github-code/lvgl
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

bidi: add bracket algorithm

Browse Source
This commit is contained in:
Gabor Kiss-Vamosi
2019-10-25 06:15:11 +02:00
parent f02d52a598
commit 57a8ee8e32
1 changed files with 104 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

110
src/lv_misc/lv_bidi.c
View File

@@ -15,10 +15,16 @@
/*********************
* DEFINES
*********************/
#define LV_BIDI_BRACKLET_DEPTH 4
/**********************
* TYPEDEFS
**********************/
typedef struct
{
uint32_t bracklet_pos;
lv_bidi_dir_t dir;
}bracket_stack_t;
/**********************
* STATIC PROTOTYPES
@@ -28,10 +34,15 @@ static uint32_t get_next_paragraph(const char * txt);
static lv_bidi_dir_t get_next_run(const char * txt, lv_bidi_dir_t base_dir, uint32_t * len);
static void rtl_reverse(char * dest, const char * src, uint32_t len);
static uint32_t char_change_to_pair(uint32_t letter);
static lv_bidi_dir_t bracket_process(const uint8_t * txt, uint32_t next_pos, uint32_t len, uint32_t letter, lv_bidi_dir_t base_dir);
/**********************
* STATIC VARIABLES
**********************/
static const uint8_t bracket_left[] = {"<({["};
static const uint8_t bracket_right[] = {">)}]"};
static bracket_stack_t br_stack[LV_BIDI_BRACKLET_DEPTH];
static uint8_t br_stack_p;
/**********************
* MACROS
@@ -43,6 +54,7 @@ static uint32_t char_change_to_pair(uint32_t letter);
void lv_bidi_process(const char * str_in, char * str_out, lv_bidi_dir_t base_dir)
{
br_stack_p = 0;
if(base_dir == LV_BIDI_DIR_AUTO) base_dir = lv_bidi_detect_base_dir(str_in);
@@ -151,6 +163,8 @@ static void process_paragraph(const char * str_in, char * str_out, uint32_t len,
while(rd < len) {
uint32_t letter = lv_txt_encoded_next(str_in, &rd);
dir = lv_bidi_get_letter_dir(letter);
if(dir == LV_BIDI_DIR_NEUTRAL) dir = bracket_process(str_in, rd, len, letter, base_dir);
if(dir != LV_BIDI_DIR_NEUTRAL && dir != LV_BIDI_DIR_WEAK) break;
}
@@ -204,11 +218,15 @@ static lv_bidi_dir_t get_next_run(const char * txt, lv_bidi_dir_t base_dir, uint
letter = lv_txt_encoded_next(txt, NULL);
lv_bidi_dir_t dir = lv_bidi_get_letter_dir(letter);
if(dir == LV_BIDI_DIR_NEUTRAL) dir = bracket_process(txt, 0, len, letter, base_dir);
/*Find the first strong char. Skip the neutrals*/
while(dir == LV_BIDI_DIR_NEUTRAL || dir == LV_BIDI_DIR_WEAK) {
letter = lv_txt_encoded_next(txt, &i);
dir = lv_bidi_get_letter_dir(letter);
if(dir == LV_BIDI_DIR_NEUTRAL) dir = bracket_process(txt, i, len, letter, base_dir);
if(txt[i] == '\0' || txt[i] == '\n' || txt[i] == '\r') {
*len = i;
return base_dir;
@@ -225,6 +243,7 @@ static lv_bidi_dir_t get_next_run(const char * txt, lv_bidi_dir_t base_dir, uint
while(txt[i] != '\0'&& txt[i] != '\n' && txt[i] != '\r') {
letter = lv_txt_encoded_next(txt, &i);
next_dir = lv_bidi_get_letter_dir(letter);
if(dir == LV_BIDI_DIR_NEUTRAL) dir = bracket_process(txt, i, len, letter, base_dir);
/*New dir found?*/
if((next_dir == LV_BIDI_DIR_RTL || next_dir == LV_BIDI_DIR_LTR) && next_dir != run_dir) {
@@ -303,19 +322,98 @@ static void rtl_reverse(char * dest, const char * src, uint32_t len)
static uint32_t char_change_to_pair(uint32_t letter)
{
static uint8_t left[] = {"<({["};
static uint8_t right[] = {">)}]"};
uint8_t i;
for(i = 0; left[i] != '\0'; i++) {
if(letter == left[i]) return right[i];
for(i = 0; bracket_left[i] != '\0'; i++) {
if(letter == bracket_left[i]) return bracket_right[i];
}
for(i = 0; right[i] != '\0'; i++) {
if(letter == right[i]) return left[i];
for(i = 0; bracket_right[i] != '\0'; i++) {
if(letter == bracket_right[i]) return bracket_left[i];
}
return letter;
}
static lv_bidi_dir_t bracket_process(const uint8_t * txt, uint32_t next_pos, uint32_t len, uint32_t letter, lv_bidi_dir_t base_dir)
{
if(br_stack_p >= LV_BIDI_BRACKLET_DEPTH) return LV_BIDI_DIR_NEUTRAL;
lv_bidi_dir_t bracket_dir = LV_BIDI_DIR_NEUTRAL;
uint8_t i;
/*Is the letter an opening bracket?*/
for(i = 0; bracket_left[i] != '\0'; i++) {
if(bracket_left[i] == letter) {
/* If so find it's matching closing bracket.
* If a char with base dir. direction is found then the brackets will have `base_dir` direction*/
uint32_t txt_i = next_pos;
while(txt_i < len) {
uint32_t letter_next = lv_txt_encoded_next(txt, &txt_i);
if(letter_next == bracket_right[i]) {
/*Closing bracket found*/
break;
} else {
/*Save the dir*/
lv_bidi_dir_t letter_dir = lv_bidi_get_letter_dir(letter);
if(letter_dir == base_dir) {
bracket_dir = base_dir;
}
}
}
/*There were no matching closing bracket*/
if(txt_i >= len) return LV_BIDI_DIR_NEUTRAL;
/*There where a strong char with base dir in the bracket so the dir is found.*/
if(bracket_dir != LV_BIDI_DIR_NEUTRAL) break;
/*If there were no matching strong chars in the brackets then check the previous chars*/
txt_i = next_pos;
if(txt_i) lv_txt_encoded_prev(txt, &txt_i);
if(txt_i) lv_txt_encoded_prev(txt, &txt_i);
while(txt_i > 0) {
uint32_t letter_next = lv_txt_encoded_prev(txt, &txt_i);
lv_bidi_dir_t letter_dir = lv_bidi_get_letter_dir(letter);
if(letter_dir == LV_BIDI_DIR_LTR || letter_dir == LV_BIDI_DIR_RTL) {
bracket_dir = letter_dir;
break;
}
}
/*There where a previous strong char which can be used*/
if(bracket_dir != LV_BIDI_DIR_NEUTRAL) break;
/*There were no strong chars before the bracket, so use the base dir.*/
if(txt_i == 0) bracket_dir = base_dir;
break;
}
}
/*The letter was an opening bracket*/
if(bracket_left[i] != '\0') {
if(bracket_dir == LV_BIDI_DIR_NEUTRAL) break;
br_stack[br_stack_p].bracklet_pos = i;
br_stack[br_stack_p].dir = bracket_dir;
br_stack_p++;
return bracket_dir;
} else {
/*Is the letter a closing bracket of the last opening?*/
if(letter == bracket_right[br_stack[br_stack_p].bracklet_pos]) {
bracket_dir = br_stack[br_stack_p].dir;
br_stack_p--;
return bracket_dir;
}
}
return LV_BIDI_DIR_NEUTRAL;
}
#endif /*LV_USE_BIDI*/