upstream: https://bugs.freedesktop.org/show_bug.cgi?id=31397

Allow limiting the "touchable" area of the display.

The intel driver only allows for one X screen in dual-head mode, and
elographics normally uses the size of the entire screen to calculate
touch event locations.

This patch adds ScreenWidth and ScreenHeight configuration options to
override the screen size, and ScreenXOffset and ScreenYOffset in case
the touchscreen covers part of the screen that doesn't begin at (0,0).


--- xf86-input-elographics-1.2.3/src/xf86Elo.c.orig	2008-10-13 19:52:10.000000000 -0400
+++ xf86-input-elographics-1.2.3/src/xf86Elo.c	2009-07-14 01:50:21.000000000 -0400
@@ -196,6 +196,8 @@
   int		screen_no;		/* Screen associated with the device		*/
   int		screen_width;		/* Width of the associated X screen		*/
   int		screen_height;		/* Height of the screen				*/
+  int		screen_x_offset;	/* X offset within the screen			*/
+  int		screen_y_offset;	/* Y offset within the screen			*/
   Bool		inited;			/* The controller has already been configured ?	*/
   Bool		is_a_2310;		/* Set if the smartset is a 2310.		*/
   int		checksum;		/* Current checksum of data in assembly buffer	*/
@@ -355,9 +357,11 @@
     input_x = v0;
     input_y = v1;
   }
-  *x = (priv->screen_width * (input_x - priv->min_x)) / width;
+  *x = (priv->screen_width * (input_x - priv->min_x)) / width
+       + priv->screen_x_offset;
   *y = (priv->screen_height -
-	(priv->screen_height * (input_y - priv->min_y)) / height);
+	(priv->screen_height * (input_y - priv->min_y)) / height)
+       + priv->screen_y_offset;
 
   /*
    * MHALAS: Based on the description in xf86XInputSetScreen
@@ -791,8 +795,14 @@
 	  priv->screen_no < 0) {
 	priv->screen_no = 0;
       }
-      priv->screen_width = screenInfo.screens[priv->screen_no]->width;
-      priv->screen_height = screenInfo.screens[priv->screen_no]->height;
+      if (priv->screen_width == -1) {
+        priv->screen_width = screenInfo.screens[priv->screen_no]->width;
+      }
+      if (priv->screen_height == -1) {
+        priv->screen_height = screenInfo.screens[priv->screen_no]->height;
+      }
+      xf86Msg(X_CONFIG, "Elographics screen dimensions: %dx%d\n",
+              priv->screen_width, priv->screen_height);
 
       /*
        * Device reports button press for up to 1 button.
@@ -996,6 +1006,8 @@
   priv->screen_no = 0;
   priv->screen_width = -1;
   priv->screen_height = -1;
+  priv->screen_x_offset = 0;
+  priv->screen_y_offset = 0;
   priv->inited = 0;
   priv->is_a_2310 = 0;
   priv->checksum = ELO_INIT_CHECKSUM;
@@ -1104,8 +1116,18 @@
 
   local->name = xf86SetStrOption(local->options, "DeviceName", XI_TOUCHSCREEN);
   xf86Msg(X_CONFIG, "Elographics X device name: %s\n", local->name);
+
   priv->screen_no = xf86SetIntOption(local->options, "ScreenNo", 0);
   xf86Msg(X_CONFIG, "Elographics associated screen: %d\n", priv->screen_no);
+
+  priv->screen_width = xf86SetIntOption(local->options, "ScreenWidth", -1);
+  priv->screen_height = xf86SetIntOption(local->options, "ScreenHeight", -1);
+
+  priv->screen_x_offset = xf86SetIntOption(local->options, "ScreenXOffset", 0);
+  priv->screen_y_offset = xf86SetIntOption(local->options, "ScreenYOffset", 0);
+  xf86Msg(X_CONFIG, "Elographics screen offset: (%d,%d)\n",
+          priv->screen_x_offset, priv->screen_y_offset);
+
   priv->untouch_delay = xf86SetIntOption(local->options, "UntouchDelay", ELO_UNTOUCH_DELAY);
   xf86Msg(X_CONFIG, "Elographics untouch delay: %d ms\n", priv->untouch_delay*10);
   priv->report_delay = xf86SetIntOption(local->options, "ReportDelay", ELO_REPORT_DELAY);