointer.scroll_throw_vect.x, 0, LV_ANIM_OFF);
}
/*With snapping find the nearest snap point and scroll there*/
else {
lv_coord_t diff_x = scroll_throw_predict_x(proc);
proc->types.pointer.scroll_throw_vect.x = 0;
scroll_limit_diff(proc, &diff_x, NULL);
lv_coord_t x = find_snap_point_x(scroll_obj, LV_COORD_MIN, LV_COORD_MAX, diff_x);
lv_obj_scroll_by(scroll_obj, x + diff_x, 0, LV_ANIM_ON);
}
}
/*Check if the scroll has finished*/
if(proc->types.pointer.scroll_throw_vect.x == 0 && proc->types.pointer.scroll_throw_vect.y == 0) {
/*Revert if scrolled in*/
/*If vertically scrollable and not controlled by snap*/
if(align_y == LV_SCROLL_SNAP_NONE) {
lv_coord_t st = lv_obj_get_scroll_top(scroll_obj);
lv_coord_t sb = lv_obj_get_scroll_bottom(scroll_obj);
if(st > 0 || sb > 0) {
if(st < 0) {
lv_obj_scroll_by(scroll_obj, 0, st, LV_ANIM_ON);
}
else if(sb < 0) {
lv_obj_scroll_by(scroll_obj, 0, -sb, LV_ANIM_ON);
}
}
}
/*If horizontally scrollable and not controlled by snap*/
if(align_x == LV_SCROLL_SNAP_NONE) {
lv_coord_t sl = lv_obj_get_scroll_left(scroll_obj);
lv_coord_t sr = lv_obj_get_scroll_right(scroll_obj);
if(sl > 0 || sr > 0) {
if(sl < 0) {
lv_obj_scroll_by(scroll_obj, sl, 0, LV_ANIM_ON);
}
else if(sr < 0) {
lv_obj_scroll_by(scroll_obj, -sr, 0, LV_ANIM_ON);
}
}
}
lv_event_send(scroll_obj, LV_EVENT_SCROLL_END, indev_act);
if(proc->reset_query) return;
proc->types.pointer.scroll_dir = LV_DIR_NONE;
proc->types.pointer.scroll_obj = NULL;
}
}
/**
* Predict where would a scroll throw end
* @param indev pointer to an input device
* @param dir `LV_DIR_VER` or `LV_DIR_HOR`
* @return the difference compared to the current position when the throw would be finished
*/
lv_coord_t lv_indev_scroll_throw_predict(lv_indev_t * indev, lv_dir_t dir)
{
if(indev == NULL) return 0;
lv_coord_t v;
switch(dir) {
case LV_DIR_VER:
v = indev->proc.types.pointer.scroll_throw_vect_ori.y;
break;
case LV_DIR_HOR:
v = indev->proc.types.pointer.scroll_throw_vect_ori.x;
break;
default:
return 0;
}
lv_coord_t scroll_throw = indev->driver->scroll_throw;
lv_coord_t sum = 0;
while(v) {
sum += v;
v = v * (100 - scroll_throw) / 100;
}
return sum;
}
void lv_indev_scroll_get_snap_dist(lv_obj_t * obj, lv_point_t * p)
{
p->x = find_snap_point_x(obj, obj->coords.x1, obj->coords.x2, 0);
p->y = find_snap_point_y(obj, obj->coords.y1, obj->coords.y2, 0);
}
/**********************
* STATIC FUNCTIONS
**********************/
static lv_obj_t * find_scroll_obj(_lv_indev_proc_t * proc)
{
lv_obj_t * obj_candidate = NULL;
lv_dir_t dir_candidate = LV_DIR_NONE;
lv_indev_t * indev_act = lv_indev_get_act();
lv_coord_t scroll_limit = indev_act->driver->scroll_limit;
/*Go until find a scrollable object in the current direction
*More precisely:
* 1. Check the pressed object and all of its ancestors and try to find an object which is scrollable
* 2. Scrollable means it has some content out of its area
* 3. If an object can be scrolled into the current direction then use it ("real match"")
* 4. If can be scrolled on the current axis (hor/ver) save it as candidate (at least show an elastic scroll effect)
* 5. Use the last candidate. Always the "deepest" parent or the object from point 3*/
lv_obj_t * obj_act = proc->types.pointer.act_obj;
/*Decide if it's a horizontal or vertical scroll*/
bool hor_en = false;
bool ver_en = false;
if(LV_ABS(proc->types.pointer.scroll_sum.x) > LV_ABS(proc->types.pointer.scroll_sum.y)) {
hor_en = true;
}
else {
ver_en = true;
}
while(obj_act) {
if(lv_obj_has_flag(obj_act, LV_OBJ_FLAG_SCROLLABLE) == false) {
/*If this object don't want to chain the scroll to the parent stop searching*/
if(lv_obj_has_flag(obj_act, LV_OBJ_FLAG_SCROLL_CHAIN_HOR) == false && hor_en) break;
if(lv_obj_has_flag(obj_act, LV_OBJ_FLAG_SCROLL_CHAIN_VER) == false && ver_en) break;
obj_act = lv_obj_get_parent(obj_act);
continue;
}
/*Consider both up-down or left/right scrollable according to the current direction*/
bool up_en = ver_en;
bool down_en = ver_en;
bool left_en = hor_en;
bool right_en = hor_en;
/*The object might have disabled some directions.*/
lv_dir_t scroll_dir = lv_obj_get_scroll_dir(obj_act);
if((scroll_dir & LV_DIR_LEFT) == 0) left_en = false;
if((scroll_dir & LV_DIR_RIGHT) == 0) right_en = false;
if((scroll_dir & LV_DIR_TOP) == 0) up_en = false;
if((scroll_dir & LV_DIR_BOTTOM) == 0) down_en = false;
/*The object is scrollable to a direction if its content overflow in that direction.*/
lv_coord_t st = lv_obj_get_scroll_top(obj_act);
lv_coord_t sb = lv_obj_get_scroll_bottom(obj_act);
lv_coord_t sl = lv_obj_get_scroll_left(obj_act);
lv_coord_t sr = lv_obj_get_scroll_right(obj_act);
/*If this object is scrollable into the current scroll direction then save it as a candidate.
*It's important only to be scrollable on the current axis (hor/ver) because if the scroll
*is propagated to this object it can show at least elastic scroll effect.
*But if not hor/ver scrollable do not scroll it at all (so it's not a good candidate)*/
if((st > 0 || sb > 0) &&
((up_en && proc->types.pointer.scroll_sum.y >= scroll_limit) ||
(down_en && proc->types.pointer.scroll_sum.y <= - scroll_limit))) {
obj_candidate = obj_act;
dir_candidate = LV_DIR_VER;
}
if((sl > 0 || sr > 0) &&
((left_en && proc->types.pointer.scroll_sum.x >= scroll_limit) ||
(right_en && proc->types.pointer.scroll_sum.x <= - scroll_limit))) {
obj_candidate = obj_act;
dir_candidate = LV_DIR_HOR;
}
if(st <= 0) up_en = false;
if(sb <= 0) down_en = false;
if(sl <= 0) left_en = false;
if(sr <= 0) right_en = false;
/*If the object really can be scrolled into the current direction the use it.*/
if((left_en && proc->types.pointer.scroll_sum.x >= scroll_limit) ||
(right_en && proc->types.pointer.scroll_sum.x <= - scroll_limit) ||
(up_en && proc->types.pointer.scroll_sum.y >= scroll_limit) ||
(down_en && proc->types.pointer.scroll_sum.y <= - scroll_limit)) {
proc->types.pointer.scroll_dir = hor_en ? LV_DIR_HOR : LV_DIR_VER;
break;
}
/*If this object don't want to chain the scroll to the parent stop searching*/
if(lv_obj_has_flag(obj_act, LV_OBJ_FLAG_SCROLL_CHAIN_HOR) == false && hor_en) break;
if(lv_obj_has_flag(obj_act, LV_OBJ_FLAG_SCROLL_CHAIN_VER) == false && ver_en) break;
/*Try the parent*/
obj_act = lv_obj_get_parent(obj_act);
}
/*Use the last candidate*/
if(obj_candidate) {
proc->types.pointer.scroll_dir = dir_candidate;
proc->types.pointer.scroll_obj = obj_candidate;
proc->types.pointer.scroll_sum.x = 0;
proc->types.pointer.scroll_sum.y = 0;
}
return obj_candidate;
}
static void init_scroll_limits(_lv_indev_proc_t * proc)
{
lv_obj_t * obj = proc->types.pointer.scroll_obj;
/*If there no STOP allow scrolling anywhere*/
if(lv_obj_has_flag(obj, LV_OBJ_FLAG_SCROLL_ONE) == false) {
lv_area_set(&proc->types.pointer.scroll_area, LV_COORD_MIN, LV_COORD_MIN, LV_COORD_MAX, LV_COORD_MAX);
}
/*With STOP limit the scrolling to the perv and next snap point*/
else {
switch(lv_obj_get_scroll_snap_y(obj)) {
case LV_SCROLL_SNAP_START:
proc->types.pointer.scroll_area.y1 = find_snap_point_y(obj, obj->coords.y1 + 1, LV_COORD_MAX, 0);
proc->types.pointer.scroll_area.y2 = find_snap_point_y(obj, LV_COORD_MIN, obj->coords.y1 - 1, 0);
break;
case LV_SCROLL_SNAP_END:
proc->types.pointer.scroll_area.y1 = find_snap_point_y(obj, obj->coords.y2, LV_COORD_MAX, 0);
proc->types.pointer.scroll_area.y2 = find_snap_point_y(obj, LV_COORD_MIN, obj->coords.y2, 0);
break;
case LV_SCROLL_SNAP_CENTER: {
lv_coord_t y_mid = obj->coords.y1 + lv_area_get_height(&obj->coords) / 2;
proc->types.pointer.scroll_area.y1 = find_snap_point_y(obj, y_mid + 1, LV_COORD_MAX, 0);
proc->types.pointer.scroll_area.y2 = find_snap_point_y(obj, LV_COORD_MIN, y_mid - 1, 0);
break;
}
default:
proc->types.pointer.scroll_area.y1 = LV_COORD_MIN;
proc->types.pointer.scroll_area.y2 = LV_COORD_MAX;
break;
}
switch(lv_obj_get_scroll_snap_x(obj)) {
case LV_SCROLL_SNAP_START:
proc->types.pointer.scroll_area.x1 = find_snap_point_x(obj, obj->coords.x1, LV_COORD_MAX, 0);
proc->types.pointer.scroll_area.x2 = find_snap_point_x(obj, LV_COORD_MIN, obj->coords.x1, 0);
break;
case LV_SCROLL_SNAP_END:
proc->types.pointer.scroll_area.x1 = find_snap_point_x(obj, obj->coords.x2, LV_COORD_MAX, 0);
proc->types.pointer.scroll_area.x2 = find_snap_point_x(obj, LV_COORD_MIN, obj->coords.x2, 0);
break;
case LV_SCROLL_SNAP_CENTER: {
lv_coord_t x_mid = obj->coords.x1 + lv_area_get_width(&obj->coords) / 2;
proc->types.pointer.scroll_area.x1 = find_snap_point_x(obj, x_mid + 1, LV_COORD_MAX, 0);
proc->types.pointer.scroll_area.x2 = find_snap_point_x(obj, LV_COORD_MIN, x_mid - 1, 0);
break;
}
default:
proc->types.pointer.scroll_area.x1 = LV_COORD_MIN;
proc->types.pointer.scroll_area.x2 = LV_COORD_MAX;
break;
}
}
/*Allow scrolling on the edges. It will be reverted to the edge due to snapping anyway*/
if(proc->types.pointer.scroll_area.x1 == 0) proc->types.pointer.scroll_area.x1 = LV_COORD_MIN;
if(proc->types.pointer.scroll_area.x2 == 0) proc->types.pointer.scroll_area.x2 = LV_COORD_MAX;
if(proc->types.pointer.scroll_area.y1 == 0) proc->types.pointer.scroll_area.y1 = LV_COORD_MIN;
if(proc->types.pointer.scroll_area.y2 == 0) proc->types.pointer.scroll_area.y2 = LV_COORD_MAX;
}
/**
* Search for snap point in the `min` - `max` range.
* @param obj the object on which snap point should be found
* @param min ignore snap points smaller than this. (Absolute coordinate)
* @param max ignore snap points greater than this. (Absolute coordinate)
* @param ofs offset to snap points. Useful the get a snap point in an imagined case
* what if children are already moved by this value
* @return the distance of the snap point.
*/
static lv_coord_t find_snap_point_x(const lv_obj_t * obj, lv_coord_t min, lv_coord_t max, lv_coord_t ofs)
{
lv_scroll_snap_t align = lv_obj_get_scroll_snap_x(obj);
if(align == LV_SCROLL_SNAP_NONE) return 0;
lv_coord_t dist = LV_COORD_MAX;
lv_coord_t pad_left = lv_obj_get_style_pad_left(obj, LV_PART_MAIN);
lv_coord_t pad_right = lv_obj_get_style_pad_right(obj, LV_PART_MAIN);
uint32_t i;
uint32_t child_cnt = lv_obj_get_child_cnt(obj);
for(i = 0; i < child_cnt; i++) {
lv_obj_t * child = obj->spec_attr->children[i];
if(lv_obj_has_flag_any(child, LV_OBJ_FLAG_HIDDEN | LV_OBJ_FLAG_FLOATING)) continue;
if(lv_obj_has_flag(child, LV_OBJ_FLAG_SNAPPABLE)) {
lv_coord_t x_child = 0;
lv_coord_t x_parent = 0;
switch(align) {
case LV_SCROLL_SNAP_START:
x_child = child->coords.x1;
x_parent = obj->coords.x1 + pad_left;
break;
case LV_SCROLL_SNAP_END:
x_child = child->coords.x2;
x_parent = obj->coords.x2 - pad_right;
break;
case LV_SCROLL_SNAP_CENTER:
x_child = child->coords.x1 + lv_area_get_width(&child->coords) / 2;
x_parent = obj->coords.x1 + pad_left + (lv_area_get_width(&obj->coords) - pad_left - pad_right) / 2;
break;
default:
continue;
}
x_child += ofs;
if(x_child >= min && x_child <= max) {
lv_coord_t x = x_child - x_parent;
if(LV_ABS(x) < LV_ABS(dist)) dist = x;
}
}
}
return dist == LV_COORD_MAX ? 0 : -dist;
}
/**
* Search for snap point in the `min` - `max` range.
* @param obj the object on which snap point should be found
* @param min ignore snap points smaller than this. (Absolute coordinate)
* @param max ignore snap points greater than this. (Absolute coordinate)
* @param ofs offset to snap points. Useful to get a snap point in an imagined case
* what if children are already moved by this value
* @return the distance of the snap point.
*/
static lv_coord_t find_snap_point_y(const lv_obj_t * obj, lv_coord_t min, lv_coord_t max, lv_coord_t ofs)
{
lv_scroll_snap_t align = lv_obj_get_scroll_snap_y(obj);
if(align == LV_SCROLL_SNAP_NONE) return 0;
lv_coord_t dist = LV_COORD_MAX;
lv_coord_t pad_top = lv_obj_get_style_pad_top(obj, LV_PART_MAIN);
lv_coord_t pad_bottom = lv_obj_get_style_pad_bottom(obj, LV_PART_MAIN);
uint32_t i;
uint32_t child_cnt = lv_obj_get_child_cnt(obj);
for(i = 0; i < child_cnt; i++) {
lv_obj_t * child = obj->spec_attr->children[i];
if(lv_obj_has_flag_any(child, LV_OBJ_FLAG_HIDDEN | LV_OBJ_FLAG_FLOATING)) continue;
if(lv_obj_has_flag(child, LV_OBJ_FLAG_SNAPPABLE)) {
lv_coord_t y_child = 0;
lv_coord_t y_parent = 0;
switch(align) {
case LV_SCROLL_SNAP_START:
y_child = child->coords.y1;
y_parent = obj->coords.y1 + pad_top;
break;
case LV_SCROLL_SNAP_END:
y_child = child->coords.y2;
y_parent = obj->coords.y2 - pad_bottom;
break;
case LV_SCROLL_SNAP_CENTER:
y_child = child->coords.y1 + lv_area_get_height(&child->coords) / 2;
y_parent = obj->coords.y1 + pad_top + (lv_area_get_height(&obj->coords) - pad_top - pad_bottom) / 2;
break;
default:
continue;
}
y_child += ofs;
if(y_child >= min && y_child <= max) {
lv_coord_t y = y_child - y_parent;
if(LV_ABS(y) < LV_ABS(dist)) dist = y;
}
}
}
return dist == LV_COORD_MAX ? 0 : -dist;
}
static void scroll_limit_diff(_lv_indev_proc_t * proc, lv_coord_t * diff_x, lv_coord_t * diff_y)
{
if(diff_y) {
if(proc->types.pointer.scroll_sum.y + *diff_y < proc->types.pointer.scroll_area.y1) {
*diff_y = proc->types.pointer.scroll_area.y1 - proc->types.pointer.scroll_sum.y;
}
if(proc->types.pointer.scroll_sum.y + *diff_y > proc->types.pointer.scroll_area.y2) {
*diff_y = proc->types.pointer.scroll_area.y2 - proc->types.pointer.scroll_sum.y;
}
}
if(diff_x) {
if(proc->types.pointer.scroll_sum.x + *diff_x < proc->types.pointer.scroll_area.x1) {
*diff_x = proc->types.pointer.scroll_area.x1 - proc->types.pointer.scroll_sum.x;
}
if(proc->types.pointer.scroll_sum.x + *diff_x > proc->types.pointer.scroll_area.x2) {
*diff_x = proc->types.pointer.scroll_area.x2 - proc->types.pointer.scroll_sum.x;
}
}
}
static lv_coord_t scroll_throw_predict_y(_lv_indev_proc_t * proc)
{
lv_coord_t y = proc->types.pointer.scroll_throw_vect.y;
lv_coord_t move = 0;
lv_indev_t * indev_act = lv_indev_get_act();
lv_coord_t scroll_throw = indev_act->driver->scroll_throw;
while(y) {
move += y;
y = y * (100 - scroll_throw) / 100;
}
return move;
}
static lv_coord_t scroll_throw_predict_x(_lv_indev_proc_t * proc)
{
lv_coord_t x = proc->types.pointer.scroll_throw_vect.x;
lv_coord_t move = 0;
lv_indev_t * indev_act = lv_indev_get_act();
lv_coord_t scroll_throw = indev_act->driver->scroll_throw;
while(x) {
move += x;
x = x * (100 - scroll_throw) / 100;
}
return move;
}
static lv_coord_t elastic_diff(lv_obj_t * scroll_obj, lv_coord_t diff, lv_coord_t scroll_start, lv_coord_t scroll_end,
lv_dir_t dir)
{
if(lv_obj_has_flag(scroll_obj, LV_OBJ_FLAG_SCROLL_ELASTIC)) {
/*If there is snapping in the current direction don't use the elastic factor because
*it's natural that the first and last items are scrolled (snapped) in.*/
lv_scroll_snap_t snap;
snap = dir == LV_DIR_HOR ? lv_obj_get_scroll_snap_x(scroll_obj) : lv_obj_get_scroll_snap_y(scroll_obj);
lv_obj_t * act_obj = lv_indev_get_obj_act();
lv_coord_t snap_point = 0;
lv_coord_t act_obj_point = 0;
if(dir == LV_DIR_HOR) {
lv_coord_t pad_left = lv_obj_get_style_pad_left(scroll_obj, LV_PART_MAIN);
lv_coord_t pad_right = lv_obj_get_style_pad_right(scroll_obj, LV_PART_MAIN);
switch(snap) {
case LV_SCROLL_SNAP_CENTER:
snap_point = pad_left + (lv_area_get_width(&scroll_obj->coords) - pad_left - pad_right) / 2 + scroll_obj->coords.x1;
act_obj_point = lv_area_get_width(&act_obj->coords) / 2 + act_obj->coords.x1;
break;
case LV_SCROLL_SNAP_START:
snap_point = scroll_obj->coords.x1 + pad_left;
act_obj_point = act_obj->coords.x1;
break;
case LV_SCROLL_SNAP_END:
snap_point = scroll_obj->coords.x2 - pad_right;
act_obj_point = act_obj->coords.x2;
break;
}
}
else {
lv_coord_t pad_top = lv_obj_get_style_pad_top(scroll_obj, LV_PART_MAIN);
lv_coord_t pad_bottom = lv_obj_get_style_pad_bottom(scroll_obj, LV_PART_MAIN);
switch(snap) {
case LV_SCROLL_SNAP_CENTER:
snap_point = pad_top + (lv_area_get_height(&scroll_obj->coords) - pad_top - pad_bottom) / 2 + scroll_obj->coords.y1;
act_obj_point = lv_area_get_height(&act_obj->coords) / 2 + act_obj->coords.y1;
break;
case LV_SCROLL_SNAP_START:
snap_point = scroll_obj->coords.y1 + pad_top;
act_obj_point = act_obj->coords.y1;
break;
case LV_SCROLL_SNAP_END:
snap_point = scroll_obj->coords.y2 - pad_bottom;
act_obj_point = act_obj->coords.y2;
break;
}
}
if(scroll_end < 0) {
if(snap != LV_SCROLL_SNAP_NONE && act_obj_point > snap_point) return diff;
/*Rounding*/
if(diff < 0) diff -= ELASTIC_SLOWNESS_FACTOR / 2;
if(diff > 0) diff += ELASTIC_SLOWNESS_FACTOR / 2;
return diff / ELASTIC_SLOWNESS_FACTOR;
}
else if(scroll_start < 0) {
if(snap != LV_SCROLL_SNAP_NONE && act_obj_point < snap_point) return diff;
/*Rounding*/
if(diff < 0) diff -= ELASTIC_SLOWNESS_FACTOR / 2;
if(diff > 0) diff += ELASTIC_SLOWNESS_FACTOR / 2;
return diff / ELASTIC_SLOWNESS_FACTOR;
}
}
else {
/*Scroll back to the boundary if required*/
if(scroll_end + diff < 0) diff = - scroll_end;
if(scroll_start - diff < 0) diff = scroll_start;
}
return diff;
}
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