Merge pull request #1276 from thinkyhead/lcd_z_reformat

Format Z like XY on LCD

Marlin/ultralcd.cpp

   return conv;
 }
 
-// Convert int to lj string with +123.0 format
+//  convert float to space-padded string with -_23.4_ format
+char *ftostr32sp(const float &x) {
+  long xx = abs(x * 100);
+  uint8_t dig;
+
+  if (x < 0) { // negative val = -_0
+    conv[0] = '-';
+    dig = (xx / 1000) % 10;
+    conv[1] = dig ? '0' + dig : ' ';
+  }
+  else { // positive val = __0
+    dig = (xx / 10000) % 10;
+    if (dig) {
+      conv[0] = '0' + dig;
+      conv[1] = '0' + (xx / 1000) % 10;
+    }
+    else {
+      conv[0] = ' ';
+      dig = (xx / 1000) % 10;
+      conv[1] = dig ? '0' + dig : ' ';
+    }
+  }
+
+  conv[2] = '0' + (xx / 100) % 10; // lsd always
+
+  dig = xx % 10;
+  if (dig) { // 2 decimal places
+    conv[5] = '0' + dig;
+    conv[4] = '0' + (xx / 10) % 10;
+    conv[3] = '.';
+  }
+  else { // 1 or 0 decimal place
+    dig = (xx / 10) % 10;
+    if (dig) {
+      conv[4] = '0' + dig;
+      conv[3] = '.';
+    }
+    else {
+      conv[3] = conv[4] = ' ';
+    }
+    conv[5] = ' ';
+  }
+  conv[6] = '\0';
+  return conv;
+}
+
 char *itostr31(const int &xx)
 {
   conv[0]=(xx>=0)?'+':'-';

Marlin/ultralcd.h

 char *ftostr31(const float &x);
 char *ftostr32(const float &x);
 char *ftostr12ns(const float &x); 
+char *ftostr32sp(const float &x); // remove zero-padding from ftostr32
 char *ftostr5(const float &x);
 char *ftostr51(const float &x);
 char *ftostr52(const float &x);

Marlin/ultralcd_implementation_hitachi_HD44780.h

 # endif//LCD_WIDTH > 19
     lcd.setCursor(LCD_WIDTH - 8, 1);
     lcd.print('Z');
-    lcd.print(ftostr32(current_position[Z_AXIS] + 0.00001));
+    lcd.print(ftostr32sp(current_position[Z_AXIS] + 0.00001));
 #endif//LCD_HEIGHT > 2
 
 #if LCD_HEIGHT > 3