nxagent: Auto-detect client-side DPI at session startup.

nx-X11/programs/Xserver/hw/nxagent/Args.c

@@ -130,6 +130,8 @@ char nxagentDisplayName[NXAGENTDISPLAYNAMELENGTH];
 Bool nxagentSynchronize = False;
 Bool nxagentRealWindowProp = False;
 
+Bool nxagentAutoDPI = False;
+
 char nxagentShadowDisplayName[NXAGENTSHADOWDISPLAYNAMELENGTH] = {0};
 
 char nxagentWindowName[NXAGENTWINDOWNAMELENGTH];
@@ -743,6 +745,11 @@ int ddxProcessArgument(int argc, char *argv[], int i)
     return 1;
   }
 
+  if (!strcmp(argv[i], "-autodpi")) {
+    nxagentAutoDPI = True;
+    return 1;
+  }
+
   /*
    * The original -noreset option, disabling
    * dispatchExceptionAtReset, is the default.
@@ -2091,6 +2098,7 @@ void ddxUseMsg(void)
   ErrorF("-class string          default visual class\n");
   ErrorF("-depth int             default depth\n");
   ErrorF("-geometry WxH+X+Y      window size and position\n");
+  ErrorF("-autodpi               detect real server's DPI and use that in the session\n");
   ErrorF("-bw int                window border width\n");
   ErrorF("-name string           window name\n");
   ErrorF("-scrns int             number of screens to generate\n");

nx-X11/programs/Xserver/hw/nxagent/Extensions.c

@@ -338,15 +338,26 @@ static int nxagentRandRInitSizes(ScreenPtr pScreen)
     width = w[i];
     height = h[i];
 
-    mmWidth  = (width * 254 + monitorResolution * 5) / (monitorResolution * 10);
+    if (monitorResolution < 0)
+    {
+      mmWidth  = width * DisplayWidthMM(nxagentDisplay, DefaultScreen(nxagentDisplay)) /
+                     DisplayWidth(nxagentDisplay, DefaultScreen(nxagentDisplay));
+
+      mmHeight = height * DisplayHeightMM(nxagentDisplay, DefaultScreen(nxagentDisplay)) /
+                     DisplayHeight(nxagentDisplay, DefaultScreen(nxagentDisplay));
+    }
+    else
+    {
+      mmWidth  = (width * 254 + monitorResolution * 5) / (monitorResolution * 10);
+      mmHeight = (height * 254 + monitorResolution * 5) / (monitorResolution * 10);
+
+    }
 
     if (mmWidth < 1)
     {
       mmWidth = 1;
     }
 
-    mmHeight = (height * 254 + monitorResolution * 5) / (monitorResolution * 10);
-
     if (mmHeight < 1)
     {
       mmHeight = 1;

nx-X11/programs/Xserver/hw/nxagent/Screen.c

@@ -210,6 +210,9 @@ void nxagentShadowAdaptDepth(unsigned int, unsigned int, unsigned int, char **);
 RegionRec nxagentShadowUpdateRegion;
 
 #define NXAGENT_DEFAULT_DPI 75
+#define NXAGENT_AUTO_DPI -1
+
+extern Bool nxagentAutoDPI;
 
 /*
  * From randr/randr.c. This was originally static
@@ -1327,10 +1330,14 @@ Bool nxagentOpenScreen(ScreenPtr pScreen,
                   rootDepth, (long unsigned int)defaultVisual);
     #endif
 
-    if (monitorResolution < 1)
+    if ((monitorResolution < 1) && (nxagentAutoDPI == False))
     {
       monitorResolution = NXAGENT_DEFAULT_DPI;
     }
+    else if ((monitorResolution < 1) && (nxagentAutoDPI == True))
+    {
+      monitorResolution = NXAGENT_AUTO_DPI;
+    }
 
     if (!fbScreenInit(pScreen, pFrameBufferBits, nxagentOption(RootWidth), nxagentOption(RootHeight),
           monitorResolution, monitorResolution, PixmapBytePad(nxagentOption(RootWidth), rootDepth), bitsPerPixel))
@@ -1474,6 +1481,17 @@ N/A
      *   return FALSE;
      */
 
+    if (monitorResolution < 0)
+    {
+      pScreen->mmWidth  = nxagentOption(RootWidth) * DisplayWidthMM(nxagentDisplay,
+                              DefaultScreen(nxagentDisplay)) / DisplayWidth(nxagentDisplay,
+                                  DefaultScreen(nxagentDisplay));
+
+      pScreen->mmHeight = nxagentOption(RootHeight) * DisplayHeightMM(nxagentDisplay,
+                              DefaultScreen(nxagentDisplay)) / DisplayHeight(nxagentDisplay,
+                                  DefaultScreen(nxagentDisplay));
+    }
+
     pScreen->defColormap = (Colormap) FakeClientID(0);
     pScreen->minInstalledCmaps = MINCMAPS;
     pScreen->maxInstalledCmaps = MAXCMAPS;
@@ -2294,22 +2312,40 @@ Bool nxagentResizeScreen(ScreenPtr pScreen, int width, int height,
 
   if (mmWidth == 0)
   {
-    mmWidth  = (width * 254 + monitorResolution * 5) / (monitorResolution * 10);
+    if (monitorResolution < 0)
+    {
+      mmWidth  = width * DisplayWidthMM(nxagentDisplay, DefaultScreen(nxagentDisplay)) /
+                     DisplayWidth(nxagentDisplay, DefaultScreen(nxagentDisplay));
+    }
+    else
+    {
+      mmWidth  = (width * 254 + monitorResolution * 5) / (monitorResolution * 10);
+    }
 
     if (mmWidth < 1)
     {
       mmWidth = 1;
     }
+
   }
 
   if (mmHeight == 0)
   {
-    mmHeight = (height * 254 + monitorResolution * 5) / (monitorResolution * 10);
+    if (monitorResolution < 0)
+    {
+      mmHeight = height * DisplayHeightMM(nxagentDisplay, DefaultScreen(nxagentDisplay)) /
+                     DisplayHeight(nxagentDisplay, DefaultScreen(nxagentDisplay));
+    }
+    else
+    {
+      mmHeight = (height * 254 + monitorResolution * 5) / (monitorResolution * 10);
+    }
 
     if (mmHeight < 1)
     {
       mmHeight = 1;
     }
+
   }
 
   pScreen -> mmWidth = mmWidth;

nx-X11/programs/Xserver/hw/nxagent/man/nxagent.1

@@ -393,6 +393,9 @@ auto-disconnect timeout in seconds (minimum allowed: 60)
 .B \-norootlessexit
 don't exit if there are no clients in rootless mode
 .TP 8
+.B \-autodpi
+detect real server's DPI and set it in the agent session; the \fI-dpi <dpi>\fR cmdline option overrides \fI-autodpi\fR
+.TP 8
 .B \-nomagicpixel
 disable magic pixel support at session startup, can be re-enabled via nx/nx option on session
 resumption