Implemented Invert Y Axis Flag Feature

src/conky.cc

@@ -1009,15 +1009,17 @@ static inline void draw_graph_bars(special_node *current, std::unique_ptr<Colour
       set_foreground_color(tmpcolour[colour_idx++]);
     }
   }
+  /* Handle the case where y axis is to be inverted */
+  int offsety1 = current->inverty ? by : by + h;
+  int offsety2 = current->inverty ? by +  current->graph[j] * (h - 1) / current->scale
+                          : round_to_positive_int(static_cast<double>(by) + h -
+                          current->graph[j] * (h - 1) /
+                          current->scale);
   /* this is mugfugly, but it works */
   if (display_output()) {
     display_output()->draw_line(
-        text_offset.x() + cur_x + i + 1, text_offset.y() + by + h,
+        text_offset.x() + cur_x + i + 1, text_offset.y() + offsety1,
-        text_offset.x() + cur_x + i + 1,
+        text_offset.x() + cur_x + i + 1, text_offset.y() + offsety2);
-        text_offset.y() +
-            round_to_positive_int(static_cast<double>(by) + h -
-                                  current->graph[j] * (h - 1) /
-                                      current->scale));
   }
   ++j;
 }
@@ -1321,7 +1323,7 @@ int draw_each_line_inner(char *s, int special_index, int last_special_applied) {
               }
               colour_idx = 0;
               if(current->invertx){
-                for (i = 0; i <= w- 2; i++) {
+                for (i = 0; i <= w - 2; i++) {
                   draw_graph_bars(current, tmpcolour, text_offset, 
                   i, j, w, colour_idx, cur_x, by, h);
                 }

src/specials.cc

@@ -85,6 +85,7 @@ conky::simple_config_setting<std::string> console_graph_ticks(
 
 /* special flag for inverting axis */
 #define SF_INVERTX (1 << 0)
+#define SF_INVERTY (1 << 1)
 
 /*
  * Special data typedefs
@@ -250,6 +251,7 @@ std::pair<char *, size_t> scan_command(const char *s) {
  * -l will set the showlog flag, enabling logarithmic graph scales
  * -t will set the tempgrad member to true, enabling temperature gradient colors
  * -x will set the invertx flag to true, inverting the x axis
+ * -y will set the invertx flag to true, inverting the y axis
  *
  * @param[out] obj  struct in which to save width, height and other options
  * @param[in]  args argument string to parse
@@ -298,6 +300,12 @@ bool scan_graph(struct text_object *obj, const char *argstr, double defscale, ch
       strncmp(argstr, INVERTX, strlen(INVERTX)) == 0) {
     g->invertflag |= SF_INVERTX;
   }
+  /* set inverty to true if '-y' specified.
+   * It doesn't matter where the argument is exactly. */
+  if ((strstr(argstr, " " INVERTY) != nullptr) ||
+      strncmp(argstr, INVERTY, strlen(INVERTY)) == 0) {
+    g->invertflag |= SF_INVERTY;
+  }
 
   /* all the following functions try to interpret the beginning of a
    * a string with different format strings. If successful, they return from
@@ -322,9 +330,7 @@ bool scan_graph(struct text_object *obj, const char *argstr, double defscale, ch
    * therfore we ensure last_colour_name is not TEMPGRAD or LOGGRAPH */
   if (sscanf(argstr, "%d,%d %s %s", &g->height, &g->width, first_colour_name,
              last_colour_name) == 4 && 
-             strcmp(last_colour_name, TEMPGRAD) != 0 &&
+             strchr(last_colour_name,'-') == NULL) {
-             strcmp(last_colour_name, LOGGRAPH) != 0 &&
-             strcmp(last_colour_name, INVERTX) != 0) {
     apply_graph_colours(g, first_colour_name, last_colour_name);
     return true;
   }
@@ -365,9 +371,7 @@ bool scan_graph(struct text_object *obj, const char *argstr, double defscale, ch
    * This could match as [scale] [-l | -t], 
    * therfore we ensure last_colour_name is not TEMPGRAD or LOGGRAPH */
   if (sscanf(argstr, "%s %s", first_colour_name, last_colour_name) == 2 &&
-             strcmp(last_colour_name, TEMPGRAD) != 0 &&
+             strchr(last_colour_name,'-') == NULL) { 
-             strcmp(last_colour_name, LOGGRAPH) != 0 &&
-             strcmp(last_colour_name, INVERTX) != 0) { 
     apply_graph_colours(g, first_colour_name, last_colour_name);
     return true;
   }
@@ -647,6 +651,9 @@ void new_graph(struct text_object *obj, char *buf, int buf_max_size,
   if ((g->invertflag & SF_INVERTX) != 0){
     s->invertx = 1;
   }
+  if ((g->invertflag & SF_INVERTY) != 0){
+    s->inverty = 1;
+  }
   if (g->speedgraph) {
     s->speedgraph = TRUE;
   }

src/specials.h

@@ -40,6 +40,7 @@
 #define LOGGRAPH "-l"
 #define TEMPGRAD "-t"
 #define INVERTX "-x"
+#define INVERTY "-y"
 
 enum class text_node_t : uint32_t {
   NONSPECIAL = 0,
@@ -83,6 +84,7 @@ struct special_node {
   char tempgrad;
   char speedgraph;
   char invertx;
+  char inverty;
   struct special_node *next;
 };