diff -r 000000000000 -r 88d965579617 components/u8g2/csrc/u8g2_polygon.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/components/u8g2/csrc/u8g2_polygon.c	Tue Oct 08 12:00:31 2019 +0200
@@ -0,0 +1,346 @@
+/*
+
+  u8g22_polygon.c
+
+*/	
+
+
+#include "u8g2.h"
+
+
+
+
+/*===========================================*/
+/* local definitions */
+
+typedef int16_t pg_word_t;
+
+
+struct pg_point_struct
+{
+  pg_word_t x;
+  pg_word_t y;
+};
+
+typedef struct _pg_struct pg_struct;	/* forward declaration */
+
+struct pg_edge_struct
+{
+  pg_word_t x_direction;	/* 1, if x2 is greater than x1, -1 otherwise */
+  pg_word_t height;
+  pg_word_t current_x_offset;
+  pg_word_t error_offset;
+  
+  /* --- line loop --- */
+  pg_word_t current_y;
+  pg_word_t max_y;
+  pg_word_t current_x;
+  pg_word_t error;
+
+  /* --- outer loop --- */
+  uint8_t (*next_idx_fn)(pg_struct *pg, uint8_t i);
+  uint8_t curr_idx;
+};
+
+/* maximum number of points in the polygon */
+/* can be redefined, but highest possible value is 254 */
+#define PG_MAX_POINTS 6
+
+/* index numbers for the pge structures below */
+#define PG_LEFT 0
+#define PG_RIGHT 1
+
+
+struct _pg_struct
+{
+  struct pg_point_struct list[PG_MAX_POINTS];
+  uint8_t cnt;
+  uint8_t is_min_y_not_flat;
+  pg_word_t total_scan_line_cnt;
+  struct pg_edge_struct pge[2];	/* left and right line draw structures */
+};
+
+
+/*===========================================*/
+/* procedures, which should not be inlined (save as much flash ROM as possible */
+
+#define PG_NOINLINE U8G2_NOINLINE
+
+static uint8_t pge_Next(struct pg_edge_struct *pge) PG_NOINLINE;
+static uint8_t pg_inc(pg_struct *pg, uint8_t i) PG_NOINLINE;
+static uint8_t pg_dec(pg_struct *pg, uint8_t i) PG_NOINLINE;
+static void pg_expand_min_y(pg_struct *pg, pg_word_t min_y, uint8_t pge_idx) PG_NOINLINE;
+static void pg_line_init(pg_struct * const pg, uint8_t pge_index) PG_NOINLINE;
+
+/*===========================================*/
+/* line draw algorithm */
+
+static uint8_t pge_Next(struct pg_edge_struct *pge)
+{
+  if ( pge->current_y >= pge->max_y )
+    return 0;
+  
+  pge->current_x += pge->current_x_offset;
+  pge->error += pge->error_offset;
+  if ( pge->error > 0 )
+  {
+    pge->current_x += pge->x_direction;
+    pge->error -= pge->height;
+  }  
+  
+  pge->current_y++;
+  return 1;
+}
+
+/* assumes y2 > y1 */
+static void pge_Init(struct pg_edge_struct *pge, pg_word_t x1, pg_word_t y1, pg_word_t x2, pg_word_t y2)
+{
+  pg_word_t dx = x2 - x1;
+  pg_word_t width;
+
+  pge->height = y2 - y1;
+  pge->max_y = y2;
+  pge->current_y = y1;
+  pge->current_x = x1;
+
+  if ( dx >= 0 )
+  {
+    pge->x_direction = 1;
+    width = dx;
+    pge->error = 0;
+  }
+  else
+  {
+    pge->x_direction = -1;
+    width = -dx;
+    pge->error = 1 - pge->height;
+  }
+  
+  pge->current_x_offset = dx / pge->height;
+  pge->error_offset = width % pge->height;
+}
+
+/*===========================================*/
+/* convex polygon algorithm */
+
+static uint8_t pg_inc(pg_struct *pg, uint8_t i)
+{
+    i++;
+    if ( i >= pg->cnt )
+      i = 0;
+    return i;
+}
+
+static uint8_t pg_dec(pg_struct *pg, uint8_t i)
+{
+    i--;
+    if ( i >= pg->cnt )
+      i = pg->cnt-1;
+    return i;
+}
+
+static void pg_expand_min_y(pg_struct *pg, pg_word_t min_y, uint8_t pge_idx)
+{
+  uint8_t i = pg->pge[pge_idx].curr_idx;
+  for(;;)
+  {
+    i = pg->pge[pge_idx].next_idx_fn(pg, i);
+    if ( pg->list[i].y != min_y )
+      break;	
+    pg->pge[pge_idx].curr_idx = i;
+  }
+}
+
+static uint8_t pg_prepare(pg_struct *pg)
+{
+  pg_word_t max_y;
+  pg_word_t min_y;
+  uint8_t i;
+
+  /* setup the next index procedures */
+  pg->pge[PG_RIGHT].next_idx_fn = pg_inc;
+  pg->pge[PG_LEFT].next_idx_fn = pg_dec;
+  
+  /* search for highest and lowest point */
+  max_y = pg->list[0].y;
+  min_y = pg->list[0].y;
+  pg->pge[PG_LEFT].curr_idx = 0;
+  for( i = 1; i < pg->cnt; i++ )
+  {
+    if ( max_y < pg->list[i].y )
+    {
+      max_y = pg->list[i].y;
+    }
+    if ( min_y > pg->list[i].y )
+    {
+      pg->pge[PG_LEFT].curr_idx = i;
+      min_y = pg->list[i].y;
+    }
+  }
+
+  /* calculate total number of scan lines */
+  pg->total_scan_line_cnt = max_y;
+  pg->total_scan_line_cnt -= min_y;
+  
+  /* exit if polygon height is zero */
+  if ( pg->total_scan_line_cnt == 0 )
+    return 0;
+  
+  /* if the minimum y side is flat, try to find the lowest and highest x points */
+  pg->pge[PG_RIGHT].curr_idx = pg->pge[PG_LEFT].curr_idx;  
+  pg_expand_min_y(pg, min_y, PG_RIGHT);
+  pg_expand_min_y(pg, min_y, PG_LEFT);
+  
+  /* check if the min side is really flat (depends on the x values) */
+  pg->is_min_y_not_flat = 1;
+  if ( pg->list[pg->pge[PG_LEFT].curr_idx].x != pg->list[pg->pge[PG_RIGHT].curr_idx].x )
+  {
+    pg->is_min_y_not_flat = 0;
+  }
+  else
+  {
+    pg->total_scan_line_cnt--;
+    if ( pg->total_scan_line_cnt == 0 )
+      return 0;
+  }
+
+  return 1;
+}
+
+static void pg_hline(pg_struct *pg, u8g2_t *u8g2)
+{
+  pg_word_t x1, x2, y;
+  x1 = pg->pge[PG_LEFT].current_x;
+  x2 = pg->pge[PG_RIGHT].current_x;
+  y = pg->pge[PG_RIGHT].current_y;
+  
+  if ( y < 0 )
+    return;
+  if ( y >= u8g2_GetDisplayHeight(u8g2) )  // does not work for 256x64 display???
+    return;
+  if ( x1 < x2 )
+  {
+    if ( x2 < 0 )
+      return;
+    if ( x1 >= u8g2_GetDisplayWidth(u8g2) )
+      return;
+    if ( x1 < 0 )
+      x1 = 0;
+    if ( x2 >= u8g2_GetDisplayWidth(u8g2) )
+      x2 = u8g2_GetDisplayWidth(u8g2);
+    u8g2_DrawHLine(u8g2, x1, y, x2 - x1);
+  }
+  else
+  {
+    if ( x1 < 0 )
+      return;
+    if ( x2 >= u8g2_GetDisplayWidth(u8g2) )
+      return;
+    if ( x2 < 0 )
+      x1 = 0;
+    if ( x1 >= u8g2_GetDisplayWidth(u8g2) )
+      x1 = u8g2_GetDisplayWidth(u8g2);
+    u8g2_DrawHLine(u8g2, x2, y, x1 - x2);
+  }
+}
+
+static void pg_line_init(pg_struct * const pg, uint8_t pge_index)
+{
+  struct pg_edge_struct  *pge = pg->pge+pge_index;
+  uint8_t idx;  
+  pg_word_t x1;
+  pg_word_t y1;
+  pg_word_t x2;
+  pg_word_t y2;
+
+  idx = pge->curr_idx;  
+  y1 = pg->list[idx].y;
+  x1 = pg->list[idx].x;
+  idx = pge->next_idx_fn(pg, idx);
+  y2 = pg->list[idx].y;
+  x2 = pg->list[idx].x; 
+  pge->curr_idx = idx;
+  
+  pge_Init(pge, x1, y1, x2, y2);
+}
+
+static void pg_exec(pg_struct *pg, u8g2_t *u8g2)
+{
+  pg_word_t i = pg->total_scan_line_cnt;
+
+  /* first line is skipped if the min y line is not flat */
+  pg_line_init(pg, PG_LEFT);		
+  pg_line_init(pg, PG_RIGHT);
+  
+  if ( pg->is_min_y_not_flat != 0 )
+  {
+    pge_Next(&(pg->pge[PG_LEFT])); 
+    pge_Next(&(pg->pge[PG_RIGHT]));
+  }
+
+  do
+  {
+    pg_hline(pg, u8g2);
+    while ( pge_Next(&(pg->pge[PG_LEFT])) == 0 )
+    {
+      pg_line_init(pg, PG_LEFT);
+    }
+    while ( pge_Next(&(pg->pge[PG_RIGHT])) == 0 )
+    {
+      pg_line_init(pg, PG_RIGHT);
+    }
+    i--;
+  } while( i > 0 );
+}
+
+/*===========================================*/
+/* API procedures */
+
+static void pg_ClearPolygonXY(pg_struct *pg)
+{
+  pg->cnt = 0;
+}
+
+static void pg_AddPolygonXY(pg_struct *pg, int16_t x, int16_t y)
+{
+  if ( pg->cnt < PG_MAX_POINTS )
+  {
+    pg->list[pg->cnt].x = x;
+    pg->list[pg->cnt].y = y;
+    pg->cnt++;
+  }
+}
+
+static void pg_DrawPolygon(pg_struct *pg, u8g2_t *u8g2)
+{
+  if ( pg_prepare(pg) == 0 )
+    return;
+  pg_exec(pg, u8g2);
+}
+
+pg_struct u8g2_pg;
+
+void u8g2_ClearPolygonXY(void)
+{
+  pg_ClearPolygonXY(&u8g2_pg);
+}
+
+void u8g2_AddPolygonXY(U8X8_UNUSED u8g2_t *u8g2, int16_t x, int16_t y)
+{
+  pg_AddPolygonXY(&u8g2_pg, x, y);
+}
+
+void u8g2_DrawPolygon(u8g2_t *u8g2)
+{
+  pg_DrawPolygon(&u8g2_pg, u8g2);
+}
+
+void u8g2_DrawTriangle(u8g2_t *u8g2, int16_t x0, int16_t y0, int16_t x1, int16_t y1, int16_t x2, int16_t y2)
+{
+  u8g2_ClearPolygonXY();
+  u8g2_AddPolygonXY(u8g2, x0, y0);
+  u8g2_AddPolygonXY(u8g2, x1, y1);
+  u8g2_AddPolygonXY(u8g2, x2, y2);
+  u8g2_DrawPolygon(u8g2);
+}
+