diff --git a/.gitignore b/.gitignore
index 993160c76..6ed07ffb9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,24 +1,29 @@
 .*
-!.gitignore
 !.git-blame-ignore-rev
 !.githooks
-build/
-dist/
-*.o
+!.gitignore
 *.a
-*.so
-*.so.dSYM
-*.dylib
 *.app
+*.dylib
+*.o
 *.pc
+*.pkg
+*.so
+*.so.dSYM
+Makedefs
+QMakefile
+build/
+cmake-build-*/
+demo
+dist/
+gksm
 gr*.deb
 gr*.rpm
-cmake-build-*/
-moc_*.h
+gr_version.h
+js/fonts/
+js/gr.js
+js/libGR.js
+lib/gks/qt/gksqt
 moc_*.cpp
+moc_*.h
 qrc_*.cpp
-QMakefile
-gr_version.h
-Makedefs
-demo
-gksm
diff --git a/js/jsterm.js b/js/jsterm.js
index 20da6d196..fb42ca7ea 100644
--- a/js/jsterm.js
+++ b/js/jsterm.js
@@ -82,10 +82,14 @@ JSTerm = function(ispluto=false) {
 
     var jsterm_ispluto = ispluto;
 
+    var dpr = window.devicePixelRatio || 1;
+
     window.addEventListener('resize', function() {
       // redraw plots if window zoom changed
-      if (window.devicePixelRatio != Module.dpr) {
-        for (pid in widgets) {
+      let _dpr = window.devicePixelRatio || 1;
+      if (_dpr != dpr) {
+        dpr = _dpr;
+        for (let pid in widgets) {
           if (typeof(widgets[pid].canvas) !== 'undefined' && document.body.contains(widgets[pid].canvas)) {
             widgets[pid].draw();
           }
@@ -178,13 +182,17 @@ JSTerm = function(ispluto=false) {
         let overlay = document.createElement('canvas');
         overlay.id = 'jsterm-overlay-' + widget.id;
         overlay.style = 'position:absolute; top: 0; right: 0; z-index: 2;';
-        overlay.width = widget.width;
-        overlay.height = widget.height;
+        overlay.style.width = widget.width + "px";
+        overlay.style.height = widget.height + "px";
+        overlay.width = parseInt(widget.width * dpr, 10);
+        overlay.height = parseInt(widget.height * dpr, 10);
+        overlay.getContext('2d').setTransform(dpr, 0, 0, dpr, 0, 0);
+
         let canvas = document.createElement('canvas');
         canvas.id = 'jsterm-' + widget.id;
         canvas.style = 'position: absolute; top: 0; right: 0; z-index: 0';
-        canvas.width = widget.width;
-        canvas.height = widget.height;
+        canvas.style.width = widget.width + "px";
+        canvas.style.height = widget.height + "px";
         div.appendChild(overlay);
         div.appendChild(canvas);
         disp.appendChild(div);
@@ -421,10 +429,13 @@ JSTerm = function(ispluto=false) {
           this.width = width;
           this.height = height;
           if (this.canvas !== undefined) {
-            this.canvas.width = width;
-            this.canvas.height = height;
-            this.overlayCanvas.width = width;
-            this.overlayCanvas.height = height;
+            this.canvas.style.width = width + "px";
+            this.canvas.style.height = height + "px";
+            this.overlayCanvas.style.width = width + "px";
+            this.overlayCanvas.style.height = height + "px";
+            this.overlayCanvas.width = parseInt(width * dpr, 10);
+            this.overlayCanvas.height = parseInt(height * dpr, 10);
+            this.overlayCanvas.getContext('2d').setTransform(dpr, 0, 0, dpr, 0, 0);
             this.div.style = "position: relative; width: " + width + "px; height: " + height + "px;";
           }
           this.draw();
@@ -1116,8 +1127,8 @@ JSTerm = function(ispluto=false) {
         if (typeof grm === 'undefined') {
           let canvas = document.createElement('canvas');
           canvas.id = 'jsterm-hidden-canvas';
-          canvas.width = 640;
-          canvas.height = 480;
+          canvas.style.width = '640px';
+          canvas.style.height = '480px';
           canvas.style = 'display: none;';
           document.body.appendChild(canvas);
           grm = new GRM('jsterm-hidden-canvas');
diff --git a/js/module.js b/js/module.js
index 602b345b5..8d967a4a3 100644
--- a/js/module.js
+++ b/js/module.js
@@ -35,22 +35,14 @@ var Module = {
         }
     },
     set_dpr: function() {
-      var _dpr = window.devicePixelRatio || 1
+      var _dpr = window.devicePixelRatio || 1;
       if (!(this.canvas.id in this.dpr_per_canvas)) {
-        this.dpr_per_canvas[this.canvas.id] = 1;
-      }
-      if (this.dpr_per_canvas[this.canvas.id] != _dpr) {
-        var initial_width = this.canvas.width / this.dpr_per_canvas[this.canvas.id];
-        var initial_height = this.canvas.height / this.dpr_per_canvas[this.canvas.id];
-
-        this.canvas.style.width = initial_width + 'px';
-        this.canvas.style.height = initial_height + 'px';
-        this.canvas.width = parseInt(initial_width * _dpr, 10);
-        this.canvas.height = parseInt(initial_height * _dpr, 10);
-
-        this.context.setTransform(_dpr, 0, 0, _dpr, 0, 0);
         this.dpr_per_canvas[this.canvas.id] = _dpr;
       }
+      this.canvas.width = parseInt(this.canvas.clientWidth * _dpr, 10);
+      this.canvas.height = parseInt(this.canvas.clientHeight * _dpr, 10);
+      this.context.setTransform(_dpr, 0, 0, _dpr, 0, 0);
+      this.dpr_per_canvas[this.canvas.id] = _dpr;
       if (this.dpr != this.dpr_per_canvas[this.canvas.id]) {
         this.dpr = this.dpr_per_canvas[this.canvas.id];
       }
diff --git a/lib/gks/gks.c b/lib/gks/gks.c
index 5173d2f34..0069698ab 100644
--- a/lib/gks/gks.c
+++ b/lib/gks/gks.c
@@ -1183,6 +1183,7 @@ void gks_text(double px, double py, char *str)
                   gks_input2utf8(str, utf8_str, ENCODING_LATIN1);
 
                   gks_ft_text(px, py, utf8_str, s, gks_ft_gdp);
+                  gks_free(utf8_str);
                 }
               else
                 gks_ft_text(px, py, str, s, gks_ft_gdp);
@@ -2933,6 +2934,7 @@ void gks_inq_text_extent(int wkid, double px, double py, char *str, int *errind,
               gks_input2utf8(str, utf8_str, ENCODING_LATIN1);
 
               gks_ft_inq_text_extent(px, py, utf8_str, s, gks_ft_gdp, bx, by);
+              gks_free(utf8_str);
             }
           else
             gks_ft_inq_text_extent(px, py, str, s, gks_ft_gdp, bx, by);
diff --git a/lib/gks/quartz/GKSView.m b/lib/gks/quartz/GKSView.m
index 934b811a2..68e69067d 100644
--- a/lib/gks/quartz/GKSView.m
+++ b/lib/gks/quartz/GKSView.m
@@ -829,7 +829,7 @@ - (IBAction)saveDocumentAs:(id)sender
                       [self savePanelDidEnd:savePanel returnCode:result contextInfo:saveFormatPopUp];
                     }];
 #else
-  [savePanel beginSheetModalForWindow:cWindow
+  [savePanel beginSheetModalForWindow:[self window]
                     completionHandler:^(NSInteger result) {
                       [self savePanelDidEnd:savePanel returnCode:result contextInfo:saveFormatPopUp];
                     }];
diff --git a/lib/gks/socket.c b/lib/gks/socket.c
index 737575e93..8812034a6 100644
--- a/lib/gks/socket.c
+++ b/lib/gks/socket.c
@@ -15,8 +15,9 @@
 #include <netinet/in.h>
 #include <netdb.h>
 #include <sys/time.h>
-#include <unistd.h>
 #include <pthread.h>
+#include <unistd.h>
+#include <signal.h>
 #else
 #include <windows.h>
 #endif
@@ -93,9 +94,54 @@ static DWORD WINAPI gksqt_tread(LPVOID parm)
 
 static void *gksqt_tread(void *arg)
 {
+#ifdef __APPLE__
+  sigset_t blockMask, origMask;
+  struct sigaction saIgnore, saOrigQuit, saOrigInt, saDefault;
+  pid_t pid;
+
+  sigemptyset(&blockMask);
+  sigaddset(&blockMask, SIGCHLD);
+  sigprocmask(SIG_BLOCK, &blockMask, &origMask);
+
+  saIgnore.sa_handler = SIG_IGN;
+  saIgnore.sa_flags = 0;
+  sigemptyset(&saIgnore.sa_mask);
+  sigaction(SIGINT, &saIgnore, &saOrigInt);
+  sigaction(SIGQUIT, &saIgnore, &saOrigQuit);
+
+  pid = fork();
+  if (pid < 0)
+    {
+      fprintf(stderr, "Fork failed\n");
+      return -1;
+    }
+  else if (pid == 0)
+    {
+      saDefault.sa_handler = SIG_DFL;
+      saDefault.sa_flags = 0;
+      sigemptyset(&saDefault.sa_mask);
+
+      if (saOrigInt.sa_handler != SIG_IGN) sigaction(SIGINT, &saDefault, NULL);
+      if (saOrigQuit.sa_handler != SIG_IGN) sigaction(SIGQUIT, &saDefault, NULL);
+
+      sigprocmask(SIG_SETMASK, &origMask, NULL);
+
+      is_running = 1;
+      execl("/bin/sh", "sh", "-c", (char *)arg, (char *)NULL);
+      is_running = 0;
+
+      exit(127);
+    }
+
+  sigprocmask(SIG_SETMASK, &origMask, NULL);
+  sigaction(SIGINT, &saOrigInt, NULL);
+  sigaction(SIGQUIT, &saOrigQuit, NULL);
+#else
   is_running = 1;
   system((char *)arg);
   is_running = 0;
+#endif
+
   return NULL;
 }
 
diff --git a/lib/gr/gr.c b/lib/gr/gr.c
index 6da063e01..a9bb3c0d4 100644
--- a/lib/gr/gr.c
+++ b/lib/gr/gr.c
@@ -202,6 +202,18 @@ typedef struct
   char *candidate[3];
 } font_alias_t;
 
+typedef struct text_node
+{
+  struct text_node *next;
+  double x, y;
+  char *string;
+  int line_number;
+  double line_width;
+  int math;
+  double width, height;
+  double baseline[2];
+} text_node_t;
+
 static volume_t vt = {1, 0, 1.25, 1000, 1000, NULL, 1};
 
 static norm_xform nx = {1, 0, 1, 0};
@@ -244,6 +256,8 @@ static double arrow_size = 1;
 
 static int flag_printing = 0, flag_graphics = 0;
 
+static text_node_t *text, *head;
+
 #define DEFAULT_FIRST_COLOR 8
 #define DEFAULT_LAST_COLOR 79
 
@@ -1806,186 +1820,6 @@ void gr_polymarker(int n, double *x, double *y)
   if (flag_graphics) primitive("polymarker", n, x, y);
 }
 
-/*!
- * Draw a text at position `x`, `y` using the current text attributes.
- *
- * \param[in] x The X coordinate of the starting position of the text string
- * \param[in] y The Y coordinate of the starting position of the text string
- * \param[in] string The text to be drawn
- *
- * The values for `x` and `y` are in normalized device coordinates.
- * The attributes that control the appearance of text are text font and
- * precision, character expansion factor, character spacing, text color index,
- * character height, character up vector, text path and text alignment.
- */
-void gr_text(double x, double y, char *string)
-{
-  int errind, tnr, halign, valign, n;
-  char *s, *t;
-  double ux, uy, angle, height;
-  double rx, ry, sx, sy;
-
-  check_autoinit;
-
-  gks_inq_current_xformno(&errind, &tnr);
-  if (tnr != NDC) gks_select_xform(NDC);
-
-  if (strchr(string, '\n') != NULL)
-    {
-      gks_inq_text_align(&errind, &halign, &valign);
-      gks_inq_text_upvec(&errind, &ux, &uy);
-      angle = -atan2(ux, uy);
-      gks_inq_text_height(&errind, &height);
-      height *= 1.5;
-
-      n = 0;
-      s = string;
-      while (*s)
-        if (*s++ == '\n') n++;
-
-      rx = x;
-      ry = y;
-      switch (valign)
-        {
-        case 3:
-          rx = x - sin(angle) * 0.5 * n * height;
-          ry = y + cos(angle) * 0.5 * n * height;
-          break;
-        case 4:
-        case 5:
-          rx = x - sin(angle) * n * height;
-          ry = y + cos(angle) * n * height;
-          break;
-        }
-
-      t = gks_strdup(string);
-      n = 0;
-      s = strtok(t, "\n");
-      while (s != NULL)
-        {
-          sx = rx + sin(angle) * n * height;
-          sy = ry - cos(angle) * n * height;
-          gks_text(sx, sy, s);
-          s = strtok(NULL, "\n");
-          n++;
-        }
-      free(t);
-    }
-  else
-    gks_text(x, y, string);
-
-  if (tnr != NDC) gks_select_xform(tnr);
-
-  if (flag_graphics) gr_writestream("<text x=\"%g\" y=\"%g\" text=\"%s\"/>\n", x, y, string);
-}
-
-void gr_inqtext(double x, double y, char *string, double *tbx, double *tby)
-{
-  int errind, tnr, halign, valign;
-  char *s, *t;
-  double ux, uy, angle, width = 0.0, height, chh;
-  int i;
-  int n, wkid = 0;
-  double rx, ry, xx, yy, cpx, cpy;
-
-  check_autoinit;
-
-  gks_inq_current_xformno(&errind, &tnr);
-  if (tnr != NDC) gks_select_xform(NDC);
-
-  gks_inq_open_ws(1, &errind, &n, &wkid);
-
-  if (strchr(string, '\n') != NULL)
-    {
-      gks_inq_text_align(&errind, &halign, &valign);
-      gks_inq_text_upvec(&errind, &ux, &uy);
-
-      gks_set_text_upvec(0.0, 1.0);
-
-      t = gks_strdup(string);
-      n = 0;
-      s = strtok(t, "\n");
-      while (s != NULL)
-        {
-          gks_inq_text_extent(wkid, x, y, s, &errind, &cpx, &cpy, tbx, tby);
-          s = strtok(NULL, "\n");
-          width = max(tbx[1] - tbx[0], width);
-          n++;
-        }
-      free(t);
-
-      gks_set_text_upvec(ux, uy);
-
-      angle = -atan2(ux, uy);
-      gks_inq_text_height(&errind, &chh);
-      height = chh * n * 1.5;
-
-      rx = x;
-      switch (halign)
-        {
-        case 2:
-          rx -= 0.5 * width;
-          break;
-        case 3:
-          rx -= width;
-          break;
-        }
-      ry = y;
-      switch (valign)
-        {
-        case 1:
-          ry -= height - chh * 0.04;
-          break;
-        case 2:
-          ry -= height;
-          break;
-        case 3:
-          ry -= 0.5 * height;
-          break;
-        case 5:
-          ry -= chh * 0.04;
-          break;
-        }
-      tbx[0] = rx;
-      tbx[1] = rx + width;
-      tbx[2] = tbx[1];
-      tbx[3] = tbx[0];
-      tby[0] = ry;
-      tby[1] = tby[0];
-      tby[2] = ry + height;
-      tby[3] = tby[2];
-
-      for (i = 0; i < 4; i++)
-        {
-          xx = tbx[i] - x;
-          yy = tby[i] - y;
-          tbx[i] = x + cos(angle) * xx - sin(angle) * yy;
-          tby[i] = y + sin(angle) * xx + cos(angle) * yy;
-        }
-
-      cpx = tbx[1];
-      cpy = tby[1];
-    }
-  else
-    gks_inq_text_extent(wkid, x, y, string, &errind, &cpx, &cpy, tbx, tby);
-
-  if (tnr != NDC)
-    {
-      gks_select_xform(tnr);
-
-      for (i = 0; i < 4; i++)
-        {
-          tbx[i] = (tbx[i] - nx.b) / nx.a;
-          tby[i] = (tby[i] - nx.d) / nx.c;
-          if (lx.scale_options)
-            {
-              tbx[i] = x_log(tbx[i]);
-              tby[i] = y_log(tby[i]);
-            }
-        }
-    }
-}
-
 /*!
  * Allows you to specify a polygonal shape of an area to be filled.
  *
@@ -2911,8 +2745,8 @@ void gr_gridit(int nd, double *xd, double *yd, double *zd, int nx, int ny, doubl
   /* CALL THE SMOOTH SURFACE FIT ROUTINE */
   md = 1;
   ncp = 4;
-  iwk = (int *)calloc(31 * nd + nx * ny, sizeof(int));
-  wk = (double *)calloc(6 * (nd + 1), sizeof(double));
+  iwk = (int *)xcalloc(31 * nd + nx * ny, sizeof(int));
+  wk = (double *)xcalloc(6 * (nd + 1), sizeof(double));
 
   idsfft(&md, &ncp, &nd, xd, yd, zd, &nx, &ny, x, y, z, iwk, wk);
 
@@ -8920,10 +8754,10 @@ int gr_hexbin(int n, double *x, double *y, int nbins)
   ycorr = (vymax - vymin) - ((imax - 2) * 1.5 * R + (imax % 2) * R);
   ycorr = ycorr / 2;
 
-  cell = (int *)calloc(lmax + 1, sizeof(int));
-  cnt = (int *)calloc(lmax + 1, sizeof(int));
-  xcm = (double *)calloc(lmax + 1, sizeof(double));
-  ycm = (double *)calloc(lmax + 1, sizeof(double));
+  cell = (int *)xcalloc(lmax + 1, sizeof(int));
+  cnt = (int *)xcalloc(lmax + 1, sizeof(int));
+  xcm = (double *)xcalloc(lmax + 1, sizeof(double));
+  ycm = (double *)xcalloc(lmax + 1, sizeof(double));
 
   rx[0] = vxmin;
   rx[1] = vxmax;
@@ -10827,7 +10661,7 @@ static void mathtex(double x, double y, char *string, int inquire, double *tbx,
     }
 }
 
-void mathtex2(double x, double y, const char *formula, int inquire, double *tbx, double *tby);
+void mathtex2(double x, double y, const char *formula, int inquire, double *tbx, double *tby, double *baseline);
 
 /*!
  * Generate a character string starting at the given location. Strings can be
@@ -10847,7 +10681,7 @@ void gr_mathtex(double x, double y, char *string)
   gks_inq_text_fontprec(&unused, &unused, &prec);
   if (prec == 3)
     {
-      mathtex2(x, y, string, 0, NULL, NULL);
+      mathtex2(x, y, string, 0, NULL, NULL, NULL);
     }
   else
     {
@@ -10867,7 +10701,7 @@ void gr_inqmathtex(double x, double y, char *string, double *tbx, double *tby)
   gks_inq_text_fontprec(&unused, &unused, &prec);
   if (prec == 3)
     {
-      mathtex2(x, y, string, 1, tbx, tby);
+      mathtex2(x, y, string, 1, tbx, tby, NULL);
     }
   else
     {
@@ -10875,6 +10709,441 @@ void gr_inqmathtex(double x, double y, char *string, double *tbx, double *tby)
     }
 }
 
+static void append(double x, double y, char *string, int line_number, int math)
+{
+  text_node_t *prev = text;
+  int errInd, n, wkId, font, prec;
+  double cpx, cpy, tbx[4], tby[4];
+  char *src, *dest;
+
+  text = (text_node_t *)xcalloc(1, sizeof(text_node_t));
+  text->next = NULL;
+  if (head == NULL)
+    head = text;
+  else if (prev != NULL)
+    prev->next = text;
+
+  text->x = x;
+  text->y = y;
+  text->string = (char *)xcalloc(strlen(string) + 1, sizeof(char));
+  src = string;
+  dest = text->string;
+  while (*src)
+    {
+      if (*src == '$' && *(src + 1) == '$') src++;
+      *dest++ = *src++;
+    }
+  *dest = '\0';
+  text->line_number = line_number;
+  text->line_width = 0;
+  text->math = math;
+
+  gks_inq_open_ws(1, &errInd, &n, &wkId);
+  if (math)
+    {
+      gks_inq_text_fontprec(&errInd, &font, &prec);
+      if (prec == 3)
+        {
+          mathtex2(0, 0, text->string, 1, tbx, tby, text->baseline);
+        }
+      else
+        {
+          mathtex(0, 0, text->string, 1, tbx, tby);
+        }
+    }
+  else
+    {
+      if (*text->string)
+        gks_inq_text_extent(wkId, 0, 0, text->string, &errInd, &cpx, &cpy, tbx, tby);
+      else
+        {
+          gks_inq_text_extent(wkId, 0, 0, "Ag", &errInd, &cpx, &cpy, tbx, tby);
+          tbx[0] = tbx[1] = 0;
+        }
+    }
+
+  text->width = tbx[1] - tbx[0];
+  text->height = tby[2] - tby[1];
+}
+
+static text_node_t *parse(double x, double y, char *string, int inline_math)
+{
+  char *s, *start, *end;
+  int line_number, math;
+
+  head = text = NULL;
+  line_number = 1;
+  math = 0;
+
+  s = (char *)xcalloc(strlen(string) + 1, sizeof(char));
+  strcpy(s, string);
+
+  start = end = s;
+  while (*end)
+    {
+      if (*end == '\n')
+        {
+          math = 0;
+          *end++ = '\0';
+          append(x, y, start, line_number, math);
+          start = end;
+          line_number++;
+        }
+      else if (inline_math && !math && *end == '$' && *(end + 1) == '$')
+        {
+          end += 2;
+        }
+      else if (inline_math && *end == '$')
+        {
+          *end++ = '\0';
+          append(x, y, start, line_number, math);
+          math = !math;
+          start = end;
+        }
+      else
+        end++;
+    }
+  append(x, y, start, line_number, math);
+  free(s);
+
+  return head;
+}
+
+static void text_impl(double x, double y, char *string, int inline_math, int inquire, double *tbx, double *tby)
+{
+  int errInd, hAlign, vAlign;
+  double chuX, chuY, angle, charHeight, xOff, yOff, lineWidth, lineHeight;
+  text_node_t *textP, *p;
+  int lineNumber = 1;
+  double totalWidth = 0, totalHeight = 0, *baseLine;
+  double xx, yy, sx, sy;
+  int i;
+
+  gks_inq_text_upvec(&errInd, &chuX, &chuY);
+  gks_set_text_upvec(0, 1);
+  angle = -atan2(chuX, chuY);
+
+  gks_inq_text_height(&errInd, &charHeight);
+
+  gks_inq_text_align(&errInd, &hAlign, &vAlign);
+  gks_set_text_align(GKS_K_TEXT_HALIGN_LEFT, GKS_K_TEXT_VALIGN_HALF);
+
+  text = textP = parse(x, y, string, inline_math);
+  yOff = 0;
+  while (textP != NULL)
+    {
+      lineWidth = 0;
+      lineHeight = 0;
+      p = textP;
+      while (p != NULL)
+        {
+          if (p->line_number != lineNumber) break;
+          lineHeight = max(p->height, lineHeight);
+          lineWidth += p->width;
+          p = p->next;
+        }
+      xOff = 0;
+      yOff += 0.5 * lineHeight;
+
+      totalWidth = max(totalWidth, lineWidth);
+      totalHeight += lineHeight;
+
+      while (textP != NULL && textP->line_number == lineNumber)
+        {
+          textP->x += xOff;
+          textP->y -= yOff;
+
+          xOff += textP->width;
+          totalWidth = max(totalWidth, xOff);
+
+          textP->line_width = lineWidth;
+          textP = textP->next;
+        }
+      yOff += 0.5 * lineHeight;
+      lineNumber += 1;
+    }
+
+  gks_set_text_upvec(chuX, chuY);
+
+  if (!inquire)
+    {
+      p = text;
+      while (p != NULL)
+        {
+          if (hAlign == 2)
+            p->x += 0.5 * (totalWidth - p->line_width);
+          else if (hAlign == 3)
+            p->x += totalWidth - p->line_width;
+          p = p->next;
+        }
+
+      textP = text;
+      while (textP != NULL)
+        {
+          baseLine = NULL;
+          p = text;
+          while (p != NULL && p->line_number != textP->line_number)
+            {
+              p = p->next;
+            }
+          while (p != NULL && p->line_number == textP->line_number)
+            {
+              if (p->math)
+                {
+                  baseLine = p->baseline + 1;
+                  break;
+                }
+              else
+                p = p->next;
+            }
+
+          xx = textP->x - x;
+          switch (hAlign)
+            {
+            case 2:
+              xx -= 0.5 * totalWidth;
+              break;
+            case 3:
+              xx -= totalWidth;
+              break;
+            default:
+              break;
+            }
+
+          yy = textP->y - y;
+          if (inline_math) yy -= charHeight * 0.2;
+
+          if (!textP->math && baseLine != NULL)
+            {
+              yy += *baseLine + 0.5 * charHeight;
+            }
+          switch (vAlign)
+            {
+            case 2:
+              yy += charHeight * 0.2;
+              break;
+            case 3:
+              yy += 0.5 * totalHeight;
+              break;
+            case 4:
+              yy += totalHeight - charHeight * 0.2;
+              break;
+            case 5:
+              yy += totalHeight;
+              break;
+            default:
+              break;
+            }
+
+          sx = x + cos(angle) * xx - sin(angle) * yy;
+          sy = y + sin(angle) * xx + cos(angle) * yy;
+
+          if (textP->math)
+            gr_mathtex(sx, sy, textP->string);
+          else
+            gks_text(sx, sy, textP->string);
+
+          textP = textP->next;
+        }
+    }
+  else
+    {
+      xx = x;
+      switch (hAlign)
+        {
+        case 2:
+          xx -= 0.5 * totalWidth;
+          break;
+        case 3:
+          xx -= totalWidth;
+          break;
+        default:
+          break;
+        }
+      yy = y;
+      switch (vAlign)
+        {
+        case 3:
+          yy += 0.5 * totalHeight;
+          break;
+        case 4:
+          yy += totalHeight;
+          break;
+        case 5:
+          yy += totalHeight;
+          break;
+        default:
+          break;
+        }
+
+      tbx[0] = xx;
+      tby[0] = yy;
+      tbx[1] = tbx[0] + totalWidth;
+      tby[1] = tby[0];
+      tbx[2] = tbx[1];
+      tby[2] = tby[1] - totalHeight;
+      tbx[3] = tbx[0];
+      tby[3] = tby[2];
+
+      for (i = 0; i < 4; i++)
+        {
+          xx = tbx[i] - x;
+          yy = tby[i] - y;
+          tbx[i] = x + cos(angle) * xx - sin(angle) * yy;
+          tby[i] = y + sin(angle) * xx + cos(angle) * yy;
+        }
+    }
+
+  while (text != NULL)
+    {
+      text_node_t *next = text->next;
+      free(text->string);
+      free(text);
+      text = next;
+    }
+
+  gks_set_text_align(hAlign, vAlign);
+}
+
+/*!
+ * Draw a text at position `x`, `y` using the current text attributes.
+ *
+ * \param[in] x The X coordinate of the starting position of the text string
+ * \param[in] y The Y coordinate of the starting position of the text string
+ * \param[in] string The text to be drawn
+ *
+ * The values for `x` and `y` are in normalized device coordinates.
+ * The attributes that control the appearance of text are text font and
+ * precision, character expansion factor, character spacing, text color index,
+ * character height, character up vector, text path and text alignment.
+ */
+void gr_text(double x, double y, char *string)
+{
+  int errind, tnr;
+
+  check_autoinit;
+
+  gks_inq_current_xformno(&errind, &tnr);
+  if (tnr != NDC) gks_select_xform(NDC);
+
+  if (strchr(string, '\n') != NULL || strchr(string, '$') != NULL)
+    text_impl(x, y, string, 1, 0, NULL, NULL);
+  else
+    gks_text(x, y, string);
+
+  if (tnr != NDC) gks_select_xform(tnr);
+
+  if (flag_graphics) gr_writestream("<text x=\"%g\" y=\"%g\" text=\"%s\"/>\n", x, y, string);
+}
+
+/*!
+ * Draw a text at position `x`, `y` using the given options and current text
+ * attributes.
+ *
+ * \param[in] x The X coordinate of the starting position of the text string
+ * \param[in] y The Y coordinate of the starting position of the text string
+ * \param[in] string The text to be drawn
+ * \param[in] opts Bit mask including text options (GR_TEXT_USE_WC,
+ * GR_TEXT_ENABLE_INLINE_MATH)
+ *
+ * The values for `x` and `y` specify the text position. If the GR_TEXT_USE_WC
+ * option is set, they are interpreted as world cordinates, otherwise as
+ * normalized device coordinates. The string may contain new line characters
+ * and inline math expressions ($...$). The latter are only taken into account,
+ * if the GR_TEXT_ENABLE_INLINE_MATH option is set.
+ * The attributes that control the appearance of text are text font and
+ * precision, character expansion factor, character spacing, text color index,
+ * character height, character up vector, text path and text alignment.
+ */
+void gr_textx(double x, double y, char *string, int opts)
+{
+  int errind, tnr;
+  double xn = x, yn = y;
+  int inline_math = (opts & GR_TEXT_ENABLE_INLINE_MATH) != 0;
+
+  check_autoinit;
+
+  gks_inq_current_xformno(&errind, &tnr);
+  if (tnr != NDC)
+    {
+      if ((opts & GR_TEXT_USE_WC) != 0) gr_wctondc(&xn, &yn);
+      gks_select_xform(NDC);
+    }
+
+  if (strchr(string, '\n') != NULL || (strchr(string, '$') != NULL && inline_math))
+    text_impl(xn, yn, string, inline_math, 0, NULL, NULL);
+  else
+    gks_text(xn, yn, string);
+
+  if (tnr != NDC) gks_select_xform(tnr);
+
+  if (flag_graphics) gr_writestream("<textx x=\"%g\" y=\"%g\" text=\"%s\" opts=\"%d\"/>\n", x, y, string, opts);
+}
+
+void gr_inqtext(double x, double y, char *string, double *tbx, double *tby)
+{
+  int errind, tnr, n, wkid;
+  double cpx, cpy;
+
+  check_autoinit;
+
+  gks_inq_current_xformno(&errind, &tnr);
+  if (tnr != NDC) gks_select_xform(NDC);
+
+  if (strchr(string, '\n') != NULL || strchr(string, '$') != NULL)
+    text_impl(x, y, string, 1, 1, tbx, tby);
+  else
+    {
+      gks_inq_open_ws(1, &errind, &n, &wkid);
+      gks_inq_text_extent(wkid, x, y, string, &errind, &cpx, &cpy, tbx, tby);
+    }
+
+  if (tnr != NDC) gks_select_xform(tnr);
+}
+
+void gr_inqtextx(double x, double y, char *string, int opts, double *tbx, double *tby)
+{
+  int errind, tnr, n, wkid, i;
+  double xn = x, yn = y, cpx, cpy;
+  int inline_math = (opts & GR_TEXT_ENABLE_INLINE_MATH) != 0;
+
+  check_autoinit;
+
+  gks_inq_current_xformno(&errind, &tnr);
+  if (tnr != NDC)
+    {
+      if ((opts & GR_TEXT_USE_WC) != 0) gr_wctondc(&xn, &yn);
+      gks_select_xform(NDC);
+    }
+
+  if (strchr(string, '\n') != NULL || (strchr(string, '$') != NULL && inline_math))
+    text_impl(xn, yn, string, inline_math, 1, tbx, tby);
+  else
+    {
+      gks_inq_open_ws(1, &errind, &n, &wkid);
+      gks_inq_text_extent(wkid, xn, yn, string, &errind, &cpx, &cpy, tbx, tby);
+    }
+
+  if (tnr != NDC)
+    {
+      gks_select_xform(tnr);
+
+      if ((opts & GR_TEXT_USE_WC) != 0)
+        {
+          for (i = 0; i < 4; i++)
+            {
+              tbx[i] = (tbx[i] - nx.b) / nx.a;
+              tby[i] = (tby[i] - nx.d) / nx.c;
+              if (lx.scale_options)
+                {
+                  tbx[i] = x_log(tbx[i]);
+                  tby[i] = y_log(tby[i]);
+                }
+            }
+        }
+    }
+}
+
 void gr_beginselection(int index, int type)
 {
   check_autoinit;
diff --git a/lib/gr/gr.h b/lib/gr/gr.h
index 9d8fc6653..9f023f78b 100644
--- a/lib/gr/gr.h
+++ b/lib/gr/gr.h
@@ -26,6 +26,9 @@ extern "C" {
 #define GR_VOLUME_ABSORPTION 1
 #define GR_VOLUME_MIP 2
 
+#define GR_TEXT_USE_WC (1 << 0)
+#define GR_TEXT_ENABLE_INLINE_MATH (1 << 1)
+
 typedef struct
 {
   double x, y;
@@ -45,7 +48,9 @@ DLLEXPORT void gr_updatews(void);
 DLLEXPORT void gr_polyline(int, double *, double *);
 DLLEXPORT void gr_polymarker(int, double *, double *);
 DLLEXPORT void gr_text(double, double, char *);
+DLLEXPORT void gr_textx(double, double, char *, int);
 DLLEXPORT void gr_inqtext(double, double, char *, double *, double *);
+DLLEXPORT void gr_inqtextx(double, double, char *, int, double *, double *);
 DLLEXPORT void gr_fillarea(int, double *, double *);
 DLLEXPORT void gr_cellarray(double, double, double, double, int, int, int, int, int, int, int *);
 DLLEXPORT void gr_nonuniformcellarray(double *, double *, int, int, int, int, int, int, int *);
diff --git a/lib/gr/import.c b/lib/gr/import.c
index 014cd7717..d95c8482c 100644
--- a/lib/gr/import.c
+++ b/lib/gr/import.c
@@ -102,6 +102,7 @@ static char *format[] = {
     "surface:iiFFFi",
     "text:ffs",
     "textext:ffs",
+    "textx:ffsi",
     "titles3d:sss",
     "tricont:iFFFiF",
     "trisurf:iFFF",
@@ -535,18 +536,21 @@ static void gr(int id)
       gr_textext(f_arg[0], f_arg[1], s_arg[0]);
       break;
     case 82:
-      gr_titles3d(s_arg[0], s_arg[1], s_arg[2]);
+      gr_textx(f_arg[0], f_arg[1], s_arg[0], i_arg[0]);
       break;
     case 83:
-      gr_tricontour(i_arg[0], f_arr[0], f_arr[1], f_arr[2], i_arg[2], f_arr[3]);
+      gr_titles3d(s_arg[0], s_arg[1], s_arg[2]);
       break;
     case 84:
-      gr_trisurface(i_arg[0], f_arr[0], f_arr[1], f_arr[2]);
+      gr_tricontour(i_arg[0], f_arr[0], f_arr[1], f_arr[2], i_arg[2], f_arr[3]);
       break;
     case 85:
-      gr_uselinespec(s_arg[0]);
+      gr_trisurface(i_arg[0], f_arr[0], f_arr[1], f_arr[2]);
       break;
     case 86:
+      gr_uselinespec(s_arg[0]);
+      break;
+    case 87:
       gr_verrorbars(i_arg[0], f_arr[0], f_arr[1], f_arr[2], f_arr[3]);
       break;
     }
diff --git a/lib/gr/mathtex2.c b/lib/gr/mathtex2.c
index 44c79f487..55941e3cd 100644
--- a/lib/gr/mathtex2.c
+++ b/lib/gr/mathtex2.c
@@ -968,6 +968,7 @@ typedef struct BoxModelNode_
 
 double canvas_height = 0;
 double canvas_width = 0;
+double canvas_depth = 0;
 
 static double font_size;
 static double transformation[6];
@@ -1101,6 +1102,11 @@ static size_t make_char(unsigned int codepoint)
       return 0;
     }
   BoxModelNode bm_node;
+  double size_factor = 1.16;
+  if (codepoint == 8747)
+    {
+      size_factor *= 1.25;
+    }
   bm_node.index = 0;
   bm_node.type = BT_CHAR;
   bm_node.u.character.codepoint = codepoint;
@@ -1108,10 +1114,15 @@ static size_t make_char(unsigned int codepoint)
   bm_node.u.character.state = *get_current_state();
   double width, height, depth, advance, bearing;
   if (gks_ft_get_metrics(
-          MATH_FONT, bm_node.u.character.state.fontsize * 1.16,
+          MATH_FONT, bm_node.u.character.state.fontsize * size_factor,
           get_codepoint_for_character_variant(bm_node.u.character.codepoint, bm_node.u.character.state.font),
           bm_node.u.character.state.dpi, &width, &height, &depth, &advance, &bearing, NULL, NULL, NULL, NULL))
     {
+      if (codepoint == 8747)
+        {
+          height *= 0.75;
+          depth *= 1.25;
+        }
       if (codepoint == ' ')
         {
           bm_node.u.character.width = advance;
@@ -3104,7 +3115,12 @@ static void render_character(BoxModelNode *node, double x, double y)
     }
   /* TODO: inquire current workstation window height? */
   int window_height = 2400;
-  gks_set_text_height(node->u.character.state.fontsize / 15.0 * 12 / window_height);
+  double size_factor = 12 / 15.0 / window_height;
+  if (codepoint == 8747)
+    {
+      size_factor *= 1.25;
+    }
+  gks_set_text_height(node->u.character.state.fontsize * size_factor);
   gks_set_text_fontprec(MATH_FONT, 3);
   gks_set_text_align(GKS_K_TEXT_HALIGN_LEFT, GKS_K_TEXT_VALIGN_BASE);
   if (node->u.character.bearing < 0)
@@ -3457,6 +3473,7 @@ static void mathtex_to_box_model(const char *mathtex, double *width, double *hei
   assert(get_box_model_node(result_box_model_node_index)->type == BT_HLIST);
   canvas_height = result_node->u.hlist.height + result_node->u.hlist.depth;
   canvas_width = result_node->u.hlist.width;
+  canvas_depth = result_node->u.hlist.depth;
   if (width)
     {
       *width = result_node->u.hlist.width;
@@ -3508,7 +3525,7 @@ static void calculate_alignment_offsets(int horizontal_alignment, int vertical_a
     case GKS_K_TEXT_VALIGN_NORMAL:
     case GKS_K_TEXT_VALIGN_BASE:
     default:
-      *y_offset = 0;
+      *y_offset = -canvas_depth / window_height;
       break;
     }
 }
@@ -3772,7 +3789,7 @@ static unsigned int get_codepoint_for_character_variant(unsigned int codepoint,
     }
 }
 
-void mathtex2(double x, double y, const char *formula, int inquire, double *tbx, double *tby)
+void mathtex2(double x, double y, const char *formula, int inquire, double *tbx, double *tby, double *baseline)
 {
   int unused;
   int previous_bearing_x_direction;
@@ -3865,6 +3882,11 @@ void mathtex2(double x, double y, const char *formula, int inquire, double *tbx,
           tby[2] = ymax;
           tby[3] = ymax;
           angle = -atan2(chupx, chupy);
+          if (baseline)
+            {
+              baseline[0] = x + x_offset * cos(angle) - (y_offset + canvas_depth / window_height) * sin(angle);
+              baseline[1] = y + x_offset * sin(angle) + (y_offset + canvas_depth / window_height) * cos(angle);
+            }
           for (i = 0; i < 4; i++)
             {
               double rx, ry;
diff --git a/lib/grm/plot.c b/lib/grm/plot.c
index 43cb751de..27e5f1685 100644
--- a/lib/grm/plot.c
+++ b/lib/grm/plot.c
@@ -246,6 +246,7 @@ const char *valid_subplot_keys[] = {"adjust_xlim",
                                     "normalization",
                                     "panzoom",
                                     "phiflip",
+                                    "resample_method",
                                     "reset_ranges",
                                     "rings",
                                     "rotation",
@@ -351,6 +352,7 @@ static string_map_entry_t key_to_formats[] = {{"a", "A"},
                                               {"nbins", "i"},
                                               {"panzoom", "D"},
                                               {"raw", "s"},
+                                              {"resample_method", "s|i"},
                                               {"reset_ranges", "i"},
                                               {"rotation", "i"},
                                               {"size", "D|A"},
@@ -900,6 +902,7 @@ void plot_set_attribute_defaults(grm_args_t *plot_args)
       args_setdefault(*current_subplot, "xgrid", "i", PLOT_DEFAULT_XGRID);
       args_setdefault(*current_subplot, "ygrid", "i", PLOT_DEFAULT_YGRID);
       args_setdefault(*current_subplot, "zgrid", "i", PLOT_DEFAULT_ZGRID);
+      args_setdefault(*current_subplot, "resample_method", "i", PLOT_DEFAULT_RESAMPLE_METHOD);
       if (strcmp(kind, "heatmap") == 0)
         {
           args_setdefault(*current_subplot, "adjust_xlim", "i", 0);
@@ -1036,6 +1039,7 @@ error_t plot_pre_subplot(grm_args_t *subplot_args)
 
   plot_process_colormap(subplot_args);
   plot_process_font(subplot_args);
+  plot_process_resample_method(subplot_args);
 
   if (str_equals_any(kind, 2, "polar", "polar_histogram"))
     {
@@ -1082,6 +1086,33 @@ void plot_process_font(grm_args_t *subplot_args)
   /* TODO: Implement other datatypes for `font` and `font_precision` */
 }
 
+void plot_process_resample_method(grm_args_t *subplot_args)
+{
+  unsigned int resample_method_flag;
+  if (!args_values(subplot_args, "resample_method", "i", &resample_method_flag))
+    {
+      const char *resample_method_str;
+      args_values(subplot_args, "resample_method", "s", &resample_method_str);
+      if (strcmp(resample_method_str, "nearest") == 0)
+        {
+          resample_method_flag = GKS_K_RESAMPLE_NEAREST;
+        }
+      else if (strcmp(resample_method_str, "linear") == 0)
+        {
+          resample_method_flag = GKS_K_RESAMPLE_LINEAR;
+        }
+      else if (strcmp(resample_method_str, "lanczos") == 0)
+        {
+          resample_method_flag = GKS_K_RESAMPLE_LANCZOS;
+        }
+      else
+        {
+          resample_method_flag = GKS_K_RESAMPLE_DEFAULT;
+        }
+    }
+  gr_setresamplemethod(resample_method_flag);
+}
+
 void plot_process_viewport(grm_args_t *subplot_args)
 {
   const char *kind;
@@ -2279,7 +2310,7 @@ error_t plot_barplot(grm_args_t *subplot_args)
   const char *style = "default";
   double *y;
   unsigned int y_length;
-  unsigned int fixed_y_length;
+  unsigned int fixed_y_length = 0;
   grm_args_t **ind_bar_color = NULL;
   double(*pos_ind_bar_color)[3] = NULL;
   grm_args_t **ind_edge_color = NULL;
@@ -2318,19 +2349,19 @@ error_t plot_barplot(grm_args_t *subplot_args)
 
   /* ind_parameter */
   /* determine the length of y */
-  if (!args_first_value(*current_series, "y", "D", &y, &fixed_y_length))
+  while (*current_series != NULL)
     {
-      unsigned int temp_y_length = 0;
-      cleanup_and_set_error_if(
-          !args_first_value(*current_series, "inner_series", "A", &inner_series, &inner_series_length),
-          ERROR_PLOT_MISSING_DATA);
-      while (inner_series != NULL)
+      if (!args_first_value(*current_series, "y", "D", &y, &y_length))
         {
-          args_first_value(*inner_series, "y", "D", &y, &y_length);
-          temp_y_length += fixed_y_length;
+          cleanup_and_set_error_if(
+              !args_first_value(*current_series, "inner_series", "A", &inner_series, &inner_series_length),
+              ERROR_PLOT_MISSING_DATA);
+          y_length = inner_series_length;
         }
-      fixed_y_length = temp_y_length;
+      fixed_y_length = max(y_length, fixed_y_length);
+      ++current_series;
     }
+
   /* ind_bar_color */
   if (args_values(subplot_args, "ind_bar_color", "A", &ind_bar_color))
     {
@@ -2467,6 +2498,7 @@ error_t plot_barplot(grm_args_t *subplot_args)
         }
     }
 
+  args_values(subplot_args, "series", "A", &current_series);
   wfac = 0.9 * bar_width;
   while (*current_series != NULL)
     {
@@ -3240,7 +3272,7 @@ error_t plot_heatmap(grm_args_t *subplot_args)
                   zv = z[i];
                 }
 
-              if (zv > z_max || zv < z_min)
+              if (zv > z_max || zv < z_min || isnan(zv))
                 {
                   data[i] = -1;
                 }
@@ -4890,19 +4922,17 @@ error_t plot_pie(grm_args_t *subplot_args)
   gr_setfillintstyle(GKS_K_INTSTYLE_SOLID);
   gr_settextalign(GKS_K_TEXT_HALIGN_CENTER, GKS_K_TEXT_VALIGN_HALF);
 
-
   cleanup_and_set_error_if(!args_first_value(series, "x", "D", &x, &x_length), ERROR_PLOT_MISSING_DATA);
   normalized_x = normalize(x_length, x);
   cleanup_and_set_error_if(normalized_x == NULL, ERROR_MALLOC);
   normalized_x_int = normalize_int(x_length, x, 1000);
   cleanup_and_set_error_if(normalized_x_int == NULL, ERROR_MALLOC);
 
+  set_next_color(series, "c", GR_COLOR_FILL);
   start_angle = 90;
   for (i = 0; i < x_length; ++i)
     {
-      gr_uselinespec("");
-      gr_inqlinecolorind(&color_ind);
-      gr_setfillcolorind(color_ind);
+      gr_inqfillcolorind(&color_ind);
       gr_inqcolor(color_ind, (int *)color_rgb);
       set_text_color_for_background(color_rgb[0] / 255.0, color_rgb[1] / 255.0, color_rgb[2] / 255.0);
       end_angle = start_angle - normalized_x[i] * 360.0;
@@ -4918,7 +4948,9 @@ error_t plot_pie(grm_args_t *subplot_args)
         {
           start_angle += 360.0;
         }
+      set_next_color(NULL, NULL, GR_COLOR_FILL);
     }
+  set_next_color(NULL, NULL, GR_COLOR_RESET);
 
   if (args_values(subplot_args, "title", "s", &title))
     {
@@ -5171,8 +5203,6 @@ error_t plot_draw_axes(grm_args_t *args, unsigned int pass)
   if (strcmp("barplot", kind) == 0 && pass == 2)
     {
       /* xticklabels */
-      grm_args_t **current_series;
-      args_values(args, "series", "A", &current_series);
       char **xticklabels = NULL;
       unsigned int xticklabels_length;
       int i;
@@ -5183,14 +5213,11 @@ error_t plot_draw_axes(grm_args_t *args, unsigned int pass)
           double x1, x2;
           double x_left = 0, x_right = 1, null;
           double available_width;
-          double *y;
-          unsigned int y_length;
           const double *window;
           /* calculate width available for xticknotations */
           gr_wctondc(&x_left, &null);
           gr_wctondc(&x_right, &null);
           available_width = x_right - x_left;
-          return_error_if(!args_first_value(*current_series, "y", "D", &y, &y_length), ERROR_PLOT_MISSING_DATA);
           args_values(args, "window", "D", &window);
           gr_setcharheight(charheight);
           gr_settextalign(GKS_K_TEXT_HALIGN_CENTER, GKS_K_TEXT_VALIGN_TOP);
@@ -5453,17 +5480,17 @@ error_t plot_draw_legend(grm_args_t *subplot_args)
 
 error_t plot_draw_pie_legend(grm_args_t *subplot_args)
 {
+  grm_args_t *series;
   const char **labels, **current_label;
   unsigned int num_labels;
-  grm_args_t **current_series;
   const double *viewport;
   double px, py, w, h;
   double tbx[4], tby[4];
   int color_ind;
 
-
   return_error_if(!args_first_value(subplot_args, "labels", "S", &labels, &num_labels), ERROR_PLOT_MISSING_LABELS);
   logger((stderr, "Draw a pie legend with %d labels\n", num_labels));
+  args_values(subplot_args, "series", "a", &series); /* series exists always */
   args_values(subplot_args, "viewport", "D", &viewport);
   gr_savestate();
   gr_selntran(0);
@@ -5490,18 +5517,18 @@ error_t plot_draw_pie_legend(grm_args_t *subplot_args)
   gr_drawrect(px - 0.02, px + w + 0.02, py - 0.5 * h - 0.02, py + 0.5 * h + 0.02);
   gr_settextalign(GKS_K_TEXT_HALIGN_LEFT, GKS_K_TEXT_VALIGN_HALF);
   gr_uselinespec(" ");
+  set_next_color(series, "c", GR_COLOR_FILL);
   for (current_label = labels; *current_label != NULL; ++current_label)
     {
-      gr_uselinespec("");
-      gr_inqlinecolorind(&color_ind);
-      gr_setfillcolorind(color_ind);
       gr_fillrect(px, px + 0.02, py - 0.01, py + 0.01);
       gr_setlinecolorind(1);
       gr_drawrect(px, px + 0.02, py - 0.01, py + 0.01);
       gr_textext(px + 0.03, py, (char *)*current_label);
       gr_inqtextext(0, 0, *(char **)current_label, tbx, tby);
       px += tbx[2] + 0.05;
+      set_next_color(NULL, NULL, GR_COLOR_FILL);
     }
+  set_next_color(NULL, NULL, GR_COLOR_RESET);
   gr_selntran(1);
   gr_restorestate();
 
@@ -7184,6 +7211,110 @@ void draw_xticklabel(double x1, double x2, const char *label, double available_w
   gr_textext(x1, x2, new_label + cur_start);
 }
 
+/*!
+ * \brief Set colors from color index or rgb arrays.
+ *
+ * Call the function first with an argument container and a key. Afterwards, call the `set_next_color` with `NULL`
+ * pointers to iterate through the color arrays. If `key` does not exist in `args`, the function falls back to default
+ * colors.
+ *
+ * \param args The argument container which stores the color values.
+ * \param key The key of the colors in the argument container. The key may reference integer or double arrays.
+ *            Integer arrays describe colors of the GKS color table (0 - 1255). Double arrays contain RGB tuples in the
+ *            range [0.0, 1.0]. If key does not exist, the routine falls back to default colors (taken from
+ *            `gr_uselinespec`).
+ * \param color_type The color type to set. Can be one of `GR_COLOR_LINE`, `GR_COLOR_MARKER`, `GR_COLOR_FILL`,
+ *                   `GR_COLOR_TEXT`, `GR_COLOR_BORDER` or any combination of them (combined with OR). The special value
+ *                   `GR_COLOR_RESET` resets all color modifications.
+ */
+void set_next_color(const grm_args_t *args, const char *key, gr_color_type_t color_type)
+{
+  const static int fallback_color_indices[] = {989, 982, 980, 981, 996, 983, 995, 988, 986, 990,
+                                               991, 984, 992, 993, 994, 987, 985, 997, 998, 999};
+  static double saved_color[3];
+  static int last_array_index = -1;
+  static const int *color_indices = NULL;
+  static const double *color_rgb_values = NULL;
+  static unsigned int color_array_length = -1;
+  int current_array_index = last_array_index + 1;
+  int color_index;
+  int reset = (color_type == GR_COLOR_RESET);
+  int gks_errind = GKS_K_NO_ERROR;
+
+  if (reset || (args != NULL && key != NULL))
+    {
+      if (last_array_index >= 0 && color_rgb_values != NULL)
+        {
+          gr_setcolorrep(PLOT_CUSTOM_COLOR_INDEX, saved_color[0], saved_color[1], saved_color[2]);
+        }
+      last_array_index = -1;
+      if (!reset && args != NULL && key != NULL)
+        {
+          if (!args_first_value(args, key, "I", &color_indices, &color_array_length) &&
+              !args_first_value(args, key, "D", &color_rgb_values, &color_array_length))
+            {
+              /* use fallback colors if `key` cannot be read from `args` */
+              logger((stderr, "Cannot read \"%s\" from args, falling back to default colors\n", key));
+              color_indices = fallback_color_indices;
+              color_array_length = array_size(fallback_color_indices);
+            }
+        }
+      else
+        {
+          color_indices = NULL;
+          color_rgb_values = NULL;
+          color_array_length = -1;
+        }
+
+      if (reset)
+        {
+          return;
+        }
+    }
+
+  if (last_array_index < 0 && color_rgb_values != NULL)
+    {
+      gks_inq_color_rep(1, PLOT_CUSTOM_COLOR_INDEX, GKS_K_VALUE_SET, &gks_errind, &saved_color[0], &saved_color[1],
+                        &saved_color[2]);
+    }
+
+  current_array_index %= color_array_length;
+
+  if (color_indices != NULL)
+    {
+      color_index = color_indices[current_array_index];
+      last_array_index = current_array_index;
+    }
+  else if (color_rgb_values != NULL)
+    {
+      gr_setcolorrep(PLOT_CUSTOM_COLOR_INDEX, color_rgb_values[current_array_index],
+                     color_rgb_values[current_array_index + 1], color_rgb_values[current_array_index + 2]);
+      color_index = PLOT_CUSTOM_COLOR_INDEX;
+      last_array_index = current_array_index + 2;
+    }
+
+  if (color_type & GR_COLOR_LINE)
+    {
+      gr_setlinecolorind(color_index);
+    }
+  if (color_type & GR_COLOR_MARKER)
+    {
+      gr_setmarkercolorind(color_index);
+    }
+  if (color_type & GR_COLOR_FILL)
+    {
+      gr_setfillcolorind(color_index);
+    }
+  if (color_type & GR_COLOR_TEXT)
+    {
+      gr_settextcolorind(color_index);
+    }
+  if (color_type & GR_COLOR_BORDER)
+    {
+      gr_setbordercolorind(color_index);
+    }
+}
+
 /* ========================= methods ================================================================================ */
 
 /* ------------------------- args set ------------------------------------------------------------------------------- */
diff --git a/lib/grm/plot_int.h b/lib/grm/plot_int.h
index 15f8337f3..4c0937de1 100644
--- a/lib/grm/plot_int.h
+++ b/lib/grm/plot_int.h
@@ -35,6 +35,8 @@ extern const char *plot_clear_exclude_keys[];
 
 /* ------------------------- plot ----------------------------------------------------------------------------------- */
 
+/* ~~~~~~~~~~~~~~~~~~~~~~~~~ plot arguments ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
+
 #define ROOT_DEFAULT_APPEND_PLOTS 0
 #define PLOT_DEFAULT_WIDTH 600.0
 #define PLOT_DEFAULT_HEIGHT 450.0
@@ -56,6 +58,7 @@ extern const char *plot_clear_exclude_keys[];
 #define PLOT_DEFAULT_XGRID 1
 #define PLOT_DEFAULT_YGRID 1
 #define PLOT_DEFAULT_ZGRID 1
+#define PLOT_DEFAULT_RESAMPLE_METHOD GKS_K_RESAMPLE_DEFAULT
 #define PLOT_DEFAULT_ADJUST_XLIM 1
 #define PLOT_DEFAULT_ADJUST_YLIM 1
 #define PLOT_DEFAULT_ADJUST_ZLIM 1
@@ -79,6 +82,11 @@ extern const char *plot_clear_exclude_keys[];
 #define PLOT_SURFACE_GRIDIT_N 200
 
 
+/* ~~~~~~~~~~~~~~~~~~~~~~~~~ util ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
+
+#define PLOT_CUSTOM_COLOR_INDEX 979
+
+
 /* ========================= datatypes ============================================================================== */
 
 /* ------------------------- plot ----------------------------------------------------------------------------------- */
@@ -107,6 +115,18 @@ typedef enum
   GR_OPTION_SHADED_MESH = 6
 } gr_option_t;
 
+/* ~~~~~~~~~~~~~~~~~~~~~~~~~ util ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
+
+typedef enum
+{
+  GR_COLOR_RESET = 0,
+  GR_COLOR_LINE = 1 << 0,
+  GR_COLOR_MARKER = 1 << 1,
+  GR_COLOR_FILL = 1 << 2,
+  GR_COLOR_TEXT = 1 << 3,
+  GR_COLOR_BORDER = 1 << 4
+} gr_color_type_t;
+
 
 /* ========================= functions ============================================================================== */
 
@@ -132,6 +152,7 @@ void plot_process_wswindow_wsviewport(grm_args_t *plot_args);
 error_t plot_pre_subplot(grm_args_t *subplot_args);
 void plot_process_colormap(grm_args_t *subplot_args);
 void plot_process_font(grm_args_t *subplot_args);
+void plot_process_resample_method(grm_args_t *subplot_args);
 void plot_process_viewport(grm_args_t *subplot_args);
 void plot_process_window(grm_args_t *subplot_args);
 error_t plot_store_coordinate_ranges(grm_args_t *subplot_args);
@@ -204,6 +225,7 @@ error_t classes_polar_histogram(grm_args_t *subplot_args, double *r_max);
 double get_lightness_from_rbg(double r, double g, double b);
 void set_text_color_for_background(double r, double g, double b);
 void draw_xticklabel(double x1, double x2, const char *label, double available_width);
+void set_next_color(const grm_args_t *args, const char *key, gr_color_type_t color_type);
 
 
 #endif /* ifndef GRM_PLOT_INT_H_INCLUDED */
diff --git a/lib/grm/test/public_api/CMakeLists.txt b/lib/grm/test/public_api/CMakeLists.txt
index f2f83c60d..2df0b1c25 100644
--- a/lib/grm/test/public_api/CMakeLists.txt
+++ b/lib/grm/test/public_api/CMakeLists.txt
@@ -37,6 +37,7 @@ foreach(executable_source ${EXECUTABLE_SOURCES})
   add_executable("${PROJECT_NAME}_${executable}" "${executable_source}")
   target_link_libraries("${PROJECT_NAME}_${executable}" PRIVATE grm_shared)
   target_link_libraries("${PROJECT_NAME}_${executable}" PRIVATE gr_shared)
+  target_link_libraries("${PROJECT_NAME}_${executable}" PRIVATE gks_shared)
   target_link_libraries("${PROJECT_NAME}_${executable}" PRIVATE m)
   target_compile_options("${PROJECT_NAME}_${executable}" PRIVATE ${COMPILER_OPTION_ERROR_IMPLICIT})
   set_target_properties(
diff --git a/lib/grm/test/public_api/heatmap.c b/lib/grm/test/public_api/heatmap.c
index d7b1c6c84..e768814ba 100644
--- a/lib/grm/test/public_api/heatmap.c
+++ b/lib/grm/test/public_api/heatmap.c
@@ -6,6 +6,7 @@
 #include <stdlib.h>
 
 #include "grm.h"
+#include "gks.h"
 
 #ifndef M_PI
 #define M_PI 3.14159265358979323846
@@ -130,6 +131,64 @@ static void test_heatmap(void)
 
   grm_args_delete(args);
 
+  printf("plot a heatmap with x, y z and resample method (nearest)\n");
+  args = grm_args_new();
+  grm_args_push(args, "x", "nD", X_DIM, x);
+  grm_args_push(args, "y", "nD", Y_DIM, y);
+  grm_args_push(args, "z", "nD", X_DIM * Y_DIM, z);
+  grm_args_push(args, "kind", "s", "heatmap");
+  grm_args_push(args, "resample_method", "s", "nearest");
+  grm_plot(args);
+
+  printf("Press any key to continue...\n");
+  getchar();
+
+  grm_args_delete(args);
+
+  printf("plot a heatmap with x, y z and resample method (linear)\n");
+  args = grm_args_new();
+  grm_args_push(args, "x", "nD", X_DIM, x);
+  grm_args_push(args, "y", "nD", Y_DIM, y);
+  grm_args_push(args, "z", "nD", X_DIM * Y_DIM, z);
+  grm_args_push(args, "kind", "s", "heatmap");
+  grm_args_push(args, "resample_method", "s", "linear");
+  grm_plot(args);
+
+  printf("Press any key to continue...\n");
+  getchar();
+
+  grm_args_delete(args);
+
+  printf("plot a heatmap with x, y z and resample method (lanczos)\n");
+  args = grm_args_new();
+  grm_args_push(args, "x", "nD", X_DIM, x);
+  grm_args_push(args, "y", "nD", Y_DIM, y);
+  grm_args_push(args, "z", "nD", X_DIM * Y_DIM, z);
+  grm_args_push(args, "kind", "s", "heatmap");
+  grm_args_push(args, "resample_method", "s", "lanczos");
+  grm_plot(args);
+
+  printf("Press any key to continue...\n");
+  getchar();
+
+  grm_args_delete(args);
+
+  printf("plot a heatmap with x, y z and resample method (custom)\n");
+  args = grm_args_new();
+  grm_args_push(args, "x", "nD", X_DIM, x);
+  grm_args_push(args, "y", "nD", Y_DIM, y);
+  grm_args_push(args, "z", "nD", X_DIM * Y_DIM, z);
+  grm_args_push(args, "kind", "s", "heatmap");
+  grm_args_push(args, "resample_method", "i",
+                GKS_K_DOWNSAMPLE_HORIZONTAL_NEAREST | GKS_K_DOWNSAMPLE_VERTICAL_LINEAR |
+                    GKS_K_UPSAMPLE_HORIZONTAL_LANCZOS | GKS_K_UPSAMPLE_VERTICAL_NEAREST);
+  grm_plot(args);
+
+  printf("Press any key to continue...\n");
+  getchar();
+
+  grm_args_delete(args);
+
   printf("plot two non-uniform heatmaps\n");
   args = grm_args_new();
   x[0] = -3.25;
diff --git a/lib/grm/test/public_api/pie.c b/lib/grm/test/public_api/pie.c
index 15e0009a6..4af3acfea 100644
--- a/lib/grm/test/public_api/pie.c
+++ b/lib/grm/test/public_api/pie.c
@@ -4,9 +4,11 @@
 
 #define array_size(x) (sizeof(x) / sizeof((x)[0]))
 
-static void test_quiver(void)
+static void test_pie(void)
 {
   const double x[] = {188.6, 107.8, 100.3, 99.0};
+  const double c[] = {93 / 255.0,  57 / 255.0,  101 / 255.0, 175 / 255.0, 130 / 255.0, 185 / 255.0,
+                      207 / 255.0, 180 / 255.0, 213 / 255.0, 223 / 255.0, 205 / 255.0, 227 / 255.0};
   const char *labels[] = {"Czech Republic", "Austria", "Romania", "Germany"};
   grm_args_t *args;
 
@@ -21,13 +23,21 @@ static void test_quiver(void)
   printf("Press any key to continue...\n");
   getchar();
 
+  printf("plot a pie chart with x and custom colors\n");
+  grm_args_push(args, "c", "nD", array_size(c), c);
+
+  grm_plot(args);
+
+  printf("Press any key to continue...\n");
+  getchar();
+
   grm_args_delete(args);
 }
 
 
 int main(void)
 {
-  test_quiver();
+  test_pie();
   grm_finalize();
 
   return 0;
diff --git a/packaging/redhat/gr.spec b/packaging/redhat/gr.spec
index f979ea83a..67d30b3ca 100644
--- a/packaging/redhat/gr.spec
+++ b/packaging/redhat/gr.spec
@@ -47,7 +47,7 @@ BuildRequires: qt5-local
 BuildRequires: gcc-local
 BuildRequires: cmake-local
 %else
-%if 0%{?centos_version} < 800
+%if 0%{?rhel} < 8
 BuildRequires: qt-devel
 %endif
 %endif
@@ -77,7 +77,7 @@ BuildRequires:		libjpeg-turbo-devel
 %endif
 
 # RHEL, CentOS and Scientific Linux 7 have too old cmake version (use prebuild)
-%if 0%{?rhel_version} == 700 || 0%{?scientificlinux_version} == 700 || 0%{?centos_version} == 700
+%if 0%{?rhel} == 7
 %else
 BuildRequires:		cmake
 %endif
@@ -95,7 +95,7 @@ BuildRequires:		wxWidgets-devel
 %endif
 
 # Qt5 BuildRequires for Fedora
-%if 0%{?fedora_version} >= 23 || 0%{?centos_version} >= 800
+%if 0%{?fedora_version} >= 23 || 0%{?rhel} >= 8
 %define qmake_qt5 qmake-qt5
 BuildRequires:		qt5-qtbase-devel
 %endif
@@ -123,7 +123,7 @@ mkdir -p %{THIRDPARTY_SRC}
 
 %build
 # RHEL, CentOS and Scientific Linux 7 have too old cmake version (use prebuild)
-%if 0%{?rhel_version} == 700 || 0%{?scientificlinux_version} == 700 || 0%{?centos_version} == 700
+%if 0%{?rhel} == 7
 export PATH=`pwd`/%{THIRDPARTY}/cmake-3.6.3-Linux-x86_64/bin:$PATH
 %endif
 make -C 3rdparty GRDIR=%{grdir} DIR=`pwd`/%{THIRDPARTY}