(X11 Series 1/3) Use correct visual for user-specified depth

[Michael Karcher]

Wine looks into the registry to find out the depth requested by the
user. The validation code just checked that this depth is supported by
the X server. This is not enough. One has to check that there really is
a visual supporting this very depth. And in that case, one has to use
that visual instead of the default one.

This patch reveals that using a non-default visual is not currently
working. This is addressed by the next patch in the series.

>From 2523b0dd68505ce0566da085cf33ff2737c9c773 Mon Sep 17 00:00:00 2001
From: Michael Karcher <wine at mkarcher.dialup.fu-berlin.de>
Date: Sun, 16 Mar 2008 20:40:39 +0100
Subject: [PATCH] Fixed validation of screen-depth parameter, including choosing
 a matching visual.

---
 dlls/winex11.drv/x11drv_main.c |   22 ++++++++++++++++------
 1 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/dlls/winex11.drv/x11drv_main.c b/dlls/winex11.drv/x11drv_main.c
index d445e64..7e84ca9 100644
--- a/dlls/winex11.drv/x11drv_main.c
+++ b/dlls/winex11.drv/x11drv_main.c
@@ -505,16 +505,26 @@ static BOOL process_attach(void)
 
     if (screen_depth)  /* depth specified */
     {
-        int depth_count, i;
-        int *depth_list = XListDepths(display, DefaultScreen(display), &depth_count);
-        for (i = 0; i < depth_count; i++)
-            if (depth_list[i] == screen_depth) break;
-        XFree( depth_list );
-        if (i >= depth_count)
+        /* Priorities of visual classes */
+        static const int visclasses[] = {PseudoColor,TrueColor,DirectColor,StaticColor,GrayScale,StaticGray};
+        static const int classcount = sizeof(visclasses)/sizeof(visclasses[0]);
+        XVisualInfo visi;
+        int i;
+        
+        for (i = 0; i < classcount; i++)
+            if (XMatchVisualInfo( display, XScreenNumberOfScreen( screen ), screen_depth, visclasses[i], &visi))
+                break;
+                
+        if (i >= classcount)
         {
             WARN( "invalid depth %d, using default\n", screen_depth );
             screen_depth = 0;
         }
+        else if(visual != visi.visual)
+        {
+            WARN( "Using non-default visual. This is experimental!\n" );
+            visual = visi.visual;
+        }
     }
     if (!screen_depth) screen_depth = DefaultDepthOfScreen( screen );
     screen_bpp = depth_to_bpp( screen_depth );
-- 
1.5.4.3